Histidine is occasionally referred to as a semi-essential amino acid. This means that the body can usually produce adequate amounts of histidine, however in certain circumstances, such as periods of rapid growth, the body cannot supply enough to meet demand. Histidine is found in beans, brewer’s yeast, dairy products, eggs, fish, legumes, meat, nuts, seafood, seeds, soy, whey, and whole grains.

The body uses histidine to produce histamine, a substance that plays a central role in allergic reactions and other functions of the immune system. Histidine also helps to chelate trace minerals and copper, thus aiding their removal from the body. People with rheumatoid arthritis may have low blood levels of histidine. This discovery led to speculation that histidine supplements may be of benefit to patients with rheumatoid arthritis. However, as of yet no clinical studies have been able to find any evidence to support these theories.

DEFICIENCY SYMPTOMS: There are no known symptoms of histidine deficiency.

THERAPEUTIC DAILY AMOUNT: A typical therapeutic dosage of histidine is 4-5g per day.

Not established, however large doses of histidine can cause premature ejaculation, reduce zinc levels and possibly trigger an allergic or asthmatic reactions.

People with kidney or liver disease should consult their doctor before taking supplementary histidine.