Anyone who regularly suffers from cold sores dreads the familiar tingling on their lip, the sensation that heralds the start of another outbreak.
Caused by the herpes simplex 1 virus, present in 60% to 90% of adults, cold sores recur regularly in one-fifth of those infected. Between attacks, the virus lies dormant in the nerves of the face. But triggered by stress, illness or exposure to bright sunlight, for example, the virus occasionally invades cells in the lip and causes painful, fluid-filled blisters.
Over the last decade, cold sore creams containing the drug acyclovir have been the main treatment. Able to interfere with the replication of the virus, acyclovir, at best, slightly reduces the length of an outbreak if applied to the sore several times a day.
For those unsatisfied with such results or simply seeking a more natural approach to reducing cold sore eruptions, prevention is key--and it is here that nutrition may play a role.
Although little herpes research has focused specifically on food, experts say a well-balanced diet certainly appears to help.
Since infection and stress are well-known cold sore triggers, nutrients that support the immune system are crucial. Seafood and red meat provide the minerals selenium and zinc, and citrus fruits, peppers, sweet potatoes, dark green leafy vegetables and wheat germ oil provide the vitamins C and E.
Daily inclusion of so-called good, or probiotic, bacteria also may be helpful, with preliminary research endorsing Lactobacillus, found in some yogurt.
Meanwhile, natural health practitioners and some mainstream doctors turn to lysine to treat cold sore outbreaks. This amino acid is found naturally in red meats, fish, dairy products, eggs, beans, potatoes and brewers yeast.
In pre-acyclovir days, researchers actively pursued possible links between lysine and cold sores with laboratory work suggesting that lysine may stop a cold sore by blocking another amino acid, arginine, needed by the herpes simplex 1 virus to replicate. Subsequent small studies on people with recurrent cold sores then revealed that 1-to 3-gram supplements of lysine a day appeared in some cases to reduce flare-ups and severity and to improve healing times.
Although the supplement seems safe, animal studies have suggested that high doses of lysine may cause gallstones and elevated cholesterol levels, so people with such conditions may want to exercise caution. And, because maximum safe dosages have not been established for pregnant and nursing women, experts recommend that they consult doctors before taking this, or any, supplement.
Nonetheless, the evidence for lysine has led some nutrition and medical experts to suggest that the supplements might help head off cold sores if taken at the first tell-tale tingle.
Adhering to such nutritional advice, while ensuring that the body gets adequate sleep, might help keep cold sores at bay.
Amanda Ursell, a dietitian and nutritionist, is a London-based freelance journalist. Her column appears twice a month. She can be reached at firstname.lastname@example.org.