You Need Vitamin D, but Not This Way

Spring is finally upon us, and as the warmer days grow longer, many of us look forward to spending more time in the sunshine.

Getting a glow and enjoying the sun’s warmth can feel so good, but you may want to make sure your time in the sun doesn’t leave you depleted of vitamin D.

Wait, doesn’t being in the sun give us vitamin D?

A new study, actually, finds that too many rays could limit your skin’s ability to produce the much-needed vitamin. While it sounds confusing, here’s the deal: Researchers have long known that sun exposure helps the body make vitamin D, but now they’ve been able to confirm that too much sun exposure could contribute to deficiencies of the essential vitamin.

They’ve also confirmed that tan skin provides some degree of protection against harmful UV rays — but the pigment can also block vitamin D synthesis. In essence, the more sun exposure you have, the less likely your skin can generate the vitamin.

The findings were presented at the annual meeting of the Endocrine Society in Boston.

Dr. Francisco Bandeira, of the University of Pernambuco Medical School in Recife in Brazil, looked at about 1,000 males and females from the region whose ages ranged from 13 to 82. Some had lighter skin that burned more easily; others had darker skin that tanned more easily. All of them experienced daily sun exposure; none took vitamin D supplements or used sunscreen. They then evaluated the response of different skin types to light.

They found that most of the participants with very high daily exposure to the sun had lower-than-normal serum vitamin D levels. In fact, 72 percent of the people were deficient in vitamin D.

(The study was conducted on people living in a tropical region located 8 degrees south of the equator, with very high rates of sun exposure and extremely high UV irradiation.)

Healthier Vitamin D Source
So what does this mean for Americans who don’t live in that climate? Should we purposefully sit in the sun to get vitamin D, or do we cover ourselves in sunscreen before we ever walk out the door?

5 Vitamin D Deficiency-Related Illnesses
  • Dementia
  • Prostate cancer
  • Erectile dysfunction
  • Schizophrenia
  • Heart disease

It can be confusing to know how best to get some sun while otherwise protecting ourselves from skin cancer and other conditions that can arise from a lack of vitamin D. Deficiencies often show up in the form of constipation, cavities, Crohn's disease, asthma, cystic fibrosis, depression, high blood pressure, multiple sclerosis, osteoporosis, or even erectile dysfunction.

Dr. Shari Lipner, an assistant professor of dermatology at Weill Cornell Medicine in New York, said people should not rely on the sun for vitamin D, regardless of skin tone.

"It reinforces the point that vitamin D should be obtained from diet or supplements," Dr. Lipner told LifeZette.

Bandeira concurs about taking a supplement.

"In general, at least for the tropical areas in which the high rates of UV irradiation can increase the risk of skin cancer, the oral supplementation would be advisable," he said.

Dr. Gary Goldenberg, an assistant clinical professor of dermatology at the Icahn School of Medicine at Mount Sinai, said the notion of people with darker skin having lower vitamin D levels isn’t news.

"However, the answer to this is not more sun exposure, since skin cancer including melanoma can occur in patients with all skin types," he said. He, too, advocates for dietary supplementation to boost levels of the vitamin.

Most of us should be taking a vitamin D supplement. A 2010 study in Nutrition Journal found that 42 percent of American adults were lacking in vitamin D. Most adults should get about 600 IUs of the vitamin daily.

In the meantime, if you're worried your sunscreen could inhibit vitamin D production, it's not a problem. Dr. Lipner says that when sunscreen is applied properly, vitamin D can still be synthesized — so you have no reason not to wear it.

Last Modified: April 7, 2016, 11:26 am

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