Tuesday, March 13, 2007

Biological Flavonoids--Don't Throw them Away Just Yet

A recent study from the Linus Pauling Institute at OSU Corvallis concludes that bioflavonoids have little if any use as antioxidants.
The study, published in Free Radical Biology and Medicine, found flavonoids are highly metabolized, which alters their chemical structure and diminishes their ability to function as an antioxidant. Although the compounds appear to have three to five times more antioxidant capacity than vitamins C or E, the body sees them as foreign compounds and modifies them for rapid excretion in the urine and bile
Source

The authors further stated that biological flavonoids may induce the body to excrete more carcinogens, and possibly reduce the risks of cancer and heart disease through other mechanisms than antioxidant activity.

Another study, from Denmark, purports to show that consumption of anti-oxidant supplements such as Vitamin C, Vitamin A, Vitamin E, and Beta Carotene--among others--are of no use in prolonging life and may actually increase morbidity and mortality.

Both of these studies have been used in an attempt to prove that the consumption of vitamins and phytonutrients are of limited if any benefit in the quest to prolong life and reduce risk of illness.

Unfortunately, the Danish study appears to confuse association with causation--a common error among researchers poorly trained in epistemology--and the Linus Pauling Institute study failed to follow the physiology of ingested flavonoids far enough.

It is abundantly clear that many researchers, in their eagerness to publish, fail to think their subject through clearly enough to present a coherent and valid conclusion to either the public, or to fellow scientists. This is more the fault of the competitive environment of modern science than a sign of intellectual or character deficits in the researchers. It is a publish or perish world for academics and researchers.

Quercetin, Resveratrol, Curcumin, Green Tea, Ginger, proanthocyanidins, and other plant-derived nutrients have demonstrated significant potential for reduction of morbidity of many types.

Many flavonoids have demonstrated clear anti-inflammatory effect in various biological models and syndromes. A serious researcher would look further for the source of the physiologic effects of flavonoids, rather than issuing a blanket statement of "no effect" with respect to the narrow issue of particular ways of measuring anti-oxidant activity in vivo. Much more was left undone and unsaid that is of far more importance, than what was demonstrated.

Particularly disappointing is the response of "science blogs" reporting on these and similar studies. Unfortunately, a false image of the underlying facts has been projected to the lay public, which may have unfortunate long term results for some.

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1 Comments:

Blogger dug said...

Thanks for a rational and critically well thought out review of these flavonoid "science" publications. I personally can't excuse poor science to competition alone, but rather blame the scientist for being a part of a system that promotes it.

1:37 PM  

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