Vitamin D: The Sunshine Vitamin

Vitamin D: The Sunshine Vitamin

Vitamin D is an important vitamin for general wellness and supports many biochemical reactions throughout the body.* This essential vitamin is best known for its role in promoting calcium absorption and bone health, as well as maintaining healthy calcium and phosphorus levels in the blood.* Vitamin D has also been studied for its effects on muscle function, mood and immune health.* Vitamin D is a unique nutrient; unlike most other vitamins, the body can make its own vitamin D when skin is exposed to sunlight. This is why vitamin D3 is often referred to as “the sunshine vitamin.” This blog highlights the benefits of this critical vitamin and why supplementation of vitamin D may be an important part of your wellness regimen.*

The Sunshine Vitamin

Vitamin D refers to a group of fat-soluble secosteroids that play a role in increasing intestinal absorption of calcium, iron, and other essential minerals and nutrients.* Vitamin D is synthesized in the body by converting naturally-present healthy cholesterol via sunshine. There are two types of vitamin D widely used throughout the body: vitamin D2 (ergocalciferol), which can be found in plant-sourced foods, and vitamin D3 (cholecalciferol), which is often found in fortified food sources (such as milk and cheese) and synthesized in the skin when exposed to sunlight with UVB.*  While both are bioavailable, D3 is the considered the most active form of vitamin D.* The body sends vitamin D3 to the liver to convert it to a substance called 25(OH)D so that it can be sent to the rest of the body as activated vitamin D3 to support a variety of biochemical functions throughout the body, including supporting healthy calcium levels in the blood.*

Why is Vitamin D3 Important?

Vitamin D3 supports a variety of functions throughout the body, including calcium absorption, bone and skeletal health, healthy mood and energy levels, and immune health.*

Vitamin D & Calcium Absorption

Calcium is needed throughout the body to support healthy bones, muscles, teeth and even heart muscles.* Calcium deficiencies can lead to adverse effects such as brittle bones and fractures.* Vitamin D3 helps the body absorb the minerals calcium and phosphorus from foods, both of which may be important for developing the structure and strength of bones and teeth.* Inadequate levels of vitamin D may leave the body depleting calcium from its stores, including bones, which may adversely effect bone health.*

Vitamin D & Immune Health

Beyond its role in the skeletal system, vitamin D may also support immune health.* The immune system defends the body from foreign organisms that may lead to various illnesses, such as the common cold.* Vitamin D plays a role in activating the immune system's T-cells, which are responsible for identifying and defending the body against harmful organisms, to promote immune system health.* Vitamin D has also been linked to antiviral mechanics that make it an important nutrient in defending the body's immune system.*

Vitamin D & Mood

In addition to supporting healthy bones and immunity, vitamin D3 has been studied for its effects on mood and energy.* Adequate exposure to sunlight may help support vitamin D3 levels to support healthy mood and reduce anxiety.* Vitamin D3 may also promote healthy serotonin levels to promote restful sleep to support healthy energy levels and healthy mood.*


Why Supplement Vitamin D3?

vitamin d words written on sandAlthough vitamin D can be stored in the body until needed, it is often difficult to maintain vitamin D levels due to poor absorption and limited availability from food sources, decreased exposure to sunlight, and other environmental factors that can impact vitamin D levels.* According to studies, approximately 20 minutes of sunshine daily with over 40% of skin exposed would be necessary to prevent vitamin D deficiency, and decreased dietary intake and absorption also contributes to vitamin D deficiencies.* That's why supplementation of Vitamin D3 can play an important role in maintaining healthy levels of vitamin D3.*

Vitamin D3 from Nature's Lab 

Nature's Lab is proud to offer the following vitamin D supplements:


Vitamin D3 125 mcg, 180 Capsules

Nature's Lab Vitamin D3 contains 5,000 IU (125 mcg) of bioavailable vitamin D from cholecalciferol. This convenient, one-per-day serving contains 625% daily value of Vitamin D3 to support healthy levels of this crucial nutrient in easy-to-swallow vegetarian capsules.* 



Vitamin D3 Plus, 90 Capsules

Nature's Lab Vitamin D3 Plus contains 5,000 IU (125 mcg) of bioavailable vitamin D with the added benefit of vitamin K2. Vitamin K2 works synergistically with vitamin D3 to activate proteins to guide calcium to bone and teeth where it belongs.* This product contains 90 one-per-day vegetarian capsules.


Shop Our Collection of Vitamin D Supplements!



Teresa Kulie, MD, Amy Groff, DO, Jackie Redmer, MD, Jennie Hounshell, MD, and Sarina Schrager, MD MS. "Vitamin D: An Evidence-Based Review." Journal of the American Board of Family Medicine 22.6 (2009)

Alshahrani F, Aljohani N. Vitamin D: deficiency, sufficiency and toxicity. Nutrients. 2013 Sep 13;5(9):3605-16. doi: 10.3390/nu5093605. PMID: 24067388; PMCID: PMC3798924.

Calcium and Vitamin D: Important at Every Age. (n.d.). Available from:

Jorde, R., Sneve, M., Figenschau, Y., Svartberg, J., & Waterloo, K. (2008, September 11). Effects of vitamin D supplementation on symptoms of depression in overweight and obese subjects: Randomized double blind trial. Available from:

Gao, Q., Kou, T., Zhuang, B., Ren, Y., Dong, X., & Wang, Q. (2018, October 1). The Association between Vitamin D Deficiency and Sleep Disorders: A Systematic Review and Meta-Analysis. Available from

Aranow, C. (2011, August). Vitamin D and the immune system. Available from

Siddiqui, M., Manansala, J. S., Abdulrahman, H. A., Nasrallah, G. K., Smatti, M. K., Younes, N., Althani, A. A., & Yassine, H. M. (2020). Immune Modulatory Effects of Vitamin D on Viral Infections. Nutrients12(9). Available from

This article is for informational purposes only. It is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment and should never be relied upon for specific medical advice. To the extent that this article features the advice of physicians or medical practitioners, the views expressed are the views of the cited expert and do not necessarily represent the views of Nature's Lab or its affiliated brands.