March 15, 2021

Vitamin D


Vitamin D deficiency affects almost 50% of the world’s population, which can mostly be attributed to lifestyle and environmental factors that have reduced our exposure to sunlight over time. Our bodies naturally produce vitamin D when we’re exposed to adequate sunlight, however variables such as season, distance from the equator, time spent indoors and the amount of sunscreen worn can all impact our absorption and production of vitamin D (1). 

Vitamin D plays an essential role in our health, and without vitamin D, only 10-15% of dietary calcium and 60% of phosphorus* can be absorbed. Vitamin D receptors are present in most tissues and cells in the body, and the active form of Vitamin D has a wide range of biological actions such as inhibiting cellular proliferation and angiogenesis**, stimulating insulin and macrophage*** production and regulating up to 2000 genes in the body (2). 

*assists in the formation of bones and teeth; also needed for the body to make protein for the growth and repair of cells/tissues 
**tumor production and the growth of new blood vessels that continue to feed/grow the tumor 
***white blood cells that fight infection 
  1. Nair R, Maseeh A. Vitamin D: The "sunshine" vitamin. J Pharmacol Pharmacother. 2012;3(2):118‐126. doi:10.4103/0976-500X.95506
  2. Hossein-nezhad A, Holick MF. Vitamin D for health: a global perspective. Mayo Clin Proc. 2013;88(7):720‐755. doi:10.1016/j.mayocp.2013.05.011


Cognitive Health:

Vitamin D has been found to play an important role in brain development and function, as there is a wide distribution of vitamin D receptors throughout the brain. One study showed that vitamin D has the ability to affect proteins which are known to be directly involved in learning, memory, motor control and possibly even social behavior (1).

  1. McCann JC, Ames BN: Is there convincing biological or behavioral evidence linking vitamin D deficiency to brain dysfunction. FASEB J. 2008, 22: 982-1001. 10.1096/fj.07-9326rev. 


Bone Health:

Vitamin D has a positive effect on bone physiology; it causes an increase in the absorption of dietary calcium and phosphorus, and a decrease in parathyroid hormone levels (parathyroid hormone stimulates osteoclast activity*, resulting in bone weakness and overall decrease in bone density (1). Additionally, vitamin D receptors are located on fast-twitch muscle fibers, which are the first to respond in a fall; it is theorized that vitamin D plays a role in supporting the muscle tissue that upholds bones, thereby providing an additional protective effect (2).

*breaking down of bone stability 
  1. Bohon TM, Goolsby MA. The Role of Vitamin D Supplements in Women's Health. Clin Med Insights Women's Health. 2013;6:67‐70. Published 2013 Oct 20. doi:10.4137/CMWH.S11067
  2. Nair R, Maseeh A. Vitamin D: The "sunshine" vitamin. J Pharmacol Pharmacother. 2012;3(2):118‐126. doi:10.4103/0976-500X.95506



Vitamin D receptors are expressed on immune cells (T cells, B cells, and antigen presenting cells) and these cells are capable of synthesizing active vitamin D metabolites, giving vitamin D the capability to modulate both the innate and adaptive immune responses. Vitamin D deficiency is associated with increased autoimmunity and increased susceptibility to infection (1).

In vivo data on animals and humans has shown vitamin D supplementation to have positive effects on immune function, particularly where autoimmunity is involved. There is no worldwide consensus on whether different forms of vitamin D (D2, D3 or vitamin D analogs) have superior advantages for variable immunomodulatory responses (2). 

  1. Aranow C. Vitamin D and the immune system. J Investig Med. 2011;59(6):881‐886. doi:10.2310/JIM.0b013e31821b8755
  2. Prietl B, Treiber G, Pieber TR, Amrein K. Vitamin D and immune function. Nutrients. 2013;5(7):2502‐2521. Published 2013 Jul 5. doi:10.3390/nu5072502


Dietary vitamin D is commonly found in fish, dairy, animal, and fortified processed foods like fish liver oils or fatty fishes like salmon and tuna, milk, cereal, cheese, and egg yolks; unlike traditional sources, our source is fully plant-based. A single serving of GEM provides 100% of the recommended daily consumption of vitamin D2 for women, and is derived from Agaricus bisporus (mushroom powder, made in the USA).


What happens when your vitamin D is too low?

In the most extreme cases, vitamin D deficiency results in a condition called rickets, which manifests as weak, slow growing bones, and even visual deformities.  With a modern diet and occasional sun exposure, however, you are very unlikely to develop such a degree of vitamin D deficiency.  However, even moderate sustained vitamin D deficiency can put you at increased risk for depression and other cognitive pathologies (1), arthritis (2), inflammation (3), diabetes (4), and other serious health conditions. It’s important to get enough, and GEM has 100% of your daily recommended value, 20.5mcg.

  1. Parker GB, Brotchie H, Graham RK. Vitamin D and depression. J Affect Disord. 2017;208:56‐61. doi:10.1016/j.jad.2016.08.082
  2. Bellan M, Sainaghi PP, Pirisi M. Role of Vitamin D in Rheumatoid Arthritis. Adv Exp Med Biol. 2017;996:155‐168. doi:10.1007/978-3-319-56017-5_13
  3. Garbossa SG, Folli F. Vitamin D, sub-inflammation and insulin resistance. A window on a potential role for the interaction between bone and glucose metabolism. Rev Endocr Metab Disord. 2017;18(2):243‐258. doi:10.1007/s11154-017-9423-2
  4. Issa CM. Vitamin D and Type 2 Diabetes Mellitus. Adv Exp Med Biol. 2017;996:193‐205. doi:10.1007/978-3-319-56017-5_16


Is it possible to take too much Vitamin D?

Vitamin D is fat soluble, which means that if you eat too much of it your body is not able to immediately discharge the extra in your urine.  However, to build up a dangerous amount of vitamin D would require eating almost 100 times the daily recommended allowance.  Unless you are a big fan of fish liver oil (we didn’t think so), sneaking in an extra GEM isn’t going to hurt if you get the craving.

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