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Bill Bokunic
Registered Member

Date Joined Dec 2000
Total Posts : 65

Posted 9/23/2001 10:00 AM (GMT -4)

High-ORAC Foods May Slow Aging
Agricultural Research Service, USDA, February 8, 1999

Foods that score high in an antioxidant analysis called ORAC may protect cells and their components from oxidative damage, according to studies of animals and human blood at the Agricultural Research Services Human Nutrition Research Center on Aging at Tufts in Boston. ARS is the chief scientific agency of the U.S. Department of Agriculture.

ORAC, short for oxygen radical absorbance capacity, is a test tube analysis that measures the total antioxidant power of foods and other chemical substances. Early findings suggest that eating plenty of high-ORAC fruits and vegetables, such as spinach and blueberries, may help slow the processes associated with aging in both body and brain.

If these findings are borne out in further research, young and middle-aged people may be able to reduce risk of diseases of aging (including senility) simply by adding high-ORAC foods to their diets, said ARS Administrator Floyd P. Horn.

In the studies, eating plenty of high-ORAC foods:

Raised the antioxidant power of human blood 10 to 25 percent.
Prevented some loss of long-term memory and learning ability in middle-aged rats.
Maintained the ability of brain cells in middle-aged rats to respond to a chemical stimulus-a function that normally decreases with age.
Protected rats tiny blood vessels (capillaries) against oxygen damage.
Nutritionist Ronald L. Prior contends, If we can show some relationship between ORAC intake and health outcome in people, I think we may reach a point where the ORAC value will become a new standard for good antioxidant protection. (See the table at the bottom for ORAC values of fruits and vegetables.)

The thesis that oxidative damage culminates in many of the maladies of aging is well accepted in the health community. The evidence has spurred skyrocketing sales of antioxidant vitamins. But several large trials have had mixed results. It may be that combinations of nutrients found in foods have greater protective effects than each nutrient taken alone, said Guohua (Howard) Cao, a physician and chemist who developed the ORAC assay.

He and Prior have seen the ORAC value of human blood rise in two studies. In the first, eight women gave blood after separately ingesting spinach, strawberries, and red wine (all high-ORAC foods) or taking 1,250 milligrams of vitamin C. A large serving of fresh spinach produced the biggest rise in the womens blood antioxidant scores (up to 25 percent) followed by vitamin C, strawberries, and lastly, red wine.

In the second study, men and women had a 13- to 15-percent increase in the antioxidant power of their blood after doubling their daily fruit and vegetable intake compared to what they consumed before the study. Just doubling intake, without regard to ORAC scores of the fruits and vegetables, more than doubled the number of ORAC units the volunteers consumed, Prior reported.

Early evidence for the protecting power of these diets comes from rat studies by Prior, Cao, and colleagues. Rats fed daily doses of blueberry extract for six weeks before being subjected to two days of pure oxygen apparently suffered much less damage to the capillaries in and around their lungs, Prior said. The fluid that normally accumulates in the pleural cavity surrounding the lungs was much lower compared to the group that didnt get blueberry extract.

Neuroscientist James Joseph and psychologist Barbara Shukitt-Hale at the center tested middle-aged rats that had eaten diets fortified with spinach, strawberry extract, or vitamin E for nine months. A daily dose of spinach extract prevented some loss of long-term memory and learning ability normally experienced by the 15-month-old rats, said Shukitt-Hale.

Spinach was also the most potent in protecting different types of nerve cells in two separate parts of the brain against the effects of aging. These cells were significantly more responsive when the animals ate diets fortified with high-ORAC foods, especially spinach, compared to unfortified diets,Joseph said. The spinach group scored twice as responsive as the control animals.

Why spinach is more effective than strawberries (which score higher in the ORAC assay) is still a mystery. The researchers conjecture that it may be due to specific compounds or a specific combination of them in the greens. More details on this research appear in an article in the February issue of Agricultural Research, ARS monthly magazine. The story is also available on the World Wide Web at: http://www.ars.usda.gov/is/AR/archive/feb99/aging0299.htm.

Top-Scoring Fruits and Vegetables

ORAC units per 100 grams (about 3 = ounces)

Fruits Vegetables

Prunes 5770 Kale 1770
Raisins 2830 Spinach 1260
Blueberries 2400 Brussels sprouts 980
Blackberries 2036 Alfalfa sprouts 930
Strawberries 1540 Broccoli flowers 890
Raspberries 1220 Beets 840
Plums 949 Red bell pepper 710
Oranges 750 Onion 450
Red grapes 739 Corn 400
Cherries 670 Eggplant 390
Kiwi fruit 602
Grapefruit, pink 483

ARS News Service contact: Judy McBride, (301) 504-1628, jmcbride@asrr.arsusda.gov

Scientific contact: Ronald Prior, James Joseph, Guohua Cao, or Barbara Shukitt-Hale, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts, Boston, MA, phone (617) 557-3310, fax (617) 556-3299, prior@hnrc.tufts.edu; joseph_ne@hnrc.tufts.edu; cao_am@hnrc.tufts.edu; hale_ne@hnrc.tufts.edu.

sbflynn1
Registered Member

Date Joined Dec 2000
Total Posts : 8

Posted 10/14/2001 11:38 PM (GMT -4)

>Top-Scoring Fruits and Vegetables
>
>ORAC units per 100 grams (about 3 = ounces)
>
>Fruits Vegetables
>
>Prunes 5770 Kale 1770
>Raisins 2830 Spinach 1260
>Blueberries 2400 Brussels sprouts 980
>Blackberries 2036 Alfalfa sprouts 930
>Strawberries 1540 Broccoli flowers 890
>Raspberries 1220 Beets 840
>Plums 949 Red bell pepper 710
>Oranges 750 Onion 450
>Red grapes 739 Corn 400
>Cherries 670 Eggplant 390
>Kiwi fruit 602
>Grapefruit, pink 483
>

Tom,

Since prunes are dried plums and raisins are dried grapes, it would stand to reason that prunes have a higher number of ORAC units per 100 grams than their watery progenitors {plums} (5770:949), and the same goes for raisins with respect to grapes (2830:739). Taking the smaller ratio (2830:739) as a crude approximation, dried blueberries would appear to easily take the ORAC crown with a score of (2830/739) * 2400 = 9191.

This is not to say that many of the other foods listed above are not incredible sources of nutrition, its just to give the noble blueberry its proper due :-)

::I think your analysis is correct. It should be remembered, however, that there are many kinds of both grapes and raisins. The darkest colored ones would have the highest values. Similarly, prunes are made from only one plum of many kinds. The prune plum is a dark blue and that is likely why prunes have so high an ORAC.::

Perhaps some forum reader (it may turn out to be myself if I get a second opinion) can write to the researchers and suggest that they at least note the artificial advantage that desiccated fruits enjoy in the researchers ORAC ratings.

::Yes, they should be told that the table was highly misleading. The fruits and vegetables would best be rated in terms of ORAC units per calorie. At the least, they should be rated in terms of ORAC units per gram of dry matter.::

agabriele
Registered Member

Date Joined Dec 2001
Total Posts : 1

Posted 12/7/2001 8:22 AM (GMT -4)

Copied From: http://www.ifis.org/index.html

Accession No.: 9708 a0 019
Title: Antioxidant capacity of tea and common vegetables.
Author(s): Guohua ; Cao; Sofic E; Prior RL
Source (Bibliographic Citation): Journal of Agricultural and Food Chemistry; 44 (11) 3426-3431
Publication Year: 1996
No. References: 55
ISSN:0021-8561
Language(s): English
Address of Author: Correspondence (Reprint) address, R. L. Prior, ARS, USDA, Jean Mayer USDA Human Nutr. Res. Cent. of Aging, Tufts Univ., Boston, MA 02111, USA. Tel. (617) 556-3310. Fax (617) 556-3299. E-mail prior_us(a)hnrc.tufts.edu
Subject Code: a - Food sciences

Abstract: Previously, some fruits were shown to contain high antioxidant activities. The antioxidant activities of 22 common vegetables, 1 green tea, and 1 black tea were measured using the automated oxygen radical absorbance capacity assay with 3 different reactive species: a peroxyl radical generator, a hydroxyl radical generator, and Cu2 , a transitional metal. Based on the fresh wt. of the vegetable, garlic had the highest antioxidant activity ( mu mol of Trolox equiv./g) against peroxyl radicals (19.4) followed by kale (17.7), spinach (12.6), Brussels sprouts, alfalfa sprouts, broccoli flowers, beets, red bell pepper, onion, corn, eggplant (9.8-3.9), cauliflower, potato, sweet potato, cabbage, leaf lettuce, string bean, carrot, yellow squash, iceberg lettuce, celery, and cucumber (3.8-0.5); kale had the highest antioxidant activity against hydroxyl radicals followed by Brussel sprouts, alfalfa sprouts, beets, spinach, broccoli flowers, and the others. Green and black teas had much higher antioxidant activities against peroxyl radicals than all these vegetables. However, tea also showed a prooxidant activity in the presence of Cu2 , which was not found with any of the vegetables studied.
Descriptors: Oxidation; Vegetables; Tea; Antioxidative activity; Beverages

::It is certainly good to have someone doing these studies, but they almost always report the results in a highly irrational manner, IMO. As I stated before, what is more important than the ORAC value per gram of fresh weight, is the value per calorie or per gram of dry weight. It is ridiculous to compare by weight, foods which have quite different water content and/or caloric values. ::

steve
Registered Member

Date Joined Dec 2000
Total Posts : 98

Posted 12/10/2001 8:19 AM (GMT -4)

On the subject of ORAC values, I recently stumbled upon the following information:http://www.stopcancer.com/essential_oils_antioxidant.htm. It seems the ORAC values of essential oils are just staggering. The gold medal goes to clove oil with an ORAC score of 10,786,875. Thus two *drops* of clove oil have, according to the cited material, the antioxidant power of 4 cups of raspberries or 2.5 cups of blueberries (and without the sugar).

::The unresolved question, however, is how all these ORAC values translate into activity and benefit within the human body. Most certainly it is not a mere proportional relationship.
Anyway for purposes of eliminating existing cancer, there is good evidence that *oxidation* not antioxidant power is most important. This was recently elucidated in research on vitamin C.::

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