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JAMA studies bring up tough questions for dietary supplement researchers


Recent research examining the impact on men's health of vitamin E and saw palmetto supplementation has me wondering: If drug-like trials aren’t the appropriate way to study supplements, what is?

It’s been a rough couple of weeks for the makers of men’s health supplements.

On Sept. 21, the Journal of the American Medical Association unveiled a largest-of-its-kind trial which found that those who took saw palmetto for relief of enlarged prostate symptoms actually got less relief than those who took a placebo. Now, in this week’s JAMA, comes an even more damning study, which found that men who took Vitamin E for prostate health were 17 percent more likely to develop prostate cancer.

“The observed 17 percent increase in prostate cancer incidence demonstrates the potential for seemingly innocuous yet biologically active substances such as vitamins to cause harm,” wrote the authors of the Vitamin E study, published in the Oct. 12 issue of JAMA.

The two reports have, as expected, elicited strong rebuttals from industry, with the Council on Responsible Nutrition urging consumers not to walk away from either supplement based on a single study and pointing to a larger body of evidence with more favorable results.

But unlike with previous dietary supplement studies that showed disappointing results and were later ripped apart as poorly designed (Echinacea for colds, health benefits of multivitamins, C and E for cardiovascular health, etc.) these two trials appear to be – at least within the confines of the drug model for research – “well designed and well executed,” according to CRN.

In the saw palmetto trial, 369 senior men were divided into two groups, with half taking 320 milligrams of a carefully standardized saw palmetto extract daily and the other half taking a placebo. Over time, their doses were gradually escalated to 960 mg daily, until the trial ended at 72 weeks. At study’s end, the saw palmetto group saw their American Urological Association Symptom Index score fall by 2.2 points while the placebo group saw theirs fall 3 points.

“This was a well-designed study that addressed limitations of earlier, smaller trials – it was a multicenter study with a larger sample size and tested different doses of a carefully analyzed saw palmetto product,” said Josephine Briggs, M.D., director of the National Center for Complementary and Alternative Medicine and a vocal advocate for better study design for dietary supplements.

The Vitamin E study, which included 35,533 men from 427 study sites, was a follow-up to the 2008 Selenium and Vitamin E Cancer Prevention Trial, which found a “statistically non-significant" increase in prostate cancer risk in those taking 400 IU of vitamin E daily. Since that report, 521 additional prostate cancers have been diagnosed in the group, bringing the total in the placebo group to 529, compared to 620 in the vitamin E group, and prompting researchers to upgrade the difference to “significant.”

“Given that more than 50 percent of individuals 60 years or older are taking supplements containing vitamin E … the implications of our observations are substantial,” the authors wrote.

CRN points out that, in the group taking vitamin E combined with selenium, there was no significant increase in cancer risk. “This reinforces the theory that vitamins work synergistically and that drug-like trials of nutrients, when used in isolation from other nutrients, may not be the most appropriate way to study them,” said Duffy MacKay, N.D., vice-president of scientific and regulatory affairs for CRN, in a statement. He also questions how “significant” an increased risk of 1.6 cases per 1,000 person years really is.

Just what the impact of saw palmetto and Vitamin E is on men’s health clearly remains to be seen. But the two studies bring up several important questions for those in the supplement business:

If drug-like trials aren’t the appropriate way to study supplements, what is?

What should we make of trials conducted under this old, ill-fitting model? Do they count?

And, perhaps the most painful question of all: In an era when researchers are trying hard to design larger, more appropriate trials for supplements:

What if the study is fair, but we don’t like the results?

Discuss this Blog Entry 3

on Oct 11, 2011

I saw Dr. Briggs speak at AANP (American Association for Naturopathic Physicians). Her bias and skepticism was evident and palpable. I sensed she resented her assignment (then just 3 years old)to oversee CAM research. In speaking with other practitioners in attendance, I was not alone in this observation. She emphasized the need for 'evidence based medicine'. Several primary care physicians (which NDs are in many states) stood up and questioned her definition of "evidence based medicine". When you practice medicine, and get results with your patients, isn't that evidence enough? Also I have written on this blog in response to other topics, that each of us can simply walk into a health food store...and observe who is shopping there. Do the majority look healthy? Alert? Bright eyed? Especially those shopping in the produce sections! Then, walk into a typical box store (I don't mean to pick on Wal Mart, but they are a large retailer and the demographic that shop there can be seen on - or simply walk in to any Wal Mart). Observe those shopping in the food aisles. Compare to those shopping in the food aisles of your local natural products store....isn't that evidence enough?
This research and the reporting raise obvious questions: First, why was 400 IU of Vitamin E chosen, when other studies used much higher potencies, such as 800-1000 IU? Second, please confirm - we cannot assume - whether D-Alpha, the natural version, or DL-Alpha, the synthetic version, or Mixed Tocopherols were used in the study. These will have differing results. Third, what brand, or raw material, of Saw Palmetto was used? What standardized strength? I've seen in my practice as a nutritionist, significant results with men and saw palmetto, or saw palmetto combinations. Ideally, if they start taking at the first signs of symptoms, they get results quickly. I noticed the one downside of getting quick results: the men would then forget to take the saw palmetto and symptoms would return. I also advise everyone I consult with, to DRINK MORE WATER. If they comply, this one fact alone can affect health in a positive way! Clean water, obviously, it doesn't have to be special, or bottled, or high Ph. Although it won't hurt if it is.

on Oct 18, 2011

Statement from Natural Products Association (NPA) Vice President of Scientific and Regulatory Affairs Cara Welch, Ph.D., about a report on vitamin E and prostate cancer in the Journal of the American Medical Association:

"This is one of several studies demonstrating the effects of vitamin E, many of which are positive. Even the authors mention the reported benefit of vitamin E with Alzheimer’s disease and age-related macular degeneration.

This particular study does reveal the need for additional research into the link of vitamin E and prostate cancer, specifically clarifying the mechanism of action, before anyone can draw conclusions. I look forward to seeing additional research in order to accurately evaluate the effect of vitamin E supplementation on prostate cancer incidence.

What is important to remember is that the results of this study, specifically looking at vitamin E in isolation, cannot be extended to taking vitamin E in a combination supplement as the authors imply. In fact, the authors want to extend their initial findings onto supplementation as a whole, urging skepticism from consumers for these products, which they falsely claim are unregulated. This goes beyond the scope of the study and exhibits an unprofessional attitude.

I do not believe this study should affect the use of vitamin E supplementation for certain groups, especially those under the care of a physician. The Natural Products Association has long advocated that consumers use dietary supplements as part of a healthy lifestyle.”

on May 4, 2013

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