Antioxidants are compounds of many chemical forms, lumped together because they all have the property of counteracting the effects of highly reactive, harmful free radicals formed as the result of essential oxidation reactions performed on food to release energy for our use. Subdivisions can be formed from those that:-
a) Prevent the formation of free radicals, such as transferrin, SOD, carotenoids
b) Neutralise those that are formed, thus inhibiting chain-breaking processes, such as, the vitamins A, E and C
Natural antioxidants are synthesised by plants and are present in the foods we eat, as opposed to those synthetic antioxidants that are either added to food to extend its shelf-life (e.g. BHT), or prepared by extraction from plant sources to be taken as supplements in concentrated form.
What do they do for us?
Plants containing high concentrations of antioxidants that are eaten in moderation have been associated in epidemiological studies with human well-being, while excessive consumption has been associated with toxic reactions. Supplements have not been generally proven to replace the use of food-based antioxidants. Some supplements are known to increase mortality. Not all the antioxidants present in foods are capable of being absorbed from the digestive tract into the bloodstream (i.e. are bioavailable), whence they can be delivered to the various organs where they are required. So, even the efficacy of food-based antioxidants is still being tested.
Evidence that an antioxidant or even a class of antioxidants are effective in preventing, containing or curing a disease is difficult to confirm. Nutritional authorities are cautious until more definitive studies have been performed. In the meantime, trends indicated by peer-reviewed research are reported here.
Determining the function of each antioxidant.
The total antioxidant extract from a food can be separated by chromatography and/or electrophoresis and the isolated fractions collected and submitted to biochemical assay to decide their properties. Some key antioxidants e.g. quercetin have been studied to decide their antioxidant capacity and clinical role. As more compounds are analysed, the picture of their therapeutic use will become clear.
Anti-oxidant food sources:
- Small red bean (dried), 1/2 cup
- Wild blueberry, 1 cup
- Red kidney bean (dried), 1/2 cup
- Pinto bean, 1/2 cup
- Blueberry (cultivated), 1 cup
- Cranberry, 1 cup (whole)
- Artichoke (cooked hearts), 1 cup
- Blackberry, 1 cup
- Prune, 1/2 cup
- Raspberry, 1 cup
- Strawberry, 1 cup
- Red delicious apple, 1
- Granny Smith apple, 1
- Pecan, 1 ounce
- Sweet cherry, 1 cup
- Black plum, 1
- Russet potato, 1 cooked
- Black bean (dried), 1/2 cup
- Plum, 1
- Gala apple, 1
Best food sources of Antioxidants:
- Berries — Blueberries, blackberries, raspberries, strawberries and cranberries are among the top sources of antioxidants.
- Beans — Small red beans and kidney, pinto and black beans are all choices rich in antioxidants.
- Fruits — many apple varieties (with peel) are high in antioxidants, as are avocados, cherries, green and red pears, fresh or dried plums, pineapple, kiwi and others.
- Vegetables — those with the highest antioxidant content include artichokes, spinach, red cabbage, red and white potatoes (with peel), sweet potatoes and broccoli. Although the effect of cooking on antioxidant levels varies by cooking method and vegetable, one study showed that cooking generally increased levels among select vegetables.
- Beverages — Green tea may come to mind as a good source of antioxidants, but other beverages have high levels, too, including coffee, red wine and many fruit juices such as pomegranate.
- Nuts — Walnuts, pistachios, pecans, hazelnuts and almonds are some of the top nuts for antioxidant content.
- Herbs — these may be unexpected suppliers of antioxidants, but ground cloves, cinnamon and ginger, dried oregano leaf and turmeric powder are all good sources.
- Grains — In general, oat-based products are higher in antioxidants than are those derived from other grain sources.
- And for dessert — Done forget that a piece of dark chocolate ranks as high or higher than most fruits and vegetables in terms of antioxidant content.
More information on Nutrition and workouts coming soon…….
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