Antioxidants in Food

Antioxidant - substance that inhibits oxidation or inhibits reactions promoted by oxygen or peroxides

By LESLIE BECK
Wednesday, June 30, 2004 - Globe & Mail

If you're popping extra vitamin C and E to help ward off heart disease and cancer, you might want to take a closer look at your dinner plate. While these two antioxidants are important for our health, a new study shows that whole foods pack a powerful punch.

Earlier this month, the U.S. Department of Agriculture published a list of the best food sources of antioxidants. It came from the largest and most comprehensive study to date evaluating the antioxidant capacity of more than 100 commonly consumed foods. While many fruits and vegetables held top spots on the list, certain beans, nuts and spices also scored high.

Antioxidants protect our cells from the harmful effects of free radicals. Every day, our bodies create free radicals from oxygen as a consequence of normal metabolism. Pollution and cigarette smoke increase the number of free radicals our bodies are exposed to.

Antioxidants act as scavengers, neutralizing free radicals before they do harm. If left unchecked, free radicals damage cells. Such damage is thought to play a role in the development of heart disease, cancer, cataracts, macular degeneration, arthritis and Alzheimer's disease.

Antioxidants in foods exist as vitamins C and E, beta-carotene, selenium and natural plant chemicals such as flavonoids (tea), lycopene (tomatoes) and anthocyanins (berries).

Studies show that a diet high in fruit and vegetables can help reduce the risk of heart attack, stroke, high blood pressure and cancer, and may even preserve our eyesight. Extensive reviews have concluded that eating at least five daily servings of fruit and vegetables could lower cancer rates by 20 per cent, coronary heart disease by 20 to 40 per cent and stroke by 25 per cent.

Yet, clinical trials using supplements of vitamin C, vitamin E or beta-carotene have yielded inconsistent results.

The highest concentrations of antioxidants are found in the most deeply or brightly coloured fruits and vegetables. Blueberries, cranberries, plums, dried prunes, blackberries, apples and cherries came out winners as top fruits for antioxidant levels. Melons scored the lowest.

Among the vegetables, artichokes and russet potatoes ranked the highest and cucumber had the lowest value. Honourable mentions go to apricots, red grapes, navel oranges, asparagus, red cabbage, rapini and sweet potatoes.

Pecans, walnuts, hazelnuts and pistachios were top performers among the nuts tested. Even spices, although generally consumed in small amounts, can add antioxidant powers to your dinner. On the basis of antioxidant concentration, ground cloves, ground cinnamon and oregano were the highest among the spices studied.

The bottom line remains the same: Boost your intake of fruit and vegetables. According to the Canadian Produce Marketing Association, 70 per cent of Canadians are well aware of the protective effects of fruit and vegetables, yet only 36 per cent eat the minimum five servings each day.

Getting your daily five to 10 servings is easier than you might think. A serving size isn't that large. Basically, if it fits in your hand, you're getting one serving. A medium-sized fruit, a quarter-cup of dried fruit, 125 millilitres of unsweetened juice, and one cup of salad are all considered one serving.

The key is planning. If you forgo eating fruit and vegetables until the end of the day, you won't come close to meeting your target. Start by including a serving of fruit at breakfast -- berries or dried fruit on cereal, a small glass of citrus juice, a fruit smoothie or a bowl of fruit salad.

Next, plan to have at least one vegetable serving at lunch. A handful of baby carrots, a glass of tomato juice, a cup of vegetable soup and sliced vegetables in your sandwich are all easy choices.

Snack on fresh or dried fruit between meals. Add a small handful of pecans or walnuts to boost your antioxidant intake.

Serve at least two different vegetables at dinner, fresh or frozen. Increase your portion size to bump up the number of servings.

That's all it takes to get a minimum of five servings each day. Not so tough, really.

Finally, choose your fruits and vegetables by colour to get a wide variety of antioxidants. Think green, orange, red and blue.

Top 20 free radical fighters.
Source: The American Chemical Society

1. dried small red beans, cooked, one-half cup
2. wild blueberries, one cup
3. red kidney beans, cooked, one-half cup
4. pinto beans, cooked, one-half cup
5. cultivated blueberries, one cup
6. cranberries, one cup
7. artichoke hearts, one-half cup
8. blackberries, one cup
9. prunes, one-half cup
10. raspberries, one cup
11. strawberries, one cup
12. red delicious apple, one
13. Granny Smith apple, one
14. pecans, 28 grams
15. sweet cherries, one cup
16. black plums, one
17. russet potato, cooked, one
18. black beans, cooked, one-half cup
19. other plums, one
20. Gala apple, one

Pro-oxidant factors and antioxidant defences (from Langseth, 1995²)

Food source of antioxidant Vitamins (from Langseth, 1995²)