Antioxidant Nutrients NTR 108 Objectives Define the free radicals and explain how they can damage cells Discuss the functions and food sources of the antioxidant nutrients Antioxidant Nutrients Topics Oxidation Antioxidants Vitamin C Vitamin E Vitamin A Beta carotene Selenium Oxidation Oxidation a chemical reaction such as the metabolism reactions in which atoms lose electrons Some amount of oxidation occurs normally as a part of living in an oxygen environment and also as part of energy metabolism but too much is problematic Free radicals atoms with unpaired electron than can form as a result of oxidation or through gaining a single electron Endogenous produced In response to something in the body Energy metabolism aerobic Detoxification of drugs results in free radicals Immune system during the process of defense free radical are produced Exogenous result of external cause Exposure to air pollution Ultraviolet rays from sun Tobacco smoke Industrial chemicals Highly reactive Free radicals can result in a change in the structure of a molecule DNA protein cellular membrane LDL promote inflammation of blood vessels cell death Antioxidants Antioxidants Protect cells from damage caused by oxidation React with free radicals to make them less Certain nutrients and phytochemicals act as harmful antioxidants Two ways to defend Vitamins and phytochemicals directly stabilize free radicals Vitamin C vitamin E carotenoids Minerals work as cofactors for enzymes that convert free radicals to less damaging compounds Examples Selenium copper zinc Ascorbic Acid Vitamin C Definition classification Water soluble vitamin Functions Immune function Protects WBC from oxidative damage Skin and blood vessel health Collagen formation Collagen is a key component of skin and many other tissues Increases iron absorption Antioxidant Protects the lungs from inhaled pollutants Protects LDL cholesterol Regenerates Vitamin E Ascorbic Acid Vitamin C Deficiency signs symptoms Scurvy classic Fragile blood vessels Decreased appetite Decreased growth Anemia Increased rate of infections Groups at risk Smokers RDA is 35 mg d higher Physical stress healing from burns surgery etc Alcoholics Ascorbic Acid Vitamin C Potato low concentration but people in the US eat a lot Good dietary sources Citrus fruit Tomato Strawberries Special notes Easily destroyed by air and heat Slicing and leaving in open to the air Large doses Upper level 2000mg Stomach inflammation diarrhea May be increased risk for kidney stones Fruit salad made the night before will lose most of the Vitamin C by the next day Vitamin E Definition classification Lipid soluble vitamin Many different forms Functions Antioxidant for lipids in the body like cell membranes Deficiency signs symptoms Anemia Fragile red blood cells May cause neuromuscular issues Groups at risk Preterm infants no fat stores People eating very little fat People with fat malabsorption People who smoke or live in a smoggy area maybe Vitamin E Dietary sources Plant oils Nuts and seeds Whole grains Fortified cereals Special notes Supplements Toxicity increased risk of heart failure and prostate cancer May interact negatively with certain medications Vitamin A and Carotene Definition classification Lipid soluble Vitamin A Carotenoids Considered a phytochemical Many different types Many have antioxidant functions Yellow orange color in plants sweet potatoes pumpkin carotene Can be made into vitamin A by the human body Most of the vitamin A in the human is from carotene Vitamin A and Carotene Used during prenatal development to control what cells become Too much can cause problems Functions Vitamin A Vision Cell differentiation Bone health Immune function Antioxidant unclear Carotenoids Conversion to Vitamin A some Antioxidant Especially for lipids in cell membranes and LDL Deficiency signs symptoms Vit A Night blindness Xerophthalmia blindness Impaired immunity Hyperkeratosis skin condition Vitamin A and Carotene Vitamin A and Carotene Infants and children in developing countries still a major preventable problem Groups at risk People eating very little fat People with fat malabsorption Cystic fibrosis AIDS Dietary sources Vitamin A Fortified milk and milk products major source in US Eggs Liver Carotenoids Dark green vegetables Dark orange fruit Apricots Tomatoes Deep orange vegetables squash sweet potatoes Special notes Used as an acne medicine Retin A was the first Toxicity can cause birth defects Need to be careful with acne medications Prevention of Vitamin A Deficiency in 3rd World Countries Current solutions Vitamin A supplementation fortification of food supply and increase variety in diet foods rich in vitamin A Golden Rice Rice genetically modified to synthesize beta carotene Pros many believe if it replaced white rice as staple could alleviate Vitamin A deficiency Concerns 3rd world countries also suffer from protein fat and zinc deficiencies and when these exist the body cant use vitamin A efficiently Selenium Definition classification Trace mineral Functions Cofactor for an antioxidant enzyme Prevents oxidative damage to cell membranes Deficiency signs symptoms Form of Heart Disease Keshan disease Higher rates of some forms of cancer Groups at risk low one in China is well known Dietary sources Pork fish organ meats Plants vary based on soil levels Special notes Toxicity can result from supplement use not just foods People who only eat food from areas where the soil levels of selenium are Phytochemicals Chemical substances naturally found in plants phyto Health promoting effect when consumed Give color flavor odor protection to plants Function Carotenoids Garlic odor Tea Tannins Some have antioxidant properties Phytochemicals Not essential no deficiencies May have health functions antioxidants Obtained via diet Foods with high levels Apples citrus fruits and berries Cruciferous vegetables broccoli garlic Tomatoes and whole grains Tea herbs and spices Chocolate Many sources unidentified Antioxidants and Chronic Disease Antioxidants play a role in prevention or management treatment of disease Heart disease oxidative damage to LDL and cholesterol Age related Cataracts Cognitive function Arthritis Diabetes Cancer oxidative damage to DNA and proteins You should now be able to Define the free radicals and explain how they can damage cells Discuss the functions and food sources of the antioxidant nutrients