Vitamin D and Sunblock

     I recently read an article in the July/August 2020 Reader’s Digest. It was written by a dermatologist who had the view that getting natural Vitamin D is more important than worrying about skin cancer. According to the author, skin cancers from solar exposure are highly treatable. This sounded counterintuitive so I decided to look into it.

     Vitamin D is essential for immune function, elevated mood, muscle and tendon health, and strong bones. However, it is not found in sufficient concentrations in many foods. Due to the lack of exposure to direct sunlight, many people still aren’t getting enough vitamin D, and that deficiency is a worldwide problem.

     The benefits of having sufficient vitamin D are numerous. Studies suggest that vitamin D may prevent certain cancers[1], it may have a role in cognitive function[2], reduce the risk of developing multiple sclerosis[3], and could treat psoriasis[4]. Insufficient vitamin D is also connected to osteoporosis and some types of cancer. Low blood levels are also linked to increased risks of dying prematurely from cardiovascular disease. About 40% of Americans are deficient with vitamin D. Rates are higher for blacks 80%, and Hispanics at 70%, due to darker skin pigmentation[5].

    Vitamin D deficiency can be caused by specific medical conditions. These include cystic fibrosis, Crohn’s disease, celiac disease, weight loss surgeries, obesity, kidney and liver diseases. Some medications can cause vitamin D deficiency as well. These include laxatives, steroids (such as prednisone), cholesterol-lowering drugs, and seizure control drugs, [10].

     The best way to get enough vitamin D is from direct sunlight[6]. However, there is no clinical evidence that sunblocks inhibit vitamin D production[7]. The use of sunblocks is still recommended to prevent certain cancers. Getting 15-20 minutes of sunlight on your face, arms, back, or legs without sunscreen a few times a week is enough to generate your body’s vitamin D needs for a week[8][10] This is especially true in the winter months. There is no set standard for sufficient exposure times, but it is not necessary to get a tan.

     Diet is usually recommended by nutritionists to be the best way to obtain supplemental vitamin D. However, most foods lack sufficient amounts of vitamin D, but it may be obtained from fortified milk, fortified cereal, and fatty fish such as salmon, mackerel, and sardines[8]. Taken in appropriate doses, vitamin D supplements are generally considered safe. However, taking too much vitamin D can be harmful. Children age 9 years and older, adults, and pregnant and breast-feeding women who take more than 4,000 IU a day of vitamin D might experience adverse effects[8].

     There remain concerns about skin cancers, the most common form of cancer in The United States. Overexposure to sunlight should be avoided, especially when at a young age since the damage is accumulative over time. UV light from tanning beds is just as harmful. 

     Basal cell and squamous cell cancers are less serious types and makeup 95% of all skin cancers. Also referred to as non-melanoma skin cancers, they are highly curable when treated early. Melanoma, made up of abnormal skin pigment cells called melanocytes, is the most serious form of skin cancer and causes 75% of all skin cancer deaths. Left untreated, it can spread to other organs and is difficult to control[9].

     If you suspect you have a vitamin D deficiency, you can find out from your doctor or at-home test kits are available. Considering the cost of a kit ($35 – $80), the co-pay amount for a doctor’s visit, or whether you’re insured, should be taken into account. It’s up to you to verify the efficacy and laboratory standards of the manufacturer. 

      Vitamin D is key to the prevention of many illnesses, including hypertension. Sunblock still should be used during periods of high UV exposure. Exposure to direct sunlight, using sunblock, for 15-minutes, at least 3 times per week should be made to obtain enough vitamin D. This may be supplemented through diet and the judicious use of supplements. 


  1. National Cancer Institute (NIH) – Vitamin D and Cancer Prevention
  2. Soni et al, 2012, Vitamin D and Cognitive Function, Scand J Clin Lab Invest Suppl. 2012;243:79-82
  3. Multiple sclerosis: Vitamin D deficiency may predict onset – Medical News Today
  4. Association between Vitamin D deficiency and psoriasis: An exploratory study – International Journal of Health Sciences
  5. Forrest and Stulhdreher, 2011, Prevalence and Correlates of Vitamin D Deficiency in US Adults, Nutr Res.:31(1):48-54
  6. 3 Best Ways To Get Vitamin D This Winter – Medical News Bulletin,fish%20%28e.g.%20…%203%20Take%20vitamin%20D%20supplements
  7. Sun Protection and Vitamin D – Skin Cancer Foundation
  8. Vitamin D – The Mayo Clinic
  9. Sun Exposure & Skin Cancer – The Cleveland Clinic–skin-cancer
  10. Vitamin D Deficiency – The Cleveland Clinic–vitamin-d-deficiency