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People’s Pharmacy: Does sunscreen lead to vitamin D deficiency?

Q. I was at the beach last week and didn’t venture out without my high-powered sunscreen (SPF 45). It worked so well that I never burned. In fact, I never even got pink. I am as pale now as before the trip.

That got me to wondering whether sunscreen has any effect on vitamin D formation. I wear sunscreen daily, as my dermatologist has recommended. Do I need supplements?

A. You should ask your doctor to run a blood test to check your level of 25-hydroxyvitamin D. This is an indicator of your vitamin D status and is the best way to tell if you may need a supplement.

Your observation from the beach is on target. Sunscreen that effectively prevents sunburn also blocks most production of vitamin D in the skin (Dermatoendocrinology, January/February/March 2013). If you must avoid sun exposure for medical reasons, you may need a supplement. If you are simply being prudent about avoiding sunburn, you might consider brief (15 to 20 minute) exposures without sunscreen a few times a week. In many cases, that will produce adequate vitamin D without risking your skin.

You can learn more about the importance of vitamin D and appropriate doses for supplementation from the Guide to Vitamin D Deficiency we are sending you. Anyone who would like a copy, please send $3 in check or money order with a long (No. 10), stamped (70 cents), self-addressed envelope to: Graedons’ People’s Pharmacy, No. D-23, P.O. Box 52027, Durham, NC 27717-2027. It also can be downloaded for $2 from our website:


Q. I read your column recently about nail fungus and the proposed remedies. I had nail fungus on one fingernail and two large toenails for many years. I had tried many of the “cures” you noted, but the one that finally worked was not on your list.

I mixed a tablespoon of sea salt (available in grocery stores) with just enough water to dissolve it. (There was not much liquid.) I soaked the nails for no more than 10 minutes per day until the fungus was gone. I hope this helps others.

A. We have heard from readers that soaking in salt water can banish stubborn warts and that applying a saltwater solution can alleviate acne. Some people have found that Epsom salt soaks can help against nail fungus.

We appreciate your detailed instructions and hope that others will let us know if this remedy works for them.


Q. I read about eating raisins before bed to reduce nighttime urination, and I love this idea. It worked the first night I tried it. Instead of visiting the bathroom every hour all night long, I made half as many visits to the bathroom.

Last night, I ate about a cup of raisins, and the results were astounding. I got up only once in the middle of the night. I had no side effects, either, except a good night’s sleep!

A. We have not been able to find any scientific reason that this remedy would reduce nighttime urination. You’re not the only one to benefit, though. Another reader wrote: “I have noticed the same effect (sleeping through the night) for the past two years while taking gin-soaked raisins. I had assumed that the gin-soaked raisins lessened the aches and pains that usually woke me up when I turned over during sleep. I take my raisins each morning when I arise.”

Raisins are not for everyone. They are high in calories and sugar, so a cup of raisins could well be too much for some people.

Joe Graedon is a pharmacologist. Teresa Graedon holds a doctorate in medical anthropology and is a nutrition expert. Their syndicated radio show can be heard on public radio. In their column, Joe and Teresa Graedon answer letters from readers. Write to them via their website: