New study on supplements' effects on older women flawed, nutrition experts say

The natural health industry rallies to respond to a controversial study published yesterday in the Archives of Internal Medicine that found that dietary supplements don't contribute to lower death rates in older women. Natural health experts and the supplements industry weigh in on the flaws and biases they find in the research.

A new study published yesterday in the Archives of Internal Medicine titled "Dietary Supplements and Mortality Rate in Older Women" claims that dietary supplements overall are not helpful for increasing longevity in older women. The findings have natural health experts rallying to respond to what they say is a biased and scientifically skewed study on dietary supplements.

The study tracked the use of vitamin and mineral supplements in relation to total mortality in nearly 39,000 older women in Iowa from 1986 to 2008. Researchers found that dietary supplements, with the exception of calcium, do not reduce the death rate in older women. Calcium is by far the top-selling mineral supplement, accounting for 54 percent of the $2.2 billion in 2010 mineral supplements sales, according to Nutrition Business Journal.

The study's conclusion went on to say that "in older women, several commonly used dietary vitamin and mineral supplements may be associated with increased total mortality risk [emphasis added]." The researchers associated use of multivitamins, vitamin B6, folic acid, iron, magnesium, zinc and copper with increased risk of total mortality when compared with groups that did not take supplements.

"It's important to keep in mind that this is an associative—not a cause-and-effect—study," said Duffy MacKay, vice president of scientific and regulatory affairs for Council for Responsible Nutrition (CRN), in a statement. "This study … attempts to tease out one piece of the healthy equation for good health—dietary supplements. CRN maintains that nutrients may be robbed of their beneficial effects when viewed as if they were pharmaceutical agents, with scientists looking to isolate those effects, good or bad."

Industry experts dissect supplement study's flaws

How does the industry, which regularly comes across studies such as, "Vitamin D reduces mortality rate by 20 percent," respond to research that paints an entirely different picture of supplements' benefits?

The same way it always does: consumer education—and pointing out precise biases and flaws in the "Dietary Supplements and Mortality Rate in Older Women" study.

"What the researchers and editors seemed to miss is that older women (or men) have a greater risk of death simply because of their age, their greater likelihood of having serious diseases, and their use of multiple drugs, a common cause of illness (from side effects)," said Jack Challem, The Nutrition Reporter.

Jacob Teitelbaum, MD, a holistic physician and coauthor of Real Cause, Real Cure (Rodale, 2011), said the researchers ignored a key point of the study: the fact that women who took supplements before the study were healthier than those who did not.

"One could come to the same conclusion about exercise not being helpful using this same statistical approach," he said. Take for example a study with two control groups: those who exercise and those who do not, but both of which are put on a new exercise program. At the beginning of the study, those who already are exercisers are healthier than those who are not. By cancelling this fact out, and negating the prior health of the exercisers, you can find that exercise is not beneficial, he said.

That's what the researchers did in this supplements study, Teitelbaum said. "The people taking multivitamins at the beginning of the study were statistically doing a lot better—there was less high blood pressure, less diabetes [than the non-supplement users]. The researchers totally ignored that."

Teitelbaum adds that the omission of these facts wasn't the only flaw in the study: "The hypothesis wasn't to state whether supplements will harm or help. It was to see if they would harm, which gives you an idea of what their study was about."

In a statement, Steve Mister, president and CEO of CRN, pointed to another flaw: The publication invited a scientist whose opinion is already controversial toward supplements to comment on the study.

"In the spirit of true scientific discourse, wouldn't it have been more appropriate to invite commentary from a researcher who might have looked at the data in its entirety, with sufficient lead time, and provided a different perspective?" Mister asked. "It's time scientific journals acknowledge they have some biases, just like industry."

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