DEET, sunscreen might not mix

By The Vindicator

Q. I have to use insect repellent every time I go outside. When I also need sunscreen, which goes on first?

A. This straightforward question has no simple answer. The Centers for Disease Control and Prevention recommend that “Sunscreens should be applied to the skin before insect repellents.”

In the next sentence, however, the CDC advises travelers not to use combination products containing both repellents and sunscreens. It points out that “DEET-containing insect repellents may decrease the effectiveness of sunscreens and [sunscreens] may increase absorption of DEET through the skin.”

We also discovered research demonstrating that DEET and the sunscreen ingredient oxybenzone (benzophenone-3) mutually increased skin absorption (Toxicology and Applied Pharmacology, Sept. 1, 2007). Since oxybenzone has estrogenic activity, increased absorption is not desirable.

If you use a sunscreen that relies on zinc oxide or titanium dioxide, this should not be a concern. For more information on sunscreen safety, we are sending you our new Guide to Skin Care and Treatment. Anyone who would like a copy, please send $3 in check or money order with a long (No. 10), stamped (61 cents), self-addressed envelope to: Graedons’ People’s Pharmacy, No. S-28, P.O. Box 52027, Durham, NC 27717-2027. It also can be downloaded for $2 from our Web site:

Q. A gentleman wrote you that he had been taking a prescription heartburn pill for years. Through his own research he learned that he might have a B-12 deficiency due to his use of the drug over an extended period of time. He had symptoms such as fatigue and mild depression.

Upon reading the article, I realized that I had similar symptoms and was taking Nexium. I saw the doctor for a routine blood work-up, and he checked the B-12 level. It turned out that I was extremely deficient! The nurse called immediately, and I was put on a protocol of monthly shots.

When I visited my gastroenterologist, he said he had never heard of such a thing. I was quite surprised and would like to educate him.

A. This issue has been controversial for years, but there is growing recognition that long-term use of powerful acid-suppressing drugs can interfere with vitamin B-12 absorption (American Journal of Gastroenterology supplement, March 2009).

Calcium, iron and vitamin B-12 are all more readily absorbed from an acid environment. The blood tests for vitamin B-12 deficiency should include a measurement of methylmalonic acid (MMA) and not just serum vitamin B-12.

Q. I suffered from chronic hives for years without much help from the allergist or the dermatologist. The medicines they prescribed did little to relieve my symptoms and left me in a fog. I was becoming a hermit.

After a bout of pneumonia, I started taking vitamin C (1,000 mg twice a day) to build my immune system. I noticed that my hives were greatly reduced as well. I now take 1,000 mg of Vitamin C a day and am practically hive-free!

A. There’s not much recent research on the effectiveness of vitamin C for allergic symptoms such as hives. Back in 1982, scientists tested vitamin C and found it did not protect subjects from experimentally induced hives (Journal of Allergy and Clinical Immunology, June 1982).

Your improvement might have been coincidental, but others may wish to give it a try, since vitamin C is relatively benign.

XIn their column, Joe and Teresa Graedon answer letters from readers. Write to them in care of The Vindicator or e-mail them via their Web site: Their newest book is “Favorite Home Remedies From The People’s Pharmacy.”

2009 King Features Syndicate Inc.

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