Lysine is an amino acid, one of the building blocks of proteins. Lysine is classified as essential because the body can't make it. That means people must obtain it from their diets.
Most people in the United States get enough lysine in their diets because it is in protein-rich foods like meat, cheese, fish, eggs, and tofu. Protein deficiency is very rare in the United States, although it can occur in developing countries.
Why You Need Lysine
Since there are 21 different amino acids, tracking how much you are getting of each one would be a difficult task. If you are getting adequate protein, you are probably getting enough lysine. Adults need about 7 grams (g) of protein for every 20 pounds of body weight, so a person weighing 160 pounds would need 56g.
Lysine plays several roles in the body, including two very important ones:
- It helps the body create collagen, which is present in bones and connective tissues such as skin and cartilage.
- It produces carnitine, which converts fatty acids into energy in a process that also lowers cholesterol.
Lysine is sometimes combined with another amino acid, arginine. Scientists say that the two amino acids use the same pathways in the body. Therefore, taking arginine might lower your lysine levels.
As an essential amino acid, lysine is important to health. Although evidence is inconclusive, it has been used for these purposes:
1. Muscle Strength
Athletes have used some amino acids, including lysine, in supplement form to increase muscular strength. Research has failed to prove that lysine improves muscle strength more than strength training alone. One study of older adults showed that taking a combination of three amino acids, including lysine, improved lean body mass.
2. Bone Health
Lysine can help the body absorb calcium, and it can reduce the amount of calcium lost in your urine. Researchers have theorized that lysine could prevent osteoporosis, but they have found no evidence that this is true.
3. Mouth Health
Lysine supplements have been used as a treatment for cold sores caused by the herpes simplex virus and for canker sores. Researchers have not found conclusive evidence that lysine is effective for these problems.
4. Anti-anxiety Effects
Some studies have looked at whether supplements of lysine and arginine could reduce anxiety. In two studies, the subjects showed reduced levels of the stress hormone cortisol.
Foods with Lysine
You can buy lysine supplements, but those with liver or kidney disease should not take them without consulting a doctor. Pregnant and lactating women should use caution. Lysine supplements can also interfere with one type of antibiotic (Aminoglycoside).
Another reason to pass on lysine supplements is that taking a single amino acid in supplement form can negatively affect metabolism. It can also put a burden on the kidneys and affect growth in children.
While there are numerous warnings about taking lysine as a supplement, lysine from food sources is considered safe. Some people seek out spirulina and fenugreek seeds to boost their lysine intake, but your local supermarket has many sources of lysine, including these:
1. Meat and poultry
Beef, pork, and poultry are all good sources of lysine. To promote heart health, most people should choose lean cuts and keep serving sizes small.
Almost all cheeses are high in protein and calcium but also high in fat and cholesterol. The cheese with the most lysine is parmesan. Just one tablespoon of grated parmesan provides 2 grams of protein and 1 gram of fat.
Many health experts favor fish as a source of healthy protein. Cod and sardines are especially high in lysine.
Eggs are an inexpensive protein source, although they are high in cholesterol. The American Heart Association says that most adults can eat an egg a day without harm.
Vegans and vegetarians need not worry. Tofu is a great source of lysine. If you aren't a tofu fan, you can also get lysine from soy protein and soybean flour.
Legumes are another protein powerhouse, especially for those on plant-based diets. Choose from beans, peas, lentils, peanuts, and more.