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/NFamily, Youth, and Community SciencesUniversity of Florida/IFASCarotenoids are group of compounds including beta-carotene, alpha-carotene, lycopene, luteinThese 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, unstableattack and damage cellsFree 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 productionEnvironmental sourcesUV sunlightAlcoholOzoneCigarette smokeSmog and other pollutants
4 Functions of Antioxidants Attack free radicals in various ways, such as:Removing free radicals from bloodstreamDonating electrons to stabilize free radicalsRepair damage caused by free radicalsDifferent 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 DefinitionsRecommended Dietary Allowances (RDA): amount of nutrient that will meet the needs of 97-98% of a population groupTolerable Upper Intake Level (UL): maximum amount of a nutrient that does not pose a health risk to individualsIntakes 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/daymen: 90 mg/daysmokers: additional35 mg/dayUL: 2,000 mg/dayFood and Nutrition Board, 2000RDA increased from 60mg/day for adultsRDA higher for smokers b/c smoking causes more free radicals also breaks down vit Camts above RDA may cause diarrhea
7 Vitamin C Sources Citrus fruits Dark green vegetables Guava Papaya CantaloupeStrawberriesPeppersTomatoesMangoesPotatoesdon’t need supplements; can get amt from food. Ie: 100 mg in 8 oz OJsuppl 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 IUUL: 1,000 mg/day or 1,500 IUHigher intakes increase risk of bleeding.Food and Nutrition Board, 2000RDA increased from 8mg females and 10mg malesIntakes 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 dressingFortified cerealWheat germLeafy green vegetablesAvocadoes
10 Selenium Part of enzymes that attack free radicals Works closely with vitamin ERDA: 55 mcg/dayMost people get this amount from the diet. Supplements are not recommended.UL: 400 mcg/dayFood and Nutrition Board, 2000Narrow 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 SourcesSeafood, especially halibut, salmon, snapper, scallops, and clamsBrazil nutsLiverKidneyMeatGrains
12 Carotenoids Many in plants, including beta carotene, lycopene, lutein Body uses carotenoids to make vitamin AConflicting evidence of antioxidant benefitsNo RDA or UL setCan get too much from supplements, but not foodCarotenoid-rich fruits &vegetables recommended,NOT supplements!Food and Nutrition Board, 2000B-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 smokersNot likely to get toxic amounts from food alone
13 Carotenoid Sources Dark green leafy vegetables Broccoli, spinach, romaine lettuceDeep yellow and orange fruits and vegetablesSweet potatoes, carrots, mangoes, cantaloupe
15 UF/IFAS Publications FCS8639 - Facts About Vitamin A FCS Facts About Vitamin CFCS Facts About Vitamin E
16 Miscellaneous Factsheets National Institutes of HealthVitamin AVitamin ESeleniumThe American Dietetic AssociationAntioxidant Vitamins for Optimal Health
17 SummaryAntioxidants 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!