If you get cold sores, you're likely interested in any medication or magic potion that can prevent them. Unfortunately, magic won't help, but you may benefit from eating fewer foods high in the amino acid arginine and more foods high in lysine.
Know Your Amino Acids
Lysine and arginine are two of the 20 amino acids that your body uses to synthesize the protein that makes up much of your body's tissues, including muscle and bone. Amino acids are required for growth and development, tissue repair, digestion and other important functions.
Your body can produce some amino acids, but you must get the others from your diet. Those your body makes are called nonessential amino acids because it's not necessary to get them from your diet in most cases. Those your body cannot make are called essential amino acids as you must obtain them from food.
Arginine is a nonessential amino acid, while lysine is an essential amino acid. This distinction is important when it comes to arginine and cold sores. Since your body makes arginine, it's not crucial to get a lot of arginine from food. This is a good thing, as too much arginine may trigger the herpes virus that causes cold sores.
Lysine, on the other hand, may help counteract the activity of arginine. As a nonessential amino acid, it's important to get enough lysine from your diet both for your overall health and for potentially lowering your risk of cold sores.
A third group of amino acids is called conditional. It includes nonessential amino acids that become essential during times when your body may not be able to produce them in sufficient amounts, such as when you're ill, injured or stressed. Arginine is a conditional amino acid, so it may not be prudent to avoid it at all times.
Read more: Foods High in Branched-Chain Amino Acids
Foods High in Lysine
Whether or not adding more lysine to your diet will help is still under investigation and, so far, research is inconclusive. However, according to a review published in Integrative Medicine: A Clinician's Journal in June 2017, lysine doses over 3 grams per day improved subjective experiences in study participants. In combination with a low-arginine diet, doses over 1 gram daily may be effective, but more research is needed.
Getting this amount from foods is fairly easy. Just 3 ounces of roast beef have a little over 3 grams of lysine, according to the USDA.
Three ounces of turkey wings have 2.6 grams, and 3 ounces of pork chops have about 2.3 grams. The same amount of tuna fish and shrimp have 2.2 and 1.8 grams, respectively. Other good sources are cheese, soybeans and other soy foods, nuts and seeds, eggs and beans.
Some of these foods are also high in arginine, including nuts (peanuts, almonds and cashews) and sunflower seeds. Chocolate is a rich source of arginine too, reports the University of Wisconsin-Madison School of Medicine and Public Health.
The ideal foods are those that have a good lysine-arginine ratio. According to the USDA's Nutrient Ratio Tool, some of the foods highest in lysine and lowest in arginine include:
In general, fruits, vegetables and dairy products provide the correct ratio. The University of Wisconsin-Madison School of Medicine and Public Health says that beans, fish, turkey and chicken can also be increased in the diet.
If you're considering taking a lysine supplement to increase your intake, talk with your doctor first. Lysine supplements are likely safe, but their effects haven't been well studied, according to Winchester Hospital.
Large doses have caused gallstones and high cholesterol in animal studies, so if you are predisposed to either of these problems, take lysine with caution and only with your doctor's permission.
- U.S. National Library of Medicine: "Amino Acids"
- Mayo Clinic: "L-Arginine"
- Integrative Medicine: A Clinician's Journal: "Lysine for Herpes Simplex Prophylaxis: A Review of the Evidence"
- USDA: "Top 10 Foods Highest in Lysine"
- University of Wisconsin-Madison School of Medicine and Public Health: "Herpes Simplex Virus (HSV) 1 & 2 Infection Clinical Tool"
- USDA: "200 Foods Highest in Lysine and Lowest in Arginine"
- Winchester Hospital: "Lysine"