Vitamin D levels have been linked to a lower risk of colon and rectal cancers, following a new analysis of earlier research.
In 18 studies involving more than 10,000 people, colon cancer risk was as much as 33 percent lower in subjects with the highest blood levels of vitamin D.
This was compared to those with the lowest levels, found the researchers from The Sixth People's Hospital affiliated with Shanghai Jiao Tong University.
Those with the highest intake of vitamin D through supplements and food had 12 percent lower risk than those with the lowest intakes.
Senior author Dr. Huanlong Qin and his colleagues said the number of studies for analysis are still too few, reports Reuters.
Vitamin D has previously been linked to protection from various cancers, heart disease, diabetes and asthma, among other conditions.
Yet, how the vitamin might exert a beneficial effect is still poorly understood. Some evidence suggests that exceeding current recommended daily requirements may yield benefits.
Qin's team said up to 58 percent of U.S. adults and adolescents may have vitamin D deficiency, which is "an important health problem in the industrial world,” reports Reuters.
While there are biologically plausible mechanisms through which low vitamin D levels could increase colon cancer risk, studies have had mixed results so far, the researchers add.
