Understanding the Risks of Choline Supplements
Choline is an essential nutrient vital for several bodily functions, including cell structure, nervous system function, and fat metabolism. The human liver produces a small amount of choline, but most must be obtained from the diet, with rich sources including eggs, meat, and vegetables. For most healthy individuals, dietary intake is sufficient, and supplementation is not necessary. However, some people, such as pregnant women or those with certain genetic conditions, may be at higher risk for deficiency and might need extra choline under medical supervision. While beneficial for some, high-dose choline supplements can pose serious risks for others.
Individuals with Bipolar Disorder
For people with bipolar disorder, choline supplementation can potentially worsen depressive symptoms. Choline is a precursor to acetylcholine, a neurotransmitter that plays a role in mood and other brain functions. In individuals with this condition, excessive choline levels can disrupt the delicate balance of neurotransmitters, leading to adverse effects on mood and overall mental health. Consultation with a healthcare provider is essential for anyone with a psychiatric disorder who is considering a choline supplement.
People with Trimethylaminuria
Trimethylaminuria (TMAU), often called "fish odor syndrome," is a rare metabolic disorder where the body cannot properly break down trimethylamine (TMA), a metabolite of choline. In healthy individuals, the enzyme flavin-containing monooxygenase 3 (FMO3) converts TMA into an odorless compound. However, in people with TMAU, this enzyme is deficient, causing TMA to accumulate and be released in sweat, urine, and breath, producing a distinct fishy odor. Choline supplementation, even at moderate doses, can exacerbate this condition. Therefore, individuals with TMAU should restrict their intake of choline-rich foods and avoid supplements entirely.
Those with Low Blood Pressure
High doses of choline, typically well above the Tolerable Upper Intake Level (UL) of 3,500 mg for adults, have been associated with hypotension, or low blood pressure. This can cause dizziness, fainting, and other complications, particularly for individuals already prone to low blood pressure. The risk of reaching toxic levels from food alone is extremely low; however, the concentrated nature of supplements makes high intake levels much easier to achieve.
Individuals with Liver or Kidney Disease
While choline deficiency can contribute to liver damage and nonalcoholic fatty liver disease (NAFLD), excessive intake can also be problematic. The liver is the primary organ for metabolizing choline, and excess amounts can lead to liver toxicity. Similarly, individuals with kidney disease may have impaired metabolic pathways, increasing their risk of accumulating harmful choline metabolites. The tolerable upper intake levels for these individuals are lower than for healthy adults, and supplementation should only be done under strict medical supervision.
People at Risk of Cardiovascular Disease
Some research has linked high choline intake from supplements to an increased production of trimethylamine N-oxide (TMAO), a substance associated with a higher risk of cardiovascular events like atherosclerosis and thrombosis. Interestingly, studies have shown that high choline intake from whole foods like eggs does not significantly raise TMAO levels in the same way as supplements, suggesting that the form of choline is a crucial factor. For those with pre-existing cardiovascular issues, a high-dose choline supplement might not be the safest choice.
Other Potential Concerns
Aside from the major contraindications, there are other situations where choline supplements should be approached with caution:
- Existing Medication Interactions: While choline does not have many known interactions, atropine is an exception, as concurrent use can decrease the effects of atropine. Consulting a doctor about all supplements and medications is always advisable.
- Gastrointestinal Distress: Doses of choline supplements can cause stomach aches, nausea, diarrhea, and vomiting, even at levels within the acceptable range. This is particularly relevant for those with sensitive digestive systems.
- Excessive Sweating: Higher doses of choline can lead to excessive sweating and salivation.
Potential Risks of Choline Supplementation vs. Dietary Intake
| Feature | High-Dose Supplementation | Dietary Intake from Whole Foods |
|---|---|---|
| Toxicity Risk | Significantly higher due to concentrated doses; exceeding the UL is a real possibility. | Extremely low; nearly impossible to reach toxic levels from food alone. |
| Source of Choline | Often provided as isolated compounds like choline bitartrate, which may be more readily converted to TMA. | Primarily from sources like phosphatidylcholine, which is less likely to produce excessive TMA. |
| Associated TMAO Increase | Shown to substantially raise plasma TMAO levels, which has been linked to increased cardiovascular risk. | Does not show the same effect on TMAO levels as supplemental choline. |
| Side Effects | More likely to cause adverse effects like fishy body odor, hypotension, and gastrointestinal issues. | Generally safe with no risk of toxicity or fishy odor in healthy individuals. |
Conclusion
While choline is an essential nutrient, supplementation is not for everyone. For the vast majority of healthy adults, a balanced diet rich in choline-containing foods, such as eggs, beef, and certain vegetables, is sufficient to meet their nutritional needs and avoid deficiency. However, specific populations must be particularly cautious. Individuals with bipolar disorder, the genetic disorder trimethylaminuria, existing liver or kidney disease, or a history of hypotension should avoid high-dose choline supplements. Those with cardiovascular disease risk factors or on specific medications like atropine should also consult their doctor. The key takeaway is that concentrated supplements carry a higher risk of adverse effects compared to natural dietary sources, and professional medical advice is essential before adding a choline supplement to your routine.
References
- University of Rochester Medical Center. "Choline." Retrieved from https://www.urmc.rochester.edu/encyclopedia/content?contentid=choline&contenttypeid=19
- WebMD. "Choline - Uses, Side Effects, And More." Retrieved from https://www.webmd.com/vitamins/ai/ingredientmono-436/choline
- NIH Office of Dietary Supplements. "Choline - Consumer." Retrieved from https://ods.od.nih.gov/factsheets/Choline-Consumer/
- The Nutrition Source, Harvard T.H. Chan School of Public Health. "Choline." Retrieved from https://nutritionsource.hsph.harvard.edu/choline/
- Taylor & Francis. "Trimethylaminuria – Knowledge and References." Retrieved from https://taylorandfrancis.com/knowledge/Medicine_and_healthcare/Medical_genetics/Trimethylaminuria/
- National Institutes of Health. "Dietary Choline Supplements, but Not Eggs, Raise Fasting…" Retrieved from https://pmc.ncbi.nlm.nih.gov/articles/PMC8410632/
- Linus Pauling Institute, Oregon State University. "Choline." Retrieved from https://lpi.oregonstate.edu/mic/other-nutrients/choline
- WebMD. "Choline." Retrieved from https://www.webmd.com/vitamins-and-supplements/choline
- Healthline. "What Is Choline? An Essential Nutrient With Many Benefits." Retrieved from https://www.healthline.com/nutrition/what-is-choline
- Johns Hopkins Health Library. "Choline." Retrieved from https://johnshopkinshealthcare.staywellsolutionsonline.com/HealthyKidsTeens/19,Choline
- NIH Office of Dietary Supplements. "Choline - Health Professional Fact Sheet." Retrieved from https://ods.od.nih.gov/factsheets/Choline-HealthProfessional/
