Minerals - NFSC100 - Elements of Nutrition PDF

Minerals NFSC100 – Elements of Nutrition Margaret Slavin, PhD, RDN Associate Professor Nutrition and Food Science University of Maryland, College Park  Agenda Water Fluid and Electrolyte Balance Major Minerals...

Minerals NFSC100 – Elements of Nutrition Margaret Slavin, PhD, RDN Associate Professor Nutrition and Food Science University of Maryland, College Park  Agenda Water Fluid and Electrolyte Balance Major Minerals Minor Minerals WATER Figure 9-2: Water—Main Constituent of the Body \Digital Vision/Getty Images 4  Water – Bodily functions Carries nutrients and waste products Maintains the structure of large molecules Participates in metabolic reactions Solvent for minerals, vitamins, amino acids, glucose and others Lubricant and cushion around joints, inside the eyes, the spinal cord, and in amniotic fluid during pregnancy Regulation of body temperature Maintains blood volume  Water Balance Intoxication Dehydration Water balance = the balance between water intake and water excretion. – Keeps the body’s water content constant Wardlaw Cont Nutr 11e BODY FLUIDS & MINERALS  Water Movement Water flows freely across cell membranes. – The body can’t directly control water’s movement. Water follows salt. Therefore, if the body controls salt movement, it can control water movement!  Fluids & Electrolytes Salt – compound with positive and negative ion. – Table salt = sodium chloride (NaCl) When salt dissolves in water, it separates into ions. – Positively charged particle = cation – Negatively charged particle = anion – Carry electrical current “electrolytes”  Fluids & Electrolytes Cell membranes are selectively permeable – allow passage of some molecules. – Some electrolytes remain mostly outside cell (sodium, chloride) – Some remain mostly inside cell (potassium, magnesium, phosphate) Ion concentration controls how much water is inside vs. outside of cells Electrolyte Balance Sizer et al. (15 E) Fig. 8-7 Figure 9-12: Effects of Various Ion Concentrations on Human Cells Access the text alternative for slide images. 12 MINERALS  Minerals Overview Minerals are: Categorized by amount Individual chemical needed in diet each day: elements: Can’t be broken – Major: Need 100 mg or more down further. per day Not energy-yielding – Trace: Need less than 100 mg per day Essential when: – Dietary inadequacy causes – Ultratrace: Trace amounts in diet, not essential to human physiological or structural abnormality. health. – And addition to diet reinstates health. 14 Figure 9-13: Amounts of Minerals in Human Body 15  Absorption and Storage of Minerals in the Body Bioavailability Example: Zinc deficiencies in Middle affected by: Eastern populations are attributed partly to Age consumption of unleavened breads, such as matzo, resulting in low bioavailability of Gender dietary zinc. (Yeast enzymes in leavened break breakthe bond between Zinc and Genetic variables phytochemicals.) Nutritional status Diet Prescription drugs Fiber content of diet Robyn Mackenzie/Shutterstock 16  Minerals: Absorption Majority of minerals are absorbed in the small intestine. Fibers phytic acid and oxalic acid decrease some mineral absorption. Higher fiber diets can lower absorption of iron and zinc. Vitamin C intake increases iron absorption. Vitamin D intake increases calcium absorption. Excess of one mineral can decrease absorption of another: Higher zinc intake lowers copper absorption. 17  Minerals: Storage Minerals are stored in various tissues Some remain in the bloodstream. Calcium, phosphorus, magnesium, and fluoride stored in bone. Iron, copper, zinc and some trace minerals stored in liver. Others stored in muscle tissue, organs, glands. 18  Mineral Toxicities Supplements pose the biggest risk for toxicity. General recommendation: avoid intakes above 100% of Daily Values on supplement labels. Harmful interactions with other nutrients can occur. 19 MAJOR MINERALS Calcium Phosphorus Magnesium Sodium Potassium Chloride Sulfur  Calcium Functions: – Bone and teeth Main structural component Reservoir of calcium supply for the blood – In the blood/fluids Disease prevention: May protect against hypertension, high blood cholesterol, diabetes, and colon cancer. Blood clotting Muscle contraction (inc. heartbeat) Nerve function  Calcium In the body: – 99% in body found in bones – 1% in fluids and cells Amount of calcium in the blood is regulated by a complex hormone system: – Bone stores calcium when blood calcium is high. build new bone; kidneys excrete more calcium; limits intestine absorption – Bone releases calcium when blood calcium is low. Breakdown bone; decrease kidney excretion; vitamin D enhances intestine absorption  Bone Loss Adult bone loss / Osteoporosis: when calcium storage in bones is not adequate – Into adult years: reduction in bone mass, resulting in weak bones (and often fractures) Sizer et al. (15E) Fig. 8-10  Calcium Sources: – Milk and milk products Powdered fat free milk added to mixed dishes to help get extra calcium. 5 tbsp = 1 cup milk – Other foods: tofu, corn tortillas, some nuts/seeds, broccoli, sardines with bones – Calcium-fortified soy milk, almond milk, rice milk  Calcium Absorption: – Body absorbs more when needed Pregnant women absorb 50% Children/teens absorb 50-60% Adults absorb 25% Enhance: Inhibit: – Stomach acid – Lack of stomach acid – Vitamin D – Vitamin D deficiency – Growth stage – High phosphorus intake – Deficiency – Anti-nutritional factors  Phosphorus 2nd most abundant mineral Function: – Bone and teeth 85% found combined with calcium for structure. – Everyplace else: Buffer system DNA/RNA Assists with energy metabolism Phospholipids critical to cell membranes  Phosphorus Sources: (easily satisfy our needs) – Food rich in protein best sources. – Milk and cheese contribute ¼ of phosphorus in diet – Dark sodas – Liver  Magnesium Over ½ found in bones Rest in muscles, heart, liver and soft tissues 1% in the blood Functions: – Bone and teeth health – Energy metabolism – Assists > 300 enzymes – Muscle contraction (with calcium), inc. heartbeat – Blood pressure  Magnesium Deficiency – Average U.S. intakes are low but overt symptoms rare. – Low intake (even without symptoms) is associated with increased risk for hypertension, CVD, Type 2 Diabetes, low bone mineral density, and possibly migraine. Toxicity – From nonfood sources: supplements or magnesium salt laxatives – Symptoms: Diarrhea, dehydration (usually self-limiting) Disrupts pH balance (increases) – Toxic to liver  Magnesium Sources: – Hard water (magnesium and calcium) People who live in areas with hard water tend to have low rates of heart disease – Legumes, seeds, nuts, green leafy veggies, dairy *It IS possible to drink too much water, especially if you drink large volumes at once. If there’s NO color in your urine, you might be drinking too much water.  Sodium AKA table salt (sodium chloride) Functions: Appealing taste, enhances flavors, suppresses bitter flavors. Principal cation of extracellular fluid. Primary regulator of blood volume & fluid balance. Acid-base balance Nerve impulse transmission Muscle contraction  What is CDRR? A new DRI category! The CDRR is for Chronic Disease Risk Reduction CDRR intake level is under 2,300 mg. (There is no UL for sodium due to limited evidence of toxicity.) A link to the report outlining the new findings: https://nap.nationalacademies.org/catalog/25353/dietary- reference-intakes-for-sodium-and-potassium  Sodium Recommended Intake: – AI adults: 1,500 mg – CDRR: 2,300 mg – Recommendation: