Chapter 13 The Micronutrients: Vitamins and Minerals Images shutterstock.com
Objectives Differentiate between fat-soluble vitamins and water-soluble vitamins. List functions and sources of major minerals and trace minerals. Explain the impact food processing and preservation methods have on the nutritive value of food. continued
Objectives Identify non-nutritive functions of vitamins and minerals used as food additives. Describe how to reduce vitamin and mineral losses during home food storage and preparation.
Vitamins Vitamins are organic compounds needed in small amounts in the diet to help regulate body processes Enzyme reactions are slowed or stopped and body processes impaired if vitamins are missing Scientists gave vitamins names, letters, or numbers to identify them continued
Vitamins Fat-soluble vitamins have a nonpolar molecular structure and dissolve in fats and oils include vitamins A, D, E and K Water-soluble vitamins are polar and dissolve in water and waterbased liquids include the B vitamins and vitamin C
Fat-Soluble Vitamins Bile from the liver is needed for digestion A surplus is stored in the liver and in fatty tissue for future use They cannot be easily excreted once absorbed Megadoses can build up to poisonous levels
Vitamin A Fat-soluble vitamin A aids in night vision maintains healthy skin and internal lining of lungs and digestive tract ensures proper immune system function ensures production and regulation of hormones breaks down bone for reshaping during growth continued
Vitamin A Vitamin A is found in 2 basic forms in food Retinol is the active form of vitamin A and is found in liver, eggs, butter, milk, and cheese A precursor for retinol, found in orange and dark green fruits and vegetables, is called beta-carotene (β-carotene)
Vitamin D Fat-soluble vitamin D can be made by the body with the help of the vitamin D precursors cholecalciferol and ergocalciferol teams with other nutrients to regulate calcium levels and form bones and teeth is available in butter, cream, egg yolks, and fatty fish and by exposing the skin to sunlight
Vitamin E Fat-soluble vitamin E is an important antioxidant that quickly reacts with oxygen, preventing damage to body tissues found in vegetable oils, whole grains, avocados, nuts, and seeds not heat stable so foods that are fried have little vitamin E remaining
Vitamin K Fat-soluble vitamin K is necessary for production of proteins involved in blood clotting produced by bacteria in the intestines found in liver and dark leafy greens Elena Elisseeva/Shutterstock.com
Water-Soluble Vitamins These vitamins cannot be stored in the body since they dissolve in water Excess quantities are excreted in urine, making it impossible to receive toxic doses of water-soluble vitamins Jag_cz/Shutterstock.com
B-Complex Vitamins Water-soluble B-complex vitamins act as coenzymes in reactions throughout the body are found in leafy greens, legumes, pork, whole grains, eggs, fish, and milk The B-complex vitamins specialize Vitamin B 1 helps nerve and muscle function Vitamin B 2 promotes healthy skin and eyesight continued
B-Complex Vitamins The B-complex vitamins specialize Vitamin B 3 keeps the skin and nervous system healthy and promotes normal digestion Pantothenic acid promotes growth and helps synthesize vital substances Biotin helps the body make fats and glycogen Vitamin B 6 promotes healthy immune systems and helps make hemoglobin Folate helps cells divide to form new cells
Vitamin C Water-soluble vitamin C is called ascorbic acid helps produce connective tissue helps protect against infections helps the body absorb iron and calcium serves as an antioxidant is found in citrus fruits, cantaloupe, tomatoes, strawberries, broccoli
Nonvitamins Several substances not classified as vitamins are recognized as needed to maintain good health Choline is found in meats, eggs, and peanuts Coenzyme Q 10 is involved in enzyme reactions found in meat, fish, poultry, and nuts
Minerals Minerals have the simplest structure of all nutrients because they are elements They are grouped into 2 categories Major minerals are needed in amounts of 100 mg or more per day Trace minerals are needed in amounts of less than 100 mg per day
Major Minerals Calcium is part of bones and teeth regulates movement of ions across cell membranes is important in sending messages along nerve fibers and for muscle contraction helps maintain blood pressure is found in milk, yogurt, cottage cheese, broccoli, collards, kale, and mustard greens continued
Major Minerals Phosphorus is found in bone tissue works as a salt buffer in the body s acid-base balance is part of the cell s genetic material forms part of cell membranes and regulates enzymes is found in meats and soft drinks continued
Major Minerals Sodium helps maintain fluid balance in cells helps regulate body temperature through sweating is found in processed foods, salt, soy sauce should be consumed in limited amounts by people who are salt-sensitive due to a link between high blood pressure and a high sodium intake continued
Major Minerals Potassium helps maintain fluid balance helps regulate body temperature plays a critical role in maintaining the heartbeat is found in meats, milk, fruits, vegetables, and grains continued
Major Minerals Chloride helps maintain the body s fluid balance is used in the stomach s hydrocholoric acid can be found in salt and soy sauce Sulfur is found in protein-rich foods helps maintain normal acid-base balance helps the liver change toxins to harmless substances continued
Major Minerals Magnesium assists hundreds of enzymatic reactions is essential for bone health is needed for energy to be released for muscle contractions helps nerves send messages is found in legumes, whole grains, and dark green vegetables
Trace Minerals Iron is needed for the production of red blood cells moves oxygen from blood throughout the body is inhibited by tea, coffee, soy protein, wheat bran, and fiber from being absorbed is aided by Vitamin C in being absorbed is found in milk, legumes, dark leafy greens, dried fruit, whole grains, breads, and cereals continued
Trace Minerals Iodine is needed for the production of thyroxine, a hormone regulating the body s use of energy found in iodized salt and seafood Roca/Shutterstock.com continued
Trace Minerals Zinc is needed for the functioning of enzymes promotes wound healing and proper immune function is found in meat, fish, poultry, legumes, whole grains, and nuts Fluoride helps strengthen bones and teeth and is found in drinking water
Other Trace Minerals Copper aids in the production of red blood cells and the use of iron Manganese is involved in metabolism of macronutrients Chromium is necessary for proper insulin action Selenium works with vitamin E to protect body tissue continued
Other Trace Minerals Molybdenum is part of several enzymes is found in legumes, grains, and nuts Other trace minerals found in even smaller quantities in the body are arsenic, boron, nickel, silicon, and vanadium
Effects of Processing and Preservation Removing components of natural food changes nutritive value Exposure to heat, oxygen, or moisture during processing affects a food s nutrient content Interactions between components can reduce or limit the ability to absorb some nutrients continued
Effects of Processing and Preservation Enrichment is the process of restoring some nutrients removed from refined grain products during processing Laws were passed to prevent deficiencies 1930s Niacin, thiamin, riboflavin, and iron were first added to processed flour 1996 Folic acid was first added to grain and cereal products continued
Effects of Processing and Preservation Fortification is adding nutrients to food to correct a nutritional deficiency A fortificant is the nutrient that is being added to the food The food vehicle is the specific food to which a fortificant is added Examples include iodine in salt, vitamin D in milk, calcium in orange juice, vitamin A in rice continued
Effects of Processing and Preservation Food scientists examine the bioavailability of the proposed fortificant The most highly soluble form may be added because of the body s ability to absorb it A fortificant may not be added to a food that contains nutrients that hinder the body s ability to absorb it
Factors Affecting Nutrient Stability Heat Vitamins A, B 1, C, and E are not heat stable Oxygen Vitamins C, E, and β-carotene are damaged by oxygen Water activity level (A W ) affects the stability of vitamins A and C
Vitamins and Minerals as Food Additives Non-nutritive functions of vitamins and minerals include vitamin C as an enzyme inhibitor calcium as a stabilizer in tofu and canned vegetables salt (sodium and chloride) as preservative and flavor enhancer in processed foods iodine as a dough conditioner
Preserving Vitamins and Minerals at Home How food is prepared determines how much damage is done to its nutritional value To reduce nutrient losses rinse fresh foods rather than soaking them keep foods in large pieces to reduce the size of surface area exposed to light, air, and water continued
Preserving Vitamins and Minerals at Home To reduce nutrient losses cut up fruits and vegetables just before cooking or serving choose stainless steel, glass, and aluminum cookware for foods that are easily oxidized avoid adding acids or alkalis to vegetables choose steaming over boiling and use the cooking water in soups, gravies, or sauces
Recap Vitamins are organic compounds that help regulate body processes Fat-soluble vitamins dissolve in fats and oils Water-soluble vitamins dissolve in water and water-based liquids Minerals can be categorized as major minerals trace minerals continued
Recap Both vitamins and minerals serve various functions in body processes Nutrients can be added to foods by enrichment or fortification Factors that affect nutrient stability are heat oxygen water activity level continued
Recap When care is taken to preserve a food s vitamin content, its mineral content and other nutrients are likely to be preserved