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Key Vitamins and Minerals Osteoporosis, Hypertension And Water Vitamins… are essential, non-caloric nutrients needed in tiny amounts from the diet that help drive cell processes. Two types: fat soluble and water soluble. Fat soluble vitamins are A, D, E, and K. Water soluble vitamins are the B vitamins and vitamin C. Fat soluble vitamins A, D, E. & K…. Are found in the fats and oils of foods. Are stored in the liver and in the fatty tissues of the body for long periods. Deficiency of these vitamins is rare though can occur with a fat-free diet over long periods. Toxicity is a greater risk if these vitamins are taken as supplements daily. Vitamin A And Beta-Carotene Copyright 2005 Wadsworth Group, a division of Thomson Learning Vitamin A Chief functions in the body Vision Maintenance of cornea, epithelial cells, mucous membranes, skin Bone and tooth growth Reproduction Immunity Vitamin A And Beta-Carotene Vitamin A in vision Copyright 2005 Wadsworth Group, a division of Thomson Learning Food Sources of Vitamin A Preformed, active vitamin A found in animal sources: liver, and fish oil (richest sources), fortified milk and milk products. Pre-cursor, Beta carotene found in yellow coloured vegetables and fruit, e.g, yellow squash, sweet potato, cantaloupe, apricots, mango. Dark green vegetables, e.g., spinach provides some beta carotene as well Vitamin A deficiency Not common in western world but very common in developing countries. causes blindness, keratinization (hardening and thickening of skin), stunted growth, impaired immunity, poor appetite and death. Diseases such as measles much more severe with vitamin A deficiency. Toxicity of vitamin A Not common unless large amounts of liver eaten. More common from supplements providing several times the recommended level. Occurs because vitamin A is stored in the liver and adipose tissue and accumulates. Toxicity from beta-carotene does not occur because conversion to retinol is inefficient. Toxicity of vitamin A continued Body can produce 1 unit of retinol from about 6 of beta-carotene. Excess beta-carotene turns people yellow, but is reversible. Symptoms of toxicity from vitamin A include: abdominal pain, hair loss, joint pain, stunted growth, bone and muscle soreness, cessation of menstruation, nausea, diarrhea, rashes, enlargement of spleen and damage to liver. Vitamin D 1,25-dihydroxycholecalciferol Precursor is the body’s own cholesterol raises blood calcium by acting on the skeleton, kidneys and the digestive tract to release calcium functions as a hormone Role of vitamin D continued It has a role in the brain, pancreas, skin, reproductive organs and some cancer cells but these roles are not fully understood. It also stimulates cell maturation including immune cells. Vitamin D Significant sources Synthesized in the body with the help of sunlight Fortified milk, margarine, butter, cereals, and chocolate mixes Veal, beef, egg yolks, liver, fatty fish (herring, salmon, sardines) and their oils How is vitamin D made from sunlight? Ultraviolet light shines on a cholesterol compound in human skin, the compound is transformed into a vitamin D precursor and is absorbed directly into the blood. Over 1 1/2 days, the kidneys and liver finish converting the precursor to active vitamin D. Kidney or liver disease may affect this process. Exposure to UV light Light-skinned people require 10-15 minutes exposure to UV light to make vitamin D. Dark-skinned people require up to 3 hours exposure depending on the climate. Clouds, smog, heavy clothing, window glass affect exposure. Elderly, institutionalized, night-shift workers may develop deficiency, therefore A.I. values higher with age. Vitamin D Deficiency symptoms: rickets in children Inadequate calcification, resulting in misshapen bones (bowing of legs) Enlargement of ends of long bones (knees, wrists) Deformities of ribs (bowed, with beads or knobs) Vitamin D Deficiency symptoms: rickets in children (continued) Delayed closing of fontanel, resulting in rapid enlargement of head Copyright 2005 Wadsworth Group, a division of Thomson Learning Vitamin D Deficiency symptoms: rickets in children (continued) Lax muscles resulting in protrusion of abdomen Muscle spasms Deficiency symptoms: osteomalacia in adults Loss of calcium, resulting in soft, flexible, brittle, and deformed bones Vitamin D Toxicity symptoms Most toxic of all the vitamins Elevated blood calcium Calcification of soft tissues (blood vessels, kidneys, heart, lungs, tissues around joints) Frequent urination Vitamin E Other name: alpha-tocopherol Chief function in the body Antioxidant (stabilization of cell membranes, regulation of oxidation reactions, protection of polyunsaturated fatty acids and vitamin A) Vitamin E Copyright 2005 Wadsworth Group, a division of Thomson Learning Vitamin E Significant sources Polyunsaturated plant oils (margarine, salad dressings, shortenings) Leafy green vegetables, wheat germ, whole grains, liver, egg yolks, nuts, seeds Copyright 2005 Wadsworth Group, a division of Thomson Learning Vitamin E Easily destroyed by heat and oxygen Deficiency symptoms Red blood cell breakage Nerve damage Toxicity symptoms Augments the effects of anticlotting medication Vitamin K Chief functions in the body Synthesis of blood-clotting proteins and bone proteins that regulate blood calcium Copyright 2005 Wadsworth Group, a division of Thomson Learning Vitamin K Sources: Bacterial synthesis in the digestive tract Liver Leafy green vegetables, cabbage-type vegetables Milk Copyright 2005 Wadsworth Group, a division of Thomson Learning Vitamin K Deficiency symptoms Hemorrhaging Toxicity symptoms None known Water Soluble vitamins B vitamins and Vitamin C are water-soluble. Cooking and washing leaches them from foods. The body absorbs them easily and easily excretes them in the urine. Some water soluble vitamins can be stored in the lean tissue for about 1 month. Toxic levels are not reached through foods but can be reached through intake of supplements. B vitamins act as co-enzymes & are involved in energy metabolism A Coenzyme is a small molecule that combines with an enzyme to make it active. B vitamins: thiamin, riboflavin, niacin, pantothenic acid and biotin participate in the release of energy from carbohydrate, protein and fat. Vitamin B6 helps the body use amino acids to make protein. Folate and B12 help cells to multiply. Folate Required to make all new cells. Helps to synthesize the DNA needed for the new cells. Deficiencies result from inadequate intake and illness that impairs absorption, increases excretion or increases the need for more folate. Folate deficiency occurs in significant numbers in Canada and USA. Folate Absorption Activation Vitamin B12 Folate Neural tube defects Spina bifida Copyright 2005 Wadsworth Group, a division of Thomson Learning Folate Heart disease Homocysteine Cancer Folate Sources Fortified grains Leafy green vegetables,legumes, seeds, orange juice, liver Copyright 2005 Wadsworth Group, a division of Thomson Learning Folate: Deficiency symptoms Anemia (large-cell type) Smooth, red tongue Mental confusion, weakness, fatigue, irritability, headache Toxicity symptoms Masks vitamin B12-deficiency symptoms Vitamin B12 - cyanocolbalamin Helps folate make red blood cells. Maintains the sheaths that surround and protect nerve fibres and may also influence cells that build bone tissue. Reforms folate coenzyme Helps to break down some fatty acids and amino acids Vitamin B12 Absorption HCl Pepsin Intrinsic factor required for activation Vitamin B12 Deficiency of folate or B12 produces pernicious anemia Copyright 2005 Wadsworth Group, a division of Thomson Learning Vitamin B12: Significant sources Animal products (meat, fish, poultry, shellfish, milk, cheese, eggs) Fortified cereals Easily destroyed by microwave cooking Vitamin B12: In Summary Deficiency symptoms Anemia (large-cell type) Fatigue, degeneration of peripheral nerves progressing to paralysis Toxicity symptoms: none reported Vitamin C Chief functions in the body Collagen synthesis Strengthens blood vessel walls, forms scar tissue, provides matrix for bone growth Antioxidant Thyroxin synthesis Amino acid metabolism Strengthens resistance to infection Helps in absorption of iron Vitamin C Significant sources Citrus fruits Cabbage-type vegetables, dark green vegetables (such as bell peppers and broccoli) Cantaloupe, strawberries Lettuce, tomatoes, potatoes Papayas, mangoes Easily destroyed by heat and oxygen Vitamin C Deficiency disease: scurvy Deficiency symptoms Anemia (small-cell type) Atherosclerotic plaques Pinpoint hemorrhages, bone fragility, joint pain Poor wound healing, frequent infections, bleeding gums, loosened teeth Muscle degeneration and pain, hysteria, depression, rough skin, blotchy bruises Vitamin C Toxicity symptoms Nausea, abdominal cramps, diarrhea Headache, fatigue, insomnia Hot flashes, rashes Interference with medical tests, aggravation of gout symptoms, urinary tract problems, kidney stones Calcium Most abundant mineral in the body. 99% of body’s calcium is in the bones and teeth Integral part of bone structure: serves as a calcium bank that can be released if calcium levels drop in the blood. Calcium in body fluids regulates transport of ions across cell membranes and is particularly important in nerve transmission. Calcium continued Helps maintain normal blood pressure Essential for muscle contraction and therefore heartbeat Allows secretion of hormones, digestive enzymes and neurotransmitters Plays important role in clotting of blood. May play role in maintaining healthy body weight. Calcium balance is tightly controlled Blood calcium is regulated by hormones sensitive to blood calcium and not by dietary intake. Inadequate intake of calcium in early life results in poor bone mass and can lead to osteoporosis. Calcium recommendations Adolescents: 1300 mg/day Adults 19 -50, 1000 mg/day Adults over 51, 1200 mg/day UL: 2500 mg/day Food sources: milk and dairy products best source, small bones of fish like salmon and sardines, dark green vegetables like broccoli, kale, and spinach; legumes Calcium in Other Foods Some brands of tofu, corn tortillas, almonds, sesame seeds. Mustard and turnip greens, bok choy, kale, parsley, watercress. Calcium fortified orange juice. Calcium Absorption Many factors affect Ca absorption. Factors that enhance Ca absorption: • Stomach acid • Vitamin D • Lactose • Growth hormones. Calcium Absorption Factors that inhibit Ca absorption: • Lack of stomach acid. • Vitamin D deficiency. • High phosphorus intake. • High- fiber intake. • Phytates (seeds, nuts, grains) • Oxalates (beet greens, rhubarb, spinach) Osteoporosis Osteoporosis is thinning of bone mass in older persons leading to porous, fragile bones that break easily. Peak bone mass is achieved by about age 20 for females and 30 for males. After age 40, bone loss occurs regardless of calcium intake though can be slowed by high calcium intake. Women lose bone faster with loss of estrogen at menopause. Healthy vs. Osteoporotic Trabecular Bones Copyright 2005 Wadsworth Group, a division of Thomson Learning Osteoporosis And Calcium Copyright 2005 Wadsworth Group, a division of Thomson Learning Preventing Osteoporosis Calcium Physical activity and body weight Smoking and alcohol Drug therapies Copyright 2005 Wadsworth Group, a division of Thomson Learning Calcium: Copyright 2005 Wadsworth Group, a division of Thomson Learning Supplements Multivitamin-mineral pills contain little or no Calcium. Typically sold as compounds of Ca carbonate, citrate, gluconate, lactate, malate, or phosphate. Some are made from bone meal, oyster shell, or limestone (dolomite). Many “natural” products contain lead. Sodium The principle cation in the extracellular fluids of the body. Helps to maintain acid-base balance Is essential to muscle contraction and nerve transmission 40% of body’s sodium thought to be stored on surface of bone crystals where body can easily draw it into blood. Sodium continued Deficiency would be harmful but few diets lack sodium. Kidneys can conserve if necessary. Excess excreted through urine. Generally amount excreted represents intake for the day. Sodium/water ratio delicately balanced by kidneys. Too much sodium, thirst mechanism kicks in, more water dilutes sodium, excesses of both excreted. Sodium continued Deficiency can occur in overzealous treatment with low-sodium diets for hypertension, kidney disease or heart disease. Vomiting, diarrhea, and excessive sweating can also deplete sodium. No DRI recommendations set because no human diet lacks sodium. Nutrition Recommendations in Canada suggest reducing sodium intake. Generally for good health maximum intake should be about 2500mg sodium chloride (salt)/day. Sodium is 40% of sodium chloride. Sodium and hypertension Controversy still exists. In salt-sensitive people, high sodium intakes raise blood pressure. Not the case with non salt-sensitive people. Overweight people also appear to be particularly sensitive to the effect of salt on blood pressure. Sodium Copyright 2005 Wadsworth Group, a division of Thomson Learning Sodium: In Summary Deficiency symptoms Toxicity symptoms Muscle cramps, mental apathy, loss of appetite Edema, acute hypertension Significant source Table salt, soy sauce Moderate amounts in meats, milks, breads, and vegetables Large amounts in processed foods Copyright 2005 Wadsworth Group, a division of Thomson Learning Potassium Principal cation within the body’s cell. Chief functions in the body Maintains normal fluid and electrolyte balance Facilitates many reactions Supports cell integrity Assists in nerve impulse transmission and muscle contractions Copyright 2005 Wadsworth Group, a division of Thomson Learning Potassium: In Summary Deficiency symptoms Muscular weakness Paralysis Confusion Toxicity symptoms Muscular weakness Vomiting If given into a vein, can stop the heart Copyright 2005 Wadsworth Group, a division of Thomson Learning Potassium: In Summary Significant sources All whole foods Meats, milks, fruits, vegetables, grains, legumes Copyright 2005 Wadsworth Group, a division of Thomson Learning Magnesium Chief functions in the body Bone mineralization. Building of protein. Enzyme action. Normal muscle contraction. Nerve impulse transmission. Maintenance of teeth. Immune system Magnesium Deficiency symptoms Weakness Confusion If extreme, convulsions, bizarre muscle movements (especially of eye and face muscles), hallucinations, and difficulty in swallowing In children, growth failure Copyright 2005 Wadsworth Group, a division of Thomson Learning Magnesium Significant sources Nuts, legumes Whole grains Dark green vegetables Seafood Chocolate, cocoa Copyright 2005 Wadsworth Group, a division of Thomson Learning Magnesium toxicity UL – 350mg/day from supplements/medications only (does not include food and water sources) Toxicity occurs in older people abusing magnesium based laxatives, antacids and other medications. Symptoms severe: diarrhea, acid-base imbalance, kidney impairment, confusion. poor coordination, coma, death. Iron Present in every living cell. It is an essential nutrient. Principal component of two proteins – hemoglobin in red blood cells and myoglobin in muscle cells. Hemoglobin in blood carries oxygen from the lungs to tissues throughout the body and myoglobin stores oxygen for muscles. Iron allows oxygen to be held and released from these proteins. Iron continued The liver makes iron sent from the bone marrow, into new red blood cells an releases them into the blood. Red blood cells live for about 3 months. When they die, the spleen and liver breaks them down, salvages the iron and sends it to the bone marrow for reuse. Small losses of iron occurs from skin, nails and hair clippings. Major losses occur through bleeding. Iron recommendations Food sources: red meat, poultry, seafood provide heme iron, best absorbed type. Dark green leafy vegetables, legumes, provide non-heme iron, less well absorbed. Iron deficiency – depleted stores May arise from inadequate intake, malnutrition, blood loss, parasitic infestation in digestive tract which results in blood loss. Severe depleted stores results in anemia. Anemia results in inability to make enough hemoglobin to fill its new red blood cells. Results in apathy, tiredness, reduced capacity to work, sensitivity to cold. Iron overload - Hemochromatosis Iron is toxic in large quantities – difficult for body to excrete. Hereditary defect which affect more men than women, causes the intestine to over-absorb iron. Tissue damage occurs especially in the liver, infections can increase because bacteria thrive in iron-rich blood. Condition worse in alcohol abusers because alcohol damages intestine impairing its defense against absorbing too much iron Bioavailability of iron Meat, poultry and fish contain an MPF factor which enhances absorption of heme iron and can triple absorption of non-heme iron from foods in the same meal. Vitamin C greatly enhances iron absorption Phytates and tannins diminish iron absorption Iron Supplements Less well absorbed than from food. Ferrous sulfate is better than other iron supplements. Absorption improves when taken between meals or a bedtime on an empty stomach or with liquids other than milk, tea or coffee which inhibit absorption. No benefit to taking supplements with vitamin C. Vitamin C does not enhance absorption from supplements as it does from foods. Zinc Required as a Co-factor by more than 100 enzymes. All cells contain Zn, but the highest concentrations are in muscle and bone. Interacts with platelets in blood clotting. Essential to normal taste perception, wound healing and making of sperm and fetal development. Help metabolize protein, fat and CHO. Participates in synthesis, storage and release of hormone insulin in the pancreas. Zinc Need to produce the active form of vitamin A (retinal). Stabilizes cell membranes, helping to strengthen their defense against free-radical attacks. Assists in immune function and in growth and development. Affects thyroid hromone function. Influences behavior and learning performance. Zinc Significant sources Proteincontaining foods Red meats, shellfish Whole grains Copyright 2005 Wadsworth Group, a division of Thomson Learning Zinc Absorption Absorption varies from 15-40% depending on a person’s Zn status. Dietary factors influence Zn absorption. Fibre and phytates bind Zn which limits its bioavailability. Once absorbed into an intestinal cell, it may become involved in the metabolic functions of the cell itself or may be retained within the cell by metallothionein (a special binding protein similar to the Fe storage protein, mucosal ferritin) Zinc Deficiency symptoms Growth retardation, delayed sexual maturation, impaired immune function, hair loss, eye and skin lesions, loss of appetite Copyright 2005 Wadsworth Group, a division of Thomson Learning Zinc deficiency Impairs immune function and increases susceptibility to infections. Stunts growth, alters digestion and absorption causing diarrhea and increases malnutrition. Zn deficiency directly impairs vitamin A metabolism so vitamin A deficiency symptoms often appear. . Impairs the immune response, making infections likely – infections of the GI tract. Disturbs thyroid function and the metabolic rate. Alters taste, causes loss of appetite and slows wound healing. Zinc toxicity Toxic in large quantities can cause serious illness and death. High doses of zinc block copper and iron absorption. Zinc from food never a problem but from supplements and medications e.g., throat lozenges. Zinc: food sources Food sources: shellfish, poultry are best sources, legumes and enriched cereals. Water Water is the most essential nutrient in the body. We can live for several days without food, but not without water. Carries nutrients throughout the body. Cleanses the blood of wastes. Serves as a solvent for minerals, vitamins, amino acids, glucose and other small molecules. Water continued Actively participates in many chemical reactions. Acts as a lubricant around joints. Serves as a shock absorber inside the eyes, spinal cord, joints, and amniotic sac surrounding a fetus in the womb. Aids in maintaining the body’s temperature. The body’s water balance Water makes up about 60% of the body’s weight. The body must excrete a pint (500 mls) of water a day to cleanse its fluids, therefore a person must drink at least that much a day to avoid life threatening losses and maintain water balance. The total amount of fluid is kept constant by delicate balancing mechanisms. Water balance continued Water balance maintains blood volume, which in turn influences blood pressure. If the body loses too much water, blood volume and blood pressure fall. When this occurs, the hypothalamus signals the pituitary gland to release the antidiuretic hormone (ADH). ADH stimulates the kidneys to reabsorb water rather than excrete it. Water balance continued Cells in the kidney respond to low blood pressure by releasing an enzyme called renin. Renin causes the kidneys to reabsorb sodium. Sodium reabsorption is always accompanied by water retention which helps restore blood volume and blood pressure. Water balance continued Renin also activates the blood protein angiotensinogen to angiotensin. Angiotensin is a powerful vasocontrictor. It narrows the diameter of the blood vessels thereby increasing blood pressure. Angiotensin also helps with the release of the hormone aldosterone which causes the kidney to retain more sodium and therefore more water. The net effect is that when more water is needed less is excreted. Thirst mechanism Thirst and satiety govern water intake. When the blood is too concentrated, water is attracted by molecules in the blood out of the salivary glands. The mouth becomes dry and you drink. The hypothalamus and the kidneys also regulate water by monitoring blood concentrations as described on the previous slide. Quenching thirst Thirst lags behind a lack of water. Thirst is the first sign of dehydration indicating that the body has lost up to 2 cups (500 mls) of its total fluid. Children and the elderly have delayed thirst mechanisms. A loss of just 5% of body fluid initiates symptoms of headache, fatigue, confusion or forgetfulness, and elevated heart rate. Severe dehydration (heat stroke) As dehydration increases, sweating stops. Water is redirected into the blood vessels to maintain blood pressure. Sweating is the cooling mechanism of the body. Without sweat, the body overheats. This can lead to rapid shallow breathing, weak irregular pulse, thickening of the blood, shock, seizures, coma and death. How much water do we need? Water needs depend on the foods eaten (because foods contain water), the environmental temperature and humidity, and a person’s activity level. Adults need between 1 and 11/2 mls of water from al sources for every calorie spent in the day. E.g, for 2000 calories, need about 2 to 3 L (8 to 12 cups of water per day. Sweating increases fluid needs. Food sources of water Nearly all foods contain water. (see table page 268 in text) Fruits and vegetables contain large amounts of water – up to 95% of their volume. Beverages like regular soft drink, juice and milk contain 80-89% water. Meats & cheeses up to 50%. Beverages containing caffeine and alcohol have a negative (diuretic) effect on water balance.