 Glutamate can then be deaminated by glutamate dehydrogenase or transaminated to form α-ketoglutarate.The Food and Nutrition Board (FNB) of the U.S. Institute of Medicine set Recommended Dietary Allowances (RDAs) for essential amino acids in 2002.For histidine, for adults 19 years and older, 14 mg/kg body weight/day.