Fever blisters, also called cold sores, are caused by one of two types of the herpes simplex virus. Some people with the virus exhibit no symptoms at all, according to dentists Paolo G. Arduino and Stephen R. Porter in the February 2008 issue of the "Journal of Oral Pathology and Oral Medicine," while others suffer repeated outbreaks of fever blisters. Some people claim that fruit --- especially citrus fruit --- provokes fever blister outbreaks. However, there is no evidence to support this.
Chemical Properties
Scientists describe the chemical properties of substances such as food in terms of acidity or alkalinity. Most foods are acidic or neutral. Strong acids such as battery acid cause severe burns when they come into contact with skin. The acids in foods are not as strong as battery acid, but they can still cause damage, especially when they come in contact with the relatively thin, sensitive skin of the mucous membranes. Acid damage may precipitate a fever blister outbreak or may make an existing outbreak worse. Fruits --- especially citrus, pineapple, plums, pomegranates and berries -- are among the most acidic of foods.
Physical Properties
Scientists describe the physical properties of substances such as food in terms of state: gas, solid or liquid. Acids in fruits that are enjoyed in a liquid state, such as juice or nectar, or a semi-liquid state, such as preserves and sauces, have more contact with mouth surfaces than whole fruit, which is enjoyed in a solid state. For people with fever blisters, the result is that juices, nectars, preserves and sauces tend to cause more damage than whole fruits.
Nutritional Properties
Scientists describe the nutritional properties of a substance in terms of macronutrients -- such as carbohydrate, fat and protein that are measured in grams --- and micronutrients --- such as vitamins, minerals and phytochemicals that are measured in milligrams or micrograms. Fruits are an excellent source of vitamins, minerals and phytochemicals that support the immune system. Some micronutrients, including vitamin C, vitamin A and flavonoids, inhibit the growth of the virus that causes fever blisters, independent of their effects on the immune system.
Expert Opinions
As of October 2010, the National Library of Medicine listed no studies that conclusively link eating fruit to fever blister outbreaks. In fact, in the 2007 edition of "Integrative Medicine," University of Wisconsin professor David Rakel, M.D., specifically recommends eating more fruit as a strategy to prevent fever blisters. MedlinePlus, a patient information website jointly maintained by the National Institutes of Health and the National Library of Medicine, counsels against eating citrus fruits, but only during an active outbreak of fever blisters.
Considerations
Fever blister triggers vary from person to person. Because fruits supply valuable nutrients, it's not a good idea to eliminate them from the diet. If the acids in fruits seem to trigger fever blister outbreaks, avoiding highly acidic fruits such as citrus can help. Consuming whole fruit instead of juices, nectars, preserves and sauces is another good strategy. People who experience frequent, severe or long-lasting --- longer than two weeks --- fever blister outbreaks should see a doctor. A doctor can rule out food allergies or other serious conditions.
References
- "Journal of Oral Pathology and Oral Medicine"; Herpes Simplex Virus Type 1 Infection; Paolo G. Arduino, D.D.S., M.Sc. and Stephen R. Porter, D.D.S, Ph.D.; February 2008
- "Integrative Medicine"; David Rakel, M.D.; 2007
- MedlinePlus: Mouth Sores
- University of Michigan Health System: Cold Sores
