Making Sense of The Vitamin D Dilemma and Sun Exposure

Cynthia Bailey, MD|January 8, 2010

SunshineFlowerScientists and doctors are finally getting a better handle on what to tell our patients about vitamin D.  Over the past few years, we've learned that:

  • vitamin D is critical for health,
  • many people have dangerously low vitamin D levels,
  • sun exposing your skin produces vitamin D
  • sun exposing your skin causes skin cancer, wrinkles, age spots and thin/fragile skin

Up until now, however, we haven’t known how to counsel patients about safely raising their vitamin D levels. That's because a persons vitamin D level is affected by their diet, their ability to actually absorb the vitamin D that they eat, and the amount of sun their skin can absorb (which is determined by  factors like where they live in the world, the seasonal variation in sun intensity, and their skin color). Maintaining a healthy amount of Vitamin D in your body is still an ongoing area of scientific study, but doctors are zeroing in on some more concrete recommendations to help you know what your should be doing for your health. Daniel J DeNoon at WebMD just wrote an excellent web based article for consumers on vitamin D and health.  It's  the best summary of the issues surrounding vitamin D that I've ever seen. His article is a must read for people concerned about their vitamin D levels and includes some recommendations for how much vitamin D a person should take every day. I've summarized my vitamin D recommendations for your overall body health and combined them with my dermatologic experience regarding skin health.  This is what I'm telling my patients in 2010: 1. Everyone should get their vitamin D levels measured. I have patients with low vitamin D levels in spite of getting a lot of sun or taking a lot of vitamin D.  Every body is different so you just need to get your levels measured.

  • The name of the vitamin D level to test is 25-hydroxyvitamin D (25-OHD).
  • If your level is below 5 ng/mL (or 37.5 nmol/L depending on the units reported by a lab) then you need more vitamin D.
  • Healthy levels are somewhere between 30 and 70 ng/mL. If your vitamin D level is normal, you don’t need to make any changes in what you're doing.

2. If your vitamin D level is low I recommend you take vitamin D supplements.

  • The name of the supplement you want to take is vitamin D3.
  • Ask your doctor how much vitamin D3 you should take and have him/her recheck your level in a few months. Standard dosage recommendations for vitamin D3 are still up in the air and it is possible to take too much. Our old recommendation was 400 IU for healthy adults and now the recommended daily dose may be climbing to 2000 IU. If you’re severely vitamin D deficient expect that your doctor will tell you to take A LOT more than that until your level normalizes.
  • Taking too much vitamin D supplements can hurt you, so ask your doctor for help recommending a dose, and get retested to be sure it’s working!
  • If your level doesn’t go up after taking supplements, have your doctor figure out why. It could be that you’re not absorbing it because of an intestinal condition such as celiac. I have one patient who had asymptomatic celiac that affected her ability to absorb vitamin D.

3. Everyone should eat vitamin D rich foods. Foods are always better than commercial vitamin pills.  Palatable (in my opinion) vitamin D rich foods are:

  • seafood: wild sockeye salmon (sockeye is the richest in vitamin D and farmed salmon has less vitamin D that wild salmon-no surprises here) cod, steelhead, halibut, shrimp, some shellfish.
  • vitamin D enriched dairy products including  soy milk
  • egg yolks

Other sources (harder to eat since they're not so palatable in my opinion) include some of the smelly fish like mackerel, herring and sardines (I would love some good sardine recipes).  Liver is also a good source of vitamin D, if you can manage it.  These foods supplied vitamin D during the winter to our ancestors who lived in the northern parts of the world that had very weak sun intensity in the winter. Cod liver oil is rich in vitamin D, but like supplements, you can OD on it and hurt yourself, so ask your doctor for help if you want to use it. For a good list of the vitamin D content in foods based on a 200 calorie serving size, visit  NutritonData.com: Foods Highest in Vitamin D. 4. Sun bathing for vitamin D production is dangerous and ages your skin's appearance, but may be a necessary last resort to raise vitamin D. If your oral vitamin D supplements don't raise your level adequately then you may need to use your skin as your vitamin D factory.  This has big down sides however, so use the 'right' sun ray and get just the dose of sun you need- and no more. Realize that sun exposure will  permanently damage the part of your skin that you're exposing.

  • Only UVB sun rays make vitamin D. UVB is the most cancer causing part of sunlight; they are the mid day (10am to 3pm), mid summer rays that doctors normally caution people to avoid. Winter sun and morning or late afternoon sun has very little UVB and thus won't really help with your vitamin D production.
  • Turn your tummy skin into your vitamin D factory. Most patients I see have very little sun damage on their tummy and as a result I rarely find skin cancer there.  Plus, if you do get a cancer on your tummy, you're more likely to see it than on your back, and it's easier to treat than on your face (depressing but true).  Sun exposure will definitely increase your risk of skin cancer on the sun exposed skin so being able to do skin exams on your exposed skin is important.  Also remember that the sun will wrinkle and age the look of your exposed skin.  I find that most people arn't as concerned about this on their tummy.  Definitely don't use your face, legs, hands or other areas that have already had too much sun in your life time.  They are already your  highest risk sites for skin cancer and they are the parts of your skin that you show off to the world so wrinkles and age spots matter.
  • Get the bare minimum amount of sun necessary to raise your vitamin D level into the normal range. Knowing how much sun you will need is impossible, so get your levels rechecked.  A person's sun absorption varies with their skin color, the time of day and season, where they are on the earth etc.  I've seen learned sources recommend 30 minutes of sun exposure twice a week, but most people will sun burn in that period of time.  Because sunburns increase the risk of melanoma you definitely want to avoid burning in your effort to turn your skin into a vitamin D factory. I therefore   recommend starting at 5 minutes 3 to 5 times a week using  12 noon sun (I need to reemphasize, only as a last resort  if you can't get your levels up with diet and vitamin D3 supplements!). 12 noon tummy sun bathing may be impractical, but it's not impossible. Again, remember, do this with your doctors supervision, and get your level rechecked to monitor your progress; you don't want to get more sun than you need!

If you liked this blog post, you may also want to read: Cynthia Bailey MD's Recommendations for The Alkaline Mediterranean Diet The Alkaline Mediterranean Diet-A Dietary Magic Wand for Overall Health and Beauty Natural Skin Health: Dermatologist's Diet Recommendations for Healthy Skin Dermatologist's Recommendations for Natural Skin Health: Kefir the best probiotic for healthy skin Photo Attribution: Matt McGee  rel="license" href="http://creativecommons.org/licenses/by-nd/2.0/">CC BY-ND 2.0</a></div>

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