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In discussions about berry and superfruit antioxidants by industry journalists and manufacturers, all the attention seems to be on polyphenolic compounds like anthocyanins, flavonoids, catechins, etc.
But by science, however, these antioxidant properties of polyphenols have been shown only in the artificial environment of laboratory test tubes. There is no evidence that polyphenols have antioxidant effects in the human body.
Blackcurrant (Ribes nigra L.), one of Nature's richest sources of vitamin C, click!
For polyphenol antioxidants to be accepted as true in vivo antioxidants, science must show
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proof of a mechanism of action on specific cells or organs in vivo
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an actual dose-response relationship in humans
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relationship to health or, conversely, essential importance to anti-disease functions demonstrated in human clinical trials
Upon proof of these effects, a polyphenol could be called an antioxidant nutrient, meaning it is essential to human health. The data would also allow assignment of a Dietary Reference Intake value, i.e., a recommended daily intake level such as used for all essential nutrients already established by science with the above properties.
The FDA is so certain of these requirements that it issued a "guidance document" for manufacturers to correctly state information about antioxidant content of their products on package labels and marketing literature (see part B), click!
Let's repeat:
No polyphenol and no currently available product on retail shelves or via multilevel marketing companies can legitimately claim antioxidant benefits.
The true antioxidant nutrients: Vitamins A, C and E
Berries are good natural sources of the true antioxidant essential nutrients, vitamins A, C and E.
Vitamins A and E come mainly from special compartments in berries -- carotenoid pro-vitamin A precursors and oil, respectively -- and, once in the human body after digestion and blood distribution, locate in the body's lipid layers which include membranes of our body's cells and organelles, i.e., sensitive defense barriers against radical oxygen species always being produced moment-by-moment throughout life.
Vitamin C, on the other hand, is water-soluble so becomes the body's free-ranging antioxidant on patrol wherever water compartments exist in the body.
Vitamin C is the universal antioxidant, even protecting and helping to restore functions of vitamins A and E.
Fortunate for us, vitamin C is easy to get in common foods and fruit juices. Look for it on the Nutrition Facts label of your favorite berry and fruit products.
We must eat sources of vitamin C because -- unlike most plants and animals -- humans do not synthesize it.
Across nutrient profiles of all berries, vitamin C is the common thread, being high in content for nearly all berries.
Russian seaberries (sea buckthorn, Hippophae rhamnoides L.),
a high-nutrient berry source of vitamin C.
Common, inexpensive whole food solutions for getting your daily vitamin C intake (for adults, at least 90 mg per day -- some experts like the Linus Pauling Institute recommend 400 mg per day!)
- red bell pepper
- broccoli
- strawberries
- navel orange, orange juice or any fortified fruit juice
- grapes
- dried goji berries
- kiwifruit
- all citrus fruits
Check out the list from World's Healthiest Foods!
Kiwifruit (Actinidia deliciosa), rich in vitamin C and
numerous other nutrients, making it a true superfruit
Take care when storing foods rich in vitamin C, as this vitamin is sensitive to (and will rapidly neutralize)
- light
- heat, any type of cooking
- oxygen
- mechanical processing
What does vitamin C do in the human body? What are some of the most recent research advances?
One of the leading research centers on vitamin C in the world is the Linus Pauling Institute of Oregon State University in Corvallis.
Dr. Linus Pauling (1901-1994) was a rare two-time winner of the Nobel Prize, one of which was for his work on chemical bonds that later stimulated interest in and advocacy of vitamin C intake in large daily doses.
Important functions of vitamin C in the human body
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synthesis of collagen (connective tissue for joints, blood vessels, skin and bones)
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synthesis of transmitters used by the nervous system
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transport of fat molecules into cells and organelles for use as energy supplies
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metabolism of cholesterol
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antioxidant protection
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regeneration of antioxidant functions by vitamins A or E
Here are a few current research topics and reports on vitamin C from the Linus Pauling Institute
Vitamin C and the common cold click!
More evidence that vitamin C may prevent cancer
The LPI "Prescription for Healthy Living"
Essential micronutrient intake recommendations for older adults
