THE ANTIOXIDANTS STORY CONTINUED #7

Continued from Yesterday.....

The Proof in the Research

"For vitamin E, evidence is available for all steps except the evidence for the last and important step is not complete," said Papas. "If ongoing major clinical trials are positive, it will achieve the burden of proof required for FDA approval."

A few results from clinical trials have already been published on vitamin E, and other long-term clinical trials, as Papas indicated, are underway. In one completed clinical study--the Cambridge Heart Antioxidant Study (CHAOS), published in the March 23, 1996 issue of The Lancet, vitamin E supplementation of 400 or 800 IUs per day decreased the risk of non-fatal heart attack in a double-blind, placebo-controlled trial of 2,002 patients with coronary disease who were treated with vitamin E or placebo and followed for a median of 510 days.

If human studies in a controlled clinical setting, especially those that evaluate health outcomes, are the key to acceptance by the medical community, why don't researchers and companies in the industry simply conduct more of these types of studies? One large reason is that these types of studies are expensive and often take a long time to conduct. Alex Sevanian, Ph.D., a professor at the University of Southern California who has conducted research on antioxidants, highlighted the formidable challenges of doing research that investigates health outcomes. "If researchers are looking for events such as heart attacks and strokes, they have to take a relatively large population and look for these coronary heart events. These types of studies take many, many years, because people live a long time."

Sevanian noted, however, that there is another research route, where rather than waiting for health outcome events, researchers look at specific indicators of future health events. "There are more refined techniques that can now monitor progress of, for example, atherosclerosis in people, which is a surrogate to predicting events," he said. "For instance, this type of study can monitor the thickening of vessel walls and quickly see if that thickening does or does not occur with the intake of an antioxidant. It does not mean that the event will occur, but statistically, there is a strong correlation. These types of studies can be done over two- or three-year periods if the researchers get enough measurements to determine some rate of progression to see if that would then change with intervention."

However, subtle but sometimes important differences between these two kinds of human studies do exist. Garry Handelman, Ph.D., associate professor and scientist at the Jean Mayer Human Nutrition Research Center on Aging at Tufts Unversity, explained, "Suppose in a study you looked at how rapidly people made an antibody in response to a tetanus shot and you intervened by making some change in their diet so they made the antibody more quickly than a second group of people who did not have a change in their diet. You still have to prove that the people in the first group had more actual resistance to the tetanus. Just because they make the antibody more rapidly does not translate into the fact that they had more resistance. That is to say that an improved result in a laboratory test is not the same thing as improved health income."

Similarly, research has shown that certain antioxidant substances increase the resistance of a person's lipoprotein against peroxidation. However, this result has not proven in itself that the person has a reduced heart disease or heart attack risk. Handelman explained that there are literally tens of thousands of tests that can be done on human beings, but in every case it is still necessary to prove that an improved result in the test corresponds to an improved health outcome.

These important distinctions between in vivo and in vitro, between epidemiological and clinical research, and between controlled human studies that look for health outcomes vs. those that do not helps explain in part why some or many in the mainstream medical community view the body of research on antioxidants as preliminary even though Medline contains aproximately 30,000 articles related to free radical oxidation and/or antioxidants. Nevertheless, research on antioxidants is continuing and expanding at an exciting pace, and there is little dispute, even from the most conservative in the medical community, that research exists that at least suggests the potential preventative or therapeutic role of antioxidants. In other words, one would be hard-pressed to find a scientist, doctor or pharmacist who would say that research on antioxidants is a waste of time and money. It should also be remembered that human studies that test for health outcomes take years to compete, and that this type of research that the medical profession wants to see for antioxidants is right now in the process of being conducted
.
"The antioxidant research completed to date has been very compelling," said Henkel's Clark. "Scientists have made great strides in understanding how antioxidants interact within the body and with each other. Each new study brings us closer to understanding how antioxidants can promote good health."

Continued Tomorrow....

http://www.naturalproductsinsider.com/articles/1999/01/winning-the-medical-community-over-to-antioxidants.aspx

http://www.depsyl.com/

http://back2basicnutrition.com/

http://bionutritionalresearch.olhblogspace.com