What Does Lysine Do for Your Body?

Spinach contains lysine.
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Lysine is one of 20 amino acids commonly used by your body to build protein. Of these 20, lysine is considered an essential amino acid, which means it must be obtained from dietary sources because your body cannot synthesize it. Plants can make lysine from aspartic acid, as can bacteria species, which is why lysine is found within leafy vegetables, legumes, fish and herbivorous animals. Lysine has a variety of positive effects on the body and can be consumed as a supplement to combat the herpes virus.

How Lysine Affects You

Like many amino acids, lysine is used to build muscles and collagen, which is an important constituent of cartilage, connective tissue and skin. "Biochemistry of Human Nutrition" author, George Gropper, reports that lysine has other important roles in your body, such as promoting absorption of calcium from the intestines, facilitating the manufacture of enzymes, hormones and antibodies, and stimulating the production of creatinine. Creatinine is used by the body to help convert fatty acids into usable forms of energy. If also reduces blood levels of LDL, the "bad" cholesterol. In "Advanced Nutrition: Macronutrients, Micronutrients and Metabolism," Carolyn D. Berdanier et al., explain lysine is also taken as a supplement to reduce the symptoms created by cold sores and genital herpes, which are caused by different forms of the herpes simplex virus, and shingles, caused by the herpes zoster virus. Specifically, lysine is able to reduce viral uptake of arginine, which inhibits replication.

Excessive Lysine Intake

Lysine in moderate amounts does not lead to any serious side effects. In her book, "Nutritional Sciences," author Michelle McGuire notes, people supplementing with lysine typically take between 500 and 1,500 mg daily, in multiple doses, without experiencing any unwanted symptoms. Lysine in higher dosages, especially taken in conjunction with antibiotics, can cause unwanted side effects, which include allergic reactions, nausea, stomach cramps and diarrhea. There is some speculation that very high levels of lysine might actually increase cholesterol levels, which could lead to increased risks of gallstone formation in the gall bladder, as cited by by Gerald Litwack in "Human Biochemistry and Disease." A medical professional should be consulted before embarking on a lysine supplement regime.

Effects of Lysine Deficiency

A lysine deficiency is considered fairly rare, even in vegetarians and people on restricted diets. However, "The New Encyclopedia of Vitamins, Minerals, Supplements, and Herbs," by Nicola Reavley, reports symptoms of lysine deficiency include kidney stone formation, dizziness, reduced appetite, fatigue and anemia. Severe deficiency can lead to hormone imbalance and affect metabolism, sexual reproduction and growth. People at risk of lysine deficiency are those who do not eat fresh fruit and vegetables, dairy products or meat, but rather consume heavily processed foods, sugary foods and soda pop.

Foods That Increase Dietary Lysine

Lysine rich foods are plentiful and include leafy vegetables, such as spinach and kale; stalk vegetables, such as cauliflower and celery; legumes, such as soybeans, green beans and lentils; fruits, such as pears, papaya, apricots, bananas and apples; nuts, such as almonds and cashews; dairy, such as eggs, some cheeses, yogurt and milk; and meats, especially red meat, pork and poultry, as well as cod and sardines.