The Lowdown on Vitamin D: Everything You Need to Know About One of the Sun’s Greatest Gifts and How to Best Optimize Your Intake
BY ASHLEY MORRIS
Vitamin D has become somewhat of a “hot topic” in the wellness world as of late: and for a good reason! Vitamin D has a wide variety of health and wellness benefits. However, it is not as easy as one might think to capture an adequate amount of this vitamin. So we decided to outline all the information you need to know about this miracle micronutrient and the best way to maximize its benefits.
What is Vitamin D?
Vitamin D, or calciferol, is a fat-soluble vitamin. It helps our body absorb a wide variety of nutrients in our GI tract, including calcium, phosphate, magnesium, etc. There are two primary forms of Vitamin D: D2 and D3. The difference between these two is minimal: overall, they are both absorbed well and work similarly. Vitamin D’s primary claim to fame is maintaining adequate bone strength and growth – which is why it is so important in women (especially as we age). The National Institute for Health recommends a goal intake of about 600 IU per day for the average adult. Still, many sources suggest closer to at least 1000 IU, especially in women.
What other benefits does Vitamin D have?
Bone health is crucial – but that’s old news. Bones are not the only reason getting adequate Vitamin D is essential! One particularly promising benefit is immune health. Deficiency in Vitamin D is linked to increased infections and autoimmune conditions, where the body’s immune system attacks itself. There were even articles coming out last year linking lower Vitamin D levels to increased COVID-19 hospitalizations and complications. Vitamin D has also been shown to be important to brain development. In several studies, low levels have been associated with depression, seasonal affective disorder, and even schizophrenia! And that’s not all; Vitamin D deficiency has also been thought to be linked with heart disease, diabetes, severe asthma in kids, even different types of cancer. We are learning new associations every day.
Where do we get Vitamin D from?
The good news about Vitamin D is that it is available from various sources – both exogenous and endogenous. In other words, we can get it by consuming different foods or beverages, but our body is also awesome at making it ourselves (given the right tools). We’ll dive a little deeper on how our body uses the sun’s power to produce Vitamin D below, but first, let’s get into how you can get it through your diet.
Foods with the best natural sources of Vitamin D include fatty fish (tuna, salmon, trout), egg yolks, and cheese. In addition, most milk in America is fortified with Vitamin D, as well as breakfast cereals and yogurts. For our vegetarians and vegans out there: look for plant-based milks that are fortified with Vitamin D or increase your dose of mushrooms, which have a moderate amount. Otherwise, it is unfortunately hard to find Vitamin D in most plants.
So how do I get it from the sun?
If you tend to avoid animal products, never fear: you can also get Vitamin D from our favorite renewable resource: the sun! However, there is an art to this absorption. UVB rays hit our skin and convert a molecule into Vitamin D. Many factors affect this process. For example, the more melanin your skin has, the less Vitamin D you will absorb naturally through sunlight. Therefore, you will need more extended amounts of exposure for your body to generate the same amount as someone with lighter skin. In addition, the time of day, time of year, cloud coverage, and amount of clothes you’re wearing all affect the amount of Vitamin D you can get from the sun. Midday is the best time for absorption, especially during the warmer months. It is all a little bit complicated, but the good news is that we have tools to help!
The app (not sponsored) called D Minder, that helps you calculate the amount of Vitamin D you are absorbing. You can enter your location, skin tone, clothing, and sun exposure times into the app. They can calculate how much Vitamin D you are producing on your own to better estimate how to supplement through diet. It is a great way to remember to get that Vitamin D and helps you gauge how much sun exposure is enough.
It is important to note that although unadulterated sun exposure is essential to obtain Vitamin D, it is just as important to protect your skin from the sun’s harmful UV rays with SPF. I usually recommend that my patients attempt to get a majority of their intake through dietary sources. Sun exposure is a supplement best for short periods. Regardless of how you consume this little powerhouse, it is clear that this is a vitamin of the future. I am excited to see what we will continue to learn about Vitamin D.
Aranow, C. (2011). Vitamin D and the Immune System. Journal of Investigative Medicine, 59(6), 881–886. https://doi.org/10.2310/jim.0b013e31821b8755
Gracious, B.L., Finucane, T.L., Friedman-Campbell, M. et al. Vitamin D deficiency and psychotic features in mentally ill adolescents: A cross-sectional study. BMC Psychiatry 12, 38 (2012). https://doi.org/10.1186/1471-244X-12-38
U.S. Department of Health and Human Services. (n.d.). Office of Dietary Supplements – Vitamin D. NIH Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/.