Nutrition Nerd: Choline Supplementation and Endurance Performance

After taking a bit of a hiatus from nerdy, science-focused posts the past few weeks it is time to jump back in. Are you all ready? Today I want to share with all of you some information I recently came across. A friend of mine (Megan Sexton, MS and current Dietetic Intern) recently wrote a review article (I apologize for not including a link, but it is not publicly available) on Choline supplementation and endurance exercise performance. So let’s put on our “learning caps” and get going!

What is Choline?:

Choline is an essential mineral that plays three key physiological roles in our bodies. First, it is a precursor of acetylcholine. Acetylcholine is a neurotransmitter that communicates between nerve cells and skeletal muscles; it is important for signal transmission during muscle contraction. Second, choline is incorporated into the lipid bilayer of cell membranes and may be involved in enhancing the integrity of the membrane. Finally, choline acts as a methyl donor in various metabolic processes (most importantly in the process by which homocysteine is converted to methionine).

How Much Choline Do I Need? What if I Don’t Get Enough?:

The Food and Nutrition Board of the Institute of Medicine (the folks who examine scientific literature and set our DRIs for nutrients) currently list 550 mg/day for adult men and 425 mg/day for adult women (who are not pregnant or lactating) as the Adequate Intake (AI) level. However, information from the National Health and Nutrition Examination Survey (NHANES), has estimates that only 10% of the population is meeting the AI for choline (abstract). To make matters worse, some researchers have indicated that the AI for choline could be too low to keep plasma choline levels in a normal range (of 10-15 nmol/mL)(abstract)! Insufficient dietary choline over time may reduce the amount of mechanical stress cells can withstand and also reduce muscle contraction (abstract). This certainly seems like it could be detrimental to athletic performance! Since choline is also required for optimal general health, please find more information at cholineinfo.org (note, this site is supported by the Egg Nutrition Center).

What Foods are Good Sources of Choline?

Choline and Endurance Performance:

Reduction in free choline concentrations has been found following exercise and has been correlated with weakened nerve impulses and cognitive performance.  This depletion of free choline during endurance exercise is also a suggested contributor to fatigue. Therefore, it is logical to think that supplementing with choline prior to endurance events could help prevent this decline and thus aid performance. In her review of the literature, Megan came across a few studies performed in runners who received a choline supplementation 30 minutes prior to an endurance exercise bout (approximately marathon distance) which found that those receiving the supplement better maintained their choline concentrations and had faster finishing times than those who received a placebo. However, a similar study performed in endurance cyclists did not find an improvement in performance with choline supplementation. Megan noted that in examining the literature it is difficult to obtain a clear consensus because each study utilized a different dose of choline (ranging from 2-6 grams, or being dosed as mg per kg of body weight) and also the time at which choline was administered prior to exercise ranged, which could impact results.

It is important to note that no adverse side effects were reported in any of the studies where choline was supplemented prior to exercise. Finally, it is important to mention that outside of possible performance advantages, supplementation with choline did prevent a drop in post-exercise free choline. This alone may be important in terms of homocysteine metabolism by reducing its accumulation and thus the damage homocysteine can have on endothelial cells.

Take Away Message:

Although research is limited in this area, endurance exercise can cause significant reductions in plasma choline levels, which could negatively impact performance. Ingestion of 2-6 grams of supplemental choline approximately 30-60 minutes before exercise could be helpful.  However, first aim to increase choline intake from whole foods to meet at least the Institute of Medicine’s Adequate Intake recommendations.

Have you ever heard much about Choline before? Are you surprised to hear that about 90% of the population is not meeting recommended guidelines? Do you commonly consume enough of the foods listed in the chart to meet the AI for Choline? Do you currently supplement (or have you ever) with Choline. If so, have you noticed any changes in fatigue, cognitive ability, etc while running?

-Tanya

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