Vitamin D: Are You Getting Enough?

By Holly Hosler

Ever since I went to Sinai Hospital Grand Rounds last week, which featured a talk on vitamin D by John Hopkins Bayview Hospital endocrinologist Suzanne M. Jan de Beur, M.D., I’ve been tempted to spend a little time outdoors during my lunch break. That’s because I learned a mere 15 minutes outside (without sunscreen) between 10 a.m. and 2 p.m. can cause the body to produce 3,000 IUs of vitamin D. This is necessary for bone mineralization and the prevention of fractures and osteoporosis, and potentially important for staving off conditions such as breast, prostate and colon cancers; diabetes; and cardiovascular disease.

Experts recommend that we get 800 to 2,000 IUs of vitamin D per day. (Levels up to 10,000 IUs per day on a continued basis are even safe, suggests a study cited by Jan de Beur.)

Unfortunately, it is believed that up to half of us have too little vitamin D in our bodies. The consequences of vitamin D deficiency include osteoporosis, osteomalacia (in adults)/rickets (in children), thyroid problems, muscle pain and weakness, and an increased risk for breast, prostate and colon cancers, as evidenced by epidemiological data. Those who are elderly, obese, spend most of their time inside, have dark skin, live in northern climates or have certain health conditions are particularly susceptible to low levels of vitamin D.

Jan de Beur explained that barring supplemental vitamins, ninety percent (90%) of our vitamin D comes from sun exposure, while the remainder comes from food sources such as sun-dried shiitake mushrooms, salmon and cod liver oil, and a slight amount from fortified products such as milk. She showed a graph illustrating that young people naturally produce more vitamin D from the sun than older folks. Of course, the elderly are at higher risk for falls and fractures, so it is critical that they receive enough vitamin D to help their bones absorb calcium.

Ironically, the UVB rays necessary for vitamin D production are the very same rays that cause skin cancer, so I decided to scrap my idea to eat lunch outside. Plus, in Maryland, the sun only helps us produce vitamin D between March and November. Therefore, Jan de Beur recommends that vitamin D be obtained through dietary supplements, as there is no evidence that this supplementary vitamin D is inferior to the vitamin D our bodies produce from the sun. She says that most people require vitamin D supplements to get the amount that they need for good health.

Do you suffer from insufficient vitamin D? Symptoms include bone pain and muscle weakness, but sometimes the signs aren’t very pronounced. Talk with your doctor if you have concerns, especially if you are not already taking a supplement with at least 800 IUs of vitamin D.