Vitamins and Supplements

Key Points

• Many people get all the nutrients they need by eating a healthy diet.

• Supplements may be recommended if a person has vitamin deficiencies or to promote health.

• More research needs to be done to understand the risks and benefits of fish oil (omega-3 fatty acids) supplements for people with Down syndrome.

Introduction

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, supplements may not be needed. 

Vitamin D

Vitamin D plays an important role in bone health. Some data from a review of studies on vitamin D and depression  in people without Down syndrome 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 places further from the equator, 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

Fish oil (omega-3 fatty acids)

Potential benefits

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 and without Down syndrome. 

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’s Do Omega-3s Help Arthritis  article 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 Down syndrome. However, we do see many people with Down syndrome 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 Down syndrome and is underdiagnosed. So, it is likely that there are people with Down syndrome 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. 

Another study on omega-3 fatty acids  found that people without Down syndrome 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 Down syndrome (such as in this study) to people with Down syndrome is that people with Down syndrome 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 Down syndrome.

Potential risks

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

A finding from a study published in 2024  complicates the decision for taking fish oil/omega-3 fatty acids. The 2024 study found that people without heart disease had a greater risk of developing atrial fibrillation when taking fish oil/omega-3 fatty acids. Atrial fibrillation is an abnormal heart rhythm that puts people at an increased risk of developing a stroke. This study was not done in people with Down syndrome so the implications for people with Down syndrome are not known.

Studies by Sobey et al. (2015)  and Ntiloudi et al. (2023)  found that people with Down syndrome have a greater risk of embolic strokes (strokes caused by a clot forming in the heart and going to the brain). This is thought to be due to congenital heart disease. One of the reasons these clots can form is abnormal heart rhythms. Abnormal heart rhythms (including atrial fibrillation) are a known complication in adults with a history of congenital heart disease. We are not aware that research has looked at whether people with congenital heart disease are even more at risk for abnormal heart rhythms if they take fish oil/omega-3 fatty acids. However, this concern could make people with Down syndrome, especially those with a history of congenital heart disease, decide to hold off on taking fish oil/omega-3 fatty acids until more research is available.

Conclusion

My recommendation for a person with Down syndrome 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 from the equator (but more data are needed to know the benefit in people with Down syndrome).

  • 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 inflammation associated with arthritis (but more data are needed to know the risks and benefits in people with Down syndrome). 

  • 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). 

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 www.myDSC.org .