Nutrition, Natural Products and Supplements
Diet can have a major impact on the health of your brain. Supplements, traditional herbs, nutraceuticals and other natural products can also affect your health. Could they protect your brain? Are they safe? Here, we rate the scientific evidence and give you the info.
* See the Evidence guide for color legend and more information.
Lithium: Dietary and Supplement Doses
Lithium is a mineral naturally found throughout the body. Lithium at dietary or supplement doses between 0.3 to 5 mg/day could theoretically protect the brain but the evidence is limited to one clinical trial. Although higher doses of lithium (eg. 150-1200 mg/day) may cause serious side effects, the doses below 5 mg found in tap water and most supplements are unlikely to cause harm.
Fish and long-chain omega-3 fatty acids, DHA & EPA
Long-chain omega-3 polyunsaturated fatty acids are found in fatty fish and fish oil. In many studies, people have been less likely to develop Alzheimer’s disease if they had more of these fatty acids in their blood or had a long-term habit of eating fish every week. However, these studies have many surprising discrepancies and, in clinical trials, supplementation has generally not improved cognitive function.
Resveratrol is an antioxidant found in foods such as grapes, berries, and peanuts, chocolate and red wine. Although it is still unclear whether resveratrol has any benefits in healthy people, some small clinical trials suggest that it may help those with certain health conditions. Taking resveratrol supplements is generally regarded as safe although long-term use has not been studied.
Extracts of the plant Rhodiola rosea are traditional herbal medicines intended to enhance performance and reduce fatigue. They have also been hypothesized to alleviate a wide range of conditions including altitude sickness, depression, influenza, and cancer, but the evidence for all of these claims is weak, contradictory and inconclusive. Rhodiola supplements are considered generally safe for healthy people.
Buckminsterfullerene (C60) is a molecule with unusual properties that was discovered in the late 1980’s and is being investigated for cancer treatments, skin care carbon nanotubes, and other applications. Several laboratory studies suggest that the water-soluble form of C60 may have neuroprotective properties and the non-hydrated forms dissolved in olive oil might extend lifespan. However, these claims have never been tested in humans. Similarly, the safety of C60 and its derivatives have never been tested in humans.
Coenzyme Q10 (CoQ10) is a natural vitamin substance that is essential for energy production in cells. While CoQ10 supplementation has shown beneficial results in animal models of neurodegenerative diseases like Alzheimer’s, it has failed in human clinical trials. There is no evidence that CoQ10 supplementation can increase human lifespan. Very few adverse effects have been reported with CoQ10 supplementation and it is generally considered safe for most people.
Fisetin is naturally found at very low levels in some plants, fruits and vegetables. Some cell and animal studies suggest that fisetin may protect brain cells from damage, potentially improve diabetes and inhibit cancer, but there is no evidence yet that it does the same in humans. While concentrated fisetin is commercially-available as a dietary supplement and often marketed as a “memory enhancer”, almost nothing is known about how it acts in the human body to cause either harm or benefit.
L-carnitine is a natural compound made by the body that helps turn fat into energy. Supplements are generally safe and well-tolerated. L-carnitine and related supplements are not likely to benefit Alzheimer’s patients to a meaningful degree but some benefits might occur in other groups of people, including elderly people with fatigue and frailty.
Coffee and Caffeine
Caffeine or coffee may protect against cognitive decline and dementia but no evidence is available from clinical trials in humans. Instead, the research has been gathered from isolated cells, animals, and observations that people who drink coffee in moderation tend to have less dementia. More research is needed. The safety of caffeine or coffee intake should be considered separately for each individual.
Multiple studies have demonstrated that Ginkgo is not effective at preventing cognitive decline or dementia. It may improve memory in people with cognitive impairment or dementia but probably not in healthy people. Ginkgo is available as an herbal supplement from many different sources and is generally considered safe for use by healthy people.
Low-to-Moderate Alcohol Consumption
Heavy drinking can raise your risk of dementia while long-term use of low-to-moderate alcohol levels might protect the brain, although the evidence for protection is weak and mixed. Moderate intake is typically defined as 1 serving (equal to 15 grams of alcohol) a day for women and 2 for men. If you have already incorporated low levels of alcohol into your diet, it is generally considered safe to continue. But it is probably not a good idea to start drinking just to prevent dementia.
Vitamin D is essential for human health and may be important in aging and age-related cognitive decline. People get vitamin D from food and from their skin, which produces vitamin D when stimulated by sunlight. Many animal studies and observational studies in humans suggest low vitamin D levels are associated with age-related diseases, lifespan and mortality but these studies do not prove that vitamin D deficiency actually causes these diseases. Vitamin D supplements are generally considered safe when used correctly by healthy people. Large randomized trials are now needed to clearly define the role of vitamin D in human health.
Medium Chain Triglycerides
Medium chain triglycerides (MCTs) are a naturally occurring source of dietary fat. MCT supplements may briefly improve brain function in people with mild to moderate cognitive impairment by providing an additional energy source for the brain. However, the clinical evidence is limited to small patient populations treated for short amounts of time. These supplements are considered generally safe for healthy people although gastrointestinal side-effects can occur.
Dietary Vitamins C and E
Vitamins C and E are essential for proper health. Some people with Alzheimer’s disease and dementia have low levels of these vitamins, although it has not been proven that the lack of vitamins caused their disease. Observational studies suggest that increasing dietary intake of vitamins C and E might protect against dementia although vitamin C and E supplements may not offer the same protection. Both vitamins are generally safe for supplementation in healthy people, although some studies have linked vitamin E supplementation with an increased risk of dying. Maintaining healthy levels of vitamins C and E in the diet may be better for most people than supplementation.
Melatonin is a powerful hormone produced by the pineal gland and is a key regulator of sleep. Melatonin production slows as we age and is especially compromised in Alzheimer’s disease, a factor that may contribute to disrupted sleep in older adults and dementia sufferers. Melatonin supplementation may improve some sleep-related symptoms in Alzheimer’s disease but there is no evidence that it slows or prevents Alzheimer’s disease or related dementias. Melatonin supplementation is usually safe for healthy people but there is limited information on its safety for long-term use.
Alpha Lipoic Acid
Alpha-lipoic acid (ALA) is a natural compound that helps cells make energy. Although a popular "anti-aging" supplement, animal research suggests that ALA can have either good or bad effects on brain health and lifespan. The evidence from human research is very limited and similarly mixed. ALA supplements are generally regarded as safe.
Ashwagandha is a common name for the plant Withania somnifera. It is used in Indian traditional medicine for symptoms of weakness, fatigue, stress, anxiety and depression. It is also claimed to prevent memory loss and improve cognition, but these claims are based primarily on anecdotal accounts and strong but not convincing research in isolated cells and animals. There is very little scientific evidence to show that ashwagandha consumption is beneficial to humans, and no evidence that it can slow cognitive decline or prevent Alzheimer's disease. Limited studies in humans suggest ashwagandha is safe for most people when used properly with some limitations.