Vitamin D deficiency is described as a global health problem in a 2010 article in the “International Journal of Health Sciences." Approximately 25 percent to 50 percent of patients seen in the clinical setting are deficient in vitamin D, according to a 2010 report in the journal "Mayo Clinic Proceedings"; and the risk of a man becoming deficient only increases with age. If left untreated, vitamin D deficiency can lead to weak bones, increased risk of fractures and osteoporosis. If you suspect you are at risk of a vitamin D deficiency, ask your doctor to check your blood levels.

Get in "D" Sun

The most common reason a man develops vitamin D deficiency is a lack of exposure to the sun. Fifty percent to 90 percent of your vitamin D is produced by sun exposure, with the remainder coming from your diet, according to the 2010 article in the “International Journal of Health Sciences.” Because very few foods contain vitamin D, it’s also difficult to meet vitamin D needs through the diet alone. Vitamin D is a fat-soluble vitamin, which means proper absorption requires that the intestines are able to properly absorb fat. Because of this, men with malabsorption issues, such as celiac disease, Crohn’s disease and ulcerative colitis, are at an increased risk of developing vitamin D deficiency.