|May 1998 U.S. Edition|
But some researchers aren't wowed by the results. "This is a seriously limited and flawed study," says Steven Ferris, director of the Alzheimer's Disease Research Center at New York University. "The improvements seen in the ginkgo-taking group were so slight that the clinicians who were taking care of the Alzheimer's patients didn't even notice any changes." And more than half of the people who started the trial dropped out before it ended, he adds, which could have exaggerated ginkgo's impact.
Then again, the world isn't exactly awash in Alzheimer's treatments. In a 1997 clinical trial, 1,000 IU of vitamin E twice a day slowed the progression of Alzheimer s.2 But it didn t stop or reverse the disease.
"This fall, a three-year study will start testing vitamin E on people at very high risk of developing Alzheimer's," says Ferris.
-- David Schardt
1 J. Amer. Med. Assoc. 278: 1327, 1997.
2 New. Eng. J. Med. 336: 1216, 1997.
Want something that can prevent heart disease, cut the risk of cancer, rejuvenate your sex life, and postpone aging? DHEA is the answer, according to a chorus of books, magazine articles, and supplement companies.
In our March 1997 article ("DHEA Not Ready for Prime Time"), we pointed out that none of the claims had been substantiated by good research. We also cautioned that the body converts DHEA into testosterone, a hormone that can stimulate the growth of prostate cancer.
Since then, two trials testing DHEA in humans found no significant benefits, though both were small and brief. What's more, several DHEA experts are now urging caution.
Proponents say that taking DHEA produces a sense of well-being. Yet, in one of the two new studies, 50 mg a day for two weeks produced no measurable psychological changes in 40 healthy older men and women compared with when they were taking a placebo.1
In the other, 36 seniors who took 50 mg of DHEA just before being given a flu shot did not produce any more flu-fighting antibodies than 35 seniors who were given a DHEA-free placebo.2
Meanwhile, Ray Sahelian, a California physician who edits a DHEA newsletter, reports that he has heard of 30 cases of heart palpitations or irregular heartbeats in people taking DHEA and/or another hormone, pregnenolone.
Until more research is done, he says, "I do not recommend more than 10 mg a day of DHEA unless you are very closely monitored by a healthcare professional familiar with these hormones."
Samuel Yen, the University of California at San Diego endocrinologist whose trials are often cited by DHEA proponents, goes even further: "I strongly discourage the use of over-the-counter DHEA."
1 J. Clin. Endocrin. Metab. 82: 2363, 1997.
2 J. Clin. Endocrin. Metab. 82: 2911, 1997.