Carnitine and athletic performance

Carnitine_ball-and-stick

The molecular structure of carnitine. Public domain

This post is similar to the one I did on arginine not too long ago. Basically, omnivores generally get enough carnitine, but many vegetarians and vegans probably don’t, so in theory they may benefit from supplementation. This may be particularly true of vegetarian and vegan endurance athletes.

What is carnitine? It is a quaternary ammonium compound biosynthesized from the amino acids lysine and methionine. It is used for the transport and metabolism of fatty acids. High amounts are found in red meat and in dairy products to a lesser extent. Little to none occurs in plants. Since the body also synthesizes carnitine from lysine and methionine, getting enough of these amino acids can help ensure adequate amounts. Whatever you do, don’t confuse carnitine with carnosine!

Thing is, plant protein generally contains less lysine and methionine than meat protein, and this may be why(besides plants not containing carnitine) some studies show that the blood of vegetarians and vegans have lower amounts of carnitine – Correlation of carnitine levels to methionine and lysine intake:

An average carnitine level in vegans was significantly reduced with hypocarnitinemia present in 52.9% of probands. Similarly, the intake of methionine and lysine was significantly lower in this group due to the exclusive consumption of plant proteins with reduced content of these amino acids.

I don’t believe this should scare anyone into eating meat. After all, I am a vegan! But it may be helpful to be mindful of such things. Don’t forget that there are some vegans out there who, for whatever reason, fail to thrive on the diet. There are also a lot of former vegans. Maybe lack of carnitine and/or some minerals like iron or zinc are part of the reason why. Another reason is that there are, unfortunately, a lot of junk food vegans out there who consume way too much sugar and fat, and not enough fresh fruits, vegetables, legumes, and whole grains. This could lead to a serious deficiency of one or more nutrients. Here is an old, though interesting carnitine study: Systemic carnitine deficiency exacerbated by a strict vegetarian diet.

Based on all this evidence, does it make sense for vegan or vegetarian athletes to supplement with carnitine? Once again, I couldn’t find anything specifically about vegan or vegetarian athletes and carnitine in the scientific literature, but did find a carnitine study done on marathon runners. According to, Effects of L-carnitine supplementation on physical performance and energy metabolism of endurance-trained athletes: a double-blind crossover field study:

In conclusion, acute administration of L-carnitine did not affect the metabolism or improve the physical performance of the endurance-trained athletes during the run and did not alter their recovery.

It did nothing! I do wonder though if the runners had been vegan if they would have benefited. Hopefully, researchers will do a study like this some day. At best, I could find a study which showed that Short-term carnitine supplementation does not augment LCPomega3 status of vegans and lacto-ovo-vegetarians. This means that supplemental carnitine in vegetarians doesn’t help convert one form of omega 3 fatty acid(ALA), to the other vital omega 3s, DHA and EPA. This conversion is important since vegans and vegetarians may sometimes be lacking in DHA and EPA. However, we are getting a little sidetracked here.

So is carnitine useless as a supplement? I don’t think there is strong evidence suggesting vegans should take it, and it doesn’t appear to be toxic in recommended amounts, however, one promising area of research involves carnitine in its acetylated form, acetyl-l-carnitine. There’s some evidence it may help with nerve regeneration. According to
Acetyl-L-carnitine improves pain, nerve regeneration, and vibratory perception in patients with chronic diabetic neuropathy: an analysis of two randomized placebo-controlled trials:

CONCLUSIONS:

These studies demonstrate that ALC treatment is efficacious in alleviating symptoms, particularly pain, and improves nerve fiber regeneration and vibration perception in patients with established diabetic neuropathy.

This sounds promising, though more research obviously needs to be done. If you’re a diabetic with nervous system problems, don’t take this as a recommendation to supplement with acetyl-l-carnitine. Speak with your doctor.

So where does this leave us with respect to carnitine? I don’t supplement with it, and I show no deficiency symptoms, and neither do most vegans I know. It’s possible the bodies of people who may be lacking in carnitine compensate somehow. After all, running 2 marathons while juggling and finishing in under 4 hours, while having been a vegan for years is pretty good evidence I’m not deficient in anything. The same goes for vegan super stars like Scott Jurek. All I take is a multi-vitamin.

Like I said before, it is possible that carnitine is something vegans may be lacking in that may explain why some fail to thrive. If this applies to you, see if you can get your blood tested for carnitine or other compounds to see if you are deficient.

 

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