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Can You Prevent Cold Sores by Avoiding Cashews?

A reader found that avoiding cashews and other trigger foods helps reduce recurrent cold sores. Taking L-lysine supplements also helps.
Can You Prevent Cold Sores by Avoiding Cashews?
Cashew nuts close up on wood background

Cold sores, also known as fever blisters, are part of the body’s reaction to herpes simplex virus type 1 (HSV-1). Although the vast majority of us have been exposed to HSV-1, not everyone gets blisters on the face as a result. Those who do have to deal with unsightly, painful lesions, sometimes repeatedly. In extreme cases, a person may suffer with sores as often as every month. They are delighted if they find a tactic that works to prevent these outbreaks. One reader discovered that the secret lay in avoiding cashews.

Preventing Recurrent Cold Sores:

Q. Years ago, I was getting cold sore after cold sore after cold sore. Then I read about trigger foods and realized that the cashews I was enjoying were probably a big source of the problem.

I began taking L-lysine daily. I later read that one shouldn’t take it all the time because it might upsets the balance of amino acids. So I now go easy on my trigger foods and just take some L-lysine if I feel a cold sore coming, or if I eat some chocolate or nuts. Along with avoiding cashews, this seems to work for me.

Avoiding Cashews for Cold Sore Prevention:

A. The idea of reducing cold sore susceptibility by limiting arginine intake and increasing lysine goes back to the early 1980s (Griffith, DeLong & Nelson, Chemotherapy, 1981). A small placebo-controlled trial found that L-lysine supplements reduced the number of cold sores and their severity and duration (Griffith et al, Dermatologica, 1987).

Cashews are not technically nuts, but are instead considered seeds. They are, however, rich sources of the amino acid arginine. So avoiding cashews makes sense for you.

L-Lysine as a Home Remedy for Cold Sores:

Some time ago, we wrote about L-lysine as a supplement to prevent the development of cold sores.

Q. You recently mentioned the value of L-lysine for dealing with cold sores. I have struggled with cold sores and fever blisters for over 50 years.

About 20 years ago, I first tried L-lysine. I’ve found that taking 1000 mg twice a day at the first sign of a “tingle” stops the cold sore immediately.

If I miss that signal and a blister forms, taking L-lysine makes the blister disappear within a few days: no scabs, no inflammation. My brother has had similar good results with L-lysine.

A. Like you, many people who suffer from recurrent cold sores report that the amino acid L-lysine can be useful in shortening the attack. Despite such testimonials, however, there is a surprising lack of recent clinical trials supporting the use of L-lysine. Older studies were inconclusive.

A veterinary study in cats found that L-lysine was not effective for preventing feline HSV-1 (Bol & Bunnik, BMC Veterinary Research, Nov. 16, 2015). Of course, cats and people are not the same. Without better research it is hard to say whether this natural product is really better than placebo. On the other hand, L-lysine appears safe.

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About the Author
Terry Graedon, PhD, is a medical anthropologist and co-host of The People’s Pharmacy radio show, co-author of The People’s Pharmacy syndicated newspaper columns and numerous books, and co-founder of The People’s Pharmacy website. Terry taught in the Duke University School of Nursing and was an adjunct assistant professor in the Department of Anthropology. She is a Fellow of the Society of Applied Anthropology. Terry is one of the country's leading authorities on the science behind folk remedies. .
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