IFWA 1318-Nutrition Vitamins and Minerals
Characteristics of Vitamins • Very small amounts are needed by the body and very small amounts are in foods. • The roles they play in the body are very important. • Most vitamins are obtained through food. Some are made by bacteria in the intestine and one is made in the skin. • There is no perfect food that contains all the vitamins in the right amount. • Vitamins do not contain kcalories, but they are involved in extracting energy from the macronutrients. • Some vitamins in foods are precursors. • Vitamins are classified according to how soluble they are in fat or water.
Fat-Soluble Vitamins • Fat-soluble vitamins are generally found in foods containing fats and are stored in the body either in the liver or in adipose tissue until needed. • Excessive intake of A or D causes them to be stored and can be undesirable. Vitamin D, when taken in excess, is the most toxic of all the vitamins. • Fat-soluble vitamins are absorbed and transported around the body like other fats. • If anything interferes with fat absorption, these vitamins may not be absorbed.
Forms of Vitamin A • Retinoids-synthetic derivatives of Vitamin A, and are taken orally • Carotenoids-naturally occurring (orange-red pigment, carrots) • Beta-carotene-anti-oxidant and such can be useful for curbing the excess of damaging free radicals in the body β-carotene is an anti-oxidant and such can be useful for curbing the excess of damaging free radicals in the body Functions of Vitamin A • Essential for health of the cornea (clear membrane surrounding eye)- Essential for retina of eye – deficiency causes night blindness • Needed to make and maintain the epithelial cells that form the protective linings of your lungs, • GI tract, urinary tract, and other organs • Also essential to make and maintain epithelial cells that produce mucus (protects cells) • Role in reproduction, growth and development, bone growth and teeth developing in children • Proper functioning of immune system • Healthy skin
Beta Carotene • A precursor of vitamin A • assist vitamin A in extracting energy from nutrients) • Functions as an antioxidant in the body – a compound that combines with oxygen to prevent oxygen from oxidizing or destroying important substances • The most abundant carotenoid Rich sources: • Deep green vegetables – spinach • Deep orange fruits and veggies – carrots Retinol • Preformed vitamin A • Found in animal products such as: • Liver • Vitamin A-fortified milk • Eggs • Fortified cereals • Butter and margarine • Supplements
Measurement of Vitamin A • Measured in retinol activity equivalents (RAE) • One RAE = • 1 microgram retinol • 12 micrograms beta-carotene • 24 micrograms of other vitamin A precursors Vitamin A: Deficiency and Toxicity • Deficiency is of most concern in developing countries where it causes night blindness, blindness, poor growth, and other problems • Prolonged use of high doses of preformed vitamin A may cause hypervitaminosis A • Hair loss • Bone pain • Skin problems • Liver damage • Nausea/diarrhea
Vitamin D • When ultraviolet rays shine on your skin, a cholesterol-like substance is converted into a precursor of vitamin D and absorbed in the blood. • Over the next few days, the precursor is converted to vitamin D3 (cholecalciferol). • Vitamin D3 is converted into its active form – a hormone – by enzymes in the liver and then the kidney. Functions of Vitamin D • Maintains blood calcium levels by: • Increasing calcium absorption in the intestine • Decreasing the amount of calcium excreted by the kidney • Pulling calcium out of the bones • Blood calcium levels must be kept high so there is enough calcium to build bones and teeth, contract muscles, and transmit nerve impulses
Sources of Vitamin D • Vitamin D fortified milk and cereals • Fatty fish Vitamin D: Deficiency and Toxicity • Deficiency in children: rickets • Deficiency in adults: osteomalacia • Toxicity: Vitamin D is most toxic of all vitamins • About 4 to 5x the Adequate Intake: symptoms will include nausea, vomiting, diarrhea, fatigue, and confusion; can lead to calcium deposits in the heart, blood vessels, and kidneys.
Functions of Vitamin E • Antioxidant in the cell membrane and other parts of cell. • Protects vitamin A from oxidation. • Important for healthy immune system, and nervous tissues. Food Sources of Vitamin E • Widely distributed in plant foods: • Vegetable oils, margarine, and shortening • Salad dressing made from vegetable oils • Seeds and nuts • Whole-grain breads and cereals
Vitamin K • Essential role in producing blood-clotting factors, such as prothrombin. • Needed to make an important protein used to form bone. • Bacteria in the intestines produce a form of vitamin K. • Food sources: liver, green leafy vegetables, broccoli, vegetable oils
Water-Soluble Vitamins • Includes Vitamin C and B-complex vitamins. • B vitamins work in every cell as coenzymes. • Only small amounts of water-soluble vitamins are stored in body (except B6 and B12). • American adults take in too little vitamin C. • Excessive supplementation of certain water-soluble vitamins can cause toxic effects.
Functions of Vitamin C • Needed to make collagen, a fibrous protein that is part of skin, bone, teeth, ligaments, and other connective structures. (Vitamin C acts like Cement). • Needed to make some hormones, such as thyroxine, and some neurotransmitters. • Needed for immune system. • Antioxidant (like vitamin E and beta-carotene). • Helps iron to be absorbed. Food Sources of Vitamin C • Citrus fruits • Bell peppers • Kiwi fruit • Strawberries • Tomatoes • Broccoli • Potatoes • Fortified juices and cereals
Vitamin C: Deficiency and Toxicity • Deficiencies resulting in scurvy are rare. • Situations that require additional vitamin C: • Pregnancy, lactation, growth, fever, infections, burns, surgery, smoking. • UL is 2 grams (upper intake level): Over 2 grams causes gastrointestinal symptoms. High levels interfere with certain medical tests.
Thiamin, Riboflavin, and Niacin • All play key roles as part of coenzymes in energy metabolism: they are essential to release energy from carbohydrates, fats, and proteins. • All are needed for normal growth. • Thiamin also plays a role in nerve function. • Riboflavin is needed to help form vitamin B6 coenzyme and to make niacin in the body. Food Sources of Thiamin, Riboflavin, and Niacin • Thiamin – pork, sunflower seeds, wheat germ, peanuts, dry beans, whole-grain and enriched breads and cereals. • Riboflavin – Milk and milk products, organ meat, whole-grain and enriched breads and cereals. • Niacin – Meat, poultry, fish, organ meats, whole-grain and enriched breads and cereals, peanut butter.
Functions of Vitamin B6 • Important role as part of a coenzyme involved in carbohydrate, fat, and protein metabolism. • In its coenzyme form, B6 is particularly crucial to protein metabolism. • Used to make red blood cells. • Used to break down glycogen to glucose. • Used to convert tryptophan to niacin. • Used to make neurotransmitters. • Important to the immune system. Sources of Vitamin B6 • Meat, poultry, fish • Not as well absorbed from plant foods • Potatoes • Some fruits (bananas and watermelons) • Some leafy green vegetables (broccoli and spinach) • Fortified ready-to-eat cereals Vitamin B6: Deficiency and Toxicity • Deficiency: may occur in women and older adults • Deficiency symptoms: fatigue, depression, irritability • More than 2 grams daily for 2 months or more than 200 mg daily for longer can cause irreversible nerve damage and symptoms such as numbness in hands and feet and difficulty walking • B6 is stored in the muscles
Functions of Folate • Part of coenzymes required to make DNA, the genetic material contained in every cell. • Therefore needed to make all new cells, especially those that need to be replenished frequently: RBC, WBC, and digestive tract cells. • Needed to form neurotransmitters in the brain. • Needed for amino acid metabolism.
Sources • Green leafy vegetables (such as spinach) • Legumes • Orange juice • Fortified breads and ready-to-eat cereals • Much folate is lost during food prep and cooking Folate Deficiency • Deficiency causes megaloblastic anemia – RDC are large and immature. anemia is a rare disorder in which the body does not absorb enough vitamin B12 from the digestive tract, resulting in an inadequate amount of red blood cells (RBCs) produced. • Other deficiency symptoms: digestive tract problems such as diarrhea, mental confusion, and depression. • During earliest weeks of pregnancy, women need folate because a deficiency can cause neural tube defects. • Some medications interfere with the normal use of folate in the body.
Functions of Vitamin B12 • Convert folate into its active forms so that it can make DNA. • Also functions as part of a coenzyme needed to make new cells and DNA. • Helps in the normal functioning of the nervous system by maintaining the protective cover around nerve fibers. Sources of Vitamin B12 • Only animal foods. • Meat • Poultry • Fish and Shellfish • Eggs • Milk • Milk Products • Vegetarian concerns Vitamin B12 Deficiency • Deficiency is usually due to problem with absorption – lack of intrinsic factor or lack of hydrochloric acid – both are more so problems as you get older. • Pernicious anemia develops when B12 is not properly absorbed. Symptoms: • Extreme weakness and fatigue • Nervous system problems – balance, numbness, confusion
Functional Foods and Phytochemicals • Functional foods: Foods supplemented with ingredients thought to help prevent diseases or to improve health. • Margarine with an ingredient to lower cholesterol • Drinks with herbs such as ginseng Phytochemicals: Substances such as beta-carotene that are found largely in fruits and veggies and that seem to be helpful in preventing cancer and/or heart disease when consumed regularly
Chapter 7 Water and Minerals
Major minerals Calcium Chloride Magnesium Phosphorus Potassium Sodium Sulfur Trace Minerals Chromium Copper Fluoride Iodine Iron Manganese Molybdenum Selenium Zinc Minerals Bioavailability Toxicity Cooking
Functions of Water • Medium for many metabolic activities and also participates in some metabolic reactions. • Carries nutrients to the cells and carries away waste materials to the kidneys and out of the body in urine. • Needed in each step of the process of converting food into energy and tissue. • Maintains blood volume in your body. • Maintain normal body temperature. • Important part of body lubricants, such as cushioning joints and internal organs
How Much Water is Enough? • AI for total water: Men: 3.7 liters/day Women: 2.7 liters/day • Number of things, including thirst, work to keep body water content within limits. • You lose water thru urine, skin, lungs, GI tract.
Calcium and Phosphorus • Used for building bones and teeth. • Calcium – • Helps blood clot • Helps muscles contract • Helps nerves transmit impulses • May lower blood pressure • Phosphorus • Helps release energy from C, F, P • Part of DNA • Buffers acids and bases • Makes some enzymes active
Calcium: Deficiency and Toxicity • About 25-30% of calcium you eat is absorbed. • Deficiency Calcium deficiency is a major contributing factor in osteoporosis. • Toxicity: UL is 2,500 milligrams Amounts above UL can contribute to calcium deposits in kidneys and other organs
Phosphorus • Widely distributed in foods • Purpose-essential component of ATP (Adenosine triphosphate), universal energy source of all cells as well as DNA(Deoxyribonucleic acid) & ( RNA (Ribonucleic acid) and phospholipids Rarely lacking in diet • Excellent sources: milk and milk products, meat, poultry, fish, eggs, legumes • High phosphorus may cause calcium loss in the bones. The most distinct symptom is itching.Low phosphorus is rare in dialysis patients but common after transplant and may cause weakness.
Functions of Magnesium • Many enzyme systems responsible for energy metabolism and making protein, fat, and nucleic acids. • Build bones and maintain teeth. • Muscle relaxation, blood clotting, & nerve transmission. • Keep immune system working properly. • May help regulate blood pressure.
Magnesium is part of chlorophyll, the green pigment found in plants. Lettuce
Sources of Magnesium • Green leafy vegetables • Potatoes • Nuts (especially almonds and cashews) • Seeds • Legumes • Whole-grain cereals • Seafood Magnesium occurs in most foods in small amounts.
Magnesium: Deficiency & Toxicity • Deficiency is rarely seen, although dietary surveys suggest that many Americans don’t get enough. • Symptoms of deficiency: muscle twitching, cramps, weakness, depression, blood clots. • Very high doses can cause diarrhea and puts a stress on the kidneys (bad for elderly).
Electrolytes • Sodium, potassium, and chlorides are referred to as electrolytes because when dissolved in body fluids, they separate into + or – charged particles called ions • Sodium + found in fluid outside cells • Chloride – found in fluid outside cells • Potassium + found inside cells
Water balance Inside the cells Outside the cells In the blood vessels Acid-base balance (Each day there is always a production of acid by the body’s metabolic processes and to maintain balance, these acids need to be excreted or metabolized. The various acids produced by the body are classified as respiratory (or volatile) acids and as metabolic (or fixed) acids. The body normally can respond very effectively to perturbations in acid or base production.) Functions of Electrolytes
Sources of Sodium • Salt – sodium chloride • Processed foods: • Canned, cured, and/or smoked meats and fish such as bacon, ham • Many cheeses, esp. processed cheese • Canned veggies, etc. • Frozen convenience foods • Dried soup mixes • Foods in brine • Certain seasonings: salt, soy sauce, Worcestershire sauce, etc.
Functions of Potassium • Helps maintain water balance. • Helps maintain acid-base balance. • Assists in muscle contraction and normal heartbeat. • Assists in sending nerve impulses.
Sources of Potassium • Widely distributed in plant and animal foods (whole foods) • Fruits (oranges & bananas) • Vegetables (potatoes) • Milk and yogurt • Legumes • Meats
Potassium: Deficiency & Toxicity • Deficiency is of concern because we don’t eat many whole foods. • Can also result from dehydration, certain diseases, or drugs (diuretics). • Symptoms: muscle cramps, weakness, nausea, abnormal heart rhythms. • Toxicity: can be toxic if too many supplements taken.
Functions of Iron • Key component of hemoglobin – a part of red blood cells that carries oxygen to body’s cells • Key component of myoglobin – a muscle protein that stores and carries oxygen that the muscles use to contract • Works with many enzymes in energy metabolism • Used to make amino acids and certain hormones and neurotransmitters • Part of enzymes found in leukocytes (immune system)
Iron Absorption • About 15% of dietary iron is absorbed. • More iron is absorbed if: • Body stores are low. • Body needs to makes lots of RBCs • Heme iron (predominant form of iron in animal food) is absorbed and used twice as readily as iron in plant foods, nonheme iron.
Increase absorption of nonheme iron: Vitamin C Meat Poultry Fish Decrease absorption of nonheme iron Calcium Substances found in tea and coffee Oxalic acid (in spinach) Phytic acid (in grain fiber) Iron Absorption (cont’d.)
Iron: Deficiency & Toxicity • Iron deficiency – a condition in which iron stores are used up • Iron-deficiency anemia –a condition in which the size and number of RBC are reduced, symptoms include: • Fatigue, pallor, irritability • Decreased immune function • In kids – slow cognitive and social development • During pregnancy – increased risk of premature delivery, LBW babies • Iron overload or hemochromatosis-extra iron builds up in organs and damages them. Without treatment, the disease can cause these organs to fail.
Wound healing Bone formation DNA synthesis Protein, carbohydrate, and fat metabolism Development of sexual organs General tissue growth and maintenance Taste perception Vitamin A activity Protection of cell membranes from free-radical attacks Storage and release of insulin Zinc: Cofactor for Almost 100 Enzymes
Sources of Zinc • Protein foods: shellfish, meat, poultry • Legumes • Dairy foods • Whole grains • Fortified cereals • Absorbed better from animal sources. • Phytates decrease absorption.
Zinc: Deficiency & Toxicity • Deficiency: more likely in pregnant women, the young and elderly, and vegetarians • Symptoms in adults: poor appetite, diarrhea, skin rash, hair loss. • Symptoms in children: growth retardation, delayed sexual maturation, poor appetite, decreased taste, delayed wound healing. • Toxicity: long-term intake of zinc over UL results in copper deficiency. Avoid zinc supplements unless prescribed.
Iodine • Required for normal thyroid gland functioning. • Thyroid gland makes 2 hormones that • maintain a normal level of metabolism • are essential to normal growth and development • are essential to normal body temperature • are essential to protein synthesis Hypothyroidism is the disease state in humans and animals caused by insufficient production of thyroid hormone by the thyroid gland. Historically, iodine deficiency was the most common cause of hypothyroidism world-wide. The disease may also be caused by a lack of thyroid gland or a deficiency of hormones from either the hypothalamus or the pituitary.(summary slide later) Hyperthyroidism is a condition in which an overactive thyroid gland is producing an excessive amount of thyroid hormones that circulate in the blood. ("Hyper" means "over" in Greek). Thyrotoxicosis is a toxic condition that is caused by an excess of thyroid hormones from any cause. Thyrotoxicosis can be caused by an excessive intake of thyroid hormone or by overproduction of thyroid hormones by the thyroid gland.
Sources of Iodine • Saltwater fish • Grains grown in iodine-rich soil • Iodized salt
Iodine Deficiency • Hypothyroidism-inflammation of the thyroid gland which leaves a large percentage of the cells of the thyroid damaged (or dead) and incapable of producing sufficient hormone. • Simple goiter-is an increase in thyroid stimulating hormone (TSH) in response to a defect in normal hormone synthesis within the thyroid gland. • Cretinism – lack of thyroid secretion causes mental and physical retardation during fetal and later development
Dietary Supplements • Dietary supplements are not drugs or replacements for conventional diets. • Role of FDA. • Types of claims: • Nutrient claims • Health claims • Nutrition support claims, which include “structure-function claims”