Why is Vitamin D so important in the winter months?

Vitamin D helps to regulate the amount of calcium and phosphate in the body. These nutrients are needed to keep bones, teeth, muscles and the immune system healthy.

There are two forms of vitamin D in the diet and supplements:

  • Vitamin D2 (ergocalciferol): found in some mushrooms.
  • Vitamin D3 (cholecalciferol): found in oily fish, fish liver oil, and egg yolks.

Significant amounts of vitamin D can also be made in your skin when exposed to UV rays from sunlight. Any excess vitamin D is stored in your body fat for later use.

From about late March/early April to the end of September, most people should be able to make all the vitamin D they need from direct sunlight. However, older individuals and dark-skinned people tend to produce less vitamin D in the skin [1]. Between October and early March we do not make enough vitamin D from sunlight, so often need to take a supplement during these months.

Here are some signs you are not getting enough vitamin D:

Tiredness and fatigue – Tiredness can be caused by many things, and one of them is vitamin D deficiency. One study in 480 older adults linked vitamin D deficiency with fatigue symptoms [2].

Bone and back Pain – As vitamin D helps maintain bone health by improving your body’s absorption of calcium, bone and lower back pain may be symptoms of inadequate vitamin D levels. A review of 81 studies found that people with arthritis, muscle pain, and chronic widespread pain tended to have lower levels of vitamin D than people without these conditions [3].

Impaired wound healing – Slow wound healing could be a sign of low vitamin D levels. In a 12-week study involving 60 people with diabetes-related foot ulcers, those who took a vitamin D supplement experienced significant improvements in wound healing compared with the placebo group [4]. Vitamin D plays a role in controlling inflammation and addressing infections may also be important for proper healing.

Vitamin D and Covid

Experts say that taking a vitamin D supplement can help boost the immune system and reduce the risk of contracting illnesses such as covid-19. In one analysis the researchers studied 489 patients at the hospital and observed that those with a vitamin D deficiency were almost twice as likely (1.77 times higher) to test positive for the novel coronavirus than those with normal levels of vitamin D [5].

A recent meta-analysis of 40 research studies found that daily, long-term doses of vitamin D seemed to help protect against acute respiratory infections [6]. Other studies also have found associations between vitamin D levels and COVID-19 susceptibility.

Epigenetics produce both a Smart Vitamin D3 in GSO and a Smart Vitamin D2 in GSO (vegan friendly option).


We also produce a Smart Vitamin D3/K2 combined in black cumin seed oil – this product is extremely useful as the two vitamins work together to support overall health and distribute calcium where it needs to be in the body.

Research Links

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5946242/

[2] https://pubmed.ncbi.nlm.nih.gov/31635199/

[3] https://pubmed.ncbi.nlm.nih.gov/29559013/

[4] https://pubmed.ncbi.nlm.nih.gov/27363929/

[5] https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2770157

[6] https://www.medrxiv.org/content/10.1101/2020.07.14.20152728v1