Ken-Won MillerHoward UniversityNutrition Care Management 1Dr. Castor
Introduction This presentation will focus mainly on the role of calcium intake and the manifestations of calcium deficiencies.
Nutrients Nutrients are essential and all play a key role to survival of the human organism. Water Energy yielding nutrients Carbohydrates, Protein, Lipids (Fat) Vitamins (organic) Fat soluble, Water soluble Minerals (inorganic) Macro, Trace
What is Calcium Calcium is the most abundant mineral in the body This mineral is naturally found in foods, added to some, available as a dietary supplement, and present in some medicines Most of the body’s calcium is found in bones and teeth. Estimated to be 99% of calcium in the body Approx 1.5-2% of the body weight An adequate intake helps grow a healthy skeleton in early life and minimize bone loss later in life
Calcium in Bones Calcium salts form crystals called hydroxyapatite on a matrix of the protein collagen. Mineralization of calcium, phosphorus, and other minerals crystallize and harden the bones. The bones gain strength and rigidity as they harden.
Calcium in Bones Bones are not like solid rock Bones gain and lose minerals continuously in an ongoing process of remodeling. The balance between bone resorption and deposition changes with aging. The lack of homeostasis can lead to manifestations of clinical problems and cause a disease state.
Calcium in Body Fluids %1 of the body’s calcium circulates in the fluid as ionized calcium that is vital to life. The serum calcium is highly regulated and doesn’t fluctuate with variations in dietary intakes Calcium also activates a protein called calmodulin Calmodulin (a inactive protein) is activated by calcium It then becomes a messenger that tells other proteins what to do and serves as an interpreter for hormone and nerve mediated messages arriving at cells
Calcium in Body Fluids vascular contraction and vasodilatation muscle function nerve transmission intracellular signaling hormonal secretion Role in maintaining normal blood pressure
Recommended Dietary Allowance (RDA): RDAs for the amounts of calcium required for bone health and to maintain adequate rates of calcium retention in healthy people. Table 1: Recommended Dietary Allowances (RDAs) for Calcium  Age Male Female Pregnant Lactating 0–6 200 mg 200 mg months* 7–12 260 mg 260 mg months* 1–3 years 700 mg 700 mg 4–8 years 1,000 mg 1,000 mg 9–13 years 1,300 mg 1,300 mg 14–18 years 1,300 mg 1,300 mg 1,300 mg 1,300 mg 19–50 years 1,000 mg 1,000 mg 1,000 mg 1,000 mg 51–70 years 1,000 mg 1,200 mg 71+ years 1,200 mg 1,200 mg* Adequate Intake (AI)
Foods that Contain Calcium Calcium is found in a variety of foods. Dairy Foods Milk, yogurt, and cheese are the most popular choice in the US. Leafy Greens Kale, broccoli, and Chinese cabbage are vegetable source Fish Canned sardines and salmon Most grains (such as breads, pastas, and unfortified cereals), while not rich in calcium, add significant amounts of calcium to the diet because people eat them often in large amounts. Fortified foods Breakfast cereals, fruit juices, soy(Silk) and rice beverages, and tofu.
Medicines that Contain Calcium The two main forms of calcium in supplements are carbonate and citrate Calcium carbonate is found in some over-the-counter antacid products, such as Tums® and Rolaids®.
Calcium Balance Homeostasis of calcium is one of the body’s most important priorities. Bone tissue is used as a reservoir and a source of calcium, to maintain constant concentrations of calcium in muscles, blood, and intercellular fluids. Vitamin D and other hormones play a essential role as well in balancing levels Three organs play a key role in calcium levels 1. The intestines 2. Bones 3. Kidneys
Calcium Balance Parathormone (Parathyroid hormone) A hormone from the parathyroid glands that regulates blood calcium by raising it when levels fall too low Calcitonin A hormone from the thyroid gland that regulates blood calcium by lowering it when levels rise too high
Absorption of Calcium Calcium is absorbed by all parts of the small intestineTwo mechanisms of absorption Active transport and passive diffusionIt is best absorbed in an acidic mediumLactose and vitamin D enhances calcium absorptionThe efficiency of absorption decreases as calcium intake increases
Likelihood of Deficiency Dietary surveys indicate that many people do not meet the Adequate Intake for calcium, especially women Consuming foods to maintain adequate vitamin D status improve absorption Dietary inadequacy is not likely if protein and calcium intake are adequate Stimulants in coffee and tea can discreetly increase calcium excretion and reduce absorption in the GI tract Phytic acid found in whole-grain breads can decrease availability
Lab Values for Nutritional Assessment The normal levels for ionized (free) Ca2+ 4.64-5.28 mg/dL The normal levels for total serum Ca2+ (bound and unbound) 8.6-10 mg/dL Status is related to many factors, including vit D, vit K, phosphate, parathyroid function, and medications
Lab Values for Nutritional Assessment Hypercalcemia (High Calcium Levels) Associated with endocrine disorders, malignancy, and hypervitaminosis D Hypocalcemia (Low Calcium Levels) Associated with Vit D deficiency and inadequate hepatic or renal activation of Vit D, hypoparathyroidism, magnesium deficiency, renal failure, and nephrotic syndrome
Hypoparathyroidism Hypoparathyroidism is the result of a decrease in production of parathyroid hormones by the parathyroid glands located behind the thyroid glands in the neck. Usually occurs after a surgery where the parathyroid glands are removed. The result is a low level of calcium in the blood or hypocalcemia.
Assessment Tools Dual-Energy X-ray absorptiometry (DXA) is thought to be one of the best tools for assessing bone mineral density Very important in early detection, treatment, and monitoring of osteoporosis Preferred approach for measuring BMD Measures bone mineral content at axial and appendicular sites Monitors changes over time Low radiation exposure Superior quality control procedures Computerized tomography (CT) scans measure variances in tissue density. This method is less precise and accurate than DXA
Osteoporosis (Adult Bone Loss) Disease in which the bones become porous and fragile due to a loss of minerals Bone strength is a function of two factors Bone mineral density and bone quality BMD is determined by peak bone mass and BQ relates to bone architecture, bone turnover, mineralization, and the accumulation of damage to the bone Peak in bone mass= late 20’s early 30’s
Classification Primary-not related to other disease Mostly seen in middle aged females and older men/females Males have greater bone mass Secondary-identifiable cause other than age or menopause is present Cushing’s syndrome, myeloma, hyperthyroidism, amenorrhea, medicines( thiazide diuretics and heparin)
Osteoporosis • Leads to a greater risk of fractures• Fractures in the hip, vertebrae, pelvis, humerus, distal forearm• Females more likely to have fractures
Five Steps to Optimize Bone Health 1. Maintain a balance diet rich in calcium and vitamin D.2. Participate in regular, weight-bearing exercise.3. Practice a healthy lifestyle with no smoking or excessive alcohol intake4. Talk to health care professional about bone health5. If indicated, obtain bone mineral density testing and take medication, if appropriate
In conclusion Calcium is the most abundant mineral in the body and is mostly found in bones and teeth. %1 of the body’s calcium circulates in the fluid as ionized calcium that is vital to life and homeostasis Many people become deficient in calcium especially those suffering from illness and the elderly It is important for dietitians to thoroughly evaluate patients for calcium defiency and provide nutritional intervention if needed.
References Chung M, Balk EM, Brendel M, et al. Vitamin D and Calcium: A Systematic Review of Health Outcomes. Rockville (MD): Agency for Healthcare Research and Quality (US); 2009 Aug. (Evidence Reports/Technology Assessments, No. 183.) 1, Introduction. Available from: http://www.ncbi.nlm.nih.gov/books/NBK32605/ National Institutes of Health. Optimal calcium intake. NIH Consensus Statement: 1994;12:1-31. [PubMed abstract] 2 Overview of Calcium." Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC: The National Academies Press, 2011. Ross AC, Manson JE, Abrams SA, Aloia JF, Brannon PM, Clinton SK, Durazo-Arvizu RA, Gallagher JC, Gallo RL, Jones G, Kovacs CS, Mayne ST, Rosen CJ, Shapses SA. Clarification of DRIs for calcium and vitamin D across age groups. J Am Diet Assoc. 2011 Oct;111(10):1467. [PubMed abstract] U.S. Department of Agriculture, Agricultural Research Service. 2011. USDA National Nutrient Database for Standard Reference, Release 24. Nutrient Data Laboratory Home Page,http://www.ars.usda.gov/ba/bhnrc/ndl.