Wednesday, November 22, 2006

Understanding Antioxidants

An antioxidant is a substance that counters the negative effect of oxygen.

In foods anti-oxidants prevent the oxidation of different food components. Oxidation of foods results for example in an undesirable brown colour and/or off-odours and off-flavours known as rancidity. Antioxidants are substances that react with oxygen and thus counteract the negative effects. Examples are vitamin C, vitamin E, Zinc, Alpha Lipoic Acid, Grape Seed Extract etc.

In the body antioxidants protect key cell components by neutralizing the damaging effects of "free radicals," natural byproducts of cell metabolism. Free radicals form when oxygen is metabolized, or burned by the body. They travel through cells, disrupting the structure of other molecules, causing cellular damage. Such cell damage is believed to contribute to aging and various health problems. Example of anti-oxidants which are active in the body are the vitamins A, C and E, and polyphenols (a group of plant chemicals, present in for example tea and fruits).

Scientists at the U.S. Department of Agriculture (USDA) are using modern technology to rank foods based on which has the highest concentrations of antioxidants, compounds that fight free radical damage and thereby block disease. Small red beans head their new Top 20 list in the June issue of the Journal of Agricultural and Food Chemistry

  1. Small red beans (dried)
  2. Wild blueberries.
  3. Red Kidney beans.
  4. Pinto beans.
  5. Blueberries (cultivated).
  6. Cranberries.
  7. Artichokes (cooked).
  8. Blackberries.
  9. Prunes.
  10. Raspberries.
  11. Strawberries.
  12. Red Delicious apples.
  13. Granny Smith apples.
  14. Pecans.
  15. Sweet cherries.
  16. Black plums.
  17. Russet potatoes (cooked).
  18. Black beans (dried).
  19. Plums.
  20. Gala apples.

Researchers note that color often characterizes antioxidant-rich foods. They also warn that just because a food tests high in nutrients in the lab, does not guarantee that it will be well-absorbed by the body. The processing of a food also affects its antioxidant potency. For instance, blueberries are best fresh; whereas, gentle cooking enhances the antioxidant properties of tomatoes.

The Journal of Agricultural and Food Chemistry reported a new research study focusing on the antioxidant capacities of over 100 foods. This study is the largest, most comprehensive analysis to date of the antioxidant content of commonly consumed foods.

Total Antioxidant Capacity (TAC) of the top 50 Foods

Rank

Food Item

Serving Size

TAC

1

small red bean

1/2 cup 92 g

13,727

2

blueberry, wild

1 cup 144 g

13,427

3

red kidney bean

1/2 cup 92 g

13,259

4

pinto bean

1/2 cup 96 g

11,864

5

blueberry, cultivated

1 cup 144 g

9,019

6

cranberry

1 cup whole 95 g

8,983

7

artichoke

1 cup hearts 84 g

7,904

8

blackberry

1 cup 144 g

7,701

9

raisin

1/2 cup 85 g

7,291

10

raspberry

1 cup 123 g

6,058

11

strawberry

1 cup 166 g

5,938

12

apple, Red Delicious

1 fruit 138 g

5,900

13

apple, Granny Smith

1 fruit 138 g

5,381

14

pecan

28.4 g (1 oz)

5,095

15

potato, russet raw

1 potato 369 g

4,882

16

cherry, sweet

1 cup 145 g

4,873

17

plum, black

1 fruit 66 g

4,844

18

potato, russet cooked

1 potato 299 g

4,649

19

black bean

1/2 cup 52 g

4,181

20

plum, red

1 fuit 66 g

4,118

21

apple, Gala

1 fruit 138 g

3,903

22

apple, Red Delicious peeled

1 fruit 128 g

3,758

23

apple, Gold Delicious

1 fruit 138 g

3,685

25

apple, Fuji

1 fruit 138 g

3,578

26

date, Medjool

1/2 cup 89 g

3,467

27

avocado, Haas

1 fruit 173 g

3,344

28

pear, green

1 fruit 166 g

3,172

29

pear, Red Anjou

1 fruit 166 g

2,943

30

apple, Gold Delicious peeled

1 fruit 128 g

2,829

31

macadamia

28.4 g (1 oz)

2,739

32

broccoli raab raw

1/5 bunch 85 g

2,621

33

navy bean

1/2 cup 104 g

2,573

34

orange, navel

1 fruit 140 g

2,540

35

prune

1/2 cup 75 g

2,537

36

cabbage, red cooked

1/2 cup 75 g

2,359

37

potato, red raw

1 potato 213 g

2,339

38

potato, red cooked

1 potato 173 g

2,294

39

walnut

28.4 g (1 oz)

2,267

40

pea, blackeye

1/2 cup 52 g

2,258

41

potato, white raw

1 potato 213 g

2,257

42

fig

1/2 cup 89 g

2,124

43

asparagus, raw

1/2 cup 67 g

2,021

44

grape, red

1 cup 160 g

2,016

45

pepper, yellow raw

1 pepper 186 g

1,905

46

grapefruit, red

half 123 g

1,904

47

beet

1/2 cup 68 g

1,886

48

potato, white cooked

1 potato 173 g

1,870

49

pepper, orange sweet raw

1 pepper 186 g

1,830

50

peach, fresh

1 fruit 98 g

1,826

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