Lysine - role in the body and requirement
Lysine is one of the amino acids or basic building blocks of proteins. The human body does not produce lysine, which is why it belongs to the group of essential amino acids. Furthermore, it cannot be obtained by transamination, so lysine must be supplied with food.
Lysine can be converted into ketones as a result of energy-generating metabolism, so it is a ketogenic amino acid. Due to its structure, lysine is a chemically active amino acid and easily reacts with other compounds. This may limit its availability from food.
The names "lysine" and "L-lysine" are used interchangeably. L-lysine is the biologically active form of lysine that occurs in living organisms.
What functions does lysine have in the human body?
- Participates in the formation of joint cartilage.
- Participates in the synthesis of nucleotides (building blocks of DNA).
- It is essential for lactation.
- Participates in tissue renewal.
- It is a component of hormones, enzymes, antibodies.
- Is a precursor for the synthesis of carnitine.
- Participates in the metabolism of fats, more specifically in the oxidation of long-chain fatty acids in the mitochondria.
Recommended products with lysine
The requirement for lysine in adults is estimated at between 12 and 45 mg per kg of body weight daily and is taken as an average of 30 mg/kg bw/d. Lysine is essential for growth, so the requirement for this amino acid per kg of body weight decreases with age.
Body requirements for lysine according to age
|Age [years]||Lysine demand [mg/kg bw/d]|
Lysine deficiency occurs primarily in countries with low protein intake.. Its symptoms include anaemia, slowed growth, chronic fatigue, dizziness, feeling confused, decreased concentration, red eyes, loss of appetite, nausea, decreased fertility.
Where does L-lysine occur?
L-lysine is found in all proteins except maize, yet in all cereals its content is low. Consequently, in developing countries with a cereal-based diet, L-lysine is a limiting amino acid - making it difficult for the body to utilise other amino acids contained in food. Therefore, in many regions of the world, L-lysine is added to cereal products to increase the nutritional value of meals. In the diets of developed countries, there is no problem of L-lysine deficiency. The average intake of this amino acid in Western countries ranges from 40 to 180 mg/kg b.w./d.
Animal products are a better source of L-lysine than vegetable products because they contain more protein in general.
Sources of L-lysine in food
- Meat and poultry - any type of meat is a good dietary source of lysine.
- Cheese - the most L-lysine is found in Parmesan cheese, but basically, any type of cheese, whether yellow, mould or cottage cheese, provides high amounts of lysine.
- Fish - sardines and cod are the richest in L-lysine, but you will get lysine from any fish.
- Eggs - eat eggs as a source of L-lysine without worrying about cholesterol. The one in food does not increase the risk of heart disease.
- Legumes - soybeans, lentils, chickpeas, peas, beans.... are the best plant sources of L-lysine and plant protein in general. Both legumes and their preparations (tofu, hummus, plant-based meat substitutes) will supplement your diet with this essential amino acid.
- Other plant sources - poorer but still valuable sources of L-lysine in plant foods include nuts, avocados, dried apricots and mangoes, beets, leeks, tomatoes, pears, peppers and potatoes
Properties and effects of lysine for health
Lysine may help with herpes
Herpes - blisters filled with secretions that appear on and around the lips - is an annoying symptom of the presence of the HSV-1 herpes virus in the body. HSV-1 becomes active during periods of decreased immunity and also as a result of chronic stress.
Lysine can be effective in preventing the formation of herpes, as well as in reducing it. Its properties and action in this aspect are based on hindering the replication and multiplication of the virus. Therefore, lysine eliminates the cause of the appearance of herpes to some extent. The HSV-1 virus uses another amino acid, arginine, for replication, and lysine blocks the virus' access to it. One of the studies showed the positive properties of lysine at a dose of 1000 mg daily taken orally. Another one proved the effect of lysine as a cream on the skin.
The studies conducted so far include small groups of participants - about 30 people, and the results do not always indicate the effectiveness of lysine. It is important to keep this in mind and not to take lysine as a sure way to get rid of herpes.
Lysine may reduce feelings of anxiety as well as stress hormone levels
Early research shows that increasing lysine intake (e.g. by adding it to wheat flour, as used in several studies) reduces the levels of perceived anxiety caused by living under chronic stress. Subjects also have lower levels of cortisol in the blood, commonly known as the stress hormone.
Lysine may reduce calcium excretion from the body
Decreased calcium levels and reduced bone mineralisation is common problem in older people. It particularly affects postmenopausal women. It appears that lysine can be helpful in improving bone mineralisation and preventing osteoporosis, as it may increase calcium absorption in the gut and retention by the kidneys.
A study on a group of 30 women, 15 with osteoporosis, 15 with healthy bones, showed that administration of calcium (3 g) together with lysine (400 mg) resulted in less calcium loss through the urine compared to taking calcium alone.
Other health-promoting effects of lysine
- Lysine can increase growth hormone levels, so its supplementation is used to increase muscle mass.
- Lysine may prevent the formation of atherosclerotic plaque in the arteries due to its affinity for lipoprotein molecules.
- As a component of collagen, lysine may increase its endogenous production.
- Lysine facilitates the absorption of zinc and iron.