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Antioxidants: Vitamin C, Vitamin E, Selenium, and Carotenoids

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Presentation on theme: "Antioxidants: Vitamin C, Vitamin E, Selenium, and Carotenoids"— Presentation transcript:

1 Antioxidants: Vitamin C, Vitamin E, Selenium, and Carotenoids
Jennifer Hillan, MSH, RD, LD/N Family, Youth, and Community Sciences University of Florida/IFAS Carotenoids are group of compounds including beta-carotene, alpha-carotene, lycopene, lutein These nutrients have other functions than as antioxidants, but we will focus on antioxidant activity.

2 Free Radicals Oxygen and nitrogen molecules with unpaired electrons
highly reactive, unstable attack and damage cells Free radical damage may lead to development of variety of diseases (including cancer, heart disease) and even the aging process itself. Rock, 1998 *takes electrons from other molecules leaves that molecule unstable and starts a chemical chain rxn that produces even more free radicals. Therefore creates the potential for serious damage to cells. *research implicates free radicals in many diseases including cancer, heart disease, and even the aging process itself

3 Sources of Free Radicals
Normal activities occurring in the body’s cells, such as energy production Environmental sources UV sunlight Alcohol Ozone Cigarette smoke Smog and other pollutants

4 Functions of Antioxidants
Attack free radicals in various ways, such as: Removing free radicals from bloodstream Donating electrons to stabilize free radicals Repair damage caused by free radicals Different antioxidants work in different ways and in different places in the body, so it’s important to eat a variety of foods to get a variety of antioxidants! In other words, vitamin E in almonds may not act the same way as the vitamin C in broccoli

5 Definitions Recommended Dietary Allowances (RDA): amount of nutrient that will meet the needs of 97-98% of a population group Tolerable Upper Intake Level (UL): maximum amount of a nutrient that does not pose a health risk to individuals Intakes above UL increase risk of harmful effects. No established benefit for healthy people to get higher amounts than the RDA.

6 Vitamin C Stabilizes free radicals by donating electrons RDA:
women: 75 mg/day men: 90 mg/day smokers: additional 35 mg/day UL: 2,000 mg/day Food and Nutrition Board, 2000 RDA increased from 60mg/day for adults RDA higher for smokers b/c smoking causes more free radicals also breaks down vit C amts above RDA may cause diarrhea

7 Vitamin C Sources Citrus fruits Dark green vegetables Guava Papaya
Cantaloupe Strawberries Peppers Tomatoes Mangoes Potatoes don’t need supplements; can get amt from food. Ie: 100 mg in 8 oz OJ suppl are needless expense, also miss out on other protective factors that are in food (ie: phytochemicals, fiber)

8 Vitamin E Converts free radicals to harmless waste products
RDA: 15 mg/day or 22 IU UL: 1,000 mg/day or 1,500 IU Higher intakes increase risk of bleeding. Food and Nutrition Board, 2000 RDA increased from 8mg females and 10mg males Intakes above UL - increases risk of bleeding as Vit E at high levels acts as anticoagulant

9 Vitamin E Sources Nuts & seeds
Vegetable oils & foods made from vegetable oils like margarine and salad dressing Fortified cereal Wheat germ Leafy green vegetables Avocadoes

10 Selenium Part of enzymes that attack free radicals
Works closely with vitamin E RDA: 55 mcg/day Most people get this amount from the diet. Supplements are not recommended. UL: 400 mcg/day Food and Nutrition Board, 2000 Narrow margin of safety (than w/ vit C & E) between RDA and UL, so suppl not recommended. Most people get adequate Se from diet.

11 Selenium Sources Seafood, especially halibut, salmon, snapper, scallops, and clams Brazil nuts Liver Kidney Meat Grains

12 Carotenoids Many in plants, including beta carotene, lycopene, lutein
Body uses carotenoids to make vitamin A Conflicting evidence of antioxidant benefits No RDA or UL set Can get too much from supplements, but not food Carotenoid-rich fruits & vegetables recommended, NOT supplements! Food and Nutrition Board, 2000 B-carotene and other carotenoids have shown antioxidant properties in lab setting, but results have been controversial in humans. Only specific function identified at this time is as a precursor of Vitamin A (beta-carotene, alpha-carotene), so they can prevent vitamin A deficiency. Beta-carotene supplements have been shown to cause harm. E.g. lung cancer in smokers Not likely to get toxic amounts from food alone

13 Carotenoid Sources Dark green leafy vegetables
Broccoli, spinach, romaine lettuce Deep yellow and orange fruits and vegetables Sweet potatoes, carrots, mangoes, cantaloupe

14 Resources for Consumers and Educators…

15 UF/IFAS Publications FCS8639 - Facts About Vitamin A
FCS Facts About Vitamin C FCS Facts About Vitamin E

16 Miscellaneous Factsheets
National Institutes of Health Vitamin A Vitamin E Selenium The American Dietetic Association Antioxidant Vitamins for Optimal Health

17 Summary Antioxidants attack free radicals and help repair cell damage caused by free radicals. Aim for RDA; avoid intakes higher than UL. Eat a variety of food, including five or more fruits and vegetables every day!

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