Vitamin B12, also known as cobalamin, is the most chemically complex vitamin. It contains a central cobalt atom and is synthesized exclusively by bacteria. Deficiency can result from inadequate dietary intake, food-bound malabsorption, or absorption issues in the gastrointestinal tract. Pernicious anemia, a historical fatal disease, is now known to be caused by B12 deficiency. Notable historical figures like Mary Todd Lincoln and Marie Curie have been diagnosed posthumously with B12 deficiency disorders. The discovery and isolation of B12 resolved the "cobalamin mystery" and led to effective treatment for pernicious anemia using liver extracts and later bacterial cultures.
This document discusses the connection between vitamin B12 deficiency and various autoimmune conditions. It begins by defining autoimmune diseases as those where the body produces antibodies that attack its own tissues. It then discusses several specific autoimmune conditions and their links to B12 deficiency, including: Pernicious anemia, an autoimmune condition where antibodies attack stomach cells needed to absorb B12; Autoimmune gastritis; Coeliac disease; Inflammatory bowel diseases; Diabetes; Hashimoto's thyroiditis; Graves' disease; and others. It provides details on the pathological mechanisms and clinical signs of B12 deficiency in each condition. The document also proposes theoretical mechanisms by which long-term B12 deficiency may influence the development of
This document discusses numerous genes involved in vitamin B12 synthesis and methylation pathways. It describes genes such as MUT, MMAA, MMAB, MMADHC, MTR, MTRR, MTHFR, TCN1, TCN2, and MMACHC that encode enzymes critical for converting vitamin B12 into forms used in metabolism. Mutations in these genes can lead to conditions like methylmalonic acidemia, homocystinuria, or methylmalonic acidemia with homocystinuria.
Cobalamin is also called vitamin b12.
Group of compounds called corrinoids (a group of cobalamin)- Coenzyme form: methylcobalamin and 5-deoxyadenosylcobalamin are forms of vitamin B12 in the human body- Humans can convert most of the other cobalamins into an active coenzyme form.
Once absorbed, cobalamin travels in the portal blood to the liver, and then to the rest ofthe body, bound to the transport protein, transcobalamin
Methionine synthase- converts homocysteine to methionine. Reduces blood homocysteine concentrations (reduces CVD).
This document discusses disorders related to vitamin deficiencies. It begins by introducing that vitamin deficiencies often occur alongside general malnutrition in developing countries and can affect certain groups in developed countries. Vitamins are classified as either fat-soluble (A, D, E, K) or water-soluble (C, B complex). The rest of the document details specific vitamin deficiencies, symptoms of deficiencies, recommended daily intake of each vitamin, and the functions of each in the body. Deficiencies of vitamins A, C, D, E, K, B1, B2, B3, B5, B6, B9, and B12 are all discussed in turn.
Vitamin B12, also known as cobalamin, is an essential water-soluble vitamin that contains cobalt. It plays important roles in maintaining healthy nerve cells and aiding in the production of DNA and RNA. A deficiency in B12 can lead to megaloblastic anemia or pernicious anemia, symptoms of which include fatigue, numbness, memory loss, and pale skin. Those at risk include the elderly, vegetarians, and those who have had gastrointestinal surgery. Food sources of B12 include meat, eggs, dairy products, and fortified foods.
This document discusses folic acid and vitamin B12, including their structure, dietary sources, absorption, metabolism, recommended daily allowances, deficiencies, clinical manifestations, laboratory assessments, and toxicity. Folic acid and vitamin B12 play important roles in one carbon metabolism and the synthesis of DNA, RNA, and proteins. Deficiencies can cause megaloblastic anemia and neurological issues. Testing includes serum levels of cobalamin, methylmalonic acid, and homocysteine. Treatment involves vitamin supplementation and dietary changes.
Pernicious anemia is an autoimmune disease where the body attacks intrinsic factor, a protein needed to absorb vitamin B12 from food. This leads to a B12 deficiency. It is caused by the destruction of gastric parietal cells which produce intrinsic factor. Without intrinsic factor, the body cannot absorb B12 from the digestive tract. Regular B12 injections or high dose oral supplements are needed to treat and prevent symptoms of the deficiency.
Absorption, transport and metabolism of cyanocobalaminDomina Petric
The document summarizes the absorption, transport, and metabolism of cyanocobalamin (vitamin B12). It discusses how vitamin B12 is released from protein complexes during digestion and bound to intrinsic factor and R proteins before being absorbed in the ileum through active transport mediated by intrinsic factor and its receptor. It is then transported bound to transcobalamin proteins, mainly transcobalamin II, and can enter cells through receptors for the transcobalamin-B12 complex. Deficiencies in intrinsic factor or pancreatic enzymes can impair absorption.
This document discusses the connection between vitamin B12 deficiency and various autoimmune conditions. It begins by defining autoimmune diseases as those where the body produces antibodies that attack its own tissues. It then discusses several specific autoimmune conditions and their links to B12 deficiency, including: Pernicious anemia, an autoimmune condition where antibodies attack stomach cells needed to absorb B12; Autoimmune gastritis; Coeliac disease; Inflammatory bowel diseases; Diabetes; Hashimoto's thyroiditis; Graves' disease; and others. It provides details on the pathological mechanisms and clinical signs of B12 deficiency in each condition. The document also proposes theoretical mechanisms by which long-term B12 deficiency may influence the development of
This document discusses numerous genes involved in vitamin B12 synthesis and methylation pathways. It describes genes such as MUT, MMAA, MMAB, MMADHC, MTR, MTRR, MTHFR, TCN1, TCN2, and MMACHC that encode enzymes critical for converting vitamin B12 into forms used in metabolism. Mutations in these genes can lead to conditions like methylmalonic acidemia, homocystinuria, or methylmalonic acidemia with homocystinuria.
Cobalamin is also called vitamin b12.
Group of compounds called corrinoids (a group of cobalamin)- Coenzyme form: methylcobalamin and 5-deoxyadenosylcobalamin are forms of vitamin B12 in the human body- Humans can convert most of the other cobalamins into an active coenzyme form.
Once absorbed, cobalamin travels in the portal blood to the liver, and then to the rest ofthe body, bound to the transport protein, transcobalamin
Methionine synthase- converts homocysteine to methionine. Reduces blood homocysteine concentrations (reduces CVD).
This document discusses disorders related to vitamin deficiencies. It begins by introducing that vitamin deficiencies often occur alongside general malnutrition in developing countries and can affect certain groups in developed countries. Vitamins are classified as either fat-soluble (A, D, E, K) or water-soluble (C, B complex). The rest of the document details specific vitamin deficiencies, symptoms of deficiencies, recommended daily intake of each vitamin, and the functions of each in the body. Deficiencies of vitamins A, C, D, E, K, B1, B2, B3, B5, B6, B9, and B12 are all discussed in turn.
Vitamin B12, also known as cobalamin, is an essential water-soluble vitamin that contains cobalt. It plays important roles in maintaining healthy nerve cells and aiding in the production of DNA and RNA. A deficiency in B12 can lead to megaloblastic anemia or pernicious anemia, symptoms of which include fatigue, numbness, memory loss, and pale skin. Those at risk include the elderly, vegetarians, and those who have had gastrointestinal surgery. Food sources of B12 include meat, eggs, dairy products, and fortified foods.
This document discusses folic acid and vitamin B12, including their structure, dietary sources, absorption, metabolism, recommended daily allowances, deficiencies, clinical manifestations, laboratory assessments, and toxicity. Folic acid and vitamin B12 play important roles in one carbon metabolism and the synthesis of DNA, RNA, and proteins. Deficiencies can cause megaloblastic anemia and neurological issues. Testing includes serum levels of cobalamin, methylmalonic acid, and homocysteine. Treatment involves vitamin supplementation and dietary changes.
Pernicious anemia is an autoimmune disease where the body attacks intrinsic factor, a protein needed to absorb vitamin B12 from food. This leads to a B12 deficiency. It is caused by the destruction of gastric parietal cells which produce intrinsic factor. Without intrinsic factor, the body cannot absorb B12 from the digestive tract. Regular B12 injections or high dose oral supplements are needed to treat and prevent symptoms of the deficiency.
Absorption, transport and metabolism of cyanocobalaminDomina Petric
The document summarizes the absorption, transport, and metabolism of cyanocobalamin (vitamin B12). It discusses how vitamin B12 is released from protein complexes during digestion and bound to intrinsic factor and R proteins before being absorbed in the ileum through active transport mediated by intrinsic factor and its receptor. It is then transported bound to transcobalamin proteins, mainly transcobalamin II, and can enter cells through receptors for the transcobalamin-B12 complex. Deficiencies in intrinsic factor or pancreatic enzymes can impair absorption.
This document discusses vitamin B6, including its functions, food sources, recommendations, deficiency, and current research. It begins by introducing vitamin B6 and its role in nervous system function, red blood cell production, and protein metabolism. It then lists foods containing vitamin B6 and its functions in making antibodies, maintaining nerve function, producing hemoglobin, breaking down proteins, and regulating blood sugar. The document establishes recommended daily allowances for vitamin B6 based on age and gender. It further discusses deficiency symptoms and conditions that can cause inadequate vitamin B6 status. Current research covers average intakes, deficiency associations, risk groups like those with kidney diseases, and effects of alcohol dependence.
Excessive vitamin D intake can lead to vitamin D toxicity. The 25-OH metabolite plays a key role in vitamin D intoxication by competing for intracellular receptors, inducing responses normally caused by 1,25-(OH)2-D3. This leads to hypercalcemia through increased calcium absorption and bone resorption, decreasing PTH and kidney function and disrupting calcium homeostasis. Long-term effects include calcinosis, the deposition of calcium and phosphorus in soft tissues like the heart and kidneys. Risk depends on calcium and phosphorus intake in addition to vitamin D exposure.
The document discusses vitamin E and its role as a biological antioxidant. It describes how vitamin E functions to protect cell membranes from free radicals by reducing or terminating chain reactions caused by peroxyl radicals and lipid peroxidation. It also outlines some of the major sources of reactive oxygen species in the body and how vitamin E helps defend against oxidative stress that can lead to aging, cancer, cardiovascular disease, cataracts, and diabetes.
Vitamin B12 deficiency can result from decreased absorption in the ileum, decreased intrinsic factor production in the stomach, inadequate dietary intake, or prolonged medication use. Clinical manifestations include neurological, psychiatric, hematological and cutaneous issues. Screening is recommended for those with risk factors or suspected symptoms. Treatment involves intramuscular B12 injections or high dose oral replacement, indefinitely for irreversible causes or until deficiency is corrected for reversible causes. Prevention focuses on supplementation in high risk groups.
Asthma, allergy and respiratory infections: the vitamin D hypothesisAriyanto Harsono
The document discusses the relationship between vitamin D and respiratory conditions like asthma. It suggests that vitamin D deficiency has been associated with increased risk of respiratory infections and asthma exacerbations. This may be because vitamin D plays important roles in immune function and lung development. The document reviews studies showing links between low vitamin D levels and higher risks of respiratory infections, asthma symptoms, and impaired lung function. However, the relationships are complex and not fully understood, as some studies have also linked high vitamin D supplementation to increased asthma risk. More research is still needed to clarify the roles and optimal levels of vitamin D.
Vitamin E is a fat-soluble vitamin that exists as both tocopherols and tocotrienols. It is an important antioxidant that protects cell membranes from oxidative damage by reacting with lipid radicals produced in the body during oxidation. The most biologically active form is alpha-tocopherol. Vitamin E is absorbed with dietary fat and transported throughout the body associated with lipoproteins. A deficiency can cause hemolytic anemia, muscular dystrophy, and neurological problems due to increased lipid peroxidation in tissues.
Vitamin D is a fat-soluble vitamin that functions like a hormone and regulates calcium levels. It is obtained through sun exposure and dietary sources like fatty fish and eggs. The skin produces vitamin D from exposure to UVB rays, especially between 10am-3pm in spring/summer/fall. Sun exposure duration depends on skin pigmentation and sunscreen use. Recommended daily intake is 400-800 IU depending on age.
Vit b12 deficiency causes and managementrajeetam123
This document discusses vitamin B12 deficiency, including its structure, dietary sources, absorption, transport, storage, and metabolic roles. It also covers the causes, manifestations, and laboratory findings of B12 deficiency. The key points are:
1. Vitamin B12 is essential for DNA synthesis and fatty acid/amino acid metabolism. Deficiency can cause megaloblastic anemia and neurological issues.
2. Dietary sources are animal products. Absorption requires intrinsic factor in the ileum. Deficiency can be caused by pernicious anemia or other issues impairing absorption.
3. Manifestations include megaloblastic anemia, neurological changes, and other issues. Laboratory findings show macro
A 65-year-old female presented with a 2-month history of tiredness, feeling faint, and memory problems. She should be tested for vitamin B12 deficiency as the most common cause is pernicious anemia, an autoimmune disease that impairs B12 absorption. Symptoms of B12 deficiency include neuropathy, anemia, and cognitive issues. Confirmatory tests for deficiency include elevated homocysteine and methylmalonic acid levels. Treatment involves B12 supplementation as it is safe and effective even at high doses.
Vitamin B12 deficiency is common in India, especially among vegetarians and the elderly. It causes hematological, neurological, gastrointestinal and vascular issues. The document discusses causes of B12 deficiency including pernicious anemia and intestinal malabsorption. Clinical manifestations and investigations for diagnosis are explained. Treatment involves lifelong B12 supplementation through injections or high dose oral supplements. Preventive measures for high risk groups like vegetarians and post-gastric surgery patients are also covered.
Vitamins are essential nutrients required in small amounts for specific biological functions. Vitamin E is an antioxidant that prevents cell damage and aids in red blood cell formation. Vitamin K is required for blood clotting as it allows clotting factors to bind calcium. Hypophosphatasia is a rare bone disorder caused by alkaline phosphatase deficiency, causing skeletal abnormalities and tooth loss. It ranges from severe in infants to mild in adults.
This document discusses vitamins, specifically vitamin D. It defines vitamins and describes the classification of fat-soluble and water-soluble vitamins. The document focuses on vitamin D, describing its sources, metabolism, functions, recommended dietary allowance, and disorders related to deficiencies or excess, including rickets. Rickets is discussed in detail, outlining its morphology, etiology, clinical features involving the head, chest, back, extremities, and hypocalcemic symptoms. Oral manifestations of rickets involving dentition, bone, and soft tissue are also summarized.
Folate and vitamin B12 (cobalamin) play key roles in cell metabolism and the production of DNA. A deficiency of either can lead to megaloblastic anemia, where red blood cells are abnormally large with impaired DNA synthesis. Cobalamin deficiency specifically results in an intracellular folate deficiency through a "folate trap" mechanism. Pernicious anemia, caused by autoimmune destruction of gastric parietal cells and a lack of intrinsic factor, is the most common cause of cobalamin deficiency. Symptoms of megaloblastic anemia include fatigue, palpitations, and shortness of breath.
The document discusses folate deficiency and toxicity. It notes that the most important factor for folate deficiency is insufficient dietary intake. Risk factors for deficiency include malabsorption, certain intestinal and gastric diseases, genetic factors, and medications. Signs of deficiency include macrocytic anemia with hypersegmented neutrophils, impaired cell growth, and neurological issues. Folate is used pharmacologically to treat megaloblastic anemia and reduce homocysteine levels.
Vitamin B12, also known as cobalamin, is an essential water-soluble vitamin that plays critical roles in DNA synthesis, fatty acid and amino acid metabolism, and nerve cell function. It is naturally found in animal products and produced by bacteria. Deficiency can result in megaloblastic anemia and neurological problems. While generally safe, high doses may cause side effects like diarrhea or allergic reactions. Vitamin B12 has various applications in treating conditions like immune dysfunction, allergies, and cyanide poisoning.
Vitamin B12 is the last vitamin discovered and is essential for nervous system and blood cell formation. Deficiency is common, affecting over 50% of women and 30% of men. It is produced by bacteria and contains cobalt. Absorption requires intrinsic factor in the stomach and occurs in the ileum. Deficiency can result from lack of intake, intrinsic factor deficiency causing pernicious anemia, or absorption issues from diseases or drugs impairing absorption. Diagnosis involves blood tests and the Schilling test to identify the cause of deficiency. Treatment involves B12 injections or high dose oral supplementation.
Vitamin D absorption, transport and metabolismDomina Petric
Vitamin D is absorbed through the small intestine and enters lymphatic circulation associated with chylomicrons. It is transported by vitamin D binding protein and distributed to tissues where it can be activated. Activation involves hydroxylation in the liver to form 25-hydroxyvitamin D and in the kidneys to form the active 1,25-dihydroxyvitamin D. Kidney production of the active form is regulated by parathyroid hormone and calcium levels to maintain calcium homeostasis. Tissues throughout the body have vitamin D receptors and the active form binds to these receptors to carry out its functions.
Vitamin B12, also known as cobalamin, is a water-soluble vitamin that plays a key role in brain and nervous system function. It was first discovered in the late 1920s as a treatment for pernicious anemia. Vitamin B12 has a complex molecular structure that was determined in 1956. It is produced by bacteria but not by plants or animals. Common sources include meat, dairy, eggs, and fortified foods. Deficiency can cause neurological and psychiatric issues.
Vitamin B12, also known as cobalamin, is a water-soluble vitamin that plays a key role in normal brain and nervous system function and blood formation. It was first discovered in the late 1920s as the substance that cured pernicious anemia. Vitamin B12 exists in several forms including cyanocobalamin, methylcobalamin, and hydroxocobalamin. It is produced through fermentation by microorganisms but not by plants or animals. Good dietary sources include meat, fish, eggs, and dairy products. Vitamin B12 deficiency can cause megaloblastic anemia and neurological problems if left untreated.
This document discusses vitamin B6, including its functions, food sources, recommendations, deficiency, and current research. It begins by introducing vitamin B6 and its role in nervous system function, red blood cell production, and protein metabolism. It then lists foods containing vitamin B6 and its functions in making antibodies, maintaining nerve function, producing hemoglobin, breaking down proteins, and regulating blood sugar. The document establishes recommended daily allowances for vitamin B6 based on age and gender. It further discusses deficiency symptoms and conditions that can cause inadequate vitamin B6 status. Current research covers average intakes, deficiency associations, risk groups like those with kidney diseases, and effects of alcohol dependence.
Excessive vitamin D intake can lead to vitamin D toxicity. The 25-OH metabolite plays a key role in vitamin D intoxication by competing for intracellular receptors, inducing responses normally caused by 1,25-(OH)2-D3. This leads to hypercalcemia through increased calcium absorption and bone resorption, decreasing PTH and kidney function and disrupting calcium homeostasis. Long-term effects include calcinosis, the deposition of calcium and phosphorus in soft tissues like the heart and kidneys. Risk depends on calcium and phosphorus intake in addition to vitamin D exposure.
The document discusses vitamin E and its role as a biological antioxidant. It describes how vitamin E functions to protect cell membranes from free radicals by reducing or terminating chain reactions caused by peroxyl radicals and lipid peroxidation. It also outlines some of the major sources of reactive oxygen species in the body and how vitamin E helps defend against oxidative stress that can lead to aging, cancer, cardiovascular disease, cataracts, and diabetes.
Vitamin B12 deficiency can result from decreased absorption in the ileum, decreased intrinsic factor production in the stomach, inadequate dietary intake, or prolonged medication use. Clinical manifestations include neurological, psychiatric, hematological and cutaneous issues. Screening is recommended for those with risk factors or suspected symptoms. Treatment involves intramuscular B12 injections or high dose oral replacement, indefinitely for irreversible causes or until deficiency is corrected for reversible causes. Prevention focuses on supplementation in high risk groups.
Asthma, allergy and respiratory infections: the vitamin D hypothesisAriyanto Harsono
The document discusses the relationship between vitamin D and respiratory conditions like asthma. It suggests that vitamin D deficiency has been associated with increased risk of respiratory infections and asthma exacerbations. This may be because vitamin D plays important roles in immune function and lung development. The document reviews studies showing links between low vitamin D levels and higher risks of respiratory infections, asthma symptoms, and impaired lung function. However, the relationships are complex and not fully understood, as some studies have also linked high vitamin D supplementation to increased asthma risk. More research is still needed to clarify the roles and optimal levels of vitamin D.
Vitamin E is a fat-soluble vitamin that exists as both tocopherols and tocotrienols. It is an important antioxidant that protects cell membranes from oxidative damage by reacting with lipid radicals produced in the body during oxidation. The most biologically active form is alpha-tocopherol. Vitamin E is absorbed with dietary fat and transported throughout the body associated with lipoproteins. A deficiency can cause hemolytic anemia, muscular dystrophy, and neurological problems due to increased lipid peroxidation in tissues.
Vitamin D is a fat-soluble vitamin that functions like a hormone and regulates calcium levels. It is obtained through sun exposure and dietary sources like fatty fish and eggs. The skin produces vitamin D from exposure to UVB rays, especially between 10am-3pm in spring/summer/fall. Sun exposure duration depends on skin pigmentation and sunscreen use. Recommended daily intake is 400-800 IU depending on age.
Vit b12 deficiency causes and managementrajeetam123
This document discusses vitamin B12 deficiency, including its structure, dietary sources, absorption, transport, storage, and metabolic roles. It also covers the causes, manifestations, and laboratory findings of B12 deficiency. The key points are:
1. Vitamin B12 is essential for DNA synthesis and fatty acid/amino acid metabolism. Deficiency can cause megaloblastic anemia and neurological issues.
2. Dietary sources are animal products. Absorption requires intrinsic factor in the ileum. Deficiency can be caused by pernicious anemia or other issues impairing absorption.
3. Manifestations include megaloblastic anemia, neurological changes, and other issues. Laboratory findings show macro
A 65-year-old female presented with a 2-month history of tiredness, feeling faint, and memory problems. She should be tested for vitamin B12 deficiency as the most common cause is pernicious anemia, an autoimmune disease that impairs B12 absorption. Symptoms of B12 deficiency include neuropathy, anemia, and cognitive issues. Confirmatory tests for deficiency include elevated homocysteine and methylmalonic acid levels. Treatment involves B12 supplementation as it is safe and effective even at high doses.
Vitamin B12 deficiency is common in India, especially among vegetarians and the elderly. It causes hematological, neurological, gastrointestinal and vascular issues. The document discusses causes of B12 deficiency including pernicious anemia and intestinal malabsorption. Clinical manifestations and investigations for diagnosis are explained. Treatment involves lifelong B12 supplementation through injections or high dose oral supplements. Preventive measures for high risk groups like vegetarians and post-gastric surgery patients are also covered.
Vitamins are essential nutrients required in small amounts for specific biological functions. Vitamin E is an antioxidant that prevents cell damage and aids in red blood cell formation. Vitamin K is required for blood clotting as it allows clotting factors to bind calcium. Hypophosphatasia is a rare bone disorder caused by alkaline phosphatase deficiency, causing skeletal abnormalities and tooth loss. It ranges from severe in infants to mild in adults.
This document discusses vitamins, specifically vitamin D. It defines vitamins and describes the classification of fat-soluble and water-soluble vitamins. The document focuses on vitamin D, describing its sources, metabolism, functions, recommended dietary allowance, and disorders related to deficiencies or excess, including rickets. Rickets is discussed in detail, outlining its morphology, etiology, clinical features involving the head, chest, back, extremities, and hypocalcemic symptoms. Oral manifestations of rickets involving dentition, bone, and soft tissue are also summarized.
Folate and vitamin B12 (cobalamin) play key roles in cell metabolism and the production of DNA. A deficiency of either can lead to megaloblastic anemia, where red blood cells are abnormally large with impaired DNA synthesis. Cobalamin deficiency specifically results in an intracellular folate deficiency through a "folate trap" mechanism. Pernicious anemia, caused by autoimmune destruction of gastric parietal cells and a lack of intrinsic factor, is the most common cause of cobalamin deficiency. Symptoms of megaloblastic anemia include fatigue, palpitations, and shortness of breath.
The document discusses folate deficiency and toxicity. It notes that the most important factor for folate deficiency is insufficient dietary intake. Risk factors for deficiency include malabsorption, certain intestinal and gastric diseases, genetic factors, and medications. Signs of deficiency include macrocytic anemia with hypersegmented neutrophils, impaired cell growth, and neurological issues. Folate is used pharmacologically to treat megaloblastic anemia and reduce homocysteine levels.
Vitamin B12, also known as cobalamin, is an essential water-soluble vitamin that plays critical roles in DNA synthesis, fatty acid and amino acid metabolism, and nerve cell function. It is naturally found in animal products and produced by bacteria. Deficiency can result in megaloblastic anemia and neurological problems. While generally safe, high doses may cause side effects like diarrhea or allergic reactions. Vitamin B12 has various applications in treating conditions like immune dysfunction, allergies, and cyanide poisoning.
Vitamin B12 is the last vitamin discovered and is essential for nervous system and blood cell formation. Deficiency is common, affecting over 50% of women and 30% of men. It is produced by bacteria and contains cobalt. Absorption requires intrinsic factor in the stomach and occurs in the ileum. Deficiency can result from lack of intake, intrinsic factor deficiency causing pernicious anemia, or absorption issues from diseases or drugs impairing absorption. Diagnosis involves blood tests and the Schilling test to identify the cause of deficiency. Treatment involves B12 injections or high dose oral supplementation.
Vitamin D absorption, transport and metabolismDomina Petric
Vitamin D is absorbed through the small intestine and enters lymphatic circulation associated with chylomicrons. It is transported by vitamin D binding protein and distributed to tissues where it can be activated. Activation involves hydroxylation in the liver to form 25-hydroxyvitamin D and in the kidneys to form the active 1,25-dihydroxyvitamin D. Kidney production of the active form is regulated by parathyroid hormone and calcium levels to maintain calcium homeostasis. Tissues throughout the body have vitamin D receptors and the active form binds to these receptors to carry out its functions.
Vitamin B12, also known as cobalamin, is a water-soluble vitamin that plays a key role in brain and nervous system function. It was first discovered in the late 1920s as a treatment for pernicious anemia. Vitamin B12 has a complex molecular structure that was determined in 1956. It is produced by bacteria but not by plants or animals. Common sources include meat, dairy, eggs, and fortified foods. Deficiency can cause neurological and psychiatric issues.
Vitamin B12, also known as cobalamin, is a water-soluble vitamin that plays a key role in normal brain and nervous system function and blood formation. It was first discovered in the late 1920s as the substance that cured pernicious anemia. Vitamin B12 exists in several forms including cyanocobalamin, methylcobalamin, and hydroxocobalamin. It is produced through fermentation by microorganisms but not by plants or animals. Good dietary sources include meat, fish, eggs, and dairy products. Vitamin B12 deficiency can cause megaloblastic anemia and neurological problems if left untreated.
Vitamin B12, also called cobalamin, is a water-soluble vitamin that plays a key role in normal brain and nervous system functioning. It was first discovered in the early 20th century and isolated in its pure form in 1948. Vitamin B12 has a complex chemical structure that contains cobalt. It is found naturally in animal products but not plants. Dietary recommendations and deficiency symptoms are discussed, along with industrial production methods and applications such as treating anemia and cyanide poisoning.
Vitamin B12 is an essential water-soluble vitamin involved in neurological function and blood formation. It was first discovered in the early 20th century and its chemical structure was elucidated in 1956. Vitamin B12 exists in several forms including cyanocobalamin, methylcobalamin, and hydroxocobalamin. It is produced industrially through microbial fermentation and found naturally in animal products. Vitamin B12 plays important roles in DNA synthesis, fatty acid and amino acid metabolism, and preventing megaloblastic anemia. Deficiency can cause neurological and psychiatric issues.
B12 metabolism..................................... and role of various proteins in b12 metabolism..... necessity of supplementation..........................................
Vitamin B12- definition, functions, absorption, storage, transportation, deficiency, pernicious anemia, relationship between vitamin B12 and folate deficiency, sign & symptoms, deficiency in case of maternal & child health care, RDA, sources, prevention and treatment.
Vitamin B12 is a water-soluble vitamin that plays important roles in energy production, DNA synthesis, and neurological function. It is found naturally in animal products like meat, fish, dairy, and eggs. Vitamin B12 deficiency can cause anemia and damage to the nervous system. It is usually caused by lack of absorption rather than intake. Treatment involves B12 injections or supplements.
Importance of Cobalt to the human system, its absorption, transportation and storage, its recommended dietary allowance, deficiency symptoms and toxicity
Megaloblastic Anaemia - Vit B12 deficiencyShahin Hameed
This document discusses megaloblastic anemia caused by vitamin B12 deficiency. It covers the normal metabolism and absorption of vitamin B12, the causes of deficiency including pernicious anemia, clinical features such as macrocytic anemia and neurological changes, diagnostic tests, and management with parenteral B12 injections. Deficiency results in defective DNA synthesis and affects all proliferating cells.
Causes of vitamin b12 and folate deficiencyfrankln
This document discusses the main causes of vitamin B12 and folate deficiency. The most common causes of vitamin B12 deficiency are inadequate dietary intake, especially among strict vegetarians who do not consume animal foods, and malabsorption in elderly people due to gastric atrophy. Low intake of animal foods can also cause vitamin B12 depletion in some lacto-ovo vegetarians and populations with low animal food consumption. The primary cause of folate deficiency is also low dietary intake of foods rich in folate such as legumes and green leafy vegetables.
Chemistry and physiological significance of VitaminsZofina Patel
This document discusses several vitamins, including their chemistry and physiological significance. It begins with definitions of vitamins and an overview of the chemistry and importance of Vitamin A, which is a fat-soluble vitamin involved in vision, immune function, and reproduction. The chemistry and roles of several B vitamins are then outlined, including Thiamin (B1) which enables the body to use carbohydrates, Riboflavin (B2) which is necessary for growth and red blood cell production, and Vitamin B12 which helps make DNA and red blood cells. Finally, the document discusses Vitamin C, noting it is water-soluble and important for its antioxidant properties.
Vitamin B12 is essential for DNA synthesis, nerve function, and blood cell formation. It is naturally found in animal products and some fortified foods. B12 has a complex molecular structure and acts as a coenzyme in important metabolic reactions involving methyl group transfers and rearrangements. Deficiency can result from pernicious anemia or other digestive disorders that impair absorption. Treatment involves B12 injections or high dose oral supplements. The recommended daily intake is 2.4 micrograms for adults.
Great follow-up to our webinar “Plant-based Eating: Enhancing Health Benefits, Minimizing Nutritional Risks” Learn more about vitamin B12 deficiency, assessment methods, and the role of B12 in the prevention and treatment of certain health conditions.
Learning Objectives:
1. List populations and groups at risk of vitamin B12 deficiency/inadequate vitamin B12 status?
2. Understand what constitutes adequate vitamin B12 intake
3. Distinguish between reliability of different vitamin B12 assessment methods
What constitutes adequate vitamin B12 status?
Indirect indicators of vitamin B12 deficiency
4. Assess the role of vitamin B12 in prevention and treatment of selected health conditions
CVD
Osteoporosis/Bone fractures
Brain Atrophy
B12 and EPA & DHA
5. Evaluate the efficacy of different vitamin B12 deficiency treatment options
PRESENTER
Roman Pawlak, Ph.D., RD
Associate Professor
Department of Nutrition Science
East Carolina University
Author of several books, Dr. Pawlak has lectured internationally about diet and nutrition.
Vitamins are organic compounds that cannot be synthesized by humans and must be obtained through diet. There are 13 essential vitamins that are divided into water-soluble and fat-soluble groups. Vitamins function as coenzymes and play important roles in metabolism. Deficiencies can result in diseases like scurvy, beriberi, and anemia. Folic acid deficiency is common and linked to neural tube defects, while B12 deficiency can cause megaloblastic anemia and neurological issues.
This document discusses megaloblastic anemia, specifically focusing on vitamin B12 and folate deficiencies. It defines megaloblastic anemia and describes the mechanisms, causes, metabolism, functions, and pathophysiology of vitamin B12 and folate. It also discusses pernicious anemia, masked megaloblastic anemia, and provides diagrams of vitamin B12 absorption, transport, and biochemical functions. The key points covered are the roles of vitamin B12 and folate in DNA synthesis, the resulting impaired cell proliferation and megaloblast formation in bone marrow, and the clinical effects of ineffective hematopoiesis.
Haematopoitic vitamin,pathogenesis of megaloblastic anaemia by dr. Tasnimdr Tasnim
Vitamin B12 and folic acid are important for hematopoiesis and a deficiency can cause megaloblastic anemia. Megaloblastic anemia is characterized by large, abnormally developed red blood cell precursors called megaloblasts in the bone marrow. It is caused by a deficiency of vitamin B12 or folic acid, which impairs DNA synthesis. This leads to ineffective hematopoiesis and macrocytic anemia. Pernicious anemia, a type of megaloblastic anemia, is caused by autoimmune gastritis that impairs vitamin B12 absorption in the stomach. Lifelong vitamin B12 replacement therapy is used to treat pernicious anemia.
Vitamins are essential organic compounds that the human body needs in small a...usharani940073
Vitamins A, B1, B2, B12, and C are described. Vitamin A (retinol) is a fat-soluble vitamin involved in immune function and vision. It has a beta-ionone ring and conjugated double bonds essential for activity. Vitamin B1 (thiamine) enables carbohydrate metabolism and is water-soluble. Vitamin B2 (riboflavin) is necessary for growth and red blood cell production and plays a role in energy metabolism. Vitamin B12 contains cobalt and helps make DNA and red blood cells. Vitamin C is a water-soluble antioxidant that supports immune function and collagen production. The chemistry, structures, and physiological roles
Vitamin B12 deficiency can result from strict vegetarian diets lacking animal products or supplements, pernicious anemia causing gastric parietal cell destruction, pancreatic insufficiency, intestinal diseases, drugs like nitrous oxide, and Helicobacter pylori infection. Deficiency signs include megaloblastic anemia from impaired DNA synthesis and neurological changes from myelin damage. Pernicious anemia presents as anemia years after gastric autoimmunity arises. Distinguishing B12 and folate deficiencies relies on elevated urinary methylmalonic acid indicating B12 deficiency.
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Basavarajeeyam is a Sreshta Sangraha grantha (Compiled book ), written by Neelkanta kotturu Basavaraja Virachita. It contains 25 Prakaranas, First 24 Chapters related to Rogas& 25th to Rasadravyas.
- Video recording of this lecture in English language: https://youtu.be/kqbnxVAZs-0
- Video recording of this lecture in Arabic language: https://youtu.be/SINlygW1Mpc
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Rasamanikya is a excellent preparation in the field of Rasashastra, it is used in various Kushtha Roga, Shwasa, Vicharchika, Bhagandara, Vatarakta, and Phiranga Roga. In this article Preparation& Comparative analytical profile for both Formulationon i.e Rasamanikya prepared by Kushmanda swarasa & Churnodhaka Shodita Haratala. The study aims to provide insights into the comparative efficacy and analytical aspects of these formulations for enhanced therapeutic outcomes.
TEST BANK For Basic and Clinical Pharmacology, 14th Edition by Bertram G. Kat...rightmanforbloodline
TEST BANK For Basic and Clinical Pharmacology, 14th Edition by Bertram G. Katzung, Verified Chapters 1 - 66, Complete Newest Version.
TEST BANK For Basic and Clinical Pharmacology, 14th Edition by Bertram G. Katzung, Verified Chapters 1 - 66, Complete Newest Version.
TEST BANK For Basic and Clinical Pharmacology, 14th Edition by Bertram G. Katzung, Verified Chapters 1 - 66, Complete Newest Version.
TEST BANK For Basic and Clinical Pharmacology, 14th Edition by Bertram G. Katzung, Verified Chapters 1 - 66, Complete Newest Version.
2. • Vitamin B12 is composed of
* Tetrapyrrole ring surrounding Cobalt atom.
* 5,6-dimethyl-benzimidazole.
* R group.
The R group may be either:
Cyanide in Cyanocobalamin (common in
supplements, not a physiological form, more
stable)
Methyl in methyl cobalamin
5’- deoxyadenosine in adenosylcobalamin
OH in hydroxocobalamin.(natural form, produced
by bacteria, used in supplements and injections)
Attached to
Cobalt
2
3. Chemistry
B12 is the most chemically complex of all vitamins.
Chemical name cobalamin is derived from its central cobalt atom (which is
positively charged) (Vitamin B12: Cobalamin 2013)
It’s impressive formula C63H88N14O14PCo reflects the intricate molecular
structure (Types of Vitamin B12 2018)
Vitamin B12 is the only metal-containing vitamin. It is also watersoluble
and stored in the liver (Vitamin B12: Cobalamin 2013)
For anaerobic bacteria to synthesize B12, cobalt must be in the soil.
3
4. Chemistry
B12 is the collective term for a group of cobalt-containing compounds
known as corrinoids, which when assembled with 5th and 6th position
ligands are known as cobalamins (Krautler 2012) (Vitamin B12:
Cobalamin 2013).
The principal cobalamins are:
cyanocobalamin & hydroxocobalamin (Types of Vitamin B12
2018).
The two co-enzyme forms are:
methylcobalamin & 5-deoxyadenosylcobalamin
(adenosylcobalamin) (Types of Vitamin B12 2018).
4
5. Chemistry
The cobalamins are the only known substances to naturally
contain cobalt
Vitamin B12 is often thus treated as synonymous with cobalamin.
It is an odourless, intensely dark-red coloured, crystallized, heat and light
sensitive substance (Vitamin B12: Cobalamin 2013).
Cobalamin is almost never found in its chemically pure form as it is
usually bound to other molecules.
5
6. Epidemiology of B12 Deficiency
Overall prevalence of B12 deficiency is unknown.
Framingham Offspring Study found up to 39% of US adults
were at risk of B12 deficiency (serum B12 <258pmol/L)
(Tucker et al. 2000).
Globally, B12 deficiency is likely to be higher, especially in
developing countries (Stabler & Allen 2004).
6
7. Aetiology
Vitamin B12 is an essential vitamin obtained only from diet or
supplementation.
Stores of vitamin B12 in the liver remain in the body for years
(O’Leary & Samman 2010).
Vitamin B12 deficiency normally results from chronic, long-
term deficiency (O’Leary & Samman 2010).
7
8. Aetiology
Decreased intake or absorption of vitamin B12 increases risk of
deficiency.
Increasing incidence of gastric bypass surgeries in Western
countries, infers potential for continued increase in the
prevalence of B12 deficiency (Majumder, Soriano, Cruz &
Dasanu 2013).
8
9. Aetiology
Generally, aetiologies of B12 deficiency can be categorised as:
• Decreased dietary intake
• Food-bound cobalamin malabsorption (FBCM) (Shipton & Thachil 2015)
• Malabsorption via GIT or methylation (Linus Pauling Institute 2014).
Patients at high risk of vitamin B12 deficiency may include:
• strict vegans
• history of gastric or intestinal surgery
• history of atrophic gastritis
• the elderly (Linus Pauling Institute 2014).
9
10. Aetiology
Other predisposing factors include:
• Particular medications (Shipton & Thachil 2015).
• Conditions causing malabsorption (Shipton & Thachil 2015).
• IBD: particularly Crohn’s disease
• Coeliac disease
• Bacterial overgrowth syndromes (SIBO)
• Helicobacter pylori may be related to atrophic gastritis
diminishing the ability to break down vitamin B12 from food
10
11. Pathophysiology
Specifically, B12 is an important cofactor in 2 specific biochemical processes
involving
methylmalonic acid (MMA) and homocysteine (Hcy) as precursors (Office
of Dietary Supplements - Vitamin B12 2018).
B12 deficiency impairs the conversion of MMA to succinyl co-A.
B12/folate deficiency impairs the conversion of Hcy to methionine.
Methionine is critical in the production of S-adenosylmethionine (SAMe)
(Office of Dietary Supplements - Vitamin B12 2018).
11
12. Pathophysiology
B12 and folate are integral for normal haematopoiesis and bone
marrow function.
Prolonged severe deficiency of B12 may eventuate in neurological and
haematologic disorders.
A relationship between neurological diseases (dementia, depression,
cognitive impairment) and B12 deficiency has also been established in
clinical literature (Soysal 2018, Kalita 2008).
http://bestpractice.bmj.com.ezproxy.une.edu.au/topics/en-us/822
12
13. What To Expect When Treating B12 Deficiency
Expected Duration
(Harvard Health Publishing 2018)
With adequate supplementation, symptoms begin to improve
within a few days.
In vegans and those whose deficiency is diet-related, oral
B12 supplementation should be adequate.
Those with PA or absorption issues require B12 injections
every 1-3 months (or more), indefinitely.
13
14. What To Expect When Treating B12 Deficiency
Treatment
(Harvard Health Publishing 2018)
People who cannot absorb B12 need regular injections. Initially, severe cases
may need 5-7 injections in the first week.
Injection response usually expected within 48-72 hours, with increased
production of RBC’s.
Once B12 reserves reach normal levels, injections every 1-3 months prevents
symptomatic return
14
15. What To Expect When Treating B12 Deficiency
In SIBO, appropriate treatment may stop bacterial overgrowth and allow
B12 absorption to normalise.
B12 deficiency resulting from inadequate dietary intake is easily reversed
via diet and oral supplementation.
In severe anaemia (very low RCC), blood transfusions may initially help until
B12 injections kick in.
15
16. Pernicious Anaemia (Destructive Anaemia)
B12 deficiency is the cause of pernicious anaemia, which was historically fatal
with an unclear aetiology. First described in medicine in 1835.
16
17. Mrs Lincoln
Mary Todd Lincoln was diagnosed post humously with pernicious anaemia (PA).
Whilst deadly at the time, it is now know to be caused by B12 deficiency (Scientist, 2018).
Lincoln’s suffered moodiness, hallucinations, the fact that she was a hypochondriac and
often bedridden, overcome by melancholy. She was hospitalised for psychiatric problems
(Scientist, 2018).
Dr John Sotos, pursuing Lincoln’s ailments for years, has concluded after researching
>100 historical documents and 678 surviving letters, that Mrs Lincoln suffered PA in its
worst manifestations (Scientist, 2018).
Lincoln died in 1882 at age 63. “In the 19th century there was no treatment, so the
disease progressed to its fatal endpoint.
A complete description and cure of pernicious anaemia were discovered in 1926
(Scientist, 2018).
17
19. The Cobalamin Mystery
1920 (approx.) whilst experimentally inducing anaemia in dogs, Whipple discovered
that ingesting large amounts of raw liver resolved the condition (Sinclair, 2008).
1926, Minot & Murphy trialled raw liver as tx for pernicious anaemia in 45 adults
(120–240 g of liver and 120g of muscle meat/day).
They observed rapid symptomatic improvement and increased red cell count (RCC).
Within 4-10 days the formation of new young RBC’s (reticulocyte count) had
increased from 1% to approx. 8%, jaundice lessened (less RBC destruction), and Hb
concentration and RCC increased (Sinclair, 2008).
Minot & Murphy published their results in the Journal of the American Medical
Association in 1926 (Sinclair, 2008).
Eating raw liver or drinking liver juice became tx for the previously fatal condition.
Whipple, Minot, and Murphy shared the 1934 Nobel Prize in Physiology or Medicine.
19
21. Raw Liver Smoothie… mmmmm
Ingredients
1/4 cup yogurt/kefir/milk
Small handful berries
1/2 banana
1 Tbsp frozen raw liver
2 raw egg yolks
1 tsp lemon/lime juice
1 tsp cinnamon
Pinch of sea salt
Honey/maple syrup
Method
1. Blend all ingredients (except egg yolks) until
smooth
2. Add egg yolks and pulse to incorporate
3. Enjoy….!!!
21
22. The Cobalamin Mystery
1928, chemist Edwin Cohn prepared a liver extract 50-100 times more potent than the
natural liver products. The extract was the first workable treatment for the disease.
These events led to discovery of the soluble vitamin B12, from bacterial broths.
1947 - Shorb & Folkers were given a US$400 grant to develop the so-called "LLD
(Lactobacillus lactis) assay" for B12. Dorner, a bacterial strain requiring "LLD factor" for
growth was eventually identified as B12 (Scott & Molloy 2012).
Shorb used the LLD assay to rapidly extract the anti-pernicious anaemia factor from
liver extracts, and pure B12 was isolated by 1948.
1956, chemical structure of the molecule was determined by Dorothy Crowfoot Hodgkin
(Scott & Molloy 2012).
1950’s, methods of producing the vitamin in large quantities from bacteria cultures
were developed, leading to the modern treatment form.
1980’s, MIT and Harvard researchers discovered the final piece of the synthesis pathway
of B12, the only vitamin synthesised exclusively by microorganisms.
22
23. The Cobalamin Mystery
The biosynthesis of this essential nutrient is intricate, involved and confined
to certain members of the prokaryotic world, seemingly never having made
the eukaryotic transition (Martens, Barg, Warren, Jah, 2002)
Prokaryote = a unicellular organism that lacks a membrane-bound nucleus,
mitochondria, or any other membrane-bound organelle.
Humans require only trace amounts of B12 (approx. 1µg/day), to assist the
functions of only two enzymes, methionine synthase and (R)-
methylmalonyl-CoA mutase (Martens, Barg, Warren, Jah, 2002).
23
24. Vitamin B12 is produced by soil
microbes that live in symbiotic
relationships with plant roots (MIT
News, 2018).
24
26. “ The Mount Everest of Biosynthetic Problems'.
B12 is pieced together as an elaborate molecular jigsaw involving around 30
individual components.
Unique amongst the vitamins as it is exclusively made by bacteria.
In the early 1990's it was discovered that two pathways exist in nature for
the de novo biosynthesis of adenosylcobalamin; the coenzyme form of
vitamin B12, to allow its construction - one requiring oxygen and the other
not
(Moore et al., 2013).
26
27. Anaerobic Pathway
The anaerobic (more common) pathway has yet to be fully characterised, due
to the instability of its oxygen-sensitive intermediates which are very unstable
and rapidly degrade (Moore & Warren 2012)
Bioscientists at the University of Kent have trained a friendly bacterium;
Bacillus megaterium to produce all of the components of the anaerobic B12
pathway (Moore & Warren 2012).
This can be used to help persuade bacteria to make the vitamin in larger
quantities, thereby contributing to its use in supplements, livestock feed and
health and medical research.
27
28. Moore, Simon J., Andrew D. Lawrence, Rebekka Biedendieck, Evelyne Deery, Stefanie Frank, Mark J. Howard, Stephen E. J. Rigby, and Martin J. Warren. “Elucidation of the Anaerobic Pathway
for the Corrin Component of Cobalamin (Vitamin B12).” Proceedings of the National Academy of Sciences 110, no. 37 (September 10, 2013): 14906–11.
https://doi.org/10.1073/pnas.1308098110.
28
29. Cobalamin - Dietary Sources & Requirements
To confirm: Cobalamin is synthesised solely by microorganisms
(Linus Pauling Institute, 2014).
Ruminants obtain cobalamin from the foregut, whereas the only
source for humans is food of animal origin, (meat, fish, and dairy
products).
Vegetables, fruits, and other foods of non-animal origin are free
from cobalamin unless contaminated with bacteria.
29
30. Cobalamin - Dietary Sources & Requirements - Summary
A normal Western diet contains 5–30μg of cobalamin daily.
Adult daily requirements are only approx. 2-2.8μg (Linus Pauling
Institute, 2014).
Adult daily losses (excreted via urine and faeces) are 1–3μg (~0.1% of
body stores).
Body stores are approx.2–3mg, sufficient for 3–4 years if supplies are
completely cut off.
30
31. Natural Sources of B12
Eat animal products, particularly liver & meat
Eat insects/worms
Eat vegetables with soil still attached
Or more adventurously…..
Eat contents of ruminant stomachs and intestines
Eat fermented and part-digested moss from reindeer gut (Inuits
evenused to eat the feaces)
Eat molluscs
Eat poop
31
32. Rabbit Food!
Faeces are a rich source of vitamin B12 and many species, including dogs, cats,
and rabbits eat faeces.
Species within the Lagomorpha (rabbits, hares, and pikas) produce two types
of feacal pellets: hard ones, and soft ones called cecotropes.
Animals in these species re-ingest their own cecotropes, which consist of
chewed plant material that was metabolised by bacteria in the cecum, a
chamber between the small and large intestines.
Cecotropes contain digestible carbohydrates and B vitamins synthesised by the
resident bacteria (Intestinal Bacteria as a Vitamin B12 Source 2018).
32
33. Insects, a Potential B12 Food Source
Insects containing B12 include:House crickets (Acheta domesticus)
(5.4μg/100g in adults and 8.7μg/100g in nymphs)(Anankware,
Fening, Osekre, Obeng-Ofori, 2015).
Mealworm larvae (Tenebrio molitor) 0.47 μg per 100 g
(Anankware, Fening, Osekre, Obeng-Ofori, 2015).
More research is needed to identify edible insects rich in B vitamins,
and the breakdown and utilisation from human consumption of
insects.
33
34. Microbial corrinoid metabolism in the gut
In ruminants, gut microbes provide a direct source of cobalamin (direct
effect)(Degnan, Taga, Goodman 2014).
In insects, corrinoids are essential cofactors for obligate symbionts that
provide key nutrients to the host (indirect effect) (Degnan, Taga, Goodman
2014).
Competition and exchange of corrinoids likely shape gut microbiota
composition and expressed functions in humans and other animals
(microbiome remodeling) (Degnan, Taga, Goodman 2014).
34
36. Cobalt Deficiency in Stock
Presence of cobalt in soils markedly improves the health of grazing
animals (Huwait, Kumosani, Moselhy, Mosaoa & Yaghmoor 2015).
An uptake of 0.20 mg/kg a day is recommended because they have no
other source of vitamin B12.
In the early 20th century during the development of farming on the
North Island Volcanic Plateau of New Zealand, cattle suffered from
what was termed "bush sickness". It was discovered that the volcanic
soils lacked the cobalt salts essential for the cattle food chain.
The "coast disease" of sheep in the Ninety Mile Desert of the Southeast
of South Australia in the 1930s was found to originate in nutritional
deficiencies of trace elements cobalt and copper (AgricWA, 2018).
36
38. Summary
B12 is only produced by some prokaryotes (certain bacteria and archaea)
(Martens, Barg, Warren, Jah, 2002).
B12 is synthesised by some gut bacteria in the human colon, however
cannot be absorbed as the colon is too far from the small intestine, where
B12 absorption occurs.
For gut bacteria of ruminants to produce B12, the animal must consume
sufficient amounts of cobalt (Huwait, Kumosani, Moselhy, Mosaoa &
Yaghmoor 2015).
Grazing animals pick up B12 and bacteria that produce it from the soil at
the roots of the plants they eat (Huwait, Kumosani, Moselhy, Mosaoa &
Yaghmoor 2015).
38
39. Methylation Pathways - Methionine Synthase
Methylcobalamin is required for the function of the folate-dependent
enzyme methionine synthase (Linus Pauling Institute, 2014).
This enzyme is required for the synthesis of the amino acid methionine
from homocysteine (Linus Pauling Institute, 2014).
Methionine is required for the synthesis of S-adenosylmethionine
(SAMe), a methyl group donor used in many biological methylation
reactions, including the methylation of a number of sites within DNA
and RNA (Linus Pauling Institute, 2014).
Inadequate function of methionine synthase can lead to an
accumulation of Hcy, which has been associated with increased risk of
cardiovascular disease (Linus Pauling Institute, 2014).
39
40. Methylation Pathway - Methylmalonyl-CoA Mutase
Methyl or Adenosylcobalamin are required by the enzyme that
catalyses the conversion of Methylmalonyl-CoA to Succinyl CoA (BMJ,
2018)
Succinyl CoA then enters the citric acid cycle (BMJ, 2018).
Succinyl CoA functions include:
an important role in the production of energy from lipids and proteins
(BMJ, 2018).
an essential role in the synthesis of Hb (oxygen-carrying component
of RBCs) (BMJ, 2018).
40
43. Transsulfuration Pathway – Hello B6☺
▶ The transsulfuration pathway is the major route for the metabolism of the sulphur-containing amino acids.
43
Higdon. 2003
44. Absorption of Vitamin B12
Passive (Linus Pauling Institute, 2014)
via buccal duodenal & ileal mucosa
rapid but inefficient with under 1% absorbed by this process
Active (Linus Pauling Institute, 2014)
occurs through the ileum
mediated by gastric intrinsic factor (gene at chromosome 11q13) (IF)
46
46. Proteins associated with vitamin B12 metabolism
R protein (aka Haptocorrin or TCN I )
Intrinsic factors
Cubilin receptors
Transcobalamin II
Cell surface receptors for TCNII-B12 complex
Enzymes involved in formation of- adenosyl and methyl cobalamin
forms (Neale 1990).
51
48. Cyanocobalamin (CNCbl)
Synthetically manufactured form of vitamin B12 (Paul & Brady
2017).
It is the most stable form of B12, due to the presence of a
cyanide molecule (Paul & Brady 2017).
While the amount of cyanide is not dangerous, it does require
the body to expend energy to convert and remove it.
CNCbl is a stable and inexpensive synthetic form commonly
used for food fortification and oral supplements (Paul & Brady
2017).
53
49. Methylcobalamin (MeCbl)
This is the most active form in the human body (Paul & Brady 2017).
Converts homocysteine to methionine, which helps protect the
cardiovascular system.
Offers overall protection to the nervous system.
Can also cross the blood-brain barrier (without assistance) to protect brain
cells.
It contributes essential methyl groups needed for detoxification and to
start the body’s biochemical reactions (Paul & Brady 2017).
In mammalian cells, MeCbl is a cofactor for the cytosolic methionine
synthase (Paul & Brady 2017).
54
50. Hydroxocobalamin
An abundant and physiologically relevant intermediate form (Paul &
Brady 2017).
Bacteria naturally create this form of vitamin B12, making it the
main type found in most foods.
It easily converts into methylcobalamin in the body (Paul & Brady
2017).
Hydroxocobalamin is commonly used via injection as a treatment
for B12 deficiency as well as a treatment for cyanide poisoning
(Thakkar, Billa 2015; Zhang, Ning 2008).
55
51. Adenosylcobalamin (AdoCbl)
AdoCbl is a cofactor for the mitochondrial methylmalonyl-CoA (MM-
CoA) mutase (Thakkar, Billa 2015, Paul & Brady 2017).
The energy formation that occurs during the Citric Acid cycle requires this
form of B12 (Thakkar, Billa 2015).
Although naturally occurring, it is the least stable of the four types of B12
outside the human body and does not translate well into a tablet-based
supplement (Thakkar, Billa 2015, Paul & Brady 2017).
Harder to find in supplement form.
56
52. Supplementation
When supplemented, CNCbl needs to be converted into MeCbl and
AdoCbl in order to exert its anticipated biological effect on the cell
(Thakkar, Billa 2015, Paul & Brady 2017).
The concept of replacing CNCbl/HOCbl with the coenzyme forms as
ready-to-use sources of the cofactors has emerged.
Supplementation of MeCbl and AdoCbl is postulated to be preferable to
HOCbl and especially CNCbl/, depending on factors including genetics,
environment, age and GIT function (Thakkar, Billa 2015, Paul & Brady
2017)
57
53. Example Dosages Found in Common Supplements
Sublingual Cyanocobalamin Spray: 500ug per spray
Sublingual Cyanocobalamin Tablet: 1000ug per tablet
Chewable Hydroxocobalamin Tablet: 2000ug per tablet
Liposomal Hydroxocobalamin Liquid: 500ug per 0.5ml dose
Liposomal Methylcobalamin: 200ug per Spray
Sublingual Methylcobalamin tablet: 5000ug (HIGH DOSE!!)
58
56. Vitamin B12 Lab Values & Deficiency Signs
While severe deficiency causes
permanent neurological damage,
earlier manifestations are
generally subtle or asymptomatic
Vitamin B12 deficiency is a
common condition that can
manifest with Neurologic signs &
sx
Psychiatric signs & sx
Hematologic disorders
(BMJ Best Practice2018)
The lab guidelines for B12 deficiency
can be vague.
In Australia :
<147 pmol/L indicates probable
deficiency
148-258 pmol/L indicates possible
deficiency
>258 pmol/L indicates that deficiency
is unlikely??
61
57. Screening Factors
Paraesthesias
Vegan/vegetarian
Medication use
Positive Romberg test - Ataxia
Decreased vibration sense
Pallor, Fatigue
B12 is required to make the protective coating (myelin sheath) surrounding nerves, so
inadequate B12 can expose nerves to damage
(Shipton & Thachil 2015).
62
Petechiae
Glossitis
Angular cheilitis
Cognitive
impairment
Swollen tongue,
bleeding gums
decreased appetite.
58. Screening Factors
Vegans
Vegans not supplementing with B12 are potentially at an increased risk of
vitamin B12 deficiency.
Up to 88% of vegans were found to have evidence of vitamin B12 deficiency in
one study.
Age >65 years
Prevalence of B12 deficiency increases with advancing age (Clarke et al. 2004).
12% to 15% of people aged >65 years have biochemical evidence of vitamin
B12 deficiency
MOA = Poorer GI absorption, and higher prevalence of atrophic gastritis
63
59. Risk factors (Medications)
H2 receptor antagonist or proton-pump inhibitors (PPIs)
Vitamin B12 bound to food must be freed by peptic acid secreted from the
stomach.
Taking H2 receptor antagonists or PPIs may increase risk of deficiency
>2 years' use of PPI or H2 receptor antagonists increase the risk of B12
deficiency (Lam 2013)
Metformin
Chronic metformin use may cause low serum vitamin B12 levels and place
patients at risk of vitamin B12 deficiency (Gupta, Jain, & Rohatgi 2018).
Patients using metformin for 4.3 years have an increased risk of vitamin B12
deficiency.
64
60. Helicobacter pylori infection
Studies reveal a potential association between H pylori infection and
vitamin B12 deficiency.
Unclear whether it is the organism or atrophic gastritis that causes vitamin
B12 deficiency (Serin et al. 2002, Avcu et al. 2001).
Risk Factors (Health Conditions)
65
61. Terminal ileum disease
The majority of patients with terminal ileum resection were found to
have evidence of vitamin B12 deficiency in an early study (Skidmore
1989).
Crohns Disease
50% of patients with Crohns disease who have had >20 cm of terminal
ileum removed have evidence of vitamin B12 deficiency.
Gastric Surgery
Gastric surgery causes inadequate B12 absorption via decreased IF
(Kapadia 1995, Rhode 1995, Sumner 1996).
Risk Factors (Health Conditions)
66
63. Diabetes
Neuropathy in patients with diabetes is common (Gupta 2018,
Wang 2017).
This means that concomitant vitamin B12 deficiency may be
easily overlooked (Tavares 2017, Pflipsen 2009, Wang 2017,
Metaxis 2018).
B12 status should therefore be part of diabetic health
screening.
68
64. Pregnancy
B12 deficiency is common during pregnancy as levels of vitamin B12
decrease from the first to the third trimester
(Rogne et al. 2017, Lai 2017, Dayaldasani 2014).
69
65. Investigations: Full Blood Count (FBC/CBC/FBE)
Provides important information about the types, populations, and
health of blood cells.
Aids diagnosis and assessment of anaemia, nutritional deficiencies,
blood disorders, infection, and many other disorders.
An FBC consists of:
RBC (including red cell indices)
WBC (including white cell indices)
Haemoglobin (Hb)
Haematocrit (Hct)
Platelets
70
66. Microscopy
A peripheral blood smear (a way of looking
at blood cells under the microscope) may
also provide useful information.
In a normal peripheral blood smear, RBC
appear regular & round with a pale centre.
Variations in the size or shape of these cells,
otherwise known as anisocytosis, may
suggest a blood disorder.
71
67. Primary Pathological Investigations
FBC – (Screening tool not diagnostic)
To determine baseline RDW (not always included in an FBC) as well as MCV, Hb
and Hct.
Many individuals with documented vitamin B12 deficiency do not have
macrocytosis or anaemia (Chui et al. 2001).
Not useful for diagnosing early vitamin B12 deficiency (except increased RDW)
Not useful to rule out vitamin B12 deficiency.
B12 deficiency may cause:
Increased RDW, increased MCV and increased Hct, depending on the stage of
deficiency.
72
68. Serum Vitamin B12
Optimal serum vitamin B12 levels for hematologic and
neurologic function are still undetermined.
<147 pmol/L indicates probable deficiency
148-258 pmol/L indicates possible deficiency
>258 pmol/L indicates that deficiency is unlikely????
73
69. Primary testing
Methylmalonic Acid (MMA)
Produced in very small amounts, used in metabolism and energy production
(Methylmalonic Acid 2018).
In one step of metabolism, B12 promotes the conversion of methylmalonyl
CoA to succinyl CoA (Methylmalonic Acid 2018).
If there is not enough B12 available, then the MMA concentration begins to
rise, resulting in an increase of MMA in the blood and urine.
Elevated urinary MMA is a sensitive and early indicator of B12 deficiency
(Sun et al. 2014).
74
70. MMA
Test
Potential differential diagnosis = renal disease, in which increased MMA
levels also occur.
Increased MMA may be misleading and requires follow-up to determine
whether MMA normalises with adequate treatment (Oh 2018).
Result
Increased (lab-specific)
75
71. Homocysteine (Hcy)
Test
Not as specific as MMA for vitamin B12 deficiency
(Vashi, Edwin, Popiel, Lammersfeld & Gupta 2016).
Differential diagnosis = folate deficiency and hypothyroidism, in which Hcy is
also increased.
More readily available than MMA
Result
Increased (lab-specific)
76
72. Intrinsic Factor (IF) antibody
Once vitamin B12 deficiency is confirmed, IF antibody can determine whether
pernicious anaemia is the cause.
Only 50% sensitive, but highly specific for pernicious anaemia.
Result
Positive if pernicious anaemia is the cause
77
73. Antiparietal Cell (APC) antibody
Parietal cell antibodies are proteins produced by the immune system
that mistakenly target a type of specialised cells that line the
stomach wall.
This test detects these antibodies in the blood to help diagnose
pernicious anaemia.
So….. Wrap your head around this…….
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74. If both parietal cell antibody and intrinsic factor antibody are positive
= Immunological evidence of Pernicious Anaemia.
If both parietal cell antibody and intrinsic factor antibody are negative
= No immunological evidence of Pernicious Anaemia.
If parietal cell antibody is positive but intrinsic factor antibody is negative
= Gastric Parietal cell antibody is associated with > 90% of patients with
Autoimmune Gastritis, the end result of which may be Pernicious Anaemia.
In 20-30% of patients, relatives of patients with pernicious anaemia, autoimmune
thyroiditis a small percentage of healthy persons may be positive and run an
increased long term risk of pernicious anaemia.
○ A negative Intrinsic Factor antibody result does not exclude the
diagnosis of Pernicious anaemia, as only 60% of patients with
pernicious anaemia will have this antibody.
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75. Intrinsic Factor Antibody
Two types:
Type 1(blocking) antibody prevents the attachment of
vitamin B12 to intrinsic factor: present in 50-60% of patients
with pernicious anaemia (RCPA 2018).
Type 2 (precipitating) antibody prevents attachment of the
vitamin B12-intrinsic factor complex to ileal receptors:
present in 30% of patients with pernicious anaemia (RCPA
2018).
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76. Active B12
Holotranscobalamin (Active B12)
Test
Measures B12 bound to transcobalamin.
Decreased values along with low normal serum vitamin B12
suggest inadequate absorption (Nexo & Hoffman-Lucke 2011).
Used more frequently
Result
<35pmol/L may be diagnostic of deficiency
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77. Reticulocyte Count
Test
Decreased reticulocyte index indicates decreased production of reticulocytes
Differential diagnosis = haemolytic anaemia, in which reticulocyte index would be
increased.
Result
Decreased corrected reticulocyte index.
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78. Serum Gastrin & Schilling Test
Serum Gastrin (Fasting) Test
Gastrin levels rise in gastric achlorhydria and can signify pernicious anaemia
(Slingerland, Cardarelli, Burrows & Miller 1984).
Result = Increased if pernicious anaemia is the cause
Schilling test (rarely available)
Performed with an initial test flushing dose of 1000ug of cyanocobalamin,
intramuscularly.
Generally unavailable and rarely used.
Result: Differs for different stages
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79. Pathophysiology
Two major pathophysiologic processes contribute to the anaemia resulting from
B12 deficiency:
Resulting haemolysis is associated with a 30% to 50% reduction in RBC lifespan
(Green 2017).
Ineffective erythropoiesis, caused by intramedullary apoptosis of
megaloblastic erythroid precursors (Green 2017).
Increased rigidity of produced erythrocytes, associated with abnormal RBC
membrane proteins, leading to shortened RBC survival (Green 2017).
http://www.bloodjournal.org/content/bloodjournal/129/19/2603.full.pdf
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80. Pathophysiology
Increased plasma bilirubin
Increased serum lactate dehydrogenase (LDH)
LDH-1 predominating over LDH-2.
Serum AST levels are however, often normal.
Moderately increased serum EPO levels.
Ineffective erythropoiesis causes decreased Fe utilisation, resulting in increased
serum Fe and ferritin levels.
Increased levels of soluble serum transferrin receptor, presumably resulting
from increased haemolysis.
Corresponding to the increase in LDH, there may be an increase in serum
muramidase, caused by increased granulocyte turnover.
(Barcellini & Fattizzo 2015)
http://www.bloodjournal.org/content/bloodjournal/129/19/2603.full.pdf?sso-checked=true.
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81. Toxicity – Upper level limits
No toxic or adverse effects have been associated with large intakes of vitamin
B12 from food or supplements in healthy people.
There is insufficient data upon which to set any upper daily limit for B12
(Nutrient Reference Values 2017).
When high doses of vitamin B12 are given orally, only a small percentage can
be absorbed, which may explain the low toxicity Because of the low toxicity
of vitamin B12, no tolerable upper intake level (UL) has been set by the US
Food and Nutrition Board.
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83. B12/Folate Methylation
Homocysteine (Hcy)
Vitamin B12 cannot fulfil its role in the deconstruction of Hcy without folate – the
two vitamins are dependent on one another (Vitamin B12 And Folic Acid 2018).
Before we explore this relationship in detail, it is important first to touch upon the
most important information regarding the role of folate (Vitamin B12 And Folic
Acid 2018).
Methionine Synthase
Both B12 & folate play important roles in the conversion of dangerous Hcy to
methionine (Vitamin B12 And Folic Acid 2018).
Tetrahydrofolate
B12 is responsible for re-activating folic acid, by converting it through various
reactions back into tetrahydrofolate, (the form of folate the body can use). A B12
deficiency thus leads to an indirect folate deficiency: even if enough folate is
provided for the body, it cannot be used unless a supply of B12 is present; its
simply sits in its inactive form (Vitamin B12 And Folic Acid 2018).
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84. B12/Folate Methylation
Cobalamin deficiency leads to Folate deficiency
Since a lack of B12 also leads to a folate deficiency, vitamin B12 has a doubly
important position in cell metabolism.
A reminder that folate is responsible for the following tasks:
Cell division
Haematopoiesis (blood formation)
Mucosal structure
DNA synthesis
Protein metabolism
Fat metabolism
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85. Folic versus Folate
Folic acid is a synthetic compound which cannot be directly used by our body
(Vitamin B12 And Folic Acid 2018).
Folate is the natural and bioactive form of folic acid, which is used in various
chemical forms in the body (Vitamin B12 And Folic Acid 2018).
Normally, the body is capable of absorbing folic acid and converting it into
folate. However, since this isn’t always the case, supplements which contain
bioactive folate instead of folic acid are now also available (Vitamin B12 And
Folic Acid 2018).
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86. Functional Folate Deficiency
Two hypotheses have been developed to explain how cobalamin-deficiency
anaemia is in fact caused by functional folate deficiency (Castellanos-Sinco et al.
2015):
Methyltetrahydrofolate trapping, or the “folate trap”.
Formate deficiency
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87. Formate deficiency
When tetrahydrofolate is depleted, stored methyltetrahydrofolate cannot
be converted into formate-mediated formyltetrahydrofolate, (another
functional form of folate used in purine synthesis) (Castellanos-Sinco et al.
2015).
Plasma formate concentration and urinary formate excretion are equally
sensitive indicators of folate deficiency, as is plasma Hcy (Castellanos-Sinco
et al. 2015).
Cobalamin and folate metabolism share another common feature: they both
require methylenetetrahydrofolate (a product of tetrahydrofolate) and
dUMP to form thymidylate synthase-mediated thymidylate and
dihydrofolate (Castellanos-Sinco et al. 2015).
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88. Summary
Diminished activity of methionine synthase in B12 deficiency inhibits the
regeneration of tetrahydrofolate (THF), trapping folate in a form that is not
usable, resulting in folate deficiency, even in the presence of adequate
folate levels (Castellanos-Sinco et al. 2015).
Thus, in both folate and vitamin B12 deficiencies, folate is unavailable to
participate in DNA synthesis (Castellanos-Sinco et al. 2015).
This impairment of DNA synthesis affects the rapidly dividing cells of the
bone marrow earlier than other cells, resulting in the production of large,
immature, Hb-poor red blood cells causing megaloblastic anaemia which is
the symptom for which the disease, pernicious anaemia was named
(Castellanos-Sinco et al. 2015).
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