Mind and memory supplement scorecard

Reliable evidence that supplements actually work is lacking, but exercise and a Mediterranean-style diet support healthy brain aging.

Can taking a pill improve your memory or boost your brain function? Never has one question launched so many health newsletter articles—not to mention so many purchases online and at the drugstore. "My patients and their families ask a lot about supplements, and I try to point them to whatever evidence we have," says Dr. Gad Marshall, an assistant professor of neurology at Harvard Medical School. He also helps to run clinical trials for Alzheimer's disease at Harvard-affiliated Brigham and Women's Hospital.

Dr. Marshall's list of supplements that people ask about include B vitamins (folic acid, B6, and B12), antioxidants (vitamins C and E, coenzyme Q10), herbal supplements (huperzine A, ginkgo biloba), and nutraceuticals (fish oil, curcumin, coconut oil). For now, you can cross most of these products off your shopping list for lack of evidence. "There are a lot of things out there for which we have no data on whether they are safe or do anything to help," Dr. Marshall says.

But there is one bright spot in the dietary approach to preserving the mind with aging. It comes in the form of healthy eating and regular exercise. "My strongest recommendations are a Mediterranean-style diet and regular physical exercise," Dr. Marshall says. "There's good evidence from multiple studies showing that these lifestyle modifications can prevent cognitive decline and dementia and also slow down existing cognitive decline."

Lack of evidence

If we have any reliable scientific information about supplements to preserve or improve memory and other mental skills, it has come from clinical trials involving people at risk of mental decline or who have already developed Alzheimer's disease. In these studies, people have been assigned at random to take either the supplement or an inactive placebo pill.

Dr. Marshall says that in large, well-designed clinical trials, only high doses of vitamin E have been shown to modestly help people who already have moderate dementia. In contrast, a growing number of clinical trials have failed to document a benefit to the mind or memory from the herbal supplement ginkgo biloba. The latest, in the October 2012 Lancet Neurology, found that ginkgo extract did not slow the decline of older adults into dementia.

Safety issues

Some popular memory supplements raise safety concerns. "Vitamin E at doses higher than 400 international units (IU) per day is risky for people with active cardiovascular disease or risk factors for it," Dr. Marshall says. "There have been several studies showing that at these high doses there was a small increase in the death rate."

Research has also found that taking 400 IU of vitamin E or more per day may raise the risk of prostate cancer. Unfortunately, the only convincing evidence for a benefit of vitamin E (for people with moderate Alzheimer's disease) comes from a study involving a relatively high dose: 2,000 IU per day.

Vitamin E, ginkgo biloba, and fish oil supplements may slightly inhibit blood clotting. That means combining these supplements with an anticoagulant drug, such as warfarin (Coumadin), could make you bleed or bruise more.

Supplement buyers: Beware

Caveat emptor, Latin for "let the buyer beware," should be your guide when it comes to considering supplements for mind and memory. Because of a legal loophole, dietary supplements do not have to pass the rigorous FDA process to ensure they are safe and effective. That means many of these products are on the shelves claiming to "support" or "help" memory because of a gap in the law—not because we have strong evidence that those claims are true.