I started going to the doctor on a regular basis last year. While I exercise fairly regularly and usually eat pretty well, I thought that regular physicals and other health maintenance efforts was a good idea. I was surprised that one of the first recommendations my doctor made was daily vitamin D supplementation. So I researched facts about vitamin D.

Important facts about vitamin D

I don’t know how many of you take vitamin D every day. After reading a new review article by Franklin D. Shuler, M.D., PhD, et al. in Sports Health, I suspect many of you should probably start.

Our diets provide very little of the vitamin D we need.

The human body uses 4000 – 5000 IU of vitamin D3, but almost none of that vitamin D3 comes from dietary intake. Most vitamin D3 is produced by our exposure to ultraviolet radiation. Lack of time spent outdoors, sunscreen use, and other factors negatively affect our vitamin D levels.

Vitamin D deficiency is very common.

Using 30 ng/mL 25-hydroxyvitamin D3 as a cutoff, 50-75% of children and adolescents are deficient in vitamin D. 75% of Caucasian adults and 90% of African-American and Latino adults are deficient as well. It has been shown to be common among adults undergoing orthopaedic surgery as well.

Elite athletes are often vitamin D deficient as well.

Among indoor athletes, 94% of basketball players and 83% of gymnasts have been shown to have deficient levels. Even outdoor athletes are at risk. A study looking at vitamin D levels among New York Giants players showed that 81% were deficient.

Lower levels of vitamin D might increase your risk of musculoskeletal injury.

A study of players on an NFL team showed that players who suffered a musculoskeletal injury had levels much lower than those players that did not get injured.

Higher vitamin D levels might improve athletic performance.

Increased vitamin D levels are associated with increased strength, jump height and power, and exercise capacity.

Vitamin D supplementation might prevent or decrease overtraining syndrome.

Inflammatory cytokines TNF-alpha and IL-6 are increased with vitamin D deficiency after intense exercise. Vitamin D supplementation might decrease inflammation after heavy physical training sessions, theoretically allowing athletes to resume training faster.

Vitamin D supplementation might decrease the risk of falling.

Fast-twitch, type II muscle fibers are thought not only to be important for athletic performance but also for fall prevention. People with adequate vitamin D supplementation are thought to have a 20% lower risk of falling, possibly due to its effects on type II muscle fibers.

Higher vitamin D levels might have many other health benefits.

Patients have lower rates of colds and flu with increased vitamin D levels. Many other aspects of physical and mental health are being investigated, including many cancers, cardiovascular disease, diabetes mellitus, hypertension, strokes, asthma, and depression.

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