Cold sores, according to the American Dental Association, are annoying and painful clusters of fluid-filled blisters that usually erupt around the lips and, sometimes, on the nose or chin. Cold sores result from infection with the herpes simplex 1 virus, which stays in the body for the rest of the infected person's life, periodically reawakening to produce new cold sores. What exactly causes these reawakenings is the subject of much debate. Diets low in lysine, an amino acid found in foods, may be one factor.
Definition
Amino acids such as lysine serve as the building blocks of protein. Some amino acids also serve specific roles in the human body. For example, lysine plays a key role in growth and wound healing through its involvement in the production of collagen and bone. In addition, lysine helps the body convert dietary fats into energy and absorb calcium from the diet. Although there are 20 other amino acids, lysine is considered one of the 10 "essential" amino acids that the body must obtain from food in order to live.
Function
While the human body relies heavily on lysine, the herpes simplex virus that causes cold sores relies equally heavily on another amino acid, arginine. The herpes simplex virus requires arginine to produce new viruses and the presence of arginine causes the virus to begin reproducing. Lysine undoes the effects of arginine on the herpes simplex virus and competes with arginine for absorption by infected cells, limiting the amount of arginine that reaches the virus in the first place.
Sources
Lysine occurs naturally in protein-rich foods like poultry, meat, fish, legumes and dairy products. Farm-raised versions of poultry, meat and fish generally contain more lysine than wild-caught equivalents. Grains contain small amounts of lysine, often added after processing. People can also purchase lysine in the form of dietary supplements, although the Food and Drug Administration does not allow manufacturers to claim effectiveness for it against cold sores or any other condition.
Doses
People interested in treating cold sores through lysine should start by adding additional servings of lysine-rich foods. If this is ineffective, in his 2007 book "Integrative Medicine," University of Wisconsin professor David Rakel, M.D., recommends taking 1 g per day from lysine supplements to prevent cold sore outbreaks, and 3 g per day, taken as 1 g three times per day, to treat them.
Effectiveness
As of November 2010, the National Library of Medicine lists no studies on lysine-rich diets to treat or prevent cold sores. In the December 2005 issue of "Alternative Medicine Reviews," holistic medicine specialist Alan R. Gaby, M.D. reviewed all eight of the published studies on lysine supplements and cold sores. While half of the studies found that lysine produced modest benefits on the severity, frequency or duration of cold sores, the other half found that it had no effect. However, Gaby cautions that many of the studies used doses of lysine that were too low to be effective.
Safety
Ideally, all people should check in with their physicians before starting any dietary supplement, including lysine. However, this is especially important for some people: Lysine supplements may interfere with normal protein metabolism in people with liver or kidney disease and women who are pregnant. Arginine helps to dilate blood vessels, so people with diseases of the heart or blood vessels should talk to their doctors before taking products such as lysine that oppose this function. Lysine may precipitate gallstone attacks in people with a history of gallstone disease. Lysine does not replace conventional medical treatments for cold sores or any other medical condition.
References
- American Dental Association: Canker Sores, Cold Sores and Common Mouth Sores
- "Integrative Medicine"; David Rakel, M.D.; 2007
- "Alternative Medicine Reviews"; Natural Remedies for Herpes Simplex; Alan R. Gaby, M.D. ; December 2005
