Vitamin D Myths 'D'-bunked

You may have heard every vitamin D myth under the sun—so many, in fact, that you might be at the point of throwing your hands up in the air in frustration. Why can’t there be a simple answer? 

First, some facts: Your body needs vitamin D. Its main job is to help the body absorb calcium from the intestines. This calcium is necessary to help “mineralize the skeleton” over the course of your lifetime and is a critical mineral for forming the hardened bone that keeps you strong and healthy.

On the other hand, “not getting enough Vitamin D can have serious consequences, including increased rates of bone loss or even osteomalacia ('soft bones') in adults and rickets (a deforming bone disorder) in children,” says Yale Medicine endocrinologist Karl Insogna, MD, director of the Yale Medicine’s Bone Center.

The short answer is from food, the sun, or supplements.

There are two main kinds of vitamin D—vitamin D2 and vitamin D3—which you can get from (and occur naturally in) certain foods like salmon, tuna, mackerel, beef, liver, and egg yolks. But because we don’t consume large enough quantities of these foods, they can’t be our sole source of vitamin D. That’s why foods like milk, cereal, and some orange juices are vitamin D2- and D3-fortified. (Since the 1930s, manufacturers have voluntarily enriched these foods with vitamin D to help reduce the incidence of nutritional rickets.)

When exposed to the sun, your skin can manufacture its own vitamin D. “We each have vitamin D receptor cells that, through a chain of reactions starting with the conversion of cholesterol in the skin, produce vitamin D3 when they’re exposed to ultraviolet B (UVB) from the sun,” says Yale Medicine dermatologist David J. Leffell, MD, chief of Dermatologic Surgery.

Another avenue to get vitamin D is by taking supplements. These come in both pill and liquid form. They are generally recommended for people with fat absorption issues, lactose intolerance, and milk allergies, as well as for people with darker skin tones or with certain medical conditions that prevent them from going outdoors.

No bones about it, the endocrinologists we interviewed agree with our dermatologist.

"Just being outdoors, you get a fair amount of sun exposure and some sun-related generation of vitamin D,” says Dr. Insogna. “Because skin cancer, particularly melanoma, can be such a devastating disease, it's best to use sunblock when outdoors in strong sunlight for any prolonged length of time. Because this may limit the amount of vitamin D you get from sun exposure, make sure your diet includes sources of vitamin D from foods or supplements,” he says.

Both your skin and your bones will thank you.