Can You Get Vitamin D From Vegetables? Uh, That's Kind Of A Trick Question

Vitamin D is one of the many essential vitamins needed daily for your body to function and thrive. Commonly known as the sunshine vitamin, this nutrient can be made in your skin through exposure to sunlight. Humans' own sort of photosynthesis, the vitamin D synthesis process is intriguing, to say the least, but it poses one big problem. In these days, none of us spend enough time outside to receive enough sunlight to produce an adequate amount of vitamin D.

Location, time of day, age, and skin tone all affect the body's ability to produce the vitamin in the skin (not to mention the fact that many of us slather on sunscreen to protect us from sun damage and signs of aging). What that leaves us with is an epidemic of vitamin D deficiency. And given the numerous functions of D in the body, this is for sure not a good thing. 

"The classical function of vitamin D is maintaining blood calcium levels, which play a role in bone health. Although, over the past 20 to 30 years we have started to understand that vitamin D may have non-bone-health functions. It plays a role in regulating blood pressure and glucose levels and is linked with muscle function,"* says Sina Gallo, Ph.D., RDN, a nutritional sciences professor at the University of Georgia.

Approximately 93% of Americans1 consume less than 400 I.U. a day, and as it turns out, we need much more than that to positively affect vitamin D status and health.* When it comes to vitamin D levels, 41% of American adults meet the criteria for clinical insufficiency, and around 30% of American adults are straight-up deficient2. That means you or one of your closest friends or family members could use some help with their D intake.

Usually when people talk about getting all of the essential vitamins and nutrients, they simply advise you to eat more veggies! And while vegetables are potent with micronutrients, adding more greens to your diet won't do you any good when it comes to this particular fat-soluble micronutrient: vitamin D. 

The only vegetable that contains the all-important vitamin D is irradiated mushrooms (and they really aren't even a vegetable, but a fungus). "Mushrooms produce vitamin D2 by converting ergosterol in their membranes via a photochemical reaction in the same way that UV from the sun converts cholesterol to vitamin D3," says Robert Bruce Beelman, Ph.D., an expert on the effects of UV light on mushrooms. 

Mushrooms contain a different type of D than what's formed as a result of sun exposure in our bodies (or what we consume from fatty fish or eggs). When hit with adequate and sustained UV light, mushrooms produce D2, while our bodies produce D3. Vitamin D2 usually comes from plant sources like mushrooms and D3 from animal sources like salmon.

Another cool thing about mushrooms is that you can expose them to more UV light to increase the amount of D2 in them. Beelman used pulsed light emitted from a Xenon lamp on mushrooms in his research8, but even placing your shrooms outdoors will do the trick to boost their D supply, according to famous mycologist Paul Stamets.  

The only other plants containing vitamin D are algae and phytoplankton, which actually contain D3 rather than D2. Though often put in the "sea vegetables" category, algae isn't actually a vegetable. Nonetheless, this marine botanical provides a potent—and highly sustainable—source of plant-based D3.*

While our bodies can still use D2 (ergocalciferol), a large body of science underscores its inferiority to vitamin D3 (cholecalciferol). Indeed, D3 is far superior for human consumption based on its bioactivity, stability, and bioefficacy.*

Not that mushrooms needed another reason (OK, fiber, minerals, B vitamins, antioxidants, etc.) to prove their hype, but their reign as the only veggie (fungus if you want to get technical) that contains vitamin D is a huge reason to add more of them to your diet.