It seems that Vitamin D is receiving a lot of publicity these days. It is estimated that 1 billion people worldwide have insufficient vitamin D levels. So what is Vitamin D? Why is this conversation important? Vitamin D is one of the fat soluble vitamins (along with A, E, and K) which is stored in the body’s fatty tissue and is both a nutrient we consume and a hormone we synthesize. In some circles it is considered a hormone because our bodies synthesize it, and it stimulates activities that take place in different locations in the body. Historically, D was identified as a marker for bone health, and while bone health is definitely important, recent research suggests that may only be part of the story.
In the human body the focus is on Vitamin D3 (cholecalciferol) and Vitamin D2 (ergocalciferol). Both forms can be ingested from the diet and from supplements. Vitamin D3 is also formed when ultraviolet rays of the sun (UVB) come in contact with the skin. These forms of Vitamin D must be converted by enzymes in the liver and kidney to perform their functions. Once activated, the now available Vitamin D can be utilized by the body in many ways. Vitamin D acts as a trigger that sets off a series of events that allows other nutrients to do their jobs. It is critical for the absorption of calcium, phosphorus, magnesium, and zinc. Calcium is necessary for bone integrity, blood clotting, regulation of enzymes, heart health, and muscle contraction Phosphorus is necessary for bone integrity, acid-base balance, and providing energy for overall body function. Magnesium is necessary for bone integrity, and providing energy for overall body function. Zinc is in all of the organs in the body and plays a role in everything from energy production to breathing. Vitamin D essentially keeps systems up and running. Not only does it help keep our bones strong, it also helps with cell growth, energy production, immune and neuromuscular function, and the reduction of inflammation. No wonder it’s important!
In order to reach optimal levels of Vitamin D try to spend 10-15 minutes 3 times a week getting sunlight on your arms, face, legs, or back. Eat whole foods like fatty fish (salmon, tuna, and mackerel), beef, liver, cheese, egg yolks, some mushrooms, and fortified milk. For many, especially those with Inflammatory Bowel Disease, obesity, and anyone over 50, supplementation may still be necessary. Product purity is important and dosing varies based on numerous factors. Consult with your provider or nutrition professional for assistance.
- Gropper SS, Smith JL, Groff JL. Advanced Nutrition and Human Metabolism. Fifth Ed. Belmont, California. Wadsworth. 2009.
- Holick MF. Vitamin D: the underappreciated D-lightful hormone that is important for skeletal and cellular health. Curr Opin Endocrinol Diabetes 2002;9:87-98.
- Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes: Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. National Academy Press, Washington, DC, 2010.
- Mattila PH, Piironen VI, Uusi-Rauva EJ, Koivistoinen PE. Vitamin D contents in edible mushrooms. J Agric Food Chem 1994;42:2449-53.