Histidine: The Hidden Gem of Amino Acids
Albrecht Kossel and Sven Gustaf Hedin were pioneering scientists in the field of biochemistry and protein research. Both discovered this amino acid in 1896, simultaneously but independently. Kossel and Hedin began their research by analyzing proteins from various sources of animal tissue, including muscle, blood, and organs. They used various techniques to extract and purify the proteins, such as precipitation and chromatography. After several attempts, they were able to extract histidine from the mixture and identify it.
Their discovery of histidine was a major milestone in the field of biochemistry and protein research. Their discovery of histidine helped to further the understanding of the structure and function of proteins and the role of amino acids in human metabolism. Their discovery also had practical applications in the field of medicine and nutrition, as histidine is important for the growth, repair, and maintenance of body tissues.
Histidine Health Benefits
Histidine has several important functions in the body, including:
- Protein synthesis: It is particularly important for the formation of structural proteins, such as collagen and elastin, which provide support and elasticity to tissues.
- Histamine synthesis: Histidine is a precursor to histamine, a chemical involved in the immune response. Histamine is released by immune cells in response to an infection or injury, and it plays a role in inflammation, allergic reactions, and blood vessel dilation.
- Metal ion coordination: Histidine is able to chelate with metal ions such as zinc, iron, and nickel. It’s important for enzymes such as carbonic anhydrase and histidine-rich proteins.
- Buffering: Histidine is an acidic amino acid that can help to buffer the pH of the blood, helping to maintain a healthy balance of acidity and alkalinity.
- Repair and growth of tissue: it is essential for the development and maintenance of healthy skin, hair, and nails.
Foods rich in Histidine
It can be found in a variety of foods including:
- Meat and poultry: High concentrations in animal-based protein sources such as beef, pork, chicken, and fish.
- Dairy products: Such as milk, cheese, and yogurt.
- Eggs: Are also a good source of histidine.
- Legumes and nuts: Lentils, chickpeas, and beans, as well as nuts such as peanuts, almonds, and cashews.
- Whole grains: Oats, wheat, and barley.
- Vegetables: Such as spinach, asparagus, and mushrooms are also good sources of histidine.
It’s worth mentioning that histidine content in food can vary depending on the specific food item, the preparation method, and the growing conditions. Additionally, cooking can lead to histidine loss, so consuming raw or minimally processed food will provide more histidine.
Recommended daily intake
The recommended daily intake (RDI) of histidine varies depending on age, sex, and other factors.
The general RDI for histidine is as follows:
- Adult men: 12 mg per kilogram of body weight per day
- Adult women: 10 mg per kilogram of body weight per day
- Infants (0-6 months): 4.5 mg per kilogram of body weight per day
- Infants (7-12 months): 6.5 mg per kilogram of body weight per day
- Children (1-3 years): 8 mg per kilogram of body weight per day
- Children (4-8 years): 9 mg per kilogram of body weight per day
- Children (9-13 years): 11 mg per kilogram of body weight per day
- Adolescents (14-18 years): 14 mg per kilogram of body weight per day.
A deficiency of histidine is relatively rare, as it is an essential amino acid that can be obtained from a varied diet. However, in certain situations, a deficiency may occur, such as:
- Malnutrition: Individuals with malnutrition or malabsorption disorders may be at risk of histidine deficiency.
- Food allergies: Individuals with food allergies to animal-based protein sources (such as meat, fish, or dairy) may be at risk of deficiency.
- Certain medical conditions: Such as urea cycle disorders, which prevent the body from processing histidine properly, may also be at risk of deficiency.
Symptoms of deficiency can include:
- Anemia: Histidine is necessary for the production of hemoglobin, the protein in red blood cells that carries oxygen.
- Skin and hair problems: It is necessary for the growth and repair of skin, hair, and nails.
- Behavioral and cognitive changes: Histidine is involved in the regulation of neurotransmitters, so deficiency may lead to changes in mood and cognitive function.
- Immune system dysfunction: Histidine is needed for the production of histamine, which plays an important role in the immune response.
It’s worth noting that deficiency symptoms are not specific to histidine, and it’s likely that if a deficiency occurs it would be accompanied by other deficiencies in other essential nutrients as well. If you suspect you may have a histidine deficiency, it’s important to consult a healthcare professional for diagnosis and treatment.
It is unlikely that individuals would consume excessive amounts of histidine through their diet alone, however, consuming high doses of histidine supplements can lead to unwanted side effects.
Research has shown that taking excessive amounts of histidine, such as 32 grams or more per day, can cause symptoms such as muscle weakness, drowsiness, fatigue, headaches, digestive issues, depression, and memory impairment.
This can be caused by a negative nitrogen balance.
Why is this amino acid important for sports performance?
Histidine is not a well-known amino acid in sports performance, but it has some properties that may be beneficial:
- Histidine is particularly important for the formation of structural proteins such as collagen and elastin, which provide support and elasticity to tissues. This is important for athletes, as structural proteins are involved in the repair and maintenance of muscles and tendons which are damaged during physical activity.
- Histidine may help to support energy metabolism during physical activity.
- Histamine may help to improve blood flow to the muscles during physical activity, which can improve endurance and performance.
- Histidine is an acidic amino acid that can help to buffer the pH of the blood, helping to maintain a healthy balance of acidity and alkalinity. This is important for athletes, as the accumulation of lactic acid in the muscles during intense physical activity can lead to fatigue and muscle soreness.
It’s worth mentioning that research on the specific effects of histidine supplementation on sports performance is limited. More studies are needed to evaluate the potential benefits and to determine the optimal dose and timing of supplementation. Additionally, histidine is an essential amino acid, meaning that it cannot be synthesized by the body and must be obtained through diet, so the best way to maintain optimal levels of histidine is to have a balanced diet that includes a variety of nutrient-rich foods.