Health Benefits Of Histidine

Graphic © herbshealthhappiness.com

If you intend to build up some muscles, are into an athletic, sporty lifestyle, or are just gearing up for a healthy living, ground beef (95% lean meat), turkey, and lamb dishes are perfect meal courses for the job. Not only do these food items pack a great deal of proteins, but also they are very good sources of histidine[1], an essential amino acid vital to tissue repair and growth in humans and other mammals. Based on levels per 200-calorie serving, cooked ground beef with 95% lean meat and 5% fat composition, such as the patty in everyone’s favorite hamburger, and roasted turkey contain 1048 mg of histidine, whereas cooked lamb and raw chicken (for stewing) both have 1047 mg histidine content. [1]

Histidine is a proteinogenic amino acid; that is, it is actually a protein precursor. Earlier studies on this amino acid once hypothesized that it is only necessary during infancy, with growth and mental retardation being the chief clinical sign of its deficiency, but long-term research has determined histidine to be a vital component in many of adult humans’ biological processes. For example, histidine’s imidazole side chain is typically utilized as a coordinating ligand in metalloproteins and serves as a constituent of catalytic sites in certain enzymes. This side chain has a nearly neutral pKa value and thus can operate as either an acid or a base, making histidine exceptionally essential to enzyme catalysis.

Histidine In The Body

One of the most important physiological roles of histidine may be in the stabilization of oxyhemoglobin and destabilization of hemoglobin bound to carbon dioxide – and hence in red blood cell production. In fact, hemoglobin protein comprises 10% histidine and the absence of histidine in one’s daily food consumption is correlated with failure of normal production of red blood cells. In a 2002 study from New York Medical College, USA, individuals suffering from folate deficiency manifested “hematological response that alleviated the anemia associated with this deficiency” upon intake of dietary histidine, which replenished the histidine levels in tissues. According to the said study, anemia results when there is inadequate dietary intake of histidine or when elimination of the amino acid through urine is abnormally elevated such as during folate deficiency. [2]

Histidine is also involved in muscular contraction and antioxidation as part of a combination with beta-alanine to synthesize carnosine (beta-alanyl-L-histidine), a dipeptide that is highly concentrated in muscles. Recent scientific studies have demonstrated that loading the muscles with carnosine results in better performance in high-intensity exercise. This effect is noted in both trained and untrained individuals. Carnosine helps maintain homeostasis of muscle cells as they undergo contraction, especially during high intensity exercise. It attenuates acidosis by acting as a pH buffer. [3]

Histidine As Histamine Precursor

Perhaps the widely appreciated function of histidine lies on its utility as the precursor of histamine. Histamine is commonly associated with inflammation and will always ring a bell for hypersensitive or allergic individuals, it being the compound that the body releases as part of the local immune response against invading bodies during an infection and allergic reaction. In the gut and in the integumentary and immune systems, histamine functions as a signaling molecule. In the nervous system however, histamine acts as a transmitter that carries signals from a nerve to another and several histaminergic neurons are located exclusively in the posterior hypothalamus and maintain wakefulness and attention when a person is awake. [4] A 2014 study from Tohoku University Graduate School of Medicine, Japan, illustrated the importance of dietary L-histidine as a precursor of brain histamine and the histaminergic nervous system. In this study, 8-week-old mice were assigned to two diet groups, namely, the control group and the group on low L-histidine diet, and histamine concentration in the mouse brain areas was measured. Results from the study revealed anxiety-like behaviors induced by low histidine diet in mice, which exhibited shorter amount of time in the central zone during open-field tests and shorter amount of time in the light box during light/dark box tests, although locomotor activity, memory functions, and social interaction were not significantly affected. This Japanese research concluded that insufficient intake of histidine led to a decrease in brain histamine content, resulting in the anxiety-like behaviors observed among experimental mice. [5]

Men suffering from premature ejaculations may find an increased intake of histidine (through diet and supplementation) beneficial since histamine promotes erection through H2 (and possibly H3) receptor activation. In vitro studies showed that histamine relaxes the corpus cavernosum of the penis and somehow contributes to better sex through its vasodilating effect, enhancing blood flow to the sex organs and making ejaculations and orgasms much easier to achieve. [6]