A review of published research has found no evidence that drugs, herbal products or vitamin supplements help prevent cognitive decline in healthy older adults.
The review, conducted at St. Michaels Hospital in Toronto and published April 15 on the website of the Canadian Medical Association Journal, found some evidence that mental exercises, such as computerized memory training programs, might help.
The issue is of particular importance given that mild cognitive impairment affects 10% to 25% of people older than 70, according to a St. Michaels Hospital news release. Mild cognitive impairment is characterized by reduced memory, judgment and decision-making skills compared to someone of a similar age, but is not enough to interfere with daily activities.
Researchers reviewed 32 randomized clinical trials involving about 25,000 patients. They found no strong evidence for pharmacologic treatments such as cholinesterase inhibitors, which were developed to improve the effectiveness of acetylcholine, a chemical messenger that assists memory, thought and judgment.
Nor was there strong evidence that herbal supplements such as gingko improved cognitive functions, nor was there significant evidence for vitamins and fatty acids such as vitamin B6 or omega-3 fatty acids.
Some studies on estrogen actually indicated an increase in cognitive decline and dementia. Evidence on the value of physical exercise, such as strength training, was weak.
The strongest evidence was for the value of mental exercises such as computerized training programs or intensive one-on-one personal cognitive training in memory, reasoning or speed of processing.