Vitamins and Your Health Unit 20
Vitamin Facts Vitamins Two basic types: Chemical substances that perform specific functions in the body Essential nutrients Two basic types: Water soluble (B-complex, C) Fat soluble (D,E,K,A)
14 Known Vitamins
Deficiency and Excess Water soluble vitamins Only B12 can be stored in the body, all others become deficient in weeks to months if not consumed Niacin, B6, choline, and C cause ill effects if consumed in excessive amounts
Deficiency and Excess Fat soluble vitamins Stored in body fat, liver, other parts of the body Deficiencies take longer to develop Excess can build up in fat
Bogus Vitamins Some substances sold as vitamins are not vitamins
What Do Vitamins Do? Many vitamins are coenzymes Coenzymes Chemical substances that activate specific enzymes that increase the rate of chemical reactions in the body, such as breakdown of energy nutrients, or building body tissues
Recommended Intakes Dietary Reference Intakes (DRIs) To prevent deficiency and chronic disease Recommended Dietary Allowances (RDAs) When data exist for set standards Adequate Intakes (AIs) When data are insufficient for set standards
Thiamin
Thiamin
Riboflavin
Riboflavin
Niacin
Niacin
Vitamin B6
Vitamin B6
Folate
Folate
Vitamin B12
Vitamin B12
Biotin
Biotin
Pantothenic Acid
Pantothenic Acid
Vitamin C
Vitamin C
Choline
Choline
Vitamin A
Vitamin A
Beta-Carotene
Beta-Carotene
Vitamin E
Vitamin E
Vitamin D
Vitamin D
Vitamin K
Vitamin K
Avoiding Vitamin Deficiencies Folate: 400 mcg/day folic acid before and early during pregnancy reduces neural tube defects Reduces risk of dementia and certain cancers
Key Terms Dementia A usually progressive condition (such as Alzheimer’s disease) marked by development of memory impairment and inability to use or comprehend words or to plan and initiate complex behaviors
Avoiding Vitamin Deficiencies Adequate Vitamin A intake: Prevents some forms of blindness Reduces severity of measles and other infectious diseases Used to treat skin for acne, wrinkles, and liver (aging) spots
Avoiding Vitamin Deficiencies Vitamin D (“sunshine vitamin”) Facilitates calcium utilization Helps reduce chronic inflammation, which reduces risks of diabetes, cardiovascular disease, multiple sclerosis, certain cancers, and rheumatoid arthritis
Key Terms Chronic inflammation Inflammation Low-grade inflammation that lasts weeks or years Inflammation First response of the body’s immune system to infection or irritation Triggers release of substances that promote oxidation and other harmful reactions
Recommended Vitamin D Intake Recommended intake levels for vitamin D are expected to increase Currently, for adults: 200 IU/day 800 IU/day is associated with lowered risks Sources: Direct sunlight exposure Fortified foods, supplements
Fortified with Vitamin D
Vitamin D and Sunlight Exposing the whole body to direct sunlight for 10-15 min generates 20,000 IU vitamin D Highest in light-skinned people Body stops producing vitamin D when adequate amounts have been produced
Vitamin D and UV Light Vitamin D status is lower in areas where sunlight is indirect or weak (e.g. Russia)
Antioxidant Vitamins Antioxidants Chemical substances that prevent or repair damage to cells caused by exposure to free radicals Includes beta-carotene, vitamin E, vitamin C Found in fruits, vegetables, whole grains
Key Terms Free radicals Chemical substances (usually oxygen or hydrogen) that are missing an electron Absence of an electron makes the substance reactive and prone to oxidizing nearby atoms or molecules by stealing an electron from them Damages DNA, cell membranes, and other cell components
Key Terms Beta-carotene is a precursor of vitamin A Precursor (provitamin) In nutrition, a nutrient that can be converted into another nutrient
Getting Enough Vitamins Five or more servings a day of a variety of fruits and vegetables can provide adequate amounts of vitamins Fortified foods can increase vitamin intake substantially
Food Sources of Vitamins Thiamin
Food Sources of Vitamins Riboflavin
Food Sources of Vitamins Niacin
Food Sources of Vitamins Vitamin B6
Food Sources of Vitamins Folate
Food Sources of Vitamins Vitamin B12
Food Sources of Vitamins Vitamin C
Food Sources of Vitamins Choline
Food Sources of Vitamins Vitamin A
Food Sources of Vitamins Beta-carotene
Food Sources of Vitamins Vitamin E
Food Sources of Vitamins Vitamin E (cont’d)
Food Sources of Vitamins Vitamin D
Preserving Vitamin Content Vitamin content of foods is affected by food preparation and storage methods Heat sensitive vitamins (vitamin C, folate) Water soluble vitamins
Vitamins Lost