As the days grow shorter and colder at this time of year, we get much less opportunity to expose our skin to sunlight. We all need to ensure an adequate Vitamin D intake during the winter months, since it’s almost impossible to produce Vitamin D in the skin at this time of year. In fact, there’s been a lot in the news recently about Vitamin D. You may be wondering what the fuss is about, and whether vegetarians and vegans need to worry about it more than anyone else, so we’ve gathered the latest facts to help you decide what to do.

Until the turn of the twentieth century, many children all over the country suffered from a devastating disease called rickets. Because of rickets, many kids grew up with deformed skeletons. No one knew what caused it. When vitamin D was discovered, and subsequently added to milk and other foods as a supplement, rickets, and the disfigurement that went with it disappeared, so for a long time vitamin D was only thought of as the anti-rickets vitamin. But recently rickets has been making a comeback, and medical science has also discovered that adults deficient in vitamin D may pay a heavy price. Vitamin D deficiency may be the most common vitamin deficiency in America today. Some reports show that as much as 60% of the American public is vitamin D deficient.

We know that vitamin D is especially important to growing children.  Traditionally, most kids made all the vitamin D they needed from sunlight, but if they lived in northern latitudes or stayed out of the sun all the time, they could easily become deficient. Today many children don’t spend so much time outdoors, and when they do, we often cover them with clothing or sunscreen to prevent skin cancer. In northern climates, where there isn’t much sun in the winter, and it’s often too cold to expose much skin to the elements, this is even more of a problem.

Breastfed babies are at particular risk. While breast-feeding has many advantages, if the mother is vitamin D deficient then the baby could be as well. Even those mothers who have adequate vitamin D levels themselves don’t transfer enough for their babies via their breast milk. This is one of the factors that has led to the recent increase in rickets. In fact, in England the incidence of rickets has quadrupled in recent years. In the United States, all baby formula sold must contain at least 400 IU vitamin D per liter by law, so formula-fed babies should get all they need. Doctors now recommend that all exclusively breastfed babies and their mothers receive a vitamin D supplement.

While in children a lack of vitamin D affects the development of the bones, adults also need to pay attention to vitamin D. A growing body of research suggests that vitamin D may very well play a role in the prevention and treatment of type 1 and type 2 diabetes, hypertension, glucose intolerance, inflammation, hospital acquired infections, cognitive decline, and multiple sclerosis. Vitamin D has also been shown to be of value when combined with calcium for the treatment and prevention of osteoporosis. Furthermore, a growing body of research suggests that vitamin D plays a protective role against breast, prostate and colon cancer.

So how can we best obtain it? Vitamin D is not widely available naturally in food (white mushrooms exposed to sunlight is one of the few vegetarian food sources –check the label to see if it was light exposed prior to sale). For adults and children over the age six months, the best source is the regular direct sunlight, taken in moderation. It is not necessary or even desirable to burn or even tan to get all the Vitamin D you need. However, given a northern latitude and lots of cloud cover in the Pacific Northwest, even modest amounts of sunlight exposure are not always feasible, so supplements are advisable for most people.

There are two forms of Vitamin D supplements: D2 (ergocalciferol) and D3 (cholecalciferol). Recent studies conducted at Boston University have shown that both forms have equivalent action and potency in the body. Vitamin D2 is a vegan product and is usually available in the vitamin section of most health food stores. Vegetarian forms of vitamin D3 are made from lanolin (from sheep’s wool). Look for supplements that contain amounts at least meeting 100% of the RDA (Recommended Daily Allowance). While Vitamin D has a wide range of safety, mega-doses are not recommended since overdoses can cause calcium deposits in the kidneys. So how much should you take? The National Institute of Health recommends a dosage of 400 IU of Vitamin D for infants, and that adults age 71 and older take 800 IU. Other age groups have a recommendation of 600 IU per day.

Recent studies show that vegetarians are no more likely to be deficient in Vitamin D than meat eaters, but they are not less likely to be deficient either. Everyone needs to make sure they have adequate levels of this vital substance. While in theory we should be able to get all the vitamins we need from a good healthy diet (and some sunshine), vitamin D is one which many of us may be lacking. A good vitamin D supplement every day will act as nutritional insurance to ensure that you are getting the nutrients you need for a long and healthy life.

Professional level article – Ensuring adequate vitamin D status for patients on a plant-based diet