Dispelling nutrition myths, ranting, and occasionally, raving

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Of wellness chats, dietitians, and L-Glutamine


The other night I had my first exposure to a “wellness chat” on twitter. It was interesting to say the least. The guest* was a registered dietitian in the US. A few of her statements surprised me, and at least a few other RDs. The most surprising tweet read:

What to do when U have a craving? Have a balanced #PFC (protein, fat, carb) snack AND take an L-Glutamine capsule #cravingfree #wellnesschat

A few of us tweeted back at her asking for her to share a link to the research supporting the use of glutamine to reduce cravings. As far as I’m aware, none of us received a satisfactory response. The only response I saw to our requests for research to support her statement was: “Get your supplements where u like, just make sure they’re high quality for effective results.”  This response was also in reply to our expressed concerns that she is selling these supplements (among many others) on her website. In my mind that’s an ethical concern. No health care professional should be profiting from the sale of medications/supplements. It’s an obvious conflict of interest. It’s also a little baffling that she’s doing podcasts extolling the benefits of real food (while also patronizingly insulting many other dietitians by suggesting that we are “brainwashed” into following obsolete dogma taught in school and don’t keep up with current research. Odd, in Canada at least, as part of our professional standards we must demonstrate continued competence by keeping up with current research and new developments in the field) yet profiting from the promotion and sale of supplements.

But… Back to the glutamine issue. My first stop to answer this question was examine.com. They do a great job of slogging through all of the research to get the facts about supplements. The short version of what they say about glutamine is:

A conditionally essential amino acid, only appears to benefit the body as supplementation when otherwise deficient (vegans, vegetarians with low dairy intake) or during prolonged endurance exercise. Anecdotally reported to reduce sugar cravings.

Yes, anecdotally reported to reduce sugar cravings. That means that there is no actual research to support the use of glutamine to reduce sugar cravings. A search of google scholar shows that there are no scientific studies supporting the use of glutamine to reduce sugar cravings. As dietitians we have an obligation to employ evidence-based best practices. This means that we cannot ethically recommend unproven treatments or supplements. I’m not saying that glutamine doesn’t work to reduce sugar cravings. I’m saying that we have no evidence either way. Until there is evidence to support its use in reducing sugar cravings dietitians cannot ethically recommend its use for that purpose.

I have yet to meet a dietitian who fails to keep up to date with current research. It does a great disservice to our profession when one of our fellow RDs suggests that many of us are not up to speed and that she is somehow special and superior to others in the field  because she is “science-based”, especially when she is making recommendations that are not actually based in science. Please be wary of any healthcare professional who is profiting from selling you a cure.


*Name has been omitted to protect the guilty. This is something that I struggled a bit with. I decided not to identify the RD in question because I don’t want this to be viewed as a personal attack, it is not.


Supplements: Should you take glutamine?

Supplements are one of the most difficult nutrition-related issues to contend with. Some people may benefit from certain supplements but oftentimes people are at best wasting their money and at worst potentially causing themselves harm by taking supplements. I was recently inspired to look into some common supplements and thought that I’d share what I found with you.

You may be wondering what glutamine is. It’s the most abundant amino acid (protein is made-up of amino acids) in the human body. We actually make most of the glutamine in our bodies and obtain more glutamine from high protein foods such as legumes, meat, eggs, milk, and tofu. Why, then, do some people believe that supplementation is necessary? Some studies have indicated that blood levels of glutamine are lowered in athletes participating in exhaustive exercise. I’d like to pause here to point out that exhaustive exercise is intense endurance exercise like running a marathon or participating in a triathalon. Exhaustive exercise is not playing a game of soccer, volley-ball, or lifting a few weights. When you think of exhaustive exercise you should think of not physically being able to continue after completing the activity. Okay, back to it… Some people believe that taking a glutamine supplement will reduce post-exercise soreness and boost the immune system. However, to-date there is no conclusive research to support this theory (1). There is no maximum level set for glutamine consumption (although 14 g/d in supplemental form has been proposed) and your risk of reaching toxicity is low. There are risks if you are taking anti-convulsant medication or lactulose (2) and, as with many supplements, you run the risk of contamination or incomplete disclosure of ingredients on the label. If you’re just a recreational athlete, and probably even if you’re a professional endurance athlete, you’d be better off spending your money on something that provides you with other nutrients as well such as actual food.