The Vitamins Fat Soluble Vitamins Water Soluble Vitamins

Objectives Characteristics of Vitamins are micronutrients n q q Vitamins are essential. n q q n Very small amounts are needed by the body (>1 gm) Very small amounts are contained in foods. The roles they play in the body are very important. Most vitamins are obtained from the foods we eat. Some are made by bacteria in the intestine One is made in the skin There is no perfect food that contains all the vitamins in the right amount.

Objectives Characteristics of Vitamins are non-energy producing n q q n n They do not contain kcalories. 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 vs. Water Soluble Vitamins

Variety is the Key e r a s n i m a a t i m V o r f d e v deri of foods. y t e i r va

Fat Soluble Vitamins Vitamin A, D, E, K

Objectives After reading Chapter 6, completing a concept map and class discussion, you will be able to: n Identify fat soluble vitamins n Distinguish fat soluble vs water soluble n Identify food sources for Vitamins A, D, E, K n Identify toxicity levels for Vitamins A, D, E, K n Describe one major role for Vitamins A, D, E, K

Fat Soluble Vitamins: Characteristics Essential n Organic Structure n Non-energy Producing n Micronutrients n Stability n Bioavailability n Toxicity n

Vitamin Misconception n “More is Better”

Toxicity is rare but it is a possibility. n Toxicity is very rarely associated with food. n Toxicity results from overuse of supplements. n

Vitamin Concept Map Food Sources FUNCTIONS Vitamin Other Facts

Vitamin A Functions SOURCES

Vitamin A Other Facts

Vitamin A n Other names q Preformed Vitamin A – retinyl esters n n q Retinol, Retinal, Retinoic acid Sources: animal foods, fortified foods, pharmaceutical supplements Provitamin A - Precursors=carotenoids n n Beta-carotene and other carotenoids Sources: plant foods

Vitamin A n 2001 RDA q q q Men: 900 g RAE/day Women: 700 g RAE/day RAE=Retinol Activity Equivalents n n 1 microgram of retinol 12 micrograms of beta-carotene 24 micrograms of other precursor carotenoid Upper level for adults: 3000 g/day

Vitamin A n Chief functions in the body q q q Vision Maintenance of cornea, epithelial cells, mucous membranes, skin Bone and tooth growth Reproduction Immunity Antioxidant effect of beta-carotene

Vitamin A in Vision

Vitamin A n Function in protein synthesis and cell differentiation

Vitamin A Deficiency Night blindness n Xerosis (corneal drying) n Bitot’s spots n Karatomalacia n Xerophtalmia n Hyperkaratosis n Impaired immunity n

Vitamin A Deficiency n Keratinization q Vitamin A deficiency symptom

Vitamin A Toxicity n Toxicity from provitamin A impossible q q n Conversion of carotenoids to retinal highly regulated by the body Homeostatic mechanisms control tightly Toxicity from preformed A inevitable q q Efficient absorption and hepatic storage of A Storage continues until pathologic condition develops; liver stores ~80% of body reserves

Vitamin A Toxicity n Large % of population in developed nations have intakes of preformed vitamin A higher than the RDA q n 75% of people may be routinely ingesting more than RDA Some studies suggest that as little as twice the RDA intake may contribute to subclinical Vitamin A toxicity

Acute Toxicity Occurs when adults ingest >100 x RDA of preformed Vitamin A for a period of hours or several days. n Occurs when children ingest >20 x RDA of preformed Vitamin A for same period. n Less of a problem than chronic toxicity n

Acute Toxicity n Acute toxicity symptoms q q Blurred vision Nausea, vomiting, vertigo Increase of pressure inside skull, mimicking brain tumor Headaches

Chronic Toxicity n Occurs when adults ingest q q >25, 000 IU preformed Vitamin A for >6 years >100, 000 IU preformed A for >6 months Wide individual variabilty n Children particularly sensitive to daily intakes of 1500 IU/kg body weight. n Elderly at significantly greater risk n

Chronic Toxicity n Chronic toxicity symptoms q q q Increased activity of osteoclasts causing reduced bone density Liver abnormalities Birth defects

Vitamin A & Macular Degeneration n n Studies in the elderly suggest that the use of large doses of certain vitamins and minerals are beneficial in the prevention of macular degeneration Some evidence exists that improvement in existing damage may be seen

Vitamin A & Macular Degeneration Vitamin/ Mineral A Amount % DV 14, 320 IU 286 C 235 mg 371 E 200 IU 667 Zinc 348 mg 232 Copper 0. 8 mg 40

WARNING

Vitamin A & Macular Degeneration n Vitamin A directs the process of borrowing and redepositing calcium in the bone Too much preformed Vitamin A (retinol) can promote fractures. Use Vitamin A in form of beta-carotene, a precurser form which does not increase fractures

Vitamin A Sources n Beta-carotene q q Dark leafy green vegetables, spinach, broccoli Deep orange veggies n q Carrots, pumpkin, squash, sweet potato Deep orange fruits n Apricots, cantaloupe

Vitamin A Sources n Retinol q q Fortified milk, butter cheese, cream Fortified margarine Eggs Liver

Copyright 2005 Wadsworth Group, a division of Thomson Learning

Vitamin D Functions SOURCES

Vitamin D Other Facts

Vitamin D n Other names q q q Calciferol 1, 25 -dihyroxy vitamin D (calcitriol) Animal version: vitamin D 3 or cholecalciferol Plant version: vitamin D 2 or ergocalciferol Precursor is the body’s own cholesterol

Vitamin D n 1997 adequate intake (AI) q q q n 19 -50 years: 5 g/day 51 -70 years: 10 g/day more than 70 years: 15 g/day Upper level for adults: 50 g/day

Vitamin D n Chief functions in the body q Mineralization of bones n n n raises blood calcium and phosphorus by increasing absorption from digestive tract withdrawing calcium from bones stimulating retention by kidneys)

Vitamin D n Calcium and phosphorous absorption q q Without D only 10 -15% dietary calcium absorbed With D absorption increased to 30 -40% Without D about 60% phosphorous absorbed With D absorption increased to ~80%

Vitamin D n Recent research indicates Vitamin D has a role in the prevention of q q q Heart disease Type-1 Diabetes Multiple Sclerosis Rheumatoid Arthritis Crohn’s Disease Certain Cancers

Vitamin D n Nonskeletal functions of Vitamin D q q q Brain, prostate, breast, colon tissues and immune cells have Vitamin D receptors and respond to 1, 25 -dihydroxyvitamin D (the active form of D) 1, 25 -dihydroxyvitamin D controls more than 200 genes Potent immunomodulator

Vitamin D n Toxicity – Hypervitaminosis D q q n Elevated blood calcium Calcification of soft tissues (blood vessels, kidneys, heart, lungs, tissues around joints) Thought to be the most frequently occurring vitamin toxicity but………. .

Vitamin D n The Sunshine Vitamin q q q Approximately 90% of Vitamin D requirement obtained from sun UV light from sun hits skin, triggers synthesis Activated in liver and kidneys

Vitamin D Sources n Fortified q q Milk Margarine Butter Cereal Veal, Beef n Egg yolk n Fatty fish (salmon, sardines, herring) n

Vitamin E Functions SOURCES

Vitamin E Other Facts

Vitamin E Other name: alpha-tocopherol n 2000 RDA n q Adults: 15 mg/day Upper level for adults: 1000 mg/day n Easily destroyed by heat and oxygen n

Vitamin E n Chief function in the body q Antioxidant n n n stabilization of cell membranes, regulation of oxidation reactions, protection of polyunsaturated fatty acids and vitamin A

Vitamin E: Antioxidant

Vitamin E Sources n Polyunsaturated plant oils q q Margarine Salad dressing Leafy green vegetables n Wheat germ n Whole grains n Egg yolks n Nuts and seeds n

Vitamin K Functions SOURCES

Vitamin K Other Facts

Vitamin K n Other names q q n Phylloquinone Manaquinone Menadione Naphthoquinone 2001 AI q q Men: 120 g/day Women: 90 g/day

Vitamin K n Family of vitamins q Naturally found in primarily two forms n n K 1 and K 2 K 3 simpler form; synthetically created Identified by German scientists n Required for normal blood clotting n q n Named “K” for German word for “clot” No Tolerable Upper Limit

Vitamin K Bacteria in intestines produce ~75% of Vitamin K absorbed by body daily n Vitamin K not stored in body n Vitamin K needs to be supplied daily n Absorption dependent on healthy liver and gall bladder n

Vitamin K K 1 produced by plants we eat n K 2 produced by bacteria in intestine; converted from K 1 n K 2 more potent (15 x); more active; and wider range of activities n q q q Better absorbed; longer biological activity Predominant form found in body tissues Used preferentially by all tissues but liver

Vitamin K n Chief functions in the body q Synthesis of blood-clotting proteins and bone proteins that regulate blood calcium

Vitamin K: Other Functions Synthesis of bone proteins that regulate blood calcium; prevent bone loss n Integration of calcium into bones n Prevent calcium deposition in blood vessels (vascular calcification) n Maintain blood vessel elasticity n

Vitamin K and Medication n n Bisphosponates – osteoporosis drugs q K improves utilization of these drugs Wafarin - anticoagulants q As little as 1 mg/day can interfere with anticoagulant activity of drug

Vitamin K Sources Bacterial synthesis in GI tract n Leafy green vegetables n Cruciferous vegetables n Liver n Milk n

Vitamin K Sources n Vitamin K 1 produced by plants and algae q Broccoli, kale, chard; plant oils like canola and soybean n n Hydrogenated soybean oil has ineffective K Vitamin K 2 produced by bacteria in gut q Food Sources: fermented soybean (Natto); dairy products, egg yolk

Objectives Antioxidants

Objectives After reading Chapter 6, completing a concept map and class discussion, you will be able to: n Identify fat soluble vitamins n Distinguish fat soluble vs water soluble n Identify food sources for Vitamins A, D, E, K n Identify toxicity levels for Vitamins A, D, E, K n Describe one major role for Vitamins A, D, E, K

Objectives Fat Soluble Vitamins