Research suggests DEET will reduce SPF of sunscreens

Q. I live in Florida and play golf at least four times a week. I also love to garden. Whenever I go outside, I apply sunblock and then spray on a potent insect repellent containing DEET. Is there any problem applying it over my sunscreen?
A. The Environmental Protection Agency and the Centers for Disease Control and Prevention state that it is safe to use insect repellent and sunscreen together. There is, however, research suggesting that DEET can reduce the SPF of sunscreen by about a third (The Lancet, July 1997).
A new study (Journal of Pharmacy and Pharmacology, May 2004) suggests that the sunscreen ingredient oxybenzone enhances the absorption of DEET through the skin. Whether this represents a hazard is unknown.
Q. My mother loves chocolate, especially imported dark chocolate. But she also needs to control her blood pressure and cholesterol. What's in chocolate? Isn't the fat bad for her heart? I've heard that there is caffeine in chocolate, and wouldn't that raise blood pressure?
A. You don't need to worry about your mother's love of dark chocolate. The antioxidant compounds in chocolate (similar to those in red wine or tea) actually help lower blood pressure and prevent blood clots. The fat in chocolate does not raise cholesterol. There is no caffeine in chocolate, though a related compound, theobromine, is present.
We are sending our 100-page book, "Chocolate Without Guilt," for your mother. It has recipes for low-fat chocolate desserts. We'll include an hourlong CD interview with experts on the health benefits of chocolate. Anyone else who would like this combination, please send $19.95 in check or money order to: Graedons' People's Pharmacy, No. CWG-476, P.O. Box 52027, Durham, NC 27717-2027.
Q. I am suffering greatly from flea bites this summer. They itch horribly and get infected if I scratch them. I have tried everything I've heard of. Doctors have been no help at all. I need something that will keep them off me. I am thinking of using the flea medicine that is used on dogs. Would it be harmful?
A. The best way to protect yourself from fleas is to apply the medicine to your dog. If you can eliminate fleas from your home, you won't have to suffer anymore. Do not use this veterinary medicine on yourself, as it has not been tested for human safety.
Q. I have been taking Coumadin for the past three years. In the past few weeks, I have had problems with my INR levels increasing from 3.5 to 4.5. Nothing has changed in my diet except for tomatoes.
Our family loves fresh tomatoes, and we have been eating them at both lunch and dinner. Someone told me that he read an article about fresh tomatoes having anticoagulant action. Apparently the fluid in the center of the tomato surrounding the seeds is the source. Could this account for my blood getting thinner?
A. Coumadin (warfarin) is prescribed to prevent blood clots. If the dose is too high, there is a risk of hemorrhage. That is why people on Coumadin need frequent blood tests to monitor how long it takes their blood to clot.
One measure of this is the INR, or International Normalized Ratio. A change from 3.5 to 4.5 might put you at risk of excessive bleeding.
Research (British Journal of Nutrition, December 2003) shows that tomato extracts may prevent blood clots. This anticoagulant effect might indeed explain why your lab results have been changing.
XIn their column, Joe and Teresa Graedon answer letters from readers. Write to them in care of King Features Syndicate, 888 Seventh Ave., New York, NY 10019, or e-mail them at pharmacy@mindspring.com or via their Web site: www.peoplespharmacy.org. Their newest book is "The People's Pharmacy Guide to Home and Herbal Remedies" (St. Martin's Press).
& copy; 2004 King Features Syndicate, Inc.