Amino acids are considered the building blocks of protein. When protein is digested, it is broken down into individual amino acids. There are 20 amino acids, which are known as either essential or nonessential. Essential amino acids must be taken through the diet to meet daily nutritional needs. Nonessential amino acids are manufactured by the body. All amino acids are required for the synthesis of protein and the repair and maintenance of tissues. Histidine, a basic amino acid constituent of protein, is unique because it is both essential and nonessential.
Function of Histidine
Histidine is utilized by your body to develop and maintain healthy tissues. It is especially important in the myelin sheath that coat nervous cells to ensure the transmission of messages from your brain to organs throughout your body. Adequate histidine levels are essential to good mental and physical health. Elevated histidine levels have been associated with physiological disorders like anxiety and schizophrenia. Additionally, low histidine levels are thought to lead to rheumatoid arthritis and deafness from nerve damage. Histidine may be implicated in the treatment of mental disorders and sexual dysfunction. There is also evidence that histidine may play a role in protecting the body from radiation damage and prevent the onset of AIDS. This is due to its ability to naturally detoxify the body and produce both red and white blood cells.
Adults can typically produce enough histidine from other amino acids in the liver to support the body's daily needs. However, children must obtain histidine through the foods they eat. Histidine is needed, especially during infancy, for proper growth and development. When histidine is metabolized by the human body, it produces histamine. Histamine is a substance involved in the inflammatory response and the production of hydrochloric acid in the stomach. If children, especially infants, do not eat enough histidine containing foods, they may experience eczema, a form of dermatitis. This condition is immediately treated when histidine is supplemented in the diet. Furthermore, some individuals suffer from a genetic disorder that prevents the proper metabolism of histidine, resulting in a histidine buildup in the blood.
Amino Acids in Food
Most foods contain at least some of the necessary amino acids. Protein-rich animal foods typically contain complete proteins, meaning that they supply the body with all essential amino acids. Plant-based foods on the other hand contain are incomplete and contain only some of the essential amino acids. Histidine is typically found in foods such as fish, meat, eggs and dairy products.
Histidine, similar to other amino acids, is found primarily in high-protein foods. Meat, poultry, fish, dairy and some grain products including rice, wheat and rye are therefore histidine-containing foods. More good food sources include seafood, beans, eggs, buckwheat, corn, cauliflower, mushrooms, potatoes, bamboo shoots, bananas, cantaloupe and citrus fruits. While it is easy for your natural histidine supplies to run short, consuming foods from each of the food groups will ensure you meet your daily histidine needs.
Therapeutic doses of histidine range from 0.5 and 20 grams per day. Supplementation of up to 30 grams of histidine per day has shown no adverse side effects in adults for short periods of time. If you are chronically ill or suffer from arthritis, you may benefit from moderate histidine supplementation, which is available in both power and capsule forms. However, if you suffer from bipolar depression, allergies or inflammatory problems should avoid histidine supplementation. Consult your physician before taking a histidine supplement.