Shedding Light on Vitamin D

The short days, cool wet weather, and limited sunlight of winter can be a real challenge – both mentally and physically. One of the outcomes of this seasonal routine is less vitamin D!

There’s a reason we call vitamin D “the sunshine vitamin.” Our main source of this essential fat-soluble vitamin is sun exposure on bare skin. It is made by the body through a complex chain of reactions beginning in the skin where the sun’s UV rays convert cholesterol into cholecalciferol, a form of vitamin D3.

During the winter season when there is limited sunlight and the body is not able to produce its own vitamin D sufficiently, supplementation is an important part of maintaining adequate levels in the body.


Vitamin D Deficiency

Research shows that 95% of Americans don’t get enough vitamin D! [1] Vegetarians and vegans are likely to be deficient, since they consume less of the foods that typically contain or are fortified with vitamin D. Supplementing your diet with vitamin D is one of the most effective ways to make up for our lower vitamin D production throughout the winter. It not only helps you prevent deficiency, but provides many health benefits for your bones, immune system, mood, and more.*  


Bone Health*

Your bones are dynamic, living tissues that are constantly being recycled and rebuilt. While calcium is the main nutrient needed for bone development, it can’t do its job properly without vitamin D. Vitamin D helps with calcium and phosphorus absorption in the intestines.* This is a critical part of keeping blood calcium and phosphate concentrations steady and allowing for normal bone mineralization.[2,3] On average, a person’s bone density and strength reaches its maximum by the age of 30. After this, bone mass progressively declines.[4] Getting sufficient calcium and vitamin D, combined with a healthy diet and regular exercise, may reduce the risk of developing osteoporosis.* In addition, supplementation with vitamin D can help lower your risk of bone fracture.*[5]


A Healthy Immune System*

Vitamin D is essential for keeping your immune system working properly.[6] A great example of the connection between vitamin D and your immune system is the presence of vitamin D receptors on most of the body’s cells, including some white blood cells.* A well-planned vegan diet is packed with plant-based foods that supply a wide scope of the vitamins, minerals, antioxidants, and enzymes that our immune systems need. An exception to this is vitamin D – which isn’t widely available in plant-based foods. There are a few foods that vegans should pay particular attention in order to get enough vitamin D to support the immune system:

  • Mushrooms – especially brown (cremini), portobello, maitake, and white mushrooms, which contain a significant amount of vitamin D. And similar to humans, mushrooms produce vitamin D from exposure to UV rays. You can set them out in the sun to boost their vitamin D content.[8,9]
  • Oat, almond, and other non-dairy milks that are fortified with vitamin D.
  • Orange juice fortified with vitamin D.
  • Plant-derived vitamin D supplements.



It makes perfect sense that low levels of the “sunshine vitamin” can influence your mood. In fact, your brain has receptors that are specifically designed for receiving chemical signals from vitamin D.[10] The phenomenon of feeling blue during the winter months has been recognized for thousands of years and has been linked with vitamin D deficiency. When your gloomy mood follows a seasonal pattern and affects your ability to go about your regular routine, you may have a form of clinical depression called seasonal affective disorder (SAD). If you’re experiencing symptoms of SAD, it is important to talk to your health professional about your diet and whether it provides all of the nutrients you need for healthy brain function.* Vitamin D has been shown to have a positive impact on brain function and mood.[11]


Sources of Vitamin D

When your exposure to sunlight is low, your body relies more on dietary sources of vitamin D, such as milk or fortified dairy alternatives; egg yolks; fatty fish, such as salmon, mackerel, and tuna; and mushrooms. But when these foods are unavailable, aren’t practical to eat in sufficient quantities, or if you follow a vegan diet, a daily vitamin D supplementation is an important option for helping to meet the body’s vitamin D needs and preventing deficiency. Whole Earth & Sea® Pure Food Vegan Bioenhanced Vitamin D3 25 mcg (1000 IU)  was developed with vegans and vegetarians in mind. It is a unique plant-based source of vitamin D3 (cholecalciferol) extracted from wild-harvested lichen. Because this formula contains the natural D3 (cholecalciferol) form of vitamin D, it is better absorbed and utilized by the body.[12] Each daily vegetarian capsule contains 25 mcg (1000 IU) of non-GMO vitamin D3 to help form and maintain strong bones and a healthy immune system.*


An Easy Solution

Winter is challenging enough as it is without suffering from low vitamin D levels. Thankfully your diet can help make up for your lack of the “sunshine vitamin” by incorporating a variety of foods that contain vitamin D into your meals and snacks. And if your diet isn’t enough, a daily vitamin D3 supplement is an easy solution to help meet your body’s needs.*



  1. Linus Pauling Institute and Oregon State University. Micronutrient Inadequacies in the US Population: an Overview. Retrieved November 24, 2020, from
  2. Bikle DD. Vitamin D metabolism, mechanism of action, and clinical applications. Chem Biol. 2014; 21(3):319-29.
  3. Holick M, Siris E, Binkley N, et al. J Clin Endocrinol Metab. 2005; 90(6):3215-24.
  4. Sidor P, Glabska D, & Wlodarek D. Rocz Panstw Zakl Hig. 2016; 67(3):279-85.
  5. Prentice R, Pettinger M, Jackson R, et al. Health risks and benefits from calcium and vitamin D supplementation: Women’s Health Initiative clinical trial and cohort study. Osteoporosis International. 2013; 24:567-580.
  6. Prietl B, Treiber G, Pieber TR, et al. Vitamin D and immune function. Nutrients. 2013; 5(7):2502-21.
  7. Chun RF, Liu PT, Modlin RL, et al. Impact of vitamin D on immune function: lessons learned from genome-wide analysis. Front Physiol. 2014; 5:151.
  8. The Mushroom Council. Vitamin D Fact Sheet. Retrieved October 31, 2019 from
  9. Cardwell G, Bornman JF, James AP, et al. A review of mushrooms as a potential source of dietary vitamin D. Nutrients. 2018; 10:1498.
  10. Anjum I, Jaffery SS, Fayyaz M, et al. The role of vitamin D in brain health: A mini literature review. Cureus. 2018; 10(7): e2960.
  11. Spedding, S. Vitamin D and depression: A systematic review and meta-analysis comparing studies with and without biological flaws. Nutrients. 2014; 6(4):1501-18.
  12. Armas L, Hollis B, & Heaney R. Vitamin D2 is much less effective than vitamin D3 in humans. J Clin Endocrinol Metab. 2004; 89(11):5387-91.