Dr. Joel SteelmanI took a break from writing posts this summer. I wish that I could say that I had taken the time off for fun filled vacations with my family, but that was not the case. The Cook Children’s endocrine practice was extremely busy and my help was needed taking care of children who needed to be seen. I did get to the pool with my 4 year old quite often, and I wrote a post about the healthful benefits of swimming and water safety. My family and I really enjoy swimming and we did manage a short vacation to the beach—so don’t feel too sorry for me!

While at the beach, the idea of writing about the importance of vitamin D crossed my mind. As a fair skinned person, I learned quickly that sunscreen is the only thing that stands between me and a painful sunburn. Though sunscreen is great to prevent sunburn, sun-related skin damage, and skin cancer, it does have the negative effect of slowing down the production of essential vitamin D that all humans make with sunlight exposure.

Vitamin D, sometimes called the ‘sunshine vitamin’, is an interesting chemical– part vitamin and part hormone—which puts it into a category by itself. Humans get vitamin D both from the foods that we eat, as well as from the ability we have to make it ourselves. Most vitamin D that is stored in our bodies comes from our own internal production and it’s really a simple process. All it takes is cholesterol plus 1-15 minutes of ultraviolet light and voilà, we become a vitamin D factory.

However, factors such as lack of sunlight exposure, the use of sunscreen, or skin pigment can interfere with this process. A darker skinned person requires about 5-10 times longer exposure to UV light compared to a lighter skinned person in order to make vitamin D due absorption (blocking) of UV light penetrate via our skin pigment.

The history of vitamin D dates back to the 2nd century AD with the first medical descriptions of rickets. Rickets is a brutal disorder, with no seeming cure, which ultimately leads to softening of bones and death in infants and young children. Sadly, a long time passed from the 2nd century AD until effective treatments were found in the 1800s and early 1900s. It was first discovered that a cod liver oil (yuck!) treatment could reverse rickets in humans and animals. Later, sunlight and artificial sunlight exposure were used as therapies. It took until the 1920s for the medical community to finally learn that it was the vitamin D in cod liver oil that cured vitamin D deficiency and rickets. It took even longer to understand the whole metabolic pathway, as shown on the left, involved in vitamin D production.

Most people are aware that vitamin D helps to build strong bones and that it is essential to help the body absorb calcium.
Actually, the benefits of this wonder vitamin are much greater, as it is known to help prevent certain types of cancer, infectious diseases, asthma, heart disease, and diabetes, to name a few.

Vitamin D is the most common nutritional deficiency in the world. In spite of improved nutrition and fortification, vitamin D deficiency remains a problem. A recent study in Tennessee found only 18% of the pediatric patients studied had sufficient vitamin D levels! The best foods to eat to ensure good stores of it are cheese, eggs, salmon, fortified milk, breakfast cereals, margarine and sardines. Those with lactose intolerance would do well with vitamin D supplements. Breastfed only babies are at risk for a deficiency as mother’s milk does not transport vitamin D very well.

Vitamin D was merely known as that vitamin that prevented rickets or osteoporosis for a longtime after its discovery. It’s only been within the last 10 years that new discoveries have made this old vitamin new again.

An important point to make is that while vitamin D is top of mind in the medical community these days, it is not without risk. Too much vitamin D can lead to dangerously high calcium levels in the body with risk for kidney stones, dehydration, and heart rhythm problems.

Be sure to ask your doctor about vitamin D testing and what blood level ranges are normal, as well as how much you and your family should eat or take as a supplement for daily allowance and supplement safety.