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Importance of vitamin d
- 1. Vitamin D Importance for Human Life Hidaa Lifescience LLP Dr. Raj kumar maurya D’bello Naturally High vitamin D Mushroom powder
- 2. Importance for Human Life
- 3. Vitamin D (Sunshine Vitamin) Vitamin D is commonly known as: The “sunshine” vitamin. Vitamin D2 (Ergocalciferol) which is found in plants. Vitamin D3 (Cholecalciferol) which can be obtained from sunlight via our skin. Both Vitamin D2 & D3 form, 25 hydroxyvit D & then Active form of vitamin D (1,25-dihydroxyvitamin D).
- 4. Vitamin D Fat Soluble Vitamin Found in trace amounts in food Formed through sunlight exposure Converted to hormone form through liver and kidney Vitamin D is needed for the absorption of calcium & Phosphorous from foods to keep bones and teeth healthy.
- 5. Functions of Vitamin D Vitamin D is needed for Calcium absorption (small intestine) urinary calcium reabsorption (kidney) and Bone mineralization Helps with the travel of calcium and phosphorous in the blood Modulation of neuromuscular and immune function. Reduction of inflammation. Prevents rickets in children and Osteomalacia in adults
- 6. How much Vitamin D do we need? Ages 19-50: 200 International Units (IU) Ages 51-69: 400 IU Age 70 and older: 600 IU
- 7. Vitamin D deficiency Global Health problem 70-90% apparently healthy population is VDD VDD is prevalent irrespective of age , sex, profession, rural/urban or regional distribution Imparts musculoskeletal health
- 8. Deficiency Symptoms and Diseases Osteoporosis results from inadequate calcium intakes Vitamin D plays a role in the prevention of colon, prostate, and breast cancers hence, lack of this vitamin can trigger these diseases. Vitamin D deficiency is also associated with heart disease and hypertension
- 9. Symptoms of VDD Vague muscle or joint pain Weakness Bonepain Tiredness Fatique or even depression Weakens bones, causes rickets, tooth decay, kidney stones, muscle weakens, poor absorption of cal.
- 10. Deficiency Symptoms and Diseases Rickets and Osteomalacia are the classical vitamin D deficiency diseases Rickets, is characterized by a failure of bone tissue to properly mineralize, resulting in soft bones and skeletal deformities Osteomalacia, is characterized by fragile bones that significantly increases the risk of bone fractures
- 11. When can vitamin D deficiency occur? Rickets Osteomalacia
- 12. These lead to:- Learning disability Impaired work capacity. Increased susceptibility to infection
- 13. Bowed legs (genu varum) Knock-knees (genu valgum) or "windswept knees. Costochondral swelling ( "rickety rosary" or "rachitic rosary") Harison’s sulcus and pot belly
- 14. Signs and Symptoms Bone pain or tenderness. muscle weakness (rickety myopathy or "floppy baby syndrome") Increased tendency for fractures (easily broken bones), especially greenstick fractures Hypocalcemia Tetany Craniotabes (soft skull) Skeletal deformity:Cranial, spinal, and pelvic deformities
- 15. Current Research Deficiency Increases Risks for Cancers Heart Disease Stroke Diabetes Depression Muscle Weakness Birth Defects Obesity
- 16. Vitamin D and chronic diseases Regulating calcium and phosphate metabolism for bone health, Autoimmune diseases, Atopic dermatitis, Cardiovascular disease, Chronic respiratory diseases Crohn’s disease and Inflammatory bowel disease, Diabetes, type 1 and type 2 Kidney disease, Osteoarthritis, Periodontal disease, Rheumatoid arthritis, Skin disorders, Some cancers, Infectious disease, Schizophrenia 1,25-dihydroxyvitamin D plays an important role in:
- 17. Why Vitamin D deficiency occurs? Due to:- Inadequate sunlight exposure. Poor access to micronutrients rich food. Disorder that limit its absorption. Deficient soil quality. Impaired conversion into active metabolites. Possible role of dietary fibers.
- 18. Diagnosis: Blood tests: Serum calcium : may show low levels of calcium serum phosphorus: may be low serum alkaline phosphatase: may be high Aerial blood gas: may reveal metabolic acidosis. Xray: Bow legs {outward curve of long bones.} Dec. Bone opacity-poor bone mineralization. square headed appearance of skull. (Changes seen in late stage)
- 19. Vitamin D and cancer Linked with colon, rectum, breast, ovarian, prostate, stomach, bladder, esophagus, kidney, lung, pancreas, and uterine cancers, as well as for non-Hodgkin lymphoma and multiple myeloma. Higher levels of serum 25(OH)D leads to lower incidence of cancers. Sunnier latitudes - Lower mortality. Black individuals: lower level of active vitamin D. Blacks have higher rates of colon, breast, prostate, and ovarian cancers.
- 20. Vitamin D and cancer Vitamin D prevents tumor angiogenesis, it allows for effective communication between cells, and it helps to maintain a healthy calcium concentration in the cells. Vitamin D also enhances cell death when appropriate.
- 22. Role in cancer prevention and recovery Calcitriol – Induces death of cancer cells Regulates Cell growth, Differentiation etc. Daily intake of 1,000IU/day reduces risks
- 23. Vitamin D and Obesity Seasons Altitude Calcium Link between other diseases Treatable
- 24. Vitamin D and cardiovascular disease Plaque results from a chronic low-grade inflammation. Endothelial dysfunction, LDL particles accumulation. Low level of vitamin D = 2 x risk for cardiovascular incidents.
- 25. Hypertension and Vitamin D Hypertension peaks in the winter. Short-term (8 wks) supplementation with vitamin D and calcium reduced blood pressure, heart rate, and parathyroid hormone levels in women 70 yrs of age or older.
- 26. Vitamin D and Diabetes Low serum levels at greater risk Lack of Vitamin D interferes with insulin secretion
- 27. Vitamin D and depression SAD( Seasonal affective disorder)- winter depression 130 patients 600 or 4,000 IU supplements Re-evaluated 1 year later Patients actually felt better with supplements
- 28. Diabetes and vitamin D Type 1 diabetes results from beta cell destruction. Vitamin D is an immunosuppressive agent. Supplementation by vitamin D reduced the risk for diabetes by about 80% in children. Vitamin D might protect pancreas. Supplementation of mother’s diet reduced incidence of type 1 diabetes in children. Children who are deficient in vitamin D have a 200% increased risk in developing type 1 diabetes.
- 29. Multiple sclerosis Lower incidence of MS in countries with more sunlight. Vitamin D intake is associated with lower incidence of MS and slower rate of progression of the disease.
- 30. Vitamin D sources Exposure to sunlight Reduced cutaneous synthesis due to Limited uv exposure due to increased skin pigmentation Topical application of sunscreen
- 31. Sun exposure Solar ultraviolet radiation (UV-radiation) beneficial harmful skin cancer Vitamin D obtained by UV-induced photosynthesis in the skin. Sunscreens and sunblocks completely blocks photosynthesis of vitamin D
- 32. Exposure to sunlight Important source of vitamin D Season, latitude, time of day
- 33. Food Sources of Vitamin D Food IUs per serving Percent DV Cod liver oil, 1 tablespoon 1,360 340 Swordfish, cooked, 3 ounces 566 142 Salmon (sockeye), cooked, 3 ounces 447 112 Tuna fish, canned in water, drained, 3 ounces 154 39 Orange juice fortified with vitamin D, 1 cup 137 34 Milk, nonfat, reduced fat, and whole, vitamin D-fortified, 1 cup 115-124 29-31 Yogurt, fortified with 20% of the DV for vitamin D, 6 ounces 80 20 Margarine, fortified, 1 tablespoon 60 15 Sardines, canned in oil, drained, 2 sardines 46 12 Liver, beef, cooked, 3 ounces 42 11 Egg, 1 large (vitamin D is found in yolk) 41 10 Ready-to-eat cereal, fortified with 10% of the DV for vitamin D, 1 cup 40 10 nih.gov
- 34. Conversion of Vitamin D to the active form Cholesterol from diet 7 dehydrocholesterol in the skin Sunlight converts 7- dehydrocholesterol to previtamin D3 Cholecalciferol (Previtamin D3) The liver converts previtamin D to 25-hydroxyvitamin D which appears in circulation. 25-hydroxyvitamin D (circulating form) The kidneys and other tissues convert it to an active form of 1,25- dihydroxyvitamin D 1,25-dihydroxyvitamin D (active form)
- 35. Vitamin D conversion The conversion of Vitamin D to its active form occurs in the kidneys, but it can also occur in the skin, prostate, brain, pancreas, adipose tissue, skeletal muscle, heart, colon, monocyte/macrophages and in neoplastic tissues.
- 36. Dietary requirement The dietary requirement for vitamin D depends upon the amount of vitamin synthesized by solar irradiation of the skin. Exposing hands, arms and face on a clear summer day for 10–15 min, two to three times a week, should yield sufficient cutaneous production of vitamin D to meet daily needs. To maintain satisfactory plasma 25(OH)D levels without any input from skin irradiation, an oral input in the region of 10–15 μg of vitamin D per day would be required.
- 37. RDA Recommended Dietary Allowances (RDAs) for Vitamin D Age Male Female Pregnancy Lactation 0–12 months* 400 IU (10 mcg) 400 IU (10 mcg) 1–13 years 600 IU (15 mcg) 600 IU (15 mcg) 14–18 years 600 IU (15 mcg) 600 IU (15 mcg) 600 IU (15 mcg) 600 IU (15 mcg) 19–50 years 600 IU (15 mcg) 600 IU (15 mcg) 600 IU (15 mcg) 600 IU (15 mcg) 51–70 years 600 IU (15 mcg) 600 IU (15 mcg) >70 years 800 IU (20 mcg) 800 IU (20 mcg) Institute of Medicine, and Endocrine Society Recommended Vitamin D intake (2011)* Adequate Intake (AI)
- 38. What are Superfoods? Functional foods that prevents us from taking medicines Vitamin D has an important role together with calcium in mineral metabolism and bone growth and maintenance. Most cells in the body have been found to have receptors for vitamin D, and is therefore now seen as an important nutrient in preventing many chronic diseases.
- 39. Vitamin D intake recommendations Obese children and adults, and children and adults on anticonvulsant medications, glucocorticoids, antifungals such as ketoconazole, and medications for AIDS be given at least two to three times more vitamin D for their age group to satisfy their body’s vitamin D requirement. The maintenance tolerable upper limits (UL) of vitamin D, which is not to be exceeded without medical supervision, should be 1000 IU/d for infants up to 6 months, 1500 IU/d for infants from 6 months to 1 yr, at least 2500 IU/d for children aged 1–3yr ,3000 IU/d for children aged 4–8yr, and 4000 IU/d for everyone over 8 yr. Higher levels of 2000 IU/d for children 0–1 yr, 4000 IU/d for children 1–18yr, and10,000IU/d for children and adults 19 yr and older may be needed to correct vitamin D deficiency.
- 40. Food As Medicine supports the immune system may reduce risk of cancer helps to maintain healthy cholesterol levels may reduce risk of heart disease
- 42. Recommendations Increase consumption of foods that have been fortified with vitamin D Sensible sun exposure limits Assess vitamin D levels in the blood at annual check ups
- 43. A mushroom has almost as much potassium as a small banana. Mushrooms contains 8% of the daily value. D’BELLO Mushroom powder contains ~250% of daily value, available online.
- 44. Conclusion Vitamin D – The wonder drug? Laboratory testing -Testing volume doubled every ear for the past four years Quest Diagnostics – Testing volume tripled between May 2006 and May 2008
- 45. THANK YOU
Editor's Notes
- The Recommended Dietary Allowance (RDA) is the average daily dietary intake level that is sufficient to meet the nutrient requirements of nearly all (97-98%) healthy individuals in each life-stage and gender group. Unlike many other nutrients, there is insufficient evidence to establish an RDA for vitamin D. Instead, an Adequate Intake (AI) -- a level of intake sufficient to maintain healthy blood levels of an active form of vitamin D -- has been established. The 2008 AIs for vitamin D for adults are the same in males and females, but increase with age. Although recent studies show the level of vitamin d we should be taking in could be as much as 4,000 IU per day.
- A deficiency of vitamin D can occur when dietary intake of vitamin D is inadequate, when there is limited exposure to sunlight, when the kidney cannot convert vitamin D to its active form, or when someone cannot adequately absorb vitamin D from the gastrointestinal tract.The classic vitamin D deficiency diseases are rickets and osteomalacia. In children, vitamin D deficiency causes rickets, which results in skeletal deformities. In adults, vitamin D deficiency can lead to osteomalacia, which results in muscular weakness in addition to weak bones.
- Current research has implicated vitamin D deficiency as a major factor in the pathology of at least 17 varieties of cancer as well as heart disease, stroke, hypertension, autoimmune diseases, diabetes, depression, chronic pain, osteoarthritis, osteoporosis, muscle weakness, muscle wasting, birth defects, periodontal disease, obesity, and more. Vitamin D's influence on key biological functions vital to one's health and well-being mandates that vitamin D no longer be ignored by the health care industry nor by individuals striving to achieve and maintain a greater state of health.
- The vitamin D receptor is expressed in virtually all cells of the body and can influence chronic systemic, metabolic conditions.
- Vitamin D is linked with colon, rectum, breast, ovarian, prostate, stomach, bladder, esophagus, kidney, lung, pancreas, and uterine cancers, as well as for non-Hodgkin lymphoma and multiple myeloma. Individuals with higher levels of serum 25(OH)D have lower incidence of cancers due to 1,25(OH)2D synthesis in the local organ epithelium. There is also an association of lower mortality rates from cancers for those residing at sunnier latitudes. Black individuals have much lower level of active vitamin D in the serum compared to Caucasians. This may explain the higher rates of colon, breast, prostate, and ovarian cancers in blacks.
- After a comprehensive and rigorous review of the scientific research, the IOM Committee that establishes RDA’s concluded that the evidence that vitamin D prevented cancer was inconsistent and did not meet criteria for establishing a cause-effect relationship. There is strong biological plausibility for a role of vitamin D in cancer prevention. Studies suggest that 1,25-(OH)2D promotes cell differentiation, inhibits cancer cell proliferation, and exhibits anti-inflammatory, pro-apoptotic, and antiangiogenic properties. 1,25-(OH)2D has been shown in laboratory studies to inhibit the growth of cancer cells by regulating several genes responsible for cell proliferation. In addition, 1,25-(OH)2D exhibits pro-apoptotic effects in cancer cells. Observational evidence is strongest for colorectal cancer but is weak or inconsistent for breast, prostate, other cancer sites, and total cancer.
- Role in cancer prevention and recovery The vitamin D hormone, calcitriol, has been found to induce death of cancer cells in vitro and in vivo. Although the anti-cancer activity of vitamin D is not fully understood, it is thought that these effects are mediated through vitamin D receptors expressed in cancer cells, and may be related to its immunomodulatory abilities. The anti-cancer activity of vitamin D observed in the laboratory has prompted some to propose that vitamin D supplementation might be beneficial in the treatment or prevention of some types of cancer.[12] A search of primary and review medical literature published between 1970 and 2007 found an increasing body of research supporting the hypothesis that the active form of vitamin D has significant, protective effects against the development of cancer. Epidemiological studies show an inverse association between sun exposure, serum levels of 25(OH)D, and intakes of vitamin D and risk of developing and/or surviving cancer. The protective effects of vitamin D result from its role as a nuclear transcription factor that regulates cell growth, differentiation, apoptosis and a wide range of cellular mechanisms central to the development of cancer.[58] In 2005, scientists released a metastudy which demonstrated a beneficial correlation between vitamin D intake and prevention of cancer. Drawing from a meta-analysis of 63 published reports, the authors showed that intake of an additional 1,000 international units (IU) (or 25 micrograms) of vitamin D daily reduced an individual's colon cancer risk by 50%, and breast and ovarian cancer risks by 30%.[59] Research has also shown a beneficial effect of high levels of calcitriol on patients with advanced prostate cancer.[60] A randomized intervention study involving 1,200 women, published in June 2007, reports that vitamin D supplementation (1,100 international units (IU)/day) resulted in a 60% reduction in cancer incidence, during a four-year clinical trial, rising to a 77% reduction for cancers diagnosed after the first year (and therefore excluding those cancers more likely to have originated prior to the vitamin D intervention).[61][62] In 2006, a study at Northwestern University found that taking the U.S. RDA of vitamin D (400 IU per day) cut the risk of pancreatic cancer by 43% in a sample of more than 120,000 people from two long-term health surveys.[63][64] A 2006 study using data on over 4 million cancer patients from 13 different countries showed a marked difference in cancer risk between countries classified as sunny and countries classified as less–sunny for a number of different cancers.[65] Research has also suggested that cancer patients who have surgery or treatment in the summer — and therefore make more endogenous vitamin D — have a better chance of surviving their cancer than those who undergo treatment in the winter when they are exposed to less sunlight.[66] However, a large scientific review undertaken by the National Cancer Institute found no link between baseline vitamin D status and overall cancer mortality. They did find that vitamin D was beneficial in preventing colorectal cancer, which showed an inverse relationship with blood levels "80 nmol/L or higher associated with a 72% risk reduction".[67]
- One third of Americans are obese. While much of that epidemic is surely due to playing Nintendo instead of baseball, or the consumption of soft drinks instead of water, does that explain it all? Is it a coincidence that the twin epidemics of obesity and vitamin D deficiency are occurring together? While the seasonal variation in weight is well known, the variations with latitude and altitude are less well known. Different explanations exist for all three associations but vitamin D provides a parsimonious explanation as vitamin D decreases with higher latitude, lower altitude and with the winter. When aboriginal populations migrate from high altitude to low altitude, without significantly changing their diet, body fat increases. As vitamin D production is less at lower altitude, a vitamin D theory of obesity would predict such a change. Studies show that populations whose religious customs dictate that the skin be covered, such as Arabs, do not show variations in weight based on altitude. Populations that do not cover the skin, such as central Asians, show variations in weight based on altitude. Saudi Arabians, who often cover their skin and make little vitamin D, show no associations between altitude and weight, while central Asians, who do not cover their skin, are leaner at higher altitudes where more vitamin D would be made in the skin Current scientific literature makes it likely that vitamin D reduces weight. Higher calcium intake is consistently associated with lower body weight, a topic recently reviewed by Heaney. As vitamin D significantly increases calcium absorption, it seems likely that higher intakes of vitamin D would decrease body weight, even if the vitamin itself had no direct effect on weight. Obese subjects obtain lower 25(OH)D levels when exposed to ultraviolet light or when they take supplemental vitamin D. They appear to deposit some their vitamin D in their excessive fatty tissue, thus impairing their ability to raise their 25(OH)D levels. The theory that vitamin D deficiency contributes to some cases of obesity, would mean that obesity is linked with other diseases associated with vitamin D deficiency, such as cancer, diabetes and heart disease. Obesity and vitamin D deficiency are comorbid with numerous diseases such as heart disease, hypertension, diabetes, osteoarthritis, osteoporosis, depression and even periodontal disease. This is consistent with the theory that vitamin D deficiency plays a role in obesity. If vitamin D deficiency is one of the treatable causes of obesity, then a study has shown that the more vitamin D in your diet, the less you weigh. Last year, a Norwegian group reported just that. The authors concluded, “placebo-controlled intervention studies with calcium and vitamin D, in which the primary end point is weight change, are warranted.” http://www.drcranton.com/nutrition/Vit_D_deficient-obesity.htm
- Plaque development involves chronic low-grade inflammatory process. Vitamin D possible reduces the inflammation in the blood vessels. Endothelial dysfuntion is an early step. Then LDL particles accumulate which attract circulating particles and form a plaque. The endothelia interact directly with vitamin D and can prevent negative changes. Low level of vitamin D (15 ng/mL or less) resulted in twice as many cases of cardiovascular incidents than those that had vitamin D levels 15 ng/mL or higher. The highest rate of cardiovascular disease was observed in those with hypertension and vitamin D deficiency
- Vitamin D is a potent endocrine suppressor of renin biosynthesis to regulate the renin–angiotensin system. Increased renin leads to hypertension. Sunlight and exposure to sunlight is limited in the winter, hence blood vitamin D levels decrease and all aspects of the system that are effected buy vitamin D are influenced by the decreasing levels in the winter.
- People with lower levels of vitamin D in their blood may be at greater risk of developing type 2 diabetes, according to research published in the journal Epidemiology Dr. Paul Knekt of the National Public Health Institute in Helsinki, Finland and colleagues found that men with the highest serum vitamin D levelswere the least likely to have developed type 2 diabetes 22 years later. Lack of vitamin D interferes with insulin secretion, and studies suggest a link between low vitamin D and diabetes most research has been cross-sectional, meaning it only focused on a single time point. Prospective studies, which follow people over time, are a better way to investigate potentially causal relationships. The researchers looked at men and women who were 40 to 74 years old and free of diabetes when they enrolled in a health examination survey. Investigators followed them for 22 years, during which time 412 developed type 2 diabetes. Knekt and colleagues compared baseline levels of blood vitamin D in the 412 cases and 986 control individuals who remained diabetes free. They found that men in the top fourth based on their blood levels of the vitamin were 72 percent less likely to have developed type 2 diabetes than men in the lowest quartile, after the researchers adjusted for body weight, physical activity and other factors. http://news.yahoo.com/s/nm/20080901/hl_nm/study_link_dc_1 No such relationship was seen for women. Certain lifestyle and diet factors could also be partially responsible for the vitamin D-diabetes risk link, the researchers note, concluding: "Further studies are needed before firm conclusions can be made about the role of vitamin D in diabetes prevention."
- Canadian researchers say the benefit of supplementation may come in creating stores of this vital vitamin in the bloodstream to carry people through the dreary months of winter, when a lack of sunlight may lead to or worsen mood disorders -- most notably seasonal affective disorder, the aptly acronymed SAD that affects some 11 million Americans. Patients with this so-called "winter depression" are advised to treat the condition with a special "light box" that mimics the effects of sunlight during winter months. Problem From Low Blood Levels? For this study, published in the July issue of Nutrition Journal, the researchers first identified 130 patients whose blood levels of vitamin D in the summer were considered normal -- about 24 ng/mL. However, some researchers believe that many Americans are vitamin D-deficient and that their blood level may be too low. "If a patient measures at 24 ng/mL or less in the summer, it will likely drop to 16 ng/mL in the winter because the value you have in the summer is greater than what you'll have in February," says lead researcher Reinhold Vieth, PhD, a vitamin D researcher at Mt. Sinai Hospital in Toronto. He then gave those patients a questionnaire to gauge their likelihood of depression. Those whose answers suggested a strong possibility of depression were then given supplements containing a daily dose of either 600 or 4,000 international units (IUs) of Vitamin D. They started taking the supplements in summer and continued through the winter. The patients were re-evaluated a year later. With both doses, patients suffering from depression improved as their vitamin D levels increased to at least 40 ng/mL, what some vitamin D researchers recommend as a normal blood level. To quote a line from the article "It appeared that instead of feeling worse in the winter, they actually felt better with the supplements."
- In type 1 diabetes, beta cells in the pancreas die and stop producing insulin. It is not known what causes this but is thought to be due to an immune system malfunction. Vitamin D acts as an immunosuppressive agent reducing inflammation and production of harmful chemicals by the cells. Supplementation by vitamin D reduced the risk for diabetes by about 80% in children (N=9124) if they received at least the recommended dose of vitamin D in infancy compared with those receiving less. It was thought that vitamin D might somehow inhibit the autoimmune reaction targeted towards the cells of the pancreas. Supplementation of mother’s diet during pregnancy has also been linked to reduced incidence of type 1 diabetes in children. Children who are deficient in vitamin D have a 200% increased risk in developing type 1 diabetes. In adults who were 40 y of age and with a body mass index of greater than 25, receiving 2000 IU or 50 micrograms of cholecalciferol, or vitamin D supplementation with or without calcium for 16 weeks improved the disposition index and insulin secretion (which was the product of insulin secretion and insulin sensitivity). These results suggested that vitamin D may have a role in delaying the progression to clinical diabetes in adults at high risk of type 2 diabetes.
- The incidence of multiple sclerosis (MS) is low in the tropics and increases with distance from the equator in both hemispheres. One hypothesis is that sunlight exposure and the resulting increase in vitamin D may exert a protective effect. Total vitamin D intake at baseline was inversely associated with risk of MS. In this large prospective study (92,253 women followed from 1980 to 2000), found that women who used supplemental vitamin D, largely from multivitamins, had a 40% lower risk of MS than women who did not use vitamin D supplements. Neurology 2004. Among people with early-stage multiple sclerosis (MS), those with higher blood levels of vitamin D had better outcomes during 5 years of follow-up. The team examined data from 465 people with early-stage MS. Identifying and correcting vitamin D insufficiency could aid in the early treatment of MS. The researchers found that higher serum 25(OH)D levels in the first 12 months predicted reduced MS activity and a slower rate of MS progression. By the end of the follow-up at 5 years, participants with serum 25(OH)D concentrations of at least 50 nmol/L (20-ng/mL, a moderate level) had significantly fewer new active lesions, a slower increase in brain lesion volume, lower loss of brain volume, and lower disability than those with serum 25(OH)D concentrations below 50 nmol/L. These results suggest that vitamin D has a protective effect on the disease process underlying MS.NIH Research Matters 2014.
- Solar ultraviolet radiation (UV-B-radiation) has both beneficial and harmful effects on human health. It is the most important environmental risk factor for the development of non-melanoma skin cancer, such as basal and squamous cell carcinomas. On the other hand, the human body's requirements of vitamin D are mainly achieved by UV-B-induced photosynthesis in the skin. The use of sunscreens for protection against the sun completely blocks photosynthesis of vitamin D and reduces circulating vitamin D metabolites.
- Exposure to sunlight Exposure to sunlight is an important source of vitamin D. Ultraviolet (UV) rays from sunlight trigger vitamin D synthesis in the skin. Season, latitude, time of day, cloud cover, smog, and sunscreens affect UV ray exposure. For example, in Boston the average amount of sunlight is insufficient to produce significant vitamin D synthesis in the skin from November through February. Sunscreens with a sun protection factor of 8 or greater will block UV rays that produce vitamin D, but it is still important to routinely use sunscreen whenever sun exposure is longer than 10 to 15 minutes. It is especially important for individuals with limited sun exposure to include good sources of vitamin D in their diet
- Very few foods in nature contain vitamin D. The flesh of fatty fish (such as salmon, tuna, and mackerel) and fish liver oils are among the best sources. Small amounts of vitamin D are found in beef liver, cheese, and egg yolks. Vitamin D in these foods is primarily in the form of vitamin D3and its metabolite 25(OH)D3. Some mushrooms provide vitamin D2 in variable amounts. Mushrooms with enhanced levels of vitamin D2 from being exposed to ultraviolet light under controlled conditions are also available. Fortified foods provide most of the vitamin D in the American diet. For example, almost all of the U.S. milk supply is voluntarily fortified with 100 IU/cup. (In Canada, milk is fortified by law with 35–40 IU/100 mL, as is margarine at ≥530 IU/100 g.) In the 1930s, a milk fortification program was implemented in the United States to combat rickets, then a major public health problem. Other dairy products made from milk, such as cheese and ice cream, are generally not fortified. Ready-to-eat breakfast cereals often contain added vitamin D, as do some brands of orange juice, yogurt, margarine and other food products. NIH.GOV
- Cholesterol from the diet undergoes conversion to 7 dehydrocholesterol. As it circulates through the bloodstream and is taken up by cells such as skin cells, it is converted to cholecalciferol by UV exposure. Once it is converted and it enters the bloodstream, it is converted to 25-hydroxyvitamin D by the liver. It then goes to the kidneys and is finally converted to 1,25 dihydroxyvitamin D (active form). It can also be converted to the active form by many other organs in the body.
- Intake reference values for vitamin D and other nutrients are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board (FNB) at the Institute of Medicine of The National Academies (formerly National Academy of Sciences). Recommended Dietary Allowance (RDA): average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%–98%) healthy people. Adequate Intake (AI): established when evidence is insufficient to develop an RDA and is set at a level assumed to ensure nutritional adequacy. Tolerable Upper Intake Level (UL): maximum daily intake unlikely to cause adverse health effects. The FNB established an RDA for vitamin D representing a daily intake that is sufficient to maintain bone health and normal calcium metabolism in healthy people. RDAs for vitamin D are listed in both International Units (IUs) and micrograms (mcg); the biological activity of 40 IU is equal to 1 mcg (Table). Even though sunlight may be a major source of vitamin D for some, the vitamin D RDAs are set on the basis of minimal sun exposure.
- Thanks to these studies and national headlines praising its apparent cancer-fighting properties it appears many people now consider vitamin d their wonder drug and are rushing to labs to have their levels tested. The patients requesting these tests through their physicains represent an increasingly health conscious-public. These patients want greater control over managing their own health, they have greater access to information related to health promotion and illness prevention, and there are a growing number of media stores that address their demand for news and information about personal health issues. Spikes are often seen when these three drivers come together – as in the case of vitamin d There is no count on how many people get their vitamin d checked. But at testing giant LabCorp, the volume of vitamin D tests doctors order has, on average, doubled every year for the past four. So far this year, test orders are up another 90%. At competitor Quest Diagnostics, the volume of D tests approximately tripled between may 2006 and last may. http://www.virginiahopkinstestkits.com/vitamindtest.html http://abcnews.go.com/video/playerIndex?id=5563319 Vitamin D video