For decades, dermatologists and other medical experts have been telling us to avoid direct sun exposure like the plague to reduce skin cancer risk. But the latest research shows that too little sunlight — particularly during the dark days of winter — has a downside, too.

In fact, getting too little sunshine can harm your health by reducing levels of vitamin D.

That’s the message being sent by endocrinologist and vitamin D expert Dr. Michael F. Holick. He’s even helped to develop an app that can tell you how long to sunbathe during any season anywhere on the planet.

“The population of the world has been brainwashed by the American Academy of Dermatology (AAD) and the sunscreen industry with the unrelenting message that you should never be exposed to direct sunlight because it is going to cause serious skin cancer and death,” says Dr. Holick, a professor at Boston University Medical Center and director of the facility’s Heliotherapy, Light, and Skin research lab.

“People are really quite surprised by the new message that sensible sun exposure, in moderation, is very important for good health.”

Holick was the first researcher to identify the major circulatory form of vitamin D and the first to make it chemically. But there’s nothing like the real thing, he adds.

“Not only does sunlight make vitamin D but also beta-endorphin, which makes you feel better,” Dr. Holick tells Newsmax Health. “There’s also nitric oxide, which can lower blood pressure, and a host of other substances that you would never get just by taking a supplement.”

Sun exposure can also help regulate circadian rhythm, lower blood pressure, ease depression, boost the immune system, and even reduce the risk of certain cancers, notes Dr. Holkick, who recommends about five to ten minutes of unprotected exposure a day.

But his enthusiasm isn’t widely shared by dermatologists, who point out it’s well documented that sun exposure causes skin cancers, premature skin aging, age spots and other problems.

“What Dr. Holick is saying goes against a majority of science opinion,” notes Dr. Ron Moy, a California-based dermatologist and past president of the AAD. “I think what he’s doing is a real disservice because we see so many people dying from skin cancer. And it’s hard to generalize about how much sun exposure an individual can tolerate. For many people, particularly those of Irish and English descent, 10 minutes a day isn’t good.”

St. Petersburg, Fla., dermatologist Dr. James Spencer adds, “Dr. Holick is a true believer that vitamin D is real magic and can cure just about any disease, but the evidence is very thin to support that. Meanwhile, skin cancer is at epic proportions with three million new cases in the U.S. every year.”

While Dr. Holick admits sun exposure can increase risk for non-melanoma skin cancers, he says deadly melanoma most commonly appears in areas of the body least exposed to the sun, and that studies show occupational sun exposure actually reduces the risk of melanoma.

Still, he stresses there’s a fine line between getting too little sun and too much. That’s why Dr. Holick helped developed the dminder app. By using the GPS data from a cell phone, dminder tracks how much sunbathing time a person needs to safely maximize vitamin D absorption, taking in factors such as location, season, time of day, weather, skin tone, age and weight.

Of course, to benefit from sun exposure, you need some sun, which can be a rare commodity in northern climes during the winter months.

Another option is to take 2,000 IUs of a vitamin D supplement every day, Dr. Holick says. Doing so avoids the potential risk of sun exposure entirely, while also making sure you’re not deficient in the vitamn.

“Our hunter-gatherer forefathers were outside every day and most likely were making thousands of IUs of vitamin D a day,” says Dr. Holick, author of “The Vitamin D Solution: A 3-Step Strategy to Cure Our Most Common Health Problems.”

“As a result, our bodies adapted to that amount of vitamin D to maximize health.

“Even the World Health Organization says, ‘The sun’s rays provide warmth and light that enhance your general feeling of well-being. It stimulates blood circulation…and the production of vitamin D. There is no doubt that a little sunlight is good for you.’”