One of the more obvious reasons for amino acid deficiency is the simple lack of proper nutrition. (drjockers.com)
Generally — amino acid deficiency leads to decreased body and mental function. (fitnessandpower.com)
For example, a strict vegetarian or vegan diet can lead to vitamin B12 and sulfur amino acid deficiency, 11 both of which increases your risk of heart disease. (articles.mercola.com)