Hey BA!

Let’s talk about vitamin D, aka the sunshine vitamin. It gets this nickname because it’s produced in the skin through sun exposure. This being said, it can also be ingested through certain foods and supplementation. While it’s considered a fat-soluble vitamin, D actually acts like a hormone in the body as it regulates blood calcium levels in the body. Blood calcium regulation is what makes vitamin D so crucial for building and maintaining healthy bones. It also supports immune function, helps regulate inflammation, decreases cell proliferation, increases cell differentiation, and enhances intestinal mineral absorption of calcium, magnesium, and phosphorus. When used therapeutically, it’s been shown to have a positive effect on the following conditions(1):

Cancer
Heart Disease
Hypertension
Obesity
Type 2 Diabetes
Depression
Cognitive Impairment
Fractures/Falls
Autoimmune Disease
Flu

Now, what about vitamin D’s impact for us here at the gym? In regards to exercise, vitamin D supports optimal performance through it’s vital role in the following functions(2):

Muscle Growth
Immune Function
Heart and Lung Function
Inflammation Regulation
Enhanced Injury Recovery/Prevention

It’s clearly important for overall health and vitality, yet a study done this past July reveals that 50% of the world’s population has vitamin D insufficiency. While most common in the elderly population, 35% of adults in the United States are considered deficient(3). What about us here in (mostly) sunny Colorado? Is it possible to still need more? Yes! Insufficient dietary intake, malabsorption issues caused by underlying health conditions, pollution, decreased outdoor activity, and certain medications that impact liver function all contribute to deficiency.

So, how do we boost our vitamin D intake and absorption?

First, let’s start with sun! The sun burns hot here which causes us to typically lather on the sunscreen. This can actually impact vitamin D production in the skin. Try to get 15-30min daily of sun exposure on bare skin. The amount of time just depends on your skin type. Cover up or put on sunscreen prior to burning.

Second, diet!

Here is a list of the top food sources:

Cod Liver Oil
Wild-Caught Salmon
Wild-Caught Tuna
Fortified Milks
Mushrooms
Wild-Caught Sardines
Pasture-Raised Eggs

The form of vitamin D produced in the skin from sunshine, as well as contained in the foods listed above is D3. This is the most natural and readily available form of vitamin D to be activated and used in the body. Therefore, if choosing to supplement with vitamin D, I recommend looking for a D3 supplement rather than D2 (which is common in supplementation). 1 Tbsp of high quality cod liver oil daily would be my top choice, followed by a D3/K2 supplement. Vitamin K2 is another fat-soluble vitamin that has a synergistic relationship with vitamin D. K2 helps ensure proper calcium absorption into the bones and prevents accumulation in the arteries(4). While recommended daily intake of vitamin D is 600IU for adults, due to absorption issues the average daily intake through supplements is 1,000-4,000IU daily. Talk to your healthcare practitioner for proper dosing, as well as if pregnant or wishing to become pregnant.

Nair R, Maseeh A. Vitamin D: The "sunshine" vitamin. J Pharmacol Pharmacother. 2012;3(2):118-126. doi:10.4103/0976-500X.95506
de la Puente Yagüe M, Collado Yurrita L, Ciudad Cabañas MJ, Cuadrado Cenzual MA. Role of Vitamin D in Athletes and Their Performance: Current Concepts and New Trends. Nutrients. 2020;12(2):579. Published 2020 Feb 23. doi:10.3390/nu12020579
Sizar O, Khare S, Goyal A, et al. Vitamin D Deficiency. [Updated 2021 Jul 21]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK532266/
van Ballegooijen AJ, Pilz S, Tomaschitz A, Grübler MR, Verheyen N. The Synergistic Interplay between Vitamins D and K for Bone and Cardiovascular Health: A Narrative Review. Int J Endocrinol. 2017;2017:7454376. doi:10.1155/2017/7454376

Vitamin D