Some people with Alzheimer’s disease may want to try supplements as a complementary therapy alongside other treatments. However, direct evidence to support using supplements for Alzheimer’s disease is scarce.

Alzheimer’s is a progressive neurodegenerative condition that causes memory loss and cognitive decline. It usually begins with mild memory loss. Over time, a person may lose the ability to continue conversations and respond to their environment.

This article examines five different supplements people may wish to try to help with symptoms of Alzheimer’s disease. It also discusses some important health considerations to think about before taking supplements and when to contact a doctor.

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Alzheimer’s disease accounts for 60-80% of dementia cases, primarily affecting people ages 65 years and older. Doctors use dementia as a general term to describe symptoms that affect memory, communication, and thinking and interfere with a person’s daily life.

Alzheimer’s affected about 5.8 million people in the United States in 2020, and experts expect this number to nearly triple to 14 million by 2060.

The National Center for Complementary and Integrative Health (NCCIH) suggests that while a small number of studies on the prevention of dementia and cognitive decline indicate that supplements may have some modest effects, direct evidence to support their use is scarce.

The Food and Drug Administration (FDA) warns people against using supplements that companies market as cures for Alzheimer’s disease.

Furthermore, the Alzheimer’s Association notes that no substantial evidence suggests supplements can cure, treat, or prevent Alzheimer’s disease. Dietary supplements are not substitutes for a healthy diet and doctor-approved medications.

It is also important to consider the following before taking any supplements:

  • Safety and effectiveness: The FDA cannot subject manufacturers of dietary supplements to the same rigorous scientific research as makers of prescription medications. Dietary supplement manufacturers are not required to provide the FDA with the evidence on which they base their claims of safety and effectiveness.
  • Unvalidated purity: The FDA does not have authority over the dietary supplement manufacturing process. Manufacturers are responsible for developing and enforcing their own guidelines and standards to ensure that products are safe and contain the ingredients listed on the label in the appropriate amounts.
  • Risk of adverse drug interactions: Taking dietary supplements with doctor-prescribed medication may cause severe adverse reactions. It is always best to speak with a doctor before using supplements, especially if people are taking any medications.

According to the NCCIH, ginkgo biloba is one of the oldest tree species in the world, with a long history in traditional Chinese medicine.

A 2017 systemic review evaluated the efficacy and effectiveness of ginkgo biloba extract in treating dementia. The researchers noted that extracts from the ginkgo plant have potentially beneficial effects for people with dementia at doses greater than 200 milligrams per day for around 22 weeks or longer.

However, the researchers also highlighted that further research is necessary due to methodological limitations and the low quality of studies they investigated in the review.

Furthermore, the NCCIH indicates that while some research suggests ginkgo may help slightly with some symptoms of dementia, scientists have described the findings as unreliable. Additionally, other studies have had conflicting results.

Potential side effects

Ginkgo leaf extracts may cause the following side effects:

Vitamin B-complex supplements include all of the essential B vitamins in one pill. There are also individual B vitamin supplements.

According to the NCCIH, findings from short-term studies into B vitamins, including B12, B6, and folic acid, suggest they do not help improve cognitive functioning in adults ages 50 years or older, regardless of dementia. However, long-term studies have had more promising results.

A French study from 2016 that examined the association between dietary B vitamins and a 10-year risk of dementia in 1,321 older adults found that a higher intake of folate was associated with a lower long-term risk of dementia. However, there was no evidence of an association between vitamin B6 and B12 intake and dementia risk.

A 2022 review and analysis of 95 studies involving 46,175 participants found that vitamin B supplementation may slow cognitive decline when people take it as an early, long-term intervention.

The authors also indicated that a higher dietary folate intake was associated with a lower risk of incident dementia in older populations without dementia.

Potential side effects

Side effects of vitamin B supplements may vary. For example, side effects of excessive vitamin B6 intake may include:

Curcumin is an active component in the turmeric plant with antioxidative and anti-inflammatory properties.

However, according to the NCCIH, clinical trials into the effects of curcumin on Alzheimer’s disease are limited, and findings are inconsistent. Researchers recommend further study in this area.

Potential side effects

High doses or long-term use of curcumin may cause:

Vitamin E is a fat-soluble vitamin that acts as an antioxidant. There are eight naturally occurring forms of vitamin E, and supplements are available in natural or synthetic forms.

A 2022 review assessed the link between vitamin E intake with the risk of dementia. According to the researchers, high vitamin E intake from supplements and diets may significantly lower the risk of dementia and Alzheimer’s disease.

However, they highlighted that their research had limitations, and their results require validation by further studies.

Potential side effects

Some common side effects of vitamin E include:

  • nausea
  • headache
  • vision changes
  • gastrointestinal upset

According to the National Institute of Health (NIH), dietary supplements containing omega-3 fatty acids include:

The authors of a 2017 research review noted that people who carry a gene called APOE4, which is associated with an increased risk of Alzheimer’s disease, may benefit from taking a type of omega-3 fatty acid called docosahexaenoic acid before they experience any symptoms of the condition.

Potential side effects

Side effects are usually mild and may include:

  • nausea
  • a fishy taste in the mouth
  • diarrhea

It is best to speak with a doctor before taking any dietary supplements due to the possibility of adverse drug interactions, which can arise from food and other supplements and medications.

A healthcare professional may also be able to suggest reputable supplement manufacturers. Alternatively, they may recommend ways to modify the diet to include foods that contain certain vitamins and other nutrients instead.

Several health organizations argue that no conclusive evidence supports taking supplements to prevent, cure, or treat Alzheimer’s disease. The FDA also does not regulate dietary supplements in the same way as prescription medications.

Research about the effects of different dietary supplements on Alzheimer’s disease, including whether they may be useful and at which doses they may be safe, is ongoing.

If a person wishes to try any supplements, it is best for them to speak with their doctor before doing so to avoid the risk of drug interactions and learn about potential side effects.