Top Supplements: Vitamin D

The last vitamin I wanted to cover is Vitamin D. Vitamin D is a fat soluble vitamin that is critical in many physiological processes such as blood pressure regulation, immune function and cell growth. 

Vitamin D is not a typical vitamin because it can actually be made in the body. It comes from UV B light hitting the skin turning a precursor form of the vitamin into vitamin D3. What is also interesting about vitamin D is that it is a steroid hormone. Because it is a hormone it has far reaching effects in the body. 

There are two primary forms of vitamin D that supplements come in, vitamin D2 and D3. D2 is produced in invertebrates like plants and fungi when they are exposed to UVB. D3 is produced in animals. There are other forms of the vitamin but these are the main two. Both of them can raise vitamin D levels in the blood. Vitamin D3 seems to be more effective at raising blood levels of vitamin D, although age, sex, smoking status and medications taken can all affect the absorption of vitamin D. 

When it comes to who needs to take vitamin D, as defined by the Endocrine Society, 30% of people in the United States have a vitamin D deficiency and 40% have a vitamin D insufficiency. Vitamin D plays a role in prevention of all causes of mortality, neurodevelopment, it can provide protection against brain volume losses, dementia, and cognitive impairment, muscle health, dental health, hallmarks of aging, and bone health.

So now that we have established that people don’t get enough and that it is very important, the question becomes how much do we need? The Food and Nutrition Board of the National Academics of Science sets the recommended dietary allowance or RDA for vitamin D at 600 IU per day with an upper limit around 4000 IU per day. There are some issues with the RDA being as low as it is. The RDA was established based on a body of research around vitamin D’s roles in calcium homeostasis. This does not take into consideration vitamin D’s effects on many other diseases and physiological processes that vitamin D is involved in. A data study found that higher doses up to 5000 IU were more effective at raising blood vitamin D levels.

There are many other layers of detail that we could go into when it comes to vitamin D but the main question on people's minds is should I take it? For me, vitamin D as a supplement checks my major boxes of effectiveness, hits many different physiological processes, levels can be improved through supplementation, and is relatively cheap and affordable. Often have people take doses higher than the RDA, or cycle up during times of year when they get less sunlight, aka the winter.