Your Guide to Vitamin D

Our skin produces vitamin D when we are exposed to sunlight, but since many of us who live far from the equator don’t get strong sunlight for much of the year, low vitamin D levels are common.

Studies have shown that treating vitamin D deficiencies can help prevent bone fractures, autoimmune diseases, diabetes, and dementia, and it may play a role in cancer risk reduction.

Supplementing vitamin D

Vitamin D is found in oily fish, eggs, fortified milk, and some mushrooms. However, it is difficult to get adequate amounts solely through diet; if you have a vitamin D deficiency, supplementation will likely be necessary.

There are different forms of vitamin D, including ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Vitamin D3 is preferable for supplementation, ideally paired with vitamin K2 (many over the counter formulations have these two nutrients combined). It is fat-soluble, so it’s important to take the supplement with a meal that contains healthy fats.

The correct dosage will depend on how low your levels are. The standard reference range for Vitamin D is 30-100 ng/ml; at levels below 30, bone health cannot be supported. However, the team of physicians at Atria determined an optimal range based on the scientific literature, and agree that blood vitamin D levels should be between 55-80 ng/ml.

It is possible to overdo it: because vitamin D helps your body absorb calcium, at levels above 100, your body may absorb too much calcium, causing you to develop kidney stones or calcification of the arteries.

For people with cardiometabolic risk factors, including calcification of either the coronary arteries in the heart or carotid arteries in the neck, pairing a Vitamin D supplement with Vitamin K is usually recommended to ensure that the calcium that is absorbed goes to the bones instead of the arteries.

Sun exposure for vitamin D

Responsible sun exposure is a good way to produce the vitamin D that your body needs, but your ability to do this will depend on your location in the world, the season, and the time of day. In general, the angle of the sun in the fall and winter months makes it difficult to produce vitamin D in your skin.

There is also a genetic component to this, and based on certain vitamin D receptor genes, some people will need higher amounts of sunlight to produce sufficient vitamin D.

Sunscreen is important—you always want to avoid burns. But “if you never get sun, or you always wear an SPF 70 where you never have an opportunity to make vitamin D, that’s a problem,” says Atria Director of Integrative Health Robert Kachko, ND, LAc. “Both extremes are not good. Get good sun in small doses. Generally speaking, you make all of the vitamin D you need with 40% of your body covered, 10 minutes on each side.”

Beyond that, it’s a good idea to wear sunscreen with physical barriers like zinc and titanium oxide rather than chemical barriers, which can have negative impacts on health.