CRN Scientists Offer ULs for Aminos

WASHINGTON—Two scientists with the Council for Responsible Nutrition (CRN) contributed a risk assessment on the amino acids taurine, glutamine and arginine, which was published in the April issue of Regulatory Toxicology and Pharmacology (50(3):376-99) (DOI:10.1016/j.yrtph.2008.01.004).

According to CRN, the scientists undertook the assessment to help regulators determine safe upper levels (ULs) for these amino acids in dietary supplements. “Over the last decade the prevalence of amino acids within sports nutrition supplements and ‘energy boosting’ functional foods and beverages has significantly increased,” said Andrew Shao, Ph.D., CRN’s vice president of scientific and regulatory affairs and co-author of the paper. Shao and John Hathcock, Ph.D., CRN’s senior vice president of scientific and international affairs, reviewed published randomized, controlled clinical trials conducted in humans involving these three amino acids to determine ULs using basic elements of the Food and Nutrition Board’s methods and the World Health Organization’s (WHO) highest observed intake (HOI). Uncontrolled trials and animal data were used for supportive information only. The ULs were selected as 3 g/d for taurine, 14 g/d for glutamine and 20 g/d for arginine; ULs identify the highest quantitative level at which there is no known toxicity.

This is the eighth in a series of risk assessments completed by CRN scientists. Previous risk assessments on vitamins C and E were published in 2005 and on vitamin D in 2007 in the American Journal of Clinical Nutrition. Risk assessments on non-essential nutrients including coenzyme Q10 (CoQ10), lutein and lycopene, creatine, carnitine, glucosamine and chondroitin sulfate were published in 2006 and 2007 in Regulatory Toxicology and Pharmacology.

“CRN is dedicated to helping ingredient manufacturers deliver the safest products possible to consumers, and risk assessments are the best indicators we have to establish upper limits,” Hathcock said. “These risk assessments, using our expansions of the UL method, represent the first time upper intake levels have been identified for amino acids. As amino acids continue to be more widely used by the general public, there needs to be a scientific method for establishing safety.”