Let The Sun Shine

The quick answer:  Aside from a healthy diet and exercise, the next best thing you can do is to get enough sunshine to maintain a healthy serum vitamin D level.  It’s good for your mood and can help prevent a long list of diseases.


About Vitamin D

It’s essential to eat vitamin-rich food because the body can’t produce them, with one exception:  With a little sunshine, the body can make it’s own vitamin D.  Unfortunately, the weathermen and dermatologists have scared us out of getting enough sunshine.  Ever had your vitamin D level tested?

Sufficient D is essential to good health; vitamin D receptors are found in cells all through your body.  The growing list of conditions where vitamin D deficiency is a risk factor includes seasonal affective disorder (SAD), osteoporosis, muscle and joint pain including back pain, certain cancers (breast, ovarian, colorectal, and prostate), obesity and diabetes, stroke or heart attack, G.I. diseases like inflammatory bowel disease (IBD) or Crohn’s disease, and immunological diseases such as MS and Parkinson’s disease.  It’s a long list. 

Vitamin D deficiency increases as you move away from the equator.  In the Sunbelt you can get adequate D year around, though it takes longer in winter.  But if you live above the 40th latitude parallel, roughly a line through Portland, OR, Salt Lake City, and New York City, you can ski all winter in your bathing suit and not get enough D.

There’s an annual cycle to your vitamin D level.  For most, our D level peaks in the last sunny days of summer, then hits rock bottom as winter turns to spring.  This is the point when you feel the blues, lack energy, or suffer muscle aches.  Because spring just started, your D is likely at its annual low-point (unless you’ve just back from sunbathing on a beach in Costa Rica). 

IOM Report

Americans love to take pills.  Maybe it’s because we’re in a rush and taking a pill is a quick fix, but we eat a lot of pills, including vitamin pills.  We get into vitamin fads—remember the vitamin C and E eras?   Usually these end badly; the hoped-for benefit proves elusive, or side effects present.  Because of the growing interest in vitamin D, the Institute of Medicine, perhaps the world’s most prestigious scientific body, was asked to study the vitamin D issue lest we run off on another pill fad.

The IOM report, issued in late 2010, disappointed many because of its cautiousness.  Basically, if you set the minimum level for serum vitamin D at 20 nanograms/mL, most people are OK.  But if you set the level at 30, as some labs do, then up to 80% are deficient.  Some doctors argue that 40-50 is a good range but the IOM couldn’t find sufficient evidence to support a target higher than 20-30.  (The IOM report also looked at calcium supplements and found little support, with the exception of girls in their teens.)

The N. Y. Times ran an article on the IOM report, repeating the message that vitamin D and calcium pills may not be indicated for most.  The article unleashed a torrent of reader comments, many from thoughtful people in the Northeast, the region with the least sunshine for vitamin D.  Readers expressed real anger that there wasn’t better guidance on the optimum vitamin D level, or on the best methods to maintain vitamin D in the winter.  This is a common problem in nutrition—after the billions spent on research, we have these basic questions without a clear answer.

The Vitamin D Solution

The best book I’ve seen on vitamin D is The Vitamin D Solution, written by Dr. Michael Holick, PhD, MD.  Holick suggests a 3-step solution of 1) testing, to know where you are, 2) sensible sunshine, and 3) safe supplementation when sunshine isn’t available. 

The book makes two remarkable statements about vitamin D and cancer:

First, on the benefit of getting sensible sunshine: “vitamin D could be the single most effective medicine in preventing cancer, perhaps even outpacing the benefits of . . . a healthy diet”.  We hear all the time that we should avoid avoid sunshine to prevent skin cancer, which brings us to the second point.

Second, the book quotes Dr. Edward Giovannucci on the benefits of sunshine for vitamin D versus the risk of skin cancer:  sufficient “vitamin D might help prevent 30 deaths for each one caused by skin cancer”.    I like those odds: 30 better outcomes at the risk of one bad outcome.

I recently saw my dermatologist.  She’s a charming woman who cares about her patients.  We talked about the trade-off between getting enough vitamin D the natural way—by sunshine—versus the risk of skin cancer.  The good doctor pointed out that in southern California, you could get sufficient vitamin D with 15 minutes of sunshine on most days.  Of course you have to show a little skin, so I do my workouts outdoors around noontime, wearing shorts and shirts without sleeves (except when it’s cold).  When no one’s around I take off my shirt, but I try to avoid the “pinkness” that’s the first stage of a sunburn. 

I’ve got a physical check-up scheduled that includes a test for vitamin D.  I’ll let you know how it comes out.  I’ll be happy if I have a serum level of 30 ng/mL, the upper range recommended by the IOM.  A number of people have told me their vitamin D levels—I’m forward about asking—and I’ve yet to meet anyone with a value of at least 30.  Per the IOM, this is a big problem, which brings us to this week's Healthy Change:

Please note the term "a little" sunshine, sun that burns or turns the skin pink may be harmful and should be avoided.  (If you live in the northern latitudes, don’t tolerate the sun, or are concerned about your vitamin D, consult your doctor.)

Please comment:  Want to share your experience with vitamin D, or how you tested?  Do you live in the northern latitudes?  If so, what do you do in winter to maintain vitamin D.

Need a reminder? Download our Healthy Change reminder card. Print and fold, then place in your kitchen or on your bathroom mirror to help you remember the Healthy Change of the week.

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Reader Comments (16)

After listening to a podcast all about Vitamin D (http://www.grc.com/health/vitamin-d.htm), I decided to get my level checked. It was low. So, I started taking supplements (5,000 IU every three days), along with calcium magnesium, and my Vitamin D serum level is now where it should be.

The guy who did the podcast is an amateur medical hobbyist and technical computer security specialist. He did an experiment where he spent like an hour in the sun (in Irvine, CA) every day completely naked. Despite his sun exposure, his Vitamin D levels were still dangerously low. It would appear that there are some folks that, even though they have sufficient sun exposure, are still unable to synthesize the appropriate Vitamin D levels, which therefore may necessitate taking some form of supplement.

The benefits of Vitamin D are unquestionable, and we are still learning more about it. It will be interesting to watch as research continues to progress in this area. In the meantime, I continue to get my Vitamin D levels checked annually at my physical, and take supplements to ensure that it falls in the normal, healthy level. This is in spite of me getting plenty of sun (yard work, swimming, and doing other outdoor activities--and I live in the south).

March 28, 2012 | Unregistered CommenterBrian Hall

I have had psoriasis for years, and it was getting worse. I noticed that it went away in the summer. I decided to try vitamin D3 supplements. I take 2000 IU each day. Then, around April, I stop and enjoy the sunshine until about October (I live in northern Utah). For the past 3 years I have had absolutely no symptoms of psoriasis. We need vitamin D, and in areas without strong sunshine, the supplements do help!

March 28, 2012 | Unregistered CommenterSheila Peterson

Brian, thanks for your note. Your approach seems wise, according to Dr. Holick's guidance: 1) get tested, 2) get sensible sunshine, and 3) get doctor guidance on supplementing with pills as needed. We're all different in how we process vitamin D. People who are dark complected, older, or overweight will always have lower levels. There are medical conditions that interfere also. Nicely done.

Sheila, what you've done makes a lot of sense. Happy for your good outcome. Have you ever been tested for serum vitamin D?

March 28, 2012 | Unregistered Commenterskip hellewell

I have my vitamin D tested in January. It was 16 ng/mL. I started laying out in the sun every afternoon when my son was napping. I don't feel like it helped at all. I think I am too far north (in Las Vegas, no less). I started taking a supplement that was recommended in an online article I read. I have noticed a difference in my mood when I don't take it. I get my levels tested again in a week or so. Now that spring is here, I'm going to start sunning myself in the afternoons again. I also read that vitamin D levels above 20 ng/mL are required for proper parathyroid function (your parathyroid regulates calcium). I am not sure if this is true, but I'd rather not risk it, given that I've had problems with my parathyroid.

March 28, 2012 | Unregistered CommenterLaura

I'd love to hear the brands/specific types of supplements that people have had success with. I live in Chicago so it's practically impossible to get enough sun to maintain healthy Vitamin D levels, and I do want to keep myself and my family healthy!

March 28, 2012 | Unregistered CommenterChristina

Just a side note, when you go to the doctor, if they are unsure about what to test in your blood, tell them it is “25-hydroxyvitamin D”. I had one doctor act a little unsure.

As far as the supplements, I take 5,000 IU “Now Foods” Vitamin D3, 120 capsules for $8.80 which lasts me all year (I take one every three days). http://www.iherb.com/Now-Foods-Vitamin-D-3-Highest-Potency-5-000-IU-120-Softgels/10421 There are other dosages available as well on iHerb.com.

March 28, 2012 | Unregistered CommenterBrian Hall

I take Bio Tech D3 50,000IU. It is a weekly supplement, rather than daily. There is also 5,000IU available. I've only found it online.

March 28, 2012 | Unregistered CommenterLaura

This is a real concern for me and my family as we live in Boston. We take Vitamin D supplements, walk to school, bike to work, run, and try to be outside daily. I also sneak button mushrooms into a lot of dishes, I think there are some fish that have Vitmin D in them as well.

March 28, 2012 | Unregistered CommenterAndrea J

Is there a way to help your body better absorb and use sunlight-vitamin D I wonder? Like how magnesium helps you absorb calcium. That'd be worth some research time IMO!

March 28, 2012 | Unregistered CommenterRill

From what I have read, vitamin K deficiency will make the effects of vitamin D deficiency worse. I don't know if it is needed for better absorption of vitamin D, though. Vitamin K2 (the form specifically mentioned) comes from natto, high quality red meats, and butter (the good kind that has more color and is from pastured cows, like KerryGold).

March 28, 2012 | Unregistered CommenterLaura

I had my levels tested after my last pregnancy. I expected it to be low since I shied from the hot summer sun while I was pregnant, but it was 41. I was relieved about that.

I don't really like taking supplements and figure that maybe it's not a bad thing to have levels drop in the winter?? Also, I've read that fermented cod liver oil contains vitamin D. I'm going to try taking that throughout next fall and winter. I've been laying out during my daughter's naps (I live in Salt Lake, so there have only been a few days warm enough to do this so far this year) and it feels so good that I know it's what my body needs right now. I read in the book Vitamin D Revolution that if the UV index (found on the local weather website) is above 7, you're body can make enough vitamin D.

March 29, 2012 | Unregistered CommenterLindsey

I remember hearing or reading that the skin needs to have natural oil on it for Vitamin D to be absorbed. Also, it takes some time after being exposed to the sun for the vitamin to make its way to the inside of the body where it can be used. If we take a shower before going out in the sun and then take a shower again after coming back inside, there probably won't be enough oil or enough time for the sun to work its miracle. I don't remember the time period that was recommended to put off bathing after sun exposure, several hours though I think, maybe 4 or 6 or so? Does anyone have that information? We used to take a bath once a week. I remember the Seventeen magazine having an article on a week's worth of hair styles lasting from one shampoo to the next a week later. The last suggested style was, of course, a ponytail : -) Chemists have formulated amazing hair products, but the necessity of more frequent use may be robbing us of Vitamin D.

March 30, 2012 | Unregistered CommenterLeah

All I know is that I am overall a happier person during the sunny months. And I live in Northern California, not northern Maine. :) I definitely see the positive effects of vitamin D. Even being in our backyard for 20 minutes of playtime with my kids can lift my spirits so I know that it's good for us in the appropriate doses.

I feel like it is a healthy and natural thing to be out in the sun on the daily basis and do my best to get me and our children out in it on a consistent (and safe) basis.

I have no idea what my Vitamin D levels are but I think I will ask about this when I get my next full physical (probably at least year a because I am expecting).

March 30, 2012 | Unregistered CommenterLisa

Skip, Dan has been working on his Vitamin D level for the last couple of
years. It is now a very robust 58. So now you can say you know somebody
who measures more than 30 (besides Lindsey).

March 31, 2012 | Unregistered CommenterSandra

I don't know what my level is. I live in Idaho and try to get three hours per week in the sun during the winter. It depends on the weather, but that's my walking time. During the summer I get more time in the sun with camping, gardening. etc.

April 1, 2012 | Unregistered CommenterAnn

Where I live in Alaska the sun hardly rises above the trees in December and January. It doesn't even get high enough for the temperature to get warmer when it's out--sometimes it will even get colder after the sun rises! So I take vitamin D supplements. I understand salmon is a decent source of vitamin D though, and most of us up here get a good freezer-full every summer to last through the year. Maybe that's God's way of taking care of us northern folk.

April 3, 2012 | Unregistered CommenterTom

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