Alternative medicine has started the year with a one-two hit.

First came the findings last week about Gingko biloba, the herbal supplement that millions of Americans have been taking to ward off memory problems as they age.

A large randomized double-blinded clinical trial (the gold standard of studies) found that the supplement did nothing to preserve or improve memory, concentration, or other cognitive (thinking) skills in the elderly.

Then, on Monday, a second randomized doubled-blinded clinical trial, this one conducted by researchers at the Mayo Clinic in Rochester, reported that another popular herbal supplement, St. John’s wort, was ineffective as a treatment for irritable bowel syndrome (IBS).

In fact, in that study, published in the January issue of The American Journal of Gastroenterology, the supplement actually did somewhat worse than the placebo at easing people’s symptoms.

 “I don’t think that we should be surprised by our findings, but we were definitely hoping that there would be a positive outcome from this, and there was not,” said Yuri Saito, MD, a gastroenterologist and the study’s lead author, in a phone interview on Monday.

Cause is unknown
IBS is a common and chronic disorder (not a disease) that affects the functioning of the colon. Its most common symptoms include abdominal pain, cramping, bloating, gas, diarrhea and constipation. The cause of IBS (what makes the colon supersensitive in some people) is unknown, but its symptoms can be aggravated by diet and stress. About 58 million people, mostly women, have the disorder.

There is no cure for IBS, but its symptoms can be controlled. Treatment usually involves a combination of dietary changes, stress management and medications aimed at specific symptoms, such as laxatives for constipation and antispasmodics for cramping.

Low doses of antidepressants have also been found to help people with IBS — perhaps because some of the same brain chemicals associated with depression (like serotonin) are also found in the gastrointestinal tract, where they may contribute to the colon’s supersensitivity. That’s one reason Saito and her colleagues wanted to study St. John’s wort. They thought it, like conventional antidepressant medications, might inhibit the uptake of these chemicals in the gut.

Saito said she had no trouble recruiting people in the Rochester area for the study.  “Everyone was really enthusiastic about this,” she said. “Part of that enthusiasm was because this was a natural herbal agent. I don’t think we could have gotten the same response if this had been a traditional medication.”

Because IBS is affected by diet and because it’s a life-long problem, people with the disorder are more prone than those with other gastrointestinal conditions to try alternative digestive supplements. “What I observe in clinic is that a lot of our patients are taking over-the-counter agents,” Saito said. “People are always asking me about them.”

“People really wanted [St. John’s wort] to work,” she added. “People were really hopeful that this would help their symptoms.”

The study details
But the study found the supplement didn’t improve IBS symptoms.

Here are the details: The researchers recruited 70 IBS patients, ranging in age from 21 to 68. They were randomly assigned to take either a placebo or 450 milligrams of St. John’s wort twice daily for 12 weeks. Neither the participants nor the researchers conducting the study knew who was taking what (the definition of a double-blinded study).

At the end of the treatment (and both groups scored high on sticking with the protocol), 15 percent of the people taking St. John’s wort said their IBS symptoms had improved either moderately or a lot.

But 26 percent of those taking the placebo reported the same.

Also, a higher percentage of those in the placebo group (50 percent) were willing to continue taking the “medication” assigned to them during the study to control their IBS symptoms than those in the St. John’s wort group (35 percent).

The study has its limitations, of course. Most notably, it involved only a small and rather heterogeneous group of patients. A larger multicenter trial would be helpful.

But don’t hold your breath waiting for such a study to get under way.

“It’s going to be hard to move forward with a significant study unless we could find somebody who would be interested in funding it,” Saito said.

And that’s unlikely. No herbal supplement manufacturer is going to want to fund a large, expensive study that may very well duplicate the findings of this smaller study — and shrink its customer base. More likely, the supplement manufacturers will say that this study is too small to be definitive — and continue to sell their product to people desperately seeking relief from their symptoms.

Supplement manufacturers are already picking away at the well-designed Gingko biloba study.

Once again: caveat emptor.