Researchers made the first connection between vitamin D deficiency and some cancers in 1980 when they noted populations at higher latitudes (with less available sunlight) were more likely to be deficient in Vitamin D, which is produced by the body through exposure to sunshine, and experience higher rates of colon cancer.
Aside from established benefits of vitamin D on bone diseases, evidence continues to emerge that vitamin D could be effective for other cancers and chronic diseases.
The protective effects of vitamin D against cancer are much more controversial in clinical studies and the results of epidemiological studies are contradictory.
They analyzed the public health records of 33,736 men and women aged 40 to 69.
It involved more than 30,000 Japanese who were followed for 16 years.
Lower levels of Vitamin D have been noticed in the majority of cancers types except lung and prostate cancers but have also been observed especially in the cases with liver cancer, as the liver is the organ that produces 25-hydroxyvitamin D.
None of the cancers examined showed an increased risk associated with higher Vitamin D levels.
Lack of vitamin D can lead to fitness injuries
A lack of vitamin D from sunshine in colder climates should be seen as a risk even into adulthood, scientists said. Vitamin D contributes to calcium level maintenance in our bodies, which in turn helps teeth, muscles and bones remain healthy.
The study published by the BMJ was carried out to determine if vitamin D was linked to site specific and total cancer. At the beginning of the study, participants provided detailed information about medical history, diet and lifestyle, and gave blood samples to measure vitamin d levels.
They were split into four groups, ranging from the lowest to highest levels of vitamin D. It also involved researchers from Memorial Sloan Kettering Cancer Center in NY.
Vitamin D levels will change depending on the time of year and higher during the summer and autumn periods than in winter or spring.
Once multiple known cancer risk factors had been accounted for, including weight (BMI), physical activity, age, dietary factors, smoking and alcohol intake, researchers discovered that high levels of vitamin D reduced the overall risk of cancer by 20% in both women and men.
On the drinks front, fortified milk and orange juice are good sources.
The researchers did not specify whether the trial participants used vitamin supplements or not.