Type-1 herpes simplex virus causes over 95 percent of fever blisters, according to the National Institute of Dental and Craniofacial Research. Once infected with the virus, it stays with you for life. It is dormant in 90 percent of those afflicted until a trigger occurs to set off an outbreak. One of those triggers is what you eat. Research has shown that when arginine, an amino acid, is introduced to live herpes cultures, the virus multiplies rapidly. The website Health911 concludes that diet can't actually cause herpes simplex, but foods high in arginine can trigger outbreaks.
Whole Food and More warns against eating many types of nuts if you are carrying the herpes simplex virus. According to Nutrition Data, a online database gathered from the USDA's National Nutrient Database for Standard Reference, 1 cup of blanched almonds contains 3,692 mg of arginine. A cup of dry roasted cashews contains 2,385 mg. Peanuts are especially bad with 4,134 mg per cup serving. Using peanut oil in cooking, however, is acceptable as the processing removes all traces of arginine.
Products such as Jell-O can contribute to fever blister outbreaks, according to Whole Food and More. Nutrition Data reports that a 3 oz. package of gelatin dessert mix contains 575 mg of arginine.
Peas are moderately high in arginine and Health911 says they can feed the herpes simplex virus. A ½ cup serving of canned peas contains 297 mg. A cup of raw snowpeas contains 131 mg.
Health911 puts oatmeal on its list of foods that can trigger fever blister flare-ups. A commercially-prepared oatmeal cookie can have up to 84 mg of arginine.
Health911 advises against coffee, saying that it can increase flare-ups if you are infected with the herpes simplex virus--but Nutrition Data advises that it has only 2.4 mg of arginine per cup.
Health911 also names whole-wheat products and grains as potential problem foods if you suffer from fever blisters. Whole Food and More mentions barley, corn, Brussels sprouts and pasta, especially wheat-based products. Both websites, as well as the National Institute of Dental and Craniofacial Research, advise against chocolate. Nutrition Data does not attribute high arginine content to most brands of chocolate, so it is possible that other undocumented properties may additionally trigger outbreaks.