Is there a connection between vitamin D levels and cancer risk? Previous studies have shown that people with low levels of vitamin D appear more susceptible to cancers of the pancreas, colon, breast and prostate. (See below for a report on bladder cancer and vitamin D.) Conversely, higher levels of vitamin D have been associated with a lower risk of several different cancers. Could vitamin D help prevent cancer?
Do Robust Vitamin D Levels Prevent Cancer?
Most of the previous epidemiological research has been done in the US or Europe. Japanese researchers recently confirmed that this link held up over a large, prospective epidemiological study (Budhathoki et al, BMJ, March 7, 2018).
Vitamin D and Cancer in Japan:
They recruited more than 33,000 middle-aged adults who provided blood samples and data about their diet and exercise patterns. Over the next 16 years, approximately 3,300 of these people developed cancer. When the investigators analyzed the data, they found that those participants with higher levels of vitamin D had a 20 percent lower likelihood of a cancer diagnosis. Liver cancer was almost 50 percent less likely among people with the highest levels of vitamin D in their bloodstream.
Previous Research on Vitamin D and Bladder Cancer:
British researchers reported in 2016 that low levels of vitamin D increase the likelihood of developing bladder cancer.
What Is the Evidence for a Link with Bladder Cancer?
The investigators reached this conclusion through a systematic review of seven studies. They also tested cells from the lining of the bladder and found that vitamin D activated an immune response. They inferred that adequate vitamin D would stimulate these cells to fight off cancer.
Inadequate Vitamin D:
In northern countries with little sunlight, people have trouble maintaining adequate vitamin D levels. That is because sun-exposed skin manufactures this crucial compound. Without sun, the chemical reaction does not happen.
Vitamin D in Great Britain:
The authors point out that one in five British adults are deficient in this nutrient and 60 percent have low blood levels. Even experts do not know whether supplementation can help prevent cancer.
This research was presented at the Society for Endocrinology Annual Meeting, Brighton, UK, November 8, 2016
Is Vitamin D Deficiency a Problem in the US?
Far more of the U.S. lies in southern latitudes where sun exposure is strong, at least during the summer. According to the CDC, around two-thirds of the US population have sufficient levels of vitamin D. That means, however, that nearly one in three Americans is at risk for insufficient or deficient vitamin D levels.
Other Health Problems Associated with Low Vitamin D Status:
Not only does this increase the chance of bladder cancer, it also makes middle-aged adults more susceptible to calcified coronary arteries (Journal of the American College of Nutrition, Sep-Oct., 2016). It may also contribute to inflammatory bowel disease (Current Medicinal Chemistry, Oct. 26, 2016). People with low vitamin D levels are also more vulnerable to gum disease (BMC Oral Health, Sep. 2, 2016). Erectile dysfunction is more common among men with vitamin D deficiency (Atherosclerosis, Sep., 2016).
We discuss this critical vitamin and how it affects our health in our Guide to Vitamin D Deficiency.