My patients often ask, “shouldn’t I get sun exposure without sunscreen to make sure I have enough vitamin D?”
We can obtain vitamin D from three sources: sunlight, dietary intake, or vitamin supplementation. While we can obtain vitamin D from dietary intake, there are few foods that do contain vitamin D in high levels naturally. However, many products such as milk and cereal are often supplemented with vitamin D. If we do not obtain much vitamin D from our foods, should we consider sun exposure as a way to get vitamin D? Dermatologists do not recommend sunlight as a way to get vitamin D, nor to increase vitamin D if low, for the following reasons I describe below.
SUNLIGHT DAMAGES DNA
One of the primary reasons we do not recommend sun exposure as a way to improve vitamin D is that studies have shown UVB induced vitamin D synthesis is associated with significant DNA damage.  DNA damage over time leads to skin cancer including melanoma, squamous cell, and basal cell skin cancers, as well as sun spots and increased wrinkles.
SUNLIGHT IS LESS EFFECTIVE THAN SUPPLEMENTATION
Sunlight has shown to be less effective than supplementation at improving vitamin D levels when low. In particular, 800 IU of vitamin D per day appears to be more effective than 100,000 IU of vitamin D every 3 months, and both more effective than 30 minutes of sunlight daily.   It also appears that most people even when using sunscreen daily and reapplying do not use sunscreen in a way that inhibits vitamin D production. One review in particular looked at studies that evaluated sunscreen use and vitamin D levels and concluded that the normal use of sunscreen does not lead to vitamin D deficiency. 
AT RISK GROUPS NEED HIGHER LEVELS OF SUPPLEMENTATION
There are some groups who are considered at risk for low vitamin D levels including older adults, breast fed infants, those with limited sun exposure due to climate or vigorous photoprotection, dark skinned individuals, persons suffering from malabsorption syndromes or obesity, those who take anticonvulsants or oral steroids, and some medical conditions such as lupus and multiple sclerosis. In at risk groups we often recommend testing for vitamin D levels and supplementation based on levels. It is not generally necessary to check vitamin D in groups at low risk for low levels.
SO, HOW MUCH SUPPLEMENTATION SHOULD YOU BE TAKING?
The institute of medicine panel (IOM) met last in 2010 and does recommend supplementation of vitamin D in healthy populations based on age:
- 0-12 mon: 400 IU/day
- 1-70 yrs: 600 IU/day-includes pregnant and lactating women
- 71+ yrs 800 IU/day
Upper intake levels (the highest daily intake likely to pose no risk):
- 0-8 years:1000-3000 IU/day
- 9-71+ years:4000 IU/day
While vitamin D is important, especially for bone health, it is best to ensure proper levels with daily supplementation rather than sun exposure. We recommend sun protection and sunscreen be used daily and to avoid extended sun exposure between the hours of 10 am and 4 pm. If you will be out in the sun between the hours above, we recommend you seek shade, wear a hat, apply sunscreen (thickly with SPF 30 and above), and reapply every hour.
- I particularly like to use the full swimsuits for my children (pictured here). The number one reason I love these swimsuits is I only have to apply sunscreen to their faces, necks, hands, and feet. This makes it a lot easier to stay and play in the water with a lot less time chasing kids around with sunscreen.
If you would like to schedule a dermatology consultation, please call 801.747.7989, or visit our website at www.grangermedical.com/specialties/dermatology for more information and a full list of locations.
Blog post was written by Rebekah H. Clifford, MD, FAAD – Board certified dermatologist.