Remember when vitamin D used to be the somewhat boring vitamin that’s just needed to get calcium into your bones? Well, in the past decade thousands of studies have shown that vitamin D is important for so much more, including immune function, cardiovascular health, normal insulin secretion and cellular growth control. An excellent review of vitamin D nutrition is available at the Linus Pauling Institute.
Vitamin D is profoundly important to your health, yet an estimated 80% of Americans don’t get enough of it. Many doctors have called the North American vitamin D deficiency a public health crisis and a group of scientists have formed an organization called GrassrootsHealth to encourage people having their vitamin tested and supplement as needed. Actually, I highly recommend joining this group and getting your vitamin D tested; I did it, and it helped me fine-tune my vitamin D nutrition. Plus, it’s for a good cause.
How much vitamin D do we need?
The Dietary Reference Intake (DRI, Natl. Academies, Food and Nutrition Board) is 600 IU (= 15 mcg) for children and adults (ages 1-70 y). Most experts, however, agree that this is too low to maintain healthy vitamin D blood levels of 40-60 ng/ml, and recommend at least 1,000 IU (= 25 mcg) a day. Note that the US average blood level is only around 25 ng/ml!
Where does Vitamin D come from?
Two major sources: Sunlight and diet. Sunlight is a controversial vitamin D source. On the one hand, the UV light of the sun is very effective in making our skin produce decent amounts of vitamin D, especially mid-day in the summer, in lower latitudes and in fair-skinned people. But on the other hand, sunlight has been shown to promote skin cancer and skin aging. In case you wonder, using sunscreen also blocks vitamin D production in the skin. Some experts recommend 10-20 minutes of unprotected sunlight exposure a day, but I think the jury is still out. And in the winter months, the sun is too weak for vitamin D production in North America.
So, that leaves diet. Vitamin D is found primarily in fatty fish, eggs and fortified milk and cereals. This list probably makes you wonder where vegans get their vitamin D from? You guessed it, vegans really have no good dietary sources, except some fortified soy products and milk substitutes. Many studies show that vegans and some vegetarians are at risk of vitamin D deficiency. That’s why experts and health authorities recommend supplements for people on plant-based diets.
Vegan Vitamin D Supplements
Navigating the vitamin D supplement market as a vegan can be difficult. There are two types of vitamin D: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Both are good for bone health and calcium metabolism, but only vitamin D3 has all the added benefits for immune function, heart health, insulin secretion and cellular growth regulation. While vitamin D2 is typically vegan, vitamin D3 is made from lanolin (sheep wool). That’s why most inexpensive vegan vitamin D supplements just provide vitamin D2. And I’ve even seen some “vegan” vitamin D supplements that are actually using the lanolin-derived vitamin D3. As of today, there is only one truly vegan source of vitamin D3 and it is derived from lichen (Vitashine, UK). It costs over twenty times more than vitamin D2 or lanolin-derived vitamin D3.
The Bottom Line
Vegans and vegetarians need to supplement with vitamin D even more so than omnivores, and I recommend at least 1,000 IU (25 mcg) every day from both vitamin D2 and D3. Most vegan multivitamins don’t provide any vitamin D3 and not enough total vitamin D. A notable exception is OptiVega which has 1,200 IU with 600 IU from Vitashine vitamin D3 and 600 IU from vitamin D2. Also, look for vitamin D fortified vegan milk substitutes (soy, almond, rice milks) and tofu, although they only use vitamin D2. Finally, use sunlight exposure at your own risk.