Research into amino acids' purported nitric oxide effects will help dispel clouds of protein pumping, experts say

By Hank Schultz

- Last updated on GMT

Research into amino acids' purported nitric oxide effects will help dispel clouds of protein pumping, experts say

Related tags Amino acids Amino acid

Ongoing research into the effects of individual amino acids will both substantiate their possible effects and counteract the negative assumption that they have been added to sports nutrition products solely to alter the protein test numbers, experts say.

The issue is whether amino acids are being used for their intrinsic physiological benefits or whether they are included in certain products in a solely cynical manner in order to “fool” a protein test. FDA regulations on the calculation of protein content are unfortunately vague enough that it leaves the door open to the use of free amino acids to provide some of the nitrogen measured by the test, thereby making the product appear to have more protein than it actually does. The practice has plagued the sports nutrition sphere recently and has become a matter of widespread discussion with new voluntary guidelines on protein labeling recently promulgated by the American Herbal Products Association (which counts a number of high profile sports nutrition product manufacturers as members) and the Council for Responsible Nutrition.

Recently Kyowa Hakko was granted a patent on an L-citrulline/L-arginine combination for its effect on rapidly increasing blood flow. Karen Todd, RN, director of marketing for Kyowa Hakko USA, says the patent shows that the company is serious about the effects of the ingredient and is not supportive of the use of amino acids solely as test adjuncts.  The amino acids creatine, glycine and taurine are most commonly mentioned in connection with this practice.

“We don’t support that at all. Companies that are doing that are buying really cheap amino acids, and they can’t do that with our product, because it is too expensive,” ​ Todd told NutraIngredients-USA.

“We have an entire portfolio of information we provide to our customers. Part of that is how the ingredient should be labeled and that it shouldn’t count as part of the protein score,”​ she said.

New standards

The new AHPA standard, called Guidance on Labeling of Protein in Food and Dietary Supplements​, creates a standard by establishing that protein is calculated to include only proteins that are chains of amino acids connected by peptide bonds and to exclude any non-protein nitrogen-containing substances from such calculations. AHPA said it hopes the new guidance will become a standard for industry, and many companies already use this method.

But not all, and there has been the rub. Some companies, that felt economically disadvantaged by competitors who were reporting higher protein content via what they saw as a fraudulent method, pushed the organization to take action. Michael McGuffin, AHPA’s executive director, sees this episode as a successful example of member companies working together to solve a problem and avoid a public row.

“When this issue was brought to AHPA’s attention by several member companies, a goal was promptly established to clarify industry practice in the light of a regulation that appears to allow options on how to quantify protein. None of our members disputed that goal. Over time it became clear that the most effective approach to reach this goal would be to establish a voluntary policy to standardize how protein is calculated in food and supplement products,” ​McGuffin said.

CRN’s new guidelines, set forth in late April, assume a year’s grace period for companies to comply. “We want to give people time to make sure they’ve gone back and accounted for this. A year is more than enough time,” ​said Steve Mister, president and CEO of CRN.

Ongoing research

The new patent granted to Kyowa Hakko was based on the observed effects of the citrulline/arginine blend in animals, Todd said.  She said Kyowa’s data shows that the blend works better than either ingredient alone.

“The big up and coming amino is citrulline.  It is almost two or three times as effective as other aminos in boosting nitric oxide. What we’ve found is that the combination is more effective than the individual amino acids,”​ Todd said.  Todd said Kyowa Hakko has additional studies underway looking into the ingredient’s benefits.

But the small scale of the studies used to support the patent application and the lack of human data give rise to some questions in the minds of researchers. The nitric oxide question has some similarities to the measurement of ORAC values in that there is some question how results in one sphere translate to physiological benefits when applied to humans in actual exercise settings.

“For arginine alone in humans, with oral ingestion, and especially in conjunction with exercise there is very little to no robustness. The relevant data for citrulline, however, is more robust than arginine. However, it is still a bit early to know for sure. In combining arginine and citrulline, it is also too early to tell. However, I do know there are studies being performed trying to answer the question,”​ said Darryn S. Willoughby, PhD, associate professor of exercise/nutritional biochemistry and molecular physiology at Baylor University.

Anthony Almada, a consultant and principal in the sports nutrition firm GENr8, said most of the most promising research on the effects of boosting nitric oxide in an exercise setting have to do with nitrates supplied directly from plant sources such as beet root juice.  A complicating factor has been trying to find a way to standardize the amount of nitrates supplied by these sources in the studies.  Anecdotal reports, such as the news that the Auburn University football team has been drinking beet root juice before games this season and apparently has seen some beneficial effects, is of almost no use to researchers.

“The evidence is modest for arginine and stronger for citrulline. However, increases in nitric oxide do not necessarily translate  into performance benefits. Indeed, arginine alone has failed miserably in this capacity. A few studies have shown a performance enhancing effect with citrulline alone,”​ Almada said.

Related topics Formulation Fortification Supplements

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