Why be D-pendent on Vitamin D

For years now, we have been hearing that we need to get more vitamin D. Where the message gets a bit mixed up is when it comes to taking action on increasing our vitamin D status.

What does it mean to get more vitamin D? Does it mean go outside without sunscreen? Does it mean to take more via supplementation? Should I fill my cart with vitamin D rich foods? Should I do all of these things? None of them? Is one better than the other?

Let’s break it down.

What is vitamin D?

Vitamin D is a fat-soluble vitamin, nicknamed the "sunshine vitamin” because it has the ability to be absorbed by the body through sunlight. Its primary role, per the National Institutes of Health's Office of Dietary Supplements, is to promote the absorption of calcium, ensuring proper bone growth and bone remodeling. In addition to bone support (which we will review), vitamin D has become a front runner as a major player in keeping the human body healthy. It offers a wide range of other benefits too. We will dive into some of the most studied as well as review ways to get more vitamin D into your daily diet.

What are some key functions of vitamin D?

Bone Health: Vitamin D is famous for its bone-building and bone-strengthening powers. Vitamin D promotes absorption of calcium in your gut. This ultimately allows for healthy mineralization of your bones. Bottom line, the calcium we consume to help our bones cannot do its job without the help of vitamin D. Without vitamin D, bones become brittle leading to ailments such as osteoporosis.

Muscle Strengthening: Vitamin D is also influential in muscle growth and development. Vitamin D deficiency has been found to be associated with decreased muscle size and strength, particularly of the large extensor and flexor muscles of the lower limbs, essential for functional mobility. Vitamin D stores were directly associated with reduced physical function and increased falls in the elderly. There is evidence that these deficits can be improved by vitamin D supplementation.

Immune Support: Vitamin D has also been found to help build immunity. Vitamin D supports the immune system by fighting off harmful bacteria and viruses. Pertinent to our ongoing pandemic, vitamin D has become increasingly looked at in preventing infections critical to COVID-19. A study analysis looked at 25 randomized control trials comparing vitamin D supplements to placebos, which found that vitamin D reduced the risk of acute respiratory infection with either daily or weekly vitamin D supplementation, particularly in individuals who were deficient in it.  Studies also indicate that high latitudes and winter season are risk factors for both low vitamin D, increased influenza, and other respiratory illness and adverse outcomes.  While more research needs to be done in this area, the correlation with COVID-19 mortality rates and vitamin D status are continuing to be looked at.

Mood Boost: The sun can brighten up your mood (I know it does for me), and so can vitamin D. According to a 2017 review article in the journal Neuropsychology, researchers found "a significant relationship between depression and vitamin D deficiency.” While they acknowledged that more research is needed to define the exact workings of it—such as, if low vitamin D levels are a cause or effect of depression—the authors recommend “screening for and treating vitamin D deficiency in subjects with depression” noting that it is an “easy, cost-effective and may improve depression outcome.”

How to get more vitamin D?

Despite being readily available through sunlight, certain foods, and supplementation, many Americans are still getting inadequate amounts of vitamin D—according to the most recent information from the Centers for Disease Control and Prevention, two-thirds of the population had sufficient vitamin D, defined by the Institute of Medicine as a serum 25-hydroxyvitamin D (25OHD) value of 50–125 nmol/L. To determine your vitamin D status, the best thing to do is to consult a medical expert. The gold standard would be to assess your vitamin D status via blood draw and then consult with a healthcare practitioner to determine whether supplementation is needed and the proper dose.  

If deficient or lacking in vitamin D intake, there are a few key take-aways for you to up your daily dosage. You can start by getting around 20 minutes of sunlight several times a week. A major cause of vitamin D deficiency is insufficient sun exposure.

Aside from the sun, you can also get extra vitamin D through a few (albeit very few) foods, like fatty fish (including salmon, tuna, mackerel, and sardines) and mushrooms. Foods such as milk, orange juice, yogurt, and breakfast cereals can also be fortified with vitamin D.

Lastly, you can always go the supplement route, in the form of vitamin D3, if your healthcare provider has deemed supplementation necessary. Many healthcare providers are now deeming a daily dose of  1000-2000 IU of D3 safe and will maintain optimal levels for most adults. But again, check in with your doctor or dietitian before you decide to try vitamin D in supplement form.