Vitamin D, also known as “the sunshine vitamin”, is crucial for optimal health. All vitamins are important, right? But vitamin D is quite unique and its effects on the human body are manifold- affecting bone integrity, immunity, and metabolism. As a result, vitamin D sufficiency is thought to fight off fatigue, chronic diseases like diabetes, and even cancer. Let’s take a closer look at this vitamin.
The word vitamin is defined as an organic compound that is essential for normal growth and is required in the diet because it can’t be synthesized by the body. This isn’t the case for vitamin D. With enough sunlight exposure, vitamin D3 can be produced in the skin, which is then processed by the body to form the active form of vitamin D [R].
Vitamin D has the chemical structure of a steroid molecule- it’s derived from cholesterol and is similar to sex hormones testosterone and estrogen [R]. Because of its chemical structure, its similarity to hormones (more so than to vitamins), and its ability to be produced by the body, vitamin D is considered a hormone [R].
Vitamin D is primarily known for its role in calcium and bone metabolism and maintenance of bone integrity. It enhances the absorption of calcium from the small intestine into the bloodstream and it stimulates the production of bone [R].
Lately, however, this hormone has been found to be involved in a lot more functions and has been shown to be important in reducing the risk for cancer, multiple sclerosis, diabetes, heart disease, and other immunological disorders [R].
It operates by influencing gene expression, controlling cell division and cell death, and inducing immune system regulation.
Its ability to control cell division and cell death makes it beneficial against, among other diseases, cancer, which occurs as a result of uncontrolled cell division [R].
The pivotal role vitamin D plays on the immune system became clear when individuals with vitamin D deficiency were found to have an increased susceptibility to infection and increased autoimmunity (when the immune system recognizes the body as foreign). Vitamin D helps the immune system recognize foreign substances, like bacteria, and subsequently destroy them [R]. It does this by activating antimicrobial immune cells[R].
As a result, vitamin D exposure decreases the incidence of infections and it facilitates treatment. This is why cod liver oil, which is a source of vitamin D as well, is used as a treatment for infections [R].
Because of its fundamental role in regulating the immune system, vitamin D deficiency is also linked to the onset of diabetes [R]. Diabetes starts when there is insulin resistance, which actually results from inflammation- an immunological process that aims to destroy infection but may turn detrimental. Vitamin D reduces inflammation and thus prevents diabetes from developing by inhibiting the development of insulin resistance. In addition, vitamin D is able to influence the expression of genes, including those that are diabetes-related [R].
Despite knowledge of the benefits of vitamin D, half of the world’s population suffers from vitamin D insufficiency and over 1 billion people worldwide have vitamin D deficiency (VDD) [R].
We know now that the sun is the primary source of vitamin D, but sometimes, getting enough sun might be a tough task. Luckily, there are also some dietary sources that include mushrooms, cod liver oil, organic pasture raised eggs (though I recommend these in moderation if at all) eggs, some omega 3 fats like avocado, and responsibly fortified food sources. [R]. The best news is that you don’t have to resort to the trend of “sunning” if that doesn’t appeal to you!