Flaxseed’s lack of effect on hot flashes may be surprising but only if no one’s keeping track

Let’s see ... St. John’s wort for depression, echinacea for colds and now flaxseed for hot flashes. Again and again, popular herbal remedies have failed to deliver when put to the scientific test. In the latest round of herbal disappointment, researchers at the Mayo Clinic in Rochester, Minn., announced that flaxseed didn’t seem to relieve hot flashes any better than a placebo. The researchers said they were “surprised,” but perhaps a successful trial would have been a little more jaw-dropping.

The study included 188 women who suffered from hot flashes, either as a result of breast cancer or menopause. Half ate a bar with 40 grams of flaxseed every day for six weeks; the other half ate a bar with no flaxseed. Roughly a third of the women in each group said their hot flashes improved, which suggests a couple of important take-home messages: Hot flashes often get better on their own. And flaxseed is, generally speaking, about as helpful as any other random thing you could find in your pantry.

Flaxseed seemed somewhat promising at first because it contained phytoestrogens, the plant versions of female hormones. Because diminishing hormones certainly help fuel hot flashes, it stood to reason that phytoestrogens might help put out the fire. Many women who take flaxseed say it helps. And a much-publicized pilot study of 29 women conducted by the same researchers at the Mayo Clinic suggested that it could bring real relief.

But that first study didn’t compare flaxseed with a placebo, which means that nobody should have believed it in the first place. People who are suffering from hot flashes — or pain or depression or allergies — have a strong desire to get better. Give them a pill, and their symptoms might very well start to fade, even if that pill contains nothing but sugar and gelatin. The original study evidently captured the placebo effect in action.

Many people often have especially high hopes for herbal products because they deeply believe that a natural product will be more effective than something cooked up in a lab. But the placebo effect isn’t limited to herbs. Studies of prescription antidepressants have found that about 30% of patients get better with the help of placebo alone, which makes sugar pills only slightly less powerful than Prozac.

The latest study from the Mayo Clinic simply confirms something that every consumer should keep in mind. A natural product may have a lot of believers and a good reputation, but it might not be the best option out there. In fact, it might not even be better than nothing at all.