Another disappointing clinical trial found that over-the-counter dietary supplements work no better than placebos at halting the detrimental effects of Alzheimer’s disease. This time, the supplements tested were antioxidants -- vitamin E, vitamin C, the omega-3 fatty acid ALA, and coenzyme Q. The same research group determined in a study published 18 months ago that fish oil supplements didn’t stop the progression of Alzheimer’s either.
The current study, published Monday in the Archives of Neurology, was small but well designed, randomly assigning two different combinations of daily antioxidants or placebos to some 60 patients with mild to moderate Alzheimer’s disease for nearly four months. At the end of the study, samples of spinal fluid collected from the patients at the beginning and end of the study showed no change in levels of markers associated with Alzheimer’s, including amyloid proteins that form telltale plaques in the brain.
What’s troubling, though, is that the group that received a combination of vitamins E, C, and the fatty acid ALA had a greater amount of cognitive decline compared with the group given placebos or the one given coenzyme Q.
“That was a really surprising finding,” said Dr. Gad Marshall, associate medical director of clinical trials at Brigham and Women’s Hospital’s Center for Alzheimer Research & Treatment, who wasn’t involved in the study. “I would have expected these supplements to have had a neutral effect on symptoms.”
The study authors, from a variety of academic institutions participating in the Alzheimer’s Disease Cooperative Study, cautioned that the worsening of symptoms in those taking the combination supplement “raises a caution” for future research studies examining the effects of antioxidants on dementia.
Marshall told me his Alzheimer’s patients and their families frequently ask him for recommendations on dietary supplements, many willing to try anything to halt the devastating progression of the disease. “I usually don’t recommend them since the data from clinical trials has been so limited, with most showing no benefit,” he said.
While several prescription drugs are approved for treating Alzheimer’s, he added, they have only modest benefits in most patients, delaying the progression of symptoms by an average of six months.
What Marshall does recommend to patients who are looking to enhance the benefits of these medications is two lifestyle factors that have proven benefits in clinical trials: daily exercise and a Mediterranean-style diet based on fruits, vegetables, nuts, legumes, whole grains, and fish, with little red meat. “Unlike supplements, both of these measures have been shown to prevent or slow the progression of Alzheimer’s disease,” he said, “at least to a certain extent.”