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Supplements found ineffective for preventing Alzheimer’s disease, osteoarthritis, and breast and prostate cancer

Three popular alternative therapies touted as helping to prevent Alzheimer’s disease, osteoarthritis and breast cancer are ineffective, new studies show. 
In addition, Bayer recently agreed to a $3.3 million settlement with the attorney

Three popular alternative therapies touted as helping to prevent Alzheimer’s disease, osteoarthritis and breast cancer are ineffective, new studies show. 

In addition, Bayer recently agreed to a $3.3 million settlement with the attorneys general of Illinois, Oregon and California for falsely implying one of its multivitamins can help prevent prostate cancer.

These studies and the settlement should serve as a reminder to consumers to be wary of all marketing hype, particularly when it comes to your health.

DHA and Alzheimer’s disease
There was good reason to hope that supplements of omega-3 fatty acid docosahexaenoic acid (DHA) might help lower the risk of developing Alzheimer’s disease. Several studies have identified an association between the consumption of fish — the main source of omega-3 fatty acids — and a reduced risk of dementia.

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But a study published last Wednesday in the Journal of the American Medical Association (JAMA) found no such benefit for DHA supplements. Researchers randomly assigned 402 people with mild to moderate Alzheimer’s disease to a daily 2-gram dose of DHA or to a placebo. After 18 months, the participants’ cognitive and functional skills were reassessed. Both groups showed similar declines; no difference was seen between them. Brain scans also revealed that both groups had experienced a similar decline in total brain volume.

The researchers did find some evidence that DHA may help a subgroup of people with a gene variant that is believed to increase the risk of Alzheimer’s disease. But that evidence was small and far from definitive.

Vitamin D and osteoarthritis
Observational studies have suggested that vitamin D might help slow down the progression of osteoarthritis, a degenerative joint disease that affects more than 20 million mostly middle-aged and elderly Americans.But a new study, whose results were presented last weekend at the American College of Rheumatology Annual Scientific Meeting in Atlanta, found that vitamin D supplements did nothing to ease the symptoms or slow the progression of osteoarthritis of the knee.

The study, which was conducted by researchers at Tufts University and funded by the National Institutes of Health, was a randomized, double-blinded, placebo-controlled trial — considered the gold standard of clinical trials. It involved 146 people (mostly white women, with an average age of 62) who had symptoms of knee osteoarthritis. They were randomly assigned to take either vitamin D or a placebo for two years. Those taking the vitamin D began with 2,000 IU of the supplement daily, a dosage that was upped in 2,000 IU increments until the amount of vitamin D in their blood was greater than 30 ng/ml (generally considered the optimal level for good health).

At the end of the study, the two groups showed no differences in tests that evaluated the physical function of their knees. Nor did MRI scans reveal any differences in such things as knee cartilage volume and thickness. The researchers concluded that vitamin D supplementation — at least in the doses used in this study — offered no benefits for knee osteoarthritis.

Green tea and breast cancer
It’s been proposed that one of the reasons the breast cancer rate is so much lower in Asian than in Western countries is because Asian women drink much more green tea.  According to this theory, the catechin in tea leaves (much higher in green than in black tea) acts as a kind of anti-estrogenic in the body.

Past epidemiological studies have produced conflicting results. Some have shown an association between green tea and reduced breast cancer; others haven’t. A new Japanese study, published late last month in the journal Breast Cancer Research, falls into the “no benefit” group. Using data from about 54,000 Japanese women, it found that the incidence of breast cancer over a five-year period was no different for women who drank more than 10 cups of green tea daily than for those who drank less than 1 cup per week.

This is the first study to include a wide range of tea consumption. Of course, like the previous studies, this one was observational, which means it can’t prove or disprove that something causes (or prevents, in this case) anything. It can just show an association. And in this case the study found no association between the drinking of green tea and the risk of breast cancer, no matter how many cups are downed daily.

Multivitamins and prostate cancer
Bayer recently handed over $3.3 million to the attorneys general of Illinois, Oregon and California for falsely suggesting on its packages of One A Day Men’s Health Formula that the multivitamins could help prevent prostate cancer.

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As the New York Times reported, the packages carried the following statement: “Did you know that prostate cancer is the most frequently diagnosed cancer in men and that emerging research suggests Selenium may reduce the risk of prostate cancer?”

But emerging research has found just the opposite to be true. The federally funded SELECT study (Selenium and Vitamin E Cancer Prevention Trial) was actually halted in 2008 after finding that not only did selenium supplements fail to reduce the risk of prostate cancer, they also increased the risk of diabetes.