Role: As a cofactor in many enzymes, it is involved with gene expression, protein metabolism, sexual maturation, sperm production, fetal development, and bone health. It is needed for vitamin A metabolism, wound healing, and taste perception.
Deficiency: Growth retardation, delayed puberty, hypogonadism; loss of taste sensations, anorexia, weight loss, diarrhea; hair loss; delayed wound healing; night blindness; impaired immunity.
Sources: Protein-rich foods, especially oysters, red meat, other seafood, whole-grain products.
Toxicity: Impaired immunity, impaired copper absorption.
Acute toxicity causes nausea, vomiting, cramping.