Sunshine in a Bottle – favorite vitamin

Sunshine in a Bottle

Dr. Kumi Swart

I know I should not play favorites, but if I had to pick a favorite vitamin, it would be vitamin D.

My love for that vitamin has grown over the last nine years, probably starting around the time my own physician discovered that I was deficient in it and that my bones were unusually thin for my age. About a year or two after that discovery, I heard colleagues touting the power of vitamin D in the prevention of illness and I decided to do a little research.

What I already knew about vitamin D, I learned in medical school. Vitamin D is not a true vitamin, it’s a hormone that has an important role in the body’s ability to absorb and maintain normal levels of calcium for the health and strength of bones. A deficiency in vitamin D leads to the bone disease known as rickets. But this vitamin does so much more than that! Nearly every cell in the body has a receptor for vitamin D, so we have only scratched the surface of figuring out all its roles. We now know that deficiencies in this vitamin contribute to a wide number of other conditions besides rickets including autoimmune disease, cardiovascular disease, obesity, depression, increased susceptibility to infection, and possibly colorectal cancer.

Now, I have not treated very many patients with rickets, but I would guess that most of my patients have been vitamin D deficient at some point. In fact, I rarely find sufficient serum levels of vitamin D during routine screens of new patients in my practice. Why is that? Well, for starters, there are few foods that are naturally rich in vitamin D, so it is difficult to ingest enough through diet alone. The body can manufacture it from cholesterol when the skin is exposed to sunlight (which is how vitamin D got the nickname “the sunshine vitamin”) but using a sunscreen with as little protection as SPF 15 can cut vitamin D production by 99 percent. Other factors that impact vitamin D production include age, time of year, altitude and distance from the equator. Compounding the problem is that the amount of vitamin D in fortified foods and beverages (100 IU in milk and orange juice) and multivitamins (400 IU, typically) is rather low. My usual recommendation for vitamin D supplementation ten years ago ranged between 400 IU to 800 IU for women. Based on research, I now recommend dosages between 1000 IU to 50,000 IU for men and women, depending on the situation.

Why should you care? You may never develop osteoporosis, autoimmune disease, cancer, heart disease or depression, but everyone…really everyone…develops a cold at some point in their lives. Some of you reading this article get so many upper respiratory tract infections that you visit your primary care physician every month or two. There are those of you who have already sat in my office and asked me, “why do I keep getting sick and what can I do about it?” I probably gave you a list of things you can do, depending on your individual circumstances, but at some point, I’m sure I told you to take vitamin D.

The role vitamin D plays in the immune system fascinates me. In 2017 a large, global study published in the British Medical Journal concluded that vitamin D supplementation protects against respiratory tract infections including colds and flu. The study included 11,000 participants in 25 clinical trials conducted in 14 countries including the UK, USA, Japan, India, Afghanistan, Belgium, Italy, Australia and Canada. I won’t go into the science but suffice it to say that scientists now know how and why vitamin D works in the immune system. I would even go so far as saying, “an apple a day keeps the doctor away” should be changed to “vitamin D every day keeps the doctor away.” Is it any wonder why the incidence of colds and flu skyrockets during the winter months when sun exposure, thus vitamin D production, is at its lowest?

My only words of caution are that the timing, dosage, and formulation of vitamin D are crucial elements that impact health. In one important study, researchers tried to determine whether one yearly mega dosage of vitamin D could safely replace smaller daily doses in older women with osteoporosis. What they found was that the annual mega doses were actually detrimental, increasing the risk of falls and fractures in those women. Other studies also concluded that large intermittent doses further than 1 week apart were more likely to have a negative impact.