Chapter 7 Vitamins 2012 Pearson Education Inc Objectives for Chapter 7 Describe the characteristics of vitamins Explain the differences between fat soluble and water soluble vitamins and classify each vitamin according to its solubility Define the term antioxidant and explain which vitamins perform this function List at least one good food source for each of vitamins A D E and K List at least one major role in the body for vitamins A D E and K Name at least one toxicity symptom for a fat soluble vitamin List at least one good food source for each of the water soluble vitamins Name at least one disease associated with a water soluble vitamin deficiency Explain the role of vitamin supplements in the diet Nutrition and You 2e 2012 Pearson Education Inc What Are Vitamins Vitamins are essential nutrients Tasteless organic compounds needed in small amounts A deficiency will cause physiological symptoms Consuming too much of some vitamins will cause adverse effects Nutrition and You 2e 2012 Pearson Education Inc What Are Vitamins Vitamins are either fat soluble or water soluble Fat soluble vitamins A D E and K are absorbed with dietary fat and can be stored in body Water soluble vitamins are absorbed with water and enter the bloodstream directly Not stored in body but excesses still harmful Nutrition and You 2e 2012 Pearson Education Inc Vitamins Found Widely in MyPlate Figure 7 1 Nutrition and You 2e 2012 Pearson Education Inc Categorizing the Vitamins Fat Soluble and Water Soluble Figure 7 2 Nutrition and You 2e 2012 Pearson Education Inc Digesting and Absorbing Vitamins Figure 7 3 Nutrition and You 2e 2012 Pearson Education Inc Table 7 1 Nutrition and You 2e 2012 Pearson Education Inc What Are Vitamins Some vitamins function as antioxidants substances that neutralize free radicals Vitamins A C and E and beta carotene are antioxidants Free radicals are unstable oxygen containing molecules that can damage the cells of the body and possibly contribute to the increased risk of chronic diseases Nutrition and You 2e 2012 Pearson Education Inc Free Radicals Figure 7 4 Nutrition and You 2e 2012 Pearson Education Inc Normal and Impaired Vision Figure 7 5 Nutrition and You 2e 2012 Pearson Education Inc What Are Vitamins Vitamins differ in bioavailability which is the degree to which a nutrient is absorbed from foods and used in the body Vitamins can be destroyed by air water or heat Don t expose your produce to air A little water is enough Reduce cooking time Keep your food cool Overconsumption of some vitamins can be toxic Provitamins can be converted to vitamins by the body Nutrition and You 2e 2012 Pearson Education Inc Table 7 2 Nutrition and You 2e 2012 Pearson Education Inc Vitamin A Vitamin A retinoids retinol retinal retinoic acid Preformed vitamin A only found in animal foods liver eggs fortified milk cheese Some plants contain provitamin A carotenoids which are converted to retinol in your body Carotenoids including beta carotene are pigments which give color to carrots cantaloupe sweet potatoes spinach broccoli Like fat soluble vitamins absorbed more efficiently if fat present in intestinal tract Nutrition and You 2e 2012 Pearson Education Inc Vitamin A Functions Essential for healthy eyes Component of rhodopsin and iodopsin lightsensitive proteins needed for vision Involved in cell differentiation reproduction and immunity by promoting gene expression for Healthy skin mucus membranes Bone growth Fetal development White blood cells to fight harmful bacteria Nutrition and You 2e 2012 Pearson Education Inc Animation Vitamin A and Epithelial Tissue Nutrition and You 2e 2012 Pearson Education Inc Vitamin A is Essential for Vision Misc 7 1 Nutrition and You 2e 2012 Pearson Education Inc Animation Vitamin A and the Visual Cycle Nutrition and You 2e 2012 Pearson Education Inc Vitamin A Daily needs Adult males 900 micrograms g retinol activity equivalents RAE Adult females 700 g RAE Nutrition and You 2e 2012 Pearson Education Inc Vitamin A Sources and Physical Needs Food source vitamin A Nutrition and You 2e 2012 Pearson Education Inc Vitamin A Too much or too little Excessive amounts of preformed vitamin A can accumulate to toxic levels Upper limit for adults 3 000 g Carotenoids in food are not toxic Excess carotenoids cause nonthreatening condition carotenodermia Chronic vitamin A deficiency causes night blindness Prolonged vitamin A deficiency leads to xerophthalmia Number one cause of preventable blindness in children mostly in developing countries As many as 500 000 children go blind each year due to vitamin A deficiency Vitamin A deficiency also associated with stunting of bones Nutrition and You 2e 2012 Pearson Education Inc Vitamin E Alpha tocopherol is most active form in body Functions Acts as a powerful antioxidant Protects cell membranes prevents oxidation of LDL cholesterol Acts as an anticoagulant inhibiting formation of harmful clots inside bloodstream Daily needs Adults need 15 mg of alphatocopherol equivalents Nutrition and You 2e 2012 Pearson Education Inc Vitamin E Food sources vegetable oils nuts seeds fortified cereals some green leafy vegetables Too much or too little No known risk of consuming too much vitamin E from natural food sources Over consumption of synthetic form in dietary supplements and fortified foods can increase risk of a hemorrhage upper limit is 1 000 mg day Although rare chronic deficiency of vitamin E can cause nerve problems muscle weakness and free radical damage to cell membranes Nutrition and You 2e 2012 Pearson Education Inc Vitamin E Sources and Physical Needs Food source vitamin E Nutrition and You 2e 2012 Pearson Education Inc Vitamin K Two forms of vitamin K Menaquinone synthesized by intestinal bacteria Phylloquinone found in green plants Functions Essential for blood clotting Involved in synthesizing four blood clotting factors Important to bone health Enables bone protein osteocalcin to bind with calcium Nutrition and You 2e 2012 Pearson Education Inc Vitamin K Daily needs based on current consumption since amount contributed by intestinal synthesis is unknown Men need 120 g day Women need 90 g day Food sources green vegetables such as broccoli asparagus spinach salad greens brussels sprouts cabbage also vegetable oils and margarine Nutrition and You 2e 2012 Pearson Education Inc Vitamin K Sources and Physical Needs Food source vitamin K Nutrition and You 2e 2012 Pearson Education Inc Vitamin K Too much or too little No known problems