Proposals for Upper Limits of Safe Intake for Methionine, Histidine, and Lysine in Healthy Humans

Authors

Luc Cynober
Dennis M Bier
Patrick Stover
Motoni Kadowaki
Sidney M Morris
Rajavel Elango
Miro Smriga

Publication Date

10-1-2020

Journal

The Journal of Nutrition

DOI

10.1093/jn/nxaa231

PMID

33000163

PubMedCentral® Posted Date

10-1-2020

Published Open-Access

yes

Keywords

Dietary Supplements, Food, Fortified, Histidine, Humans, Lysine, Methionine, Reference Values, NOAEL, histidine, lysine, methionine, safe intake

Abstract

Based on research presented during the 10th Amino Acid Assessment Workshop, no observed adverse effect levels (NOAELs) for supplemental methionine at 46 mg/(kg·d) (∼3.2 g/d), for supplemental histidine at 8.0 g/d, and for supplemental lysine at 6.0 g/d have been proposed. These NOAELs are relevant to healthy adults and are applicable only to high-purity amino acids administered in fortified foods or dietary supplements. Because individuals are exposed to the above supplemental amino acids in the context of complex combinations of essential amino acids or individually in dietary supplements for various physiologic benefits, such as body fat reduction, skin conditioning, mental energy increase, or herpes simplex treatments, the above safety recommendations will make an important contribution to regulatory and nutritional practices.