Preservatives may cause food allergies
DEAR DOCTOR: BHT, a preservative in a lot of food products, really does a number on me. One serving of food with BHT and I wake up with terrific pain in my head and right eye, upset stomach, chills and fever. How common are such allergies, and how can I avoid these reactions?
DEAR READER: BHA and BHT, short for butylated hydroxyanisole and butylated hydroxytoluene, are antioxidants used to preserve a wide array of foods, including snack foods, meats, butter, chewing gum and rice, as well as cosmetic products and medications. They help maintain product
crispness.
These antioxidants rarely cause allergic reactions, but in 2007, a study published in Toxicology and Applied Pharmacology identified the mechanism for the allergic reaction. In studying rats given BHT, researchers found an increase in immediate skin allergies, linking it to an allergic response that caused a type of white blood cells, known as mast cells, to release the chemicals histamine and leukotrienes. These chemicals caused an allergic response in the skin.
In the United States, the highest amount of
BHA that is approved in foods is 0.02 percent, which is significantly less. Overall, some studies in rats have shown an increased risk of cancer, and others have shown a decreased risk in cancer.
When it comes to humans, researchers have found little evidence of a potential cancer link. In a study published in 2000 in Food and Chemical Toxicology, researchers in the Netherlands used a dietary questionnaire to ask 120,000 men and women between the ages of 55 and 69 about their dietary intake of BHA and BHT. After six years, the authors found no increase in stomach cancer among those with higher BHA/ BHT intake.
Your reactions to BHT appear to be a form of allergy. Obviously, the best thing you can do is simply avoid this chemical. Check labels to see which foods in your home contain BHA and BHT.
Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095.