At last, summer has arrived in New England, after the blistery Nor’easters and chilly spring season. The sunshine and the salty brine of the ocean is calling to the residents of the seacoast to break out the bathing suits, flip-flops, sunscreen, and to get a daily dose of Vitamin D!

Why is Vitamin D Important?

Vitamin D has continually gained recognition over the years for its ability to optimize health due to its many roles in the human body. Vitamin D can be synthesized in the body with exposure to sunlight, and it can be obtained through diet and appropriate supplementation.

Vitamin D is a fat-soluble vitamin that has properties of both a vitamin and a hormone, thus it has many functions:

  • It is required for the absorption and utilization of calcium and phosphorus, which is associated with maintaining strong and healthy bones.
  • It protects against muscle weakness and is involved in regulation of the heartbeat.
  • It is also important in the prevention and treatment of breast, colon and skin cancer, and osteoarthritis.
  • Vitamin D enhances the function of our immune system, and is necessary for thyroid function and normal blood clotting.

Unfortunately, it is estimated that more than 40 percent of American adults have a vitamin D deficiency. (1)  As many as 70-80 percent of Hispanic-Americans and African-Americans may be deficient in vitamin D. Those with more coloring in the skin have a harder time absorbing vitamin D from sunlight. (2) In addition, those whole live above the 37th latitude obtain virtually no vitamin D between November and March.

How to optimize your vitamin D levels safely and effectively

Expose more skin. Vitamin D is made from cholesterol in the skin. Studies recommend exposing around 1/3rd of your skin to the sun for 10-30 minutes. (3)  However, be sure to prevent burning if you’re staying in the sun for longer periods of time.

Applying sunscreen. Sunscreen will reduce the production of vitamin D in the body by about 95-98%. (4)  To maximize your vitamin D production, spend the first 15-30 minutes in the sun without sunscreen, then apply.

Choosing the right sunscreen. Not all sunscreens are created equal. It is important to choose a sunscreen that is safe and protective. Zinc oxide based mineral sunscreens are best and work by blocking sun rays from penetrating the skin. Some of my favorite non-toxic sunscreens included DeVita Solar Protective Moisturizer SPF 30, Rubber Ducky, and DermaE Mineral Sunscreen SPF 30. It is important to avoid sunscreens that contain oxybenzones. These compounds are absorbed into the blood stream can cause allergic reactions, and are disruptive to hormones. Yes, hormones. Oxybenzones act like estrogens when they enter to body and have been associated conditions like endometriosis. (5)

Is there a need for a vitamin D supplement?

The prevalence of vitamin D deficiency increases in proportion to distance from the equator. If you live above the 37th parallel it is crucial to build up your vitamin D stores in the summer months.

There are foods that contain vitamin D, such as cod liver oil, swordfish, salmon, tuna, beef liver, egg yolks, and sardines. However, to obtain sufficient amounts of vitamin D from diet, you would have to consume these foods nearly every day. (2) The form of Vitamin D in food is not fully active. It requires conversion by the liver, and then by the kidneys, before it becomes fully active. This is why people with kidney and liver disorders are at a higher risk for osteoporosis.

Vitamin D is a fat-soluble vitamin. This means that your body can mobilize its own reserves if your daily intake or production is lacking. This also means that excessive doses of vitamin D can build up to toxic levels. To optimize your vitamin D stores, I recommend working with a licensed health care provider who can order testing to assess vitamin D levels. Based on results, you can work with your health care provider, who will suggest a safe and appropriate dose.

It is clear that vitamin D is necessary to human health. However, there is much debate as to how much supplementation is optimal. Aside from lack of sunshine in the winter months, and limited supply of foods, certain health conditions utilize vitamin D more readily. Vitamin D plays a large role in modulating the body’s immune response. For example, deficiency in vitamin D is associated with increased autoimmunity as well as increased susceptibility to infection. As immune cells in autoimmune disease are responsive to the ameliorative effects of vitamin D, the beneficial effects of supplementing vitamin D deficient individuals with autoimmune disease may extend beyond the effects on bone and calcium. (6)

North Coast Family Health in Portsmouth, NH offers focused laboratory testing to assess your vitamin D levels, along with a comprehensive assessment of your health history and current concerns to create an individualized treatment plan. Call our office at 603-427-6800 for more information and a free 10- minute consult. In the mean time, enjoy soaking up some all natural vitamin D from the sun!

Written by Dr. Miranda LaBant

1 Forrest, K., Stuludreher, W. Prevalance and correlates of vitamin D deficiency in US adults. Nutr Research. 2011. 31(1):48-54.

2 Balch, P. Prescription for nutritional healing 5th Ed. Penguin group. New York, NY. 2010; 60-62

3 Rhodes, L., Webb, A., Fraser, H., Kift, R., Durkin, M., et al. Recommended summer sunlight exposure levels can produce sufficient (> or =20 ng/ml (-1)) but not the proposed optimal (> or = 32 ng/ml (-1)) 25-(OH-D) levels at UK latitudes.  Journal of Investigative Dermatology. 2010. 130(5): 1411-8.

4 Holick, M., Vitamin D Deficiency. New England Journal of Medicine. 2007. 19;357(3): 266-81.

5 Wang, J., Pan, L., Wu, S., Lu, L., Xu, Y., Zhu, Y., … Zhuang, S. (2016). Recent Advances on Endocrine Disrupting Effects of UV Filters. International Journal of Environmental Research and Public Health, 13(8), 782.

6 Aranow, C. (2011). Vitamin D and the Immune System. Journal of Investigative Medicine : The Official Publication of the American Federation for Clinical Research, 59(6), 881–886.