Will a pill purchased at a vitamin store or supermarket help you remember where you left the car keys? Stave off Alzheimer’s disease? Or help a person better cope with dementia? Dietary supplements with names such as Focus Factor and Cognitex are marketed to people who want to defog fuzzy memories and age-proof their brain. However, while over-the-counter and prescription drugs go through rigorous clinical trials to prove they work before reaching pharmacy shelves, supplement sellers can peddle their products without testing them for safety or efficacy.
In fact, because there is minimal FDA regulation of dietary supplements, there’s no way to be sure how much of the active ingredient on the label is even in the product, or if it contains other potentially harmful substances—nor whether it works or is safe.
Claims made about some alleged memory supplements have come under scrutiny by regulators. In 2017, the Federal Trade Commission and the state of New York sued the makers of Prevagen, which contains a substance called apoaequorin (derived from a protein found in jellyfish), for falsely claiming that the product improves memory. A judge dismissed the case—a decision criticized by many scientists,who say there is no solid evidence that Prevagen enhances recall and fights forgetfulness. An appeals court reversed the dismissal in February 2019 and the case is proceeding.
Scientists are equally skeptical about many other dietary supplements touted as being able to prevent recall problems or bolster memory and cognition. Here’s what’s known, and not known, about some of the most widely used dietary supplements marketed “for brain health.”
Practitioners of Ayurvedic medicine, which originated in India 3,000 years ago, have long recommended the herb Bacopa monnieri for improving memory and overall brain function. However, a 2013 meta-analysis (a type of study that combines data from multiple clinical trials) in theJournal of Ethnopharmacology found no evidence that bacopa supplements sharpen memory or offer any other cognitive benefit. Moreover, some participants in the studies analyzed reported gastrointestinal problems while taking the supplement.
A nutrient found in foods such as eggs, meat, and peanuts, choline is needed to form acetylcholine, a neurotransmitter essential for forming memories. Research has shown that adding choline to the diets of lab rats improves their memory, and a few small studies detected improved performance on memory tasks in humans treated with a combination of choline and caffeine—but not with either substance alone. However, a study published in 2016 in the journalPLOS One failed to find any memory improvement in healthy young adults who drank orange juice supplemented with choline.
Short for dimethylaminoethanol, DMAE is chemically related to choline. It’s commonly sold as an individual supplement, as well as included in pills containing multiple ingredients marketed as brain boosters. But there’s little evidence that a DMAE supplement will make your mind sharper.
Some researchers believe that docosahexaenoic acid (DHA), an omega-3 fatty acid found in fatty fish and fish oil, has anti-inflammatory and antioxidant effects, and can help aging adults maintain sharp memories. DHA promotes the growth of new neurons and synapses (connections between neurons).
Eicosapentaenoic acid (EPA), another omega-3 fatty acid in fatty fish and fish oil, fights inflammation and promotes blood flow, both of which are critical for brain health. Yet evidence that fish oil supplements preserve healthy cognition and memory is mixed. A meta-analysis published in PLOS One in 2015 found evidence that taking 1 g of fish oil daily improved episodic memory—the ability to recall earlier experiences. But fish oil supplements have flopped in other studies, such as a trial published in 2018 in the American Journal of Clinical Nutrition, in which neither DHA nor EPA supplements slowed cognitive decline in aging adults.
A large, three-year randomized clinical trial published inThe Lancet Neurology in 2017 similarly found that taking an omega-3 fatty acid supplement, either alone or combined with lifestyle interventions (nutritional advice, physical activity, cognitive training), was no more effective than a placebo at slowing cognitive decline. Several studies have also indicated that fish oil supplements offer no cognitive benefit for people already diagnosed with Alzheimer’s disease. However, in yet another study, researchers found that older adults with normal age-related cognitive decline who took 900 mg of DHA daily scored slightly better on a memory test than those receiving a placebo.
One of the oldest species of trees, the ginkgo produces leaves that are used to make one of the most popular of all memory supplements. Researchers hypothesize that ginkgo biloba has anti-inflammatory and antioxidant effects, and suggest that this is how it might prevent dementia. In Europe, an extract of this herb is sold as a drug (known as EGb761) for treating age-related memory loss, poor concentration, and other cognitive problems.
There is moderate evidence that ginkgo can help treat dementia, but not prevent it. In 1997, a widely publicized study in the Journal of the American Medical Association found that ginkgo improved mental functioning in people with Alzheimer’s disease. But a review of 35 studies by the Cochrane Collaboration in 2008 concluded that the overall evidence for ginkgo as a treatment for dementia or cognitive impairment is “inconsistent and unconvincing.” Since then, many more studies have been done.
A 2014 review of seven clinical trials in Clinical Investigations in Aging found that EGb761 extract is at least modestly effective in people with dementia, as did a 2015 review of 15 trials in the Journal of Pharmaceutical Health Care and Sciences. And still another review, in the Journal of Alzheimer’s Disease in 2015, looked at nine clinical trials and concluded that EGb761 can stabilize or slow decline in cognition and function in those with impairment or dementia.
As for prevention, a large, well-designed study of healthy people 75 and older, published in the Journal of the American Medical Association in 2008, found no evidence that ginkgo (EGb761) helps prevent dementia, including Alzheimer’s. In 2009, a follow-up study found that the supplement did not slow cognitive decline or memory loss in any way. In 2012, a study in Lancet Neurology looked at 2,850 older French adults with self-reported memory complaints, half of whom took the EGb761 extract twice daily, half a placebo. After five years, ginkgo did not slow progression to Alzheimer’s.
A 2014 review in the European Archives of Psychiatry and Clinical Neuroscience concluded that ginkgo has no effect on cognition in young or healthy older people: “There are no positive effects on vigilance, attention, reaction time or higher cognitive functioning such as memory, no matter which amount of Ginkgo was used or how frequently.”
In the 1980s, scientists studying the herb Huperzia serrata, used in traditional Chinese medicine, isolated a substance they named huperzine A. This substance is a natural cholinesterase inhibitor believed to have antioxidant and neuroprotective effects similar to those of common Alzheimer’s disease drugs such as donepezil (Aricept), rivastigmine (Exelon), and galantamine (Razadyne). Several small, randomized controlled trials in China indicate that the supplement could lead to improvements in cognitive function tests, and huperzine A is prescribed in China and some other countries for Alzheimer’s disease.
A 2013 review and analysis of studies done to date, published in PLOS One, found evidence that huperzine A might improve cognitive function and quality of life in people with Alzheimer’s disease; however, the authors noted that the quality of the research was generally poor, raising doubts as to whether the supplement truly offers much benefit.
This lipid, or fat, is essential for healthy brain cells. Some research in the early 1990s suggested that consuming up to 300 mg of PS daily might improve brain function in aging humans. However, at that time, cow brains (which contain DHA) were the raw material used to produce PS supplements, a practice that ended due to concerns about bovine spongiform encephalopathy (aka mad cow disease). Today, most PS supplements are derived from soybeans, which don’t contain DHA.
Several studies by researchers in Israel have found that older adults who had complaints of poor memory and took a pill containing both PS and DHA (from fish oil) experienced improvements in theirability to recall lists of words. The authors noted, though, that people who were pretty sharp to beginwith were the ones most likely to benefit from the pills.
A purple-flowering plant called the lesser periwinkle contains a vasodilator (a compound that widens blood vessels) that served as a model for vinpocetine, a substance that is produced in a lab. Vinpocetine is considered a drug in Europe and some other countries, but is sold as a dietary supplement in the United States.
Although vinpocetine is marketed for sharpening memory and improving all-around cognitive function, there is little research to suggest it does either. Studies on its benefit for people with dementia are dated and not very convincing.
Curcumin is the primary yellow pigment in the spice turmeric; think of the color of curry powder. It’s thought to have anti-inflammatory, antioxidant, and cholesterol-lowering effects, and researchers are studying its potential as a treatment for age-related diseases. In animal models of Alzheimer’s disease, curcumin reduced brain inflammation, oxidative damage, and the accumulation of plaque deposits of beta-amyloid.
A study in the Journal of Alzheimer’s Disease found that curcumin, coupled with vitamin D3 (a form of vitamin D), may stimulate the immune system to clear beta-amyloid from the brain in animal models. But much more research is needed to confirm its role in treating Alzheimer’s disease in human beings. The few human studies done so far have yielded conflicting results.