70-97% of Americans aren’t getting enough Vitamin D – that’s including plant-based eaters and non plant-based eaters alike. Commonly known as the “sunshine vitamin,” vitamin D is a unique nutrient that doesn’t actually have many food sources. The reason for this being that our bodies are designed to obtain vitamin D through sunshine. Light from the sun allows us to naturally produce vitamin D! If it’s that easy, why are so many people deficient?
The problem is that many of us don’t spend enough time outside in the sun to be getting enough vitamin D. In addition, our body’s ability to synthesize this nutrient from UV rays is further impacted by our skin color as well as seasonal variations in the strength of the sun’s rays. Because of this, we must consider other ways of getting in our vitamin D.
Why is Vitamin D Important?
Vitamin D is like the sidekick to calcium – it enhances our body’s ability to absorb and use calcium, allowing it to more effectively do its job. Together, vitamin D and calcium function to build strong bones and regulate muscle contractions. Adequate intake of both protects against osteoporosis in older adults. And in children, vitamin D is important for supporting proper bone growth and preventing “rickets,” or bowing of the legs.
Vitamin D has a few roles of its own, as well. It is a natural anti-inflammatory, which can help to reduce the risk of chronic conditions such as heart disease, diabetes, obesity, Alzheimer’s, and cancer. Vitamin D also regulates cell growth (including cell differentiation and cell death), neuromuscular function (signaling muscles to contract), immune response, and glucose metabolism.
Every cell in the body has vitamin D receptors, and many body tissues are able to convert vitamin D to different forms, depending on what it is needed for. It really is a versatile nutrient that has a wide variety of applications (Office of Dietary Supplements – Vitamin D. (n.d.). Updated October 9, 2020)!
The RDA (Recommended Daily Allowance) for vitamin D for adults is 15mcg per day, or 20mcg for adults over 70. It is also worth noting that vitamin D is a fat-soluble nutrient, and while some forms of vitamin D can be absorbed without dietary fat, the presence of fat in the gut helps us absorb this nutrient more readily (Office of Dietary Supplements – Vitamin D. (n.d.). Updated October 9, 2020).
So, Do Vegans Get Enough Vitamin D?
It is speculated that vegans and vegetarians are more likely to be deficient in vit D, because foods containing the most vitamin D per serving are animal-derived. However, with food sources being so scarce in general, this actually puts both vegans and non-vegans equally at risk of vitamin D deficiency.
One study that compared the blood levels of vitamin D in vegetarians to that of meat-eaters found no correlation between low vitamin D and the plant-based diet – ie. diet does not have a significant effect on vitamin D status. The main obstacle preventing many of us from getting enough vitamin D is our modern day lifestyle that keeps us indoors (and out of the sun) for the majority of the day. Other things that contribute to blood vitamin D levels include vitamin D supplementation and skin tone.
Should I Supplement? Am I getting Enough from the Sun?
Unless you live in an area that gets full sun exposure year round (ie. somewhere close to the earth’s equator), you probably need to get your vitamin D elsewhere; at least during the fall and winter months. During the summer, 15 minutes of sun exposure for fair skin, and 30 minutes for darker skin is sufficient. During the rest of the year, the sun’s rays aren’t strong enough to be relied upon for our bodies to produce vitamin D. While most dietitians, health, and nutrition experts agree on the “food first” principle when it comes to vitamin D, supplementation may be a more practical way of ensuring adequate intake, since food sources are so scarce. When choosing a supplement, look for one containing D3, as that is the active form. You can also use a sunlamp for UV exposure if adequate sunlight is not available to you.
*Recommended Daily Allowance based on a 2000 kcal diet (Office of Dietary Supplements – Vitamin D. (n.d.))
Vitamin D can be a tricky nutrient for all people, regardless of diet. Seasonal and hourly variations in sunlight, as well as skin color and frequency of indoor activities, are more significant factors contributing to adequate Vitamin D intake. Due to its uniqueness, it is one of the few micronutrients that experts recommend sourcing through supplements rather than relying on whole foods. During the summer, if you are someone who gets a lot of sun exposure, Vitamin D is probably not of concern to you. However, during the rest of the year, when sunlight isn’t as strong, it might be best to include a supplement to ensure adequate intake.