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For people with Down syndrome, family members, caregivers and professionals.

Vitamins and Supplements

May 2022 | Brian Chicoine, MD - "Ask Dr. Chicoine" LuMind IDSC Foundation

We received the following question: 

What vitamins and supplements would you recommend for adults 18 with Down syndrome? I have read that 2x the recommended daily dose of fish oil has been linked to improved cognition, for instance.

For many people (not all), eating a healthy diet gives their bodies all the nutrients they need. My recommendation is to look at one's diet first before considering supplements. I recommend a well-balanced diet that provides the macronutrients (carbohydrates, protein, and fat) and the vitamins and minerals needed. If you are uncertain, a registered dietician can provide guidance. If a healthy diet is being followed, supplementations may not be needed. 

Supplements may be needed if there are vitamin deficiencies that cannot be addressed through diet. Supplements may also potentially benefit conditions of impaired health.

Vitamin D plays an important role in bone health. Some data from a review of studies in people without Down syndrome (DS) suggest that it also may reduce depression symptoms. Vitamin D is found in some foods and is made from cholesterol when the skin is exposed to sunlight. Vitamin D deficiency can be a common deficiency in northern climates, especially during the winter when there is less direct sun exposure. A vitamin supplement may be needed, especially if you live further north. 

Vitamin B12 is another vitamin to consider. Vitamin B12 deficiency is more common in people who follow certain diets that may not provide enough vitamin B12 (such as a vegan diet). Vitamin B12 deficiency is also more common in people who have certain digestive disorders (such as celiac disease). Celiac disease is more common in people with Down syndrome so these individuals may also be deficient in vitamin B12. 

There are some data (in people without Down syndrome) that fish oil (omega-3 fatty acids) may improve cognition while other studies did not demonstrate that benefit. Older studies found that individuals benefitted if the fish oil came from food rather than in a supplement form. A more recent small study of omega-3 fatty acids (33 individuals) showed that it took higher doses of fish oil for the omega-3 to reach the brain. Supplements were required to provide these higher doses, and the levels of omega-3 were measured in the spinal fluid to confirm enough was getting to the brain. The need for higher doses was especially noted for those with APOE4 gene (who are at a greater risk for Alzheimer’s disease). The answer is not yet known if those higher levels in the spinal fluid will improve cognition or reduce Alzheimer’s disease.  More study is needed to understand the potential cognitive benefit in people with or without DS. 

Fish oil has been found to reduce inflammation that may play a role in the development of Alzheimer’s disease and is also associated with arthritis. The Cleveland Clinic provides more information, including ways to get more omega-3 in your diet. We can find no studies on the use of omega-3 to treat arthritis specifically in people with DS. However, we do see many people with DS who have osteoarthritis (arthritis often attributed to wear and tear over time). It is also known that inflammatory arthritis is more common in people with DS and is underdiagnosed. So, it is likely that there are people with DS with joint discomfort or ongoing joint destruction from arthritis. Research needs to be done to know if those individuals would benefit from omega-3 supplements. 

A downside to taking omega-3 supplements is the potential side effects including: 

  • belching

  • a bad taste in the mouth

  • bad breath

  • heartburn

  • nausea

  • loose stools

Another study on omega-3 fatty acids found that people without DS who were cognitively healthy but had coronary artery disease (blockages in the arteries supplying blood to the heart) who took omega-3 supplement had better preserved brain function than those who didn’t take the supplement. There is a saying, “Good for the heart, good for the brain,” which the study would seem to support. The challenge in translating that finding from people without DS (such as in this study) to people with DS is that people with DS have much more Alzheimer’s disease but much less coronary artery disease. Our articles on heart disease in adults with Down syndrome and prevalence of common disease conditions share more information on this topic. This difference makes it clear that more study is needed to improve our understanding, especially in people with DS.

My recommendation for a person with DS is to: 

  • Review the diet and optimize nutrients from the diet.

  • Review your needs and these suggestions with your health provider to confirm they are correct for you.

  • Consider a vitamin D supplement, especially if you live further north (but more data are needed to know the benefit in people with DS).

    • Vitamin D supplements can interact with some medications, so reviewing your medication list with your physician or pharmacist before taking vitamin D supplements is recommended.

  • Consider taking an omega-3 fatty acid supplement for possible cognitive benefits and reduction of inflammation including that associated with arthritis (but more data are needed to know the benefit in people with DS). 

    • Fish oil contains some omega-3 fatty acids.

    • No interaction is anticipated between omega-3 fatty acid supplements and vitamin D supplements.

    • Omega-3 supplements can interact with a variety of medications, particularly medications that reduce blood clotting, so reviewing your medication list with your physician or pharmacist before taking omega-3 supplements is recommended.

  • Consider reviewing your food intake with a dietician to make sure you are getting appropriate nutrients, especially if you eliminate some foods from your diet (such as a vegan diet). Supplements may be needed based on that review.

  • Watch for and consider participating in studies on cognition (particularly those that look at nutritional supplements). 


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This article was adapted from a Q&A developed in partnership with LuMind IDSC Foundation. This Q&A is available for free along with other Q&As at

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