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National Center for Complementary and Integrative Health

7 Things To Know About Dietary Supplements for Cognitive Function, Dementia, and Alzheimer’s Disease

Many dietary supplements are promoted with claims that they can enhance memory or improve brain function and health. And a few trials of natural products for the prevention of cognitive decline or dementia have shown some modest effects. However, direct evidence that dietary supplements can prevent Alzheimer’s disease or other forms of dementia is lacking. 

Here are 7 things to know about current research on dietary supplements for cognitive function, dementia, and Alzheimer’s disease.

  1. There’s no conclusive evidence that the herb Ginkgo biloba can prevent or slow dementia or cognitive decline. 

  2. Among dietary factors that have been studied to see if they can prevent cognitive decline in older people, the most consistent positive research findings are for omega-3 fatty acids, often measured as how much fish people consume. However, omega-3s in supplement form have not been shown to be helpful in treating Alzheimer’s disease.

  3. Only a small number of studies in people have looked at the effect of vitamin E in the prevention or treatment of Alzheimer’s disease. Most of the findings have been negative, but moderate-quality evidence from a single study suggests that vitamin E may slow functional decline in people with Alzheimer’s disease.

  4. The evidence on curcumin (a component of the herb turmeric) is too limited and inconsistent for any conclusions to be reached.

  5. Short-term supplementation with three B vitamins—vitamin B6, vitamin B12, and folic acid—has not been shown to improve cognitive functioning in older adults. However, longer-term studies have pointed to a possible role of these B vitamins in slowing cognitive decline. Talk to your health care provider if you’re considering supplements; taking too much vitamin B6 can cause serious side effects.

  6. Don’t use complementary health approaches as a reason to postpone seeing a health care provider about memory loss. Treatable conditions, such as depression, bad reactions to medications, or thyroid, liver, or kidney problems, can impair memory.

  7. Take charge of your health—talk with your health care providers about any complementary health approaches you use. Together, you can make shared, well-informed decisions.