We want you to know that Vitamin D is a BIG DEAL. We recently shared in a Bone Health Series over on our Instagram about it and today are going to dive a little deeper into the subject. Vitamin D is an essential nutrient, especially with regard to bone health. We need it in to regulate healthy calcium and phosphorus levels in our body for bone mineralization and is, thus, essential for our body’s structure, proper growth and development (more on that later).
First, let's talk about how we get it.
Unlike most vitamins and minerals, our primary source of Vitamin D isn't from our diet. It's from the SUN! Our body has been equipped with the unique ability to create a whole vitamin just by spending time outdoors. How incredible!
Vitamin D, also known as the 'sunshine vitamin', comes in two forms: Vitamin D2 (ergocalciferol) and Vitamin D3 (cholecalciferol). When your skin is exposed to UV rays from the sun, it is able to convert a universally present form of cholesterol into the hormonally active form of Vitamin D: Vitamin D3.
Like I mentioned above, we get most of the Vitamin D that we need from the sun - as much as 80-90% in those who don’t supplement actually (1). So that means that the remaining 10-20% is provided from what we eat. Some common sources of Vitamin D include, egg yolks, fatty fish, beef liver, mushrooms, along with fortified dairy products and breakfast cereals (2).
So what's the big deal? Is Vitamin D really all that important?
To answer the question, we're going to take a closer look at what the sunshine vitamin ACTUALLY does in the body. First of all, Vitamin D plays a key role in calcium and phosphorus homeostasis and bone metabolism (which basically means it is essential in the building of strong bones). The importance of maintaining healthy bones cannot be overstated! Together with calcium and phosphorus, Vitamin D helps keep bones strong and healthy for the long haul.
While maintaining adequate Vitamin D stores in the short-term can make a difference, the key is to achieve and maintain adequate stores starting at a young age. It’s never to early or to late to care about Vitamin D.
If that isn't enough, the sunshine vitamin is also believed to play a central role in the functioning of our immune system, decreasing our risk for certain cancers and autoimmune diseases, as well as enhancing our neuromuscular function, improving our mood, and protecting our brain from toxins (3).
Whew! Now that's what I'd call important. For this reason, we should be vigilant about keeping our levels in check. If Vitamin D deficiency is allowed to develop, it can contribute to other several serious health conditions including obesity, diabetes, hypertension, depression, osteoporosis, immune system disorder, improper muscle function, neurodegenerative diseases (e.g. Alzheimer's disease) and potentially much more. According to current research, Vitamin D deficiency has also been linked to the growth of at least 17 different kinds of cancer, including breast, prostate and colon cancer (3). This is an ignored epidemic!
Unfortunately, because few people realize the importance of getting their levels checked regularly, the prevalence of Vitamin D deficiency has slowly but steadily increased, resulting in a full-on epidemic! It is estimated that approximately 1 BILLION PEOPLE worldwide now suffer from inadequate blood levels of Vitamin D. This deficiency can be found across all ethnicities and age groups (4).
There are a couple factors that are contributing to the increased prevalence of Vitamin D deficiency. First of all, with work and play taking place primarily indoors, people are far less frequently exposed to the sun. The impact of this shift is particularly pronounced for those living in northern regions, which already experience less sun exposure overall.
Secondly, those with darker skin tones are also at an increased risk of deficiency. This is due to the fact that darker skin contains a greater concentration of a compound called melanin, which prevents UV rays from being readily absorbed.
Third, certain health conditions, such as kidney and liver diseases, can lead to the inability of the body to properly convert Vitamin D into its active form. And lastly, a diet poor in Vitamin D-rich foods can also increase the risk of deficiency (5).
So, how do you know if you're deficient?
The best way to determine whether you have a Vitamin D deficiency is to measure the levels of serum 25-hydroxyvitamin D in your blood (6). Here's a quick run-down of what your results might look like and what you could do moving forward:
Normal: 20-80 ng/ml
Insufficient: < 20 ng/ml
Significant Deficiency: < 12 ng/ml
SUGGESTED SUPPLEMENTATION (7) - According to the Institute for Medicine
All Ages: 600 IU (international units) of Vitamin D
Elderly (age > 70): 800 IU
Safe Upper Limit: 4000 IU
I personally supplement with around 4000 IU per day. According to several scientific studies, the current recommendations are set too low and those who supplement with this much (I’ve heard even as much as 8000 IU recommended) or who achieve closer to the upper range of the target serum levels (55-80 ng/ml) have lower risk of deficiency complications with virtually no negative side effects (8).
Lastly, while we won’t dive into this (yet), it’s worth noting that metabolism of Vitamin D metabolism is best when the diet is adequate in healthy fats, Vitamin A, Vitamin K2, zinc and magnesium. More on those at a later date.
That was a lot of information :) If you made it this far, thanks for sticking with me! A little information can be a powerful tool, especially for something as critical as your long-term health.
At the end of the day, it's pretty simple: get out in the sun, eat your salmon and don't forget to get your blood work done so you can be sure of where you stand. If you find that you are deficient, consult a dietitian who can help you get those levels back up into a healthy range!
That's all for now! :)
Schmid, A., & Walther, B. (2013). Natural vitamin D content in animal products. Advances in nutrition (Bethesda, Md.), 4(4), 453–462. doi:10.3945/an.113.003780
Parva, N. R., Tadepalli, S., Singh, P., Qian, A., Joshi, R., Kandala, H., . . . Cheriyath, P. (2018). Prevalence of Vitamin D Deficiency and Associated Risk Factors in the US Population (2011-2012). Cureus. doi:10.7759/cureus.2741
Shaheen, S. O. (2008). Vitamin D deficiency and the asthma epidemic. Thorax, 63(3), 293-293. doi:10.1136/thx.2007.091728
Vitamin D and Health. (2019, January 08). Retrieved from https://www.hsph.harvard.edu/nutritionsource/vitamins/vitamin-d/
Harvard Health Publishing. (n.d.). Vitamin D and your health: Breaking old rules, raising new hopes. Retrieved from https://www.health.harvard.edu/newsletter_article/vitamin-d-and-your-health-breaking-old-rules-raising-new-hopes
Rosen, C. J. (2011). Vitamin D Insufficiency. New England Journal of Medicine, 364(3), 248-254. doi:10.1056/nejmcp1009570
Vitamin D Deficiency: 6 Causes, Common Symptoms & Health Risks. (n.d.). Retrieved from https://www.webmd.com/diet/guide/vitamin-d-deficiency#1
Holick M. F. (2009). Vitamin D status: measurement, interpretation, and clinical application. Annals of epidemiology, 19(2), 73–78. doi:10.1016/j.annepidem.2007.12.001
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