Sunshine vitamin protects mothers and their unborn babies

As you’re probably well aware by now, vitamin D plays a critical role in human health. In fact, new research comes out just about every other day underscoring the importance of this nutrient. So over the next week, I’ll tell you about the most recent–and exciting–study results.

Starting with one that suggests the importance of vitamin D actually begins before birth.

U.S. researchers recently conducted a clinical trial at community health centers in South Carolina. They asked pregnant women to take either 2,000 IU or 4,000 IU of vitamin D daily. They wanted to see if either dose would safely improve maternal and neonatal outcomes. And they also wanted to see if the larger dose gave the women and babies a bigger boost.

The researchers measured all the mothers’ blood levels of vitamin D at the beginning of the study. They found that mothers averaged just 23 ng/mL.

But after one month of supplementation, the 2,000 IU per day group raised their vitamin D levels to an average of 36 ng/mL. The 4,000 IU per day group went up to 38 ng/mL on average. (However, according to guidelines for optimal health, this is still far from an ideal level. More on that in just a moment.)

The babies born to both groups of mothers also showed improved vitamin D levels. The mothers also improved their rates of infection, premature labor, and premature birth. So imagine how much infant mortality rates might improve if every mother in the country got adequate vitamin D.

But those aren’t the only benefits women can get from vitamin D.

Another recent study showed that vitamin D seems to improve uterine health as well. (Which may help explain some of the above outcomes for maternal-newborn health.)

For this study, researchers from the National Institute of Environmental Health Sciences in North Carolina analyzed medical records for more than 1,000 women. They classified anything below 20 ng/mL as “low” vitamin D.

Women who had vitamin D levels above 20 ng/mL had a one-third lower rate of fibroid tumors. Also, the researchers found that women exposed to sunlight for just one hour per day had a 40 percent reduction in the rate of fibroid tumors.

This kind of outcome is extremely rare–even with dangerous and expensive drugs. Let alone from a common nutrient.

The study author commented, “It would be wonderful if something as simple and inexpensive as getting some natural sunshine on their skin each day could help women reduce their chance of getting fibroids.”

That kind of perspective makes sense. Which makes it especially surprising coming from a government institute.

Fibroid tumors are a bane to many women. Yet there has been relatively little effort over the decades to find ways to understand and prevent their occurrence. Hysterectomy, on the other hand, is an extremely aggressive medical intervention. And it’s “promoted” as a cure. Indeed, it’s been a burgeoning industry for gynecologists. Especially for gynecologists who have given up practicing obstetrics.

But what strikes me the most about these new studies is how low the subjects’ original blood levels of vitamin D actually were.

Clearly, vitamin D affects many different aspects of our health. Subjects experienced significant benefits just from raising their levels slightly. I can only imagine the benefits that might occur if more people got optimum levels of vitamin D .

You should have your vitamin D levels tested every time you have routine blood work. Or at least once a year. If you’re below 75 nmol/L–and especially below 30 nmol/L–it’s time to add a high-quality supplement.


1. American Journal of Obstetrics & Gynecology Feb 2013; 208: 137 e 131-113.

2. Epidemiology 2013; 24: 447-453.