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Posts Tagged ‘bone loss’

Soy saves bones

Posted by Richard on February 29, 2008

Two new meta-analyses of soy studies provide strong confirmation that women can improve bone mineral density, inhibit bone resorption, and increase bone formation by supplementing with soy isoflavones. The meta-analyses, one by Chinese and one by Japanese researchers, appear in the February issue of the European Journal of Clinical Nutrition and the journal Clinical Nutrition, respectively. According to Life Extension Foundation (emphasis added):

The first meta-analysis found an average decrease in urinary deoxypyridinoline [bone resorption marker] of 2.08 nanomoles per millimole, and an average increase of 1.48 micrograms per liter of BAP [bone formation marker] in women who received isoflavones compared with those who received a placebo. “Isoflavone intervention significantly inhibits bone resorption and stimulates bone formation,” the authors stated. “These favorable effects occur even if less than 90 milligrams per day of isoflavones are consumed or the intervention lasts less than 12 weeks.”

The second review also found a bone-building benefit for soy. In the clinical trials examined, women who received soy experienced a significant increase of 20.6 milligrams per cubic centimeter in spine bone mineral density compared with those who received a placebo. Bone mineral content also increased, but to a lesser extent. Benefits were greater when more than 90 milligrams per day isoflavones were consumed, or when the trial lasted at least six months. “The results clearly suggested that isoflavones contributed significantly to the increase of spinal bone mineral density, especially in postmenopausal women,” Dr Wang and his coauthors conclude.

… The lower incidence of osteoporosis-related fracture among Asian women who consume 10 to 20 times more soy than Western women may point to a bone-protective effect of soy isoflavones. The authors recommend large randomized clinical trials using graded dosages of isoflavones to measure their long term effects on bone mass as well as fracture risk.

Larger studies would indeed be helpful. But if you're concerned about osteoporosis, you may not want to wait for those. You may want to take soy supplements or add soy milk, edamame, tempeh, or tofu to your diet. The latter, I understand, can be made quite palatable by wrapping it in bacon.  

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They call this science?

Posted by Richard on March 31, 2006

In the past few months, several studies have been widely reported that supposedly discredited some widely-used nutritional supplement or alternative treatment. The fine folks at the Life Extension Foundation (LEF) have had enough of the shoddy studies, misleading press releases, and terrible reporting, and they’re preparing a full-fledged response. A preliminary article is available on their website now:

Over the past several months, the media has questioned the efficacy of several popular dietary supplements. In the upcoming June 2006 issue of Life Extension magazine, we dissect these negative media reports down to the bone to reveal the hard scientific facts.

In doing so, we expose the absurdity of the headline-hungry media making proclamations such as “another natural remedy bit the dust” when describing the recent glucosamine study. We also reveal the inappropriateness of conventional doctors, with little knowledge about the proper use of nutrients, but with strong financial ties to the pharmaceutical industry, conducting studies that contain so many flaws that their findings are largely irrelevant.

As usual for LEF, this article is footnoted to a fare-thee-well — 181 references, most to studies published in peer-reviewed medical and scientific journals. If you print the article, it runs about 6 pages, depending on margin settings, etc. The references add about 6 more pages. The article provides brief preliminary critiques — scathing ones — of studies claiming that:

  • Eating a low-fat diet doesn’t reduce women’s risk of heart attacks, strokes, breast cancer, or colon cancer.
  • Calcium and vitamin D don’t protect women’s bones.
  • Glucosamine and chondroitin aren’t effective for osteoarthritis of the knee.
  • Saw palmetto is ineffective in treating prostate enlargement.

Each of those four claims is easily shown to be false. In fact, a couple of them are even contradicted by the studies, which were mischaracterized in press releases and media reports.

My favorite is the calcium and vitamin D study, which appeared in February’s New England Journal of Medicine. LEF’s Bill Faloon said it may be  "one of the most poorly designed studies in the history of modern medicine."

In theory, one group of women was assigned to take a calcium – vitamin D supplement and another group was assigned to take a placebo. Reportedly, the supplement group had just as many hip fractures as the placebo group.

Actually, the study did find a 29% reduction in hip fractures among the subset of the supplement group who actually took the supplements. You see, about 40% of the supplement group didn’t "achieve a standard rate of compliance," meaning they took less than 80% of the calcium and vitamin D they were supposed to take. But that didn’t matter to the MDs and PhDs conducting the study (emphasis and footnote from article):

This meant that women in the active group (the one given the calcium-vitamin D supplements) were counted as having taken the calcium-vitamin D, whether they really took the supplement or not. According to the scientists who conducted this study:

“Participants were followed for major outcomes, regardless of their adherence to the study medication…”

The “study medication” mentioned above is the calcium-vitamin D supplement. The fact that a study could be published in a medical journal “regardless” of whether the participants actually took the active ingredient defies logic.

Presumably, the placebo group had the same poor rate of compliance (since participants didn’t know whether it was the supplement or the placebo they were failing to take). So what we really have here is a $10 million federally-funded study proving that women who fail to take their calcium and vitamin D are just as likely to break a hip as women who fail to take a placebo. Unbe-frickin-lievable.

There’s more. That’s only one of several serious flaws with the calcium study. And the other studies are equally unimpressive. Read the whole thing — it’s your tax dollars at work and your health at stake.

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