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Spring Break, Cancun
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Lots of D goin' on
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Dr. Katherine Farady, Barton Springs
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It's a good thing I take supplements!
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Dear Friends,
This is a little long, but I hope you'll find it illuminating!
-KF
What do mad dogs, Englishmen, and Spring breakers have in common? If you guessed, "They go out in the midday sun," you are correct! In Europe, the English, as well as the rest of their northern European counterparts, flock to Italy, Greece, Spain, and other tropical locales for their vacations, where they can't wait to get their pasty white selves into the sun. I wince when I think of the sunburns! More about mad dogs later.
As for Spring breakers, we're all very familiar with the annual invasion of our southern coasts by thousands of students from all over the country. After having been cooped up in libraries and dorm rooms all winter, they descend on the beach in droves, for a week of beer, volleyball and sun, sun, sun! We dermatologists joke about "future patients" and "job security." LOL! Aren't we clever! But now it's time for a little confession on my part. I have a small guilty pleasure. Well, actually, I have several, but this is the one I'll confess to now. :-) Anyway, I have to admit that sometimes, like around this time of year, when the temperature finally dips below 90, I enjoy the feeling of sun on my skin. It feels good! There, I've said it. Of course, I can't enjoy this pleasure for long, as my dermatologist guilt quickly sets in and I force myself to go inside or seek shade.
But let's look at why people are drawn to the sun. Studies have shown that ultraviolet exposure, whether it's from the sun or from indoor tanning beds, stimulates the production of endorphins, our natural "feel good" hormone. There have even been studies showing that tanning is addictive in some people. So, why, if the sun is so bad for us, does it feel so good?
Well, maybe because it is good for you. What? Did I just say that? Yes, the sun is good for you because of the sunshine vitamin, vitamin D. Vitamin D is actually a hormone, and the active form of the hormone is synthesized in the skin from its precursor. Ultraviolet radiation from the sun catalyzes this reaction. Without sun, we cannot make vitamin D. There are no natural dietary sources, except for wild salmon and other oily fish. (Thus the reason for giving cod liver oil to children in the olden days.) Milk and orange juice contain vitamin D, but only because they've been fortified. Egg yolks contain very small amounts.
Vitamin D has been the subject of a lot of press lately, at least in medical circles. Most people know that it is important for bone and calcium homeostasis, but recent research has shown that vitamin D also plays an important role in maintaining our immune systems (fighting off infections), preventing high blood pressure and coronary disease, prevention of many internal cancers and regulation of blood sugar and insulin levels. This is very exciting stuff! But not too surprising when you realize that over 1000 of our genes contain vitamin D response elements, meaning that vitamin D is required for the genes to work. Thus, vitamin D is an integral nutrient that our bodies need to function correctly. And we can't get enough of it through our diet alone.
Now, I'm going to delve into some history. Bear with me; this is actually pretty interesting. Around 50,000 years ago, our ancestors started migrating from Africa northward into Asia and Europe. At that time, humans were all dark skinned. The melanin pigment protected them from frying in the equatorial sun. (They wore little clothing and were outside every day.) Between 12,000 and 8,000 years ago, a gene mutation occurred that resulted in loss of pigment in the skin. This mutation conferred a survival benefit in northern latitudes. Why? Because there wasn't as much sun, and the primitive humans were not making enough vitamin D. Heavy pigment in the skin, while protecting from burns, leads to decreased absorption of UV radiation, and decreased D synthesis. Low vitamin D levels resulted in adult osteomalacia, or softening of the bones, which contributed to pelvic contracture, making childbirth impossible. This mutation coincided with the transition to an agricultural society (plant foods do not contain vitamin D).
OK, so enough history. Now, people of all skin types live everywhere, and most of us wear clothes every day and spend most of our time indoors. Vitamin D deficiency and insufficiency has been identified as the top public health issue in the US by the American Public Health Association. But it's not just a US problem; the problem is worldwide.
We have now arrived at one of the most important dilemmas in dermatology today. This is what makes us dermatologists squirm. We've spent our whole careers educating our patients to avoid the sun and wear sunscreens. We've inadvertently contributed to the Vitamin D crisis. What to do? I can't speak for all my colleagues, but I still can't easily bring myself to tell patients to go out in the sun. As a cosmetic dermatologist, I see the evidence of photoaging every day (wrinkles, dark spots, rough texture, sallowness.) As a general dermatologist, I diagnose and treat skin cancer every day. Skin cancer is undeniably correlated with long term sun exposure. And our ancient ancestors didn't live long enough to worry about skin cancer and wrinkles.
In any event, what is the right amount of sun exposure to get enough Vitamin D? You'd think the answer would be simple, but it is not. Data are conflicting and confusing. The dermatologic literature indicates that anywhere from 2 to 30 minutes of unprotected exposure of limited areas (such as arms and legs) per week is enough, while the endocrine literature indicates much longer exposures, and larger surface areas are needed. Other variables that impact vitamin D synthesis include latitude, season, air pollution, skin type, and obesity. It's pretty complex.
The good news is that we do have supplements. The bad news is that no one can agree on how much vitamin D to take. After researching this article, here is what I can tell you:
1. Everyone should take a vitamin D supplement; I recommend 1000-2000 units per day of vitamin D3 (the active form) daily for adults. You may need more if you are elderly, or dark skinned, or ill. If you have kidney disease, check with your primary physician. If you can't find D3 at your drugstore or grocery store, try www.swansonvitamins.com.
2. The current recommended daily intake levels are pitifully low. Everyone recognizes that, and the numbers are expected to be revised upward soon.
3. Vitamin D toxicity is theoretically possible, but very rare. Studies in MS patients taking up to 40,000 units daily (not that I would recommend this much!) have not shown any increase in urine or serum calcium levels. There has never been a reported case of vitamin D toxicity from natural sunlight exposure.
4. Adequate D levels are defined as greater than 30 ng/ml. Optimal levels (similar to a lifeguard or to our equatorial ancestors) would be in the 50-70 ng/ml range. Aim for this level. At this level, your body can start to store D for future use.
5. If you are in doubt, have your level checked. It's an easy blood test. We can order it for you. Insurance may or may not cover the test. You may also choose to get your own test at AnyLabTestNow! for $99.00.
6. Stop feeling guilty about limited amounts of sun exposure. Life is too short!
So, that's a brief overview of the Vitamin D issue. Speaking of mad dogs and Englishmen, economist John Maynard Keynes was once quoted as saying, "When the facts change, I change my mind. What do you do, sir?" I used to be a skeptic when this debate first came to my attention several years ago, but now I'm changing my tune. And now, I think I'll go out to my patio for 10 minutes of endorphins. :-)
Here's wishing you all a happy fall season filled with cooler weather, football games, and good times. Thanks for reading,
Kathy Farady
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Call Theresa for cosmetic scheduling:
786-3498 (voice or text)
email: drfaradyoffice@gmail.com
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