Researchers have found that higher vitamin D levels in the body correspond to a reduced risk for cancer.
In a study published in the journal PLOS One, researchers from UC San Diego's School of Medicine showed that adequate amounts of vitamin D, particularly serum 25-hydroxyvitamin D or 25(OH)D, has the ability to prevent all types of invasive cancers. This is the first time that the vitamin's ability had been quantified and documented.
Cedrick and Frank Garland made the first connection involving vitamin D and certain cancers back in 1980 when they observed that people living in higher latitudes, where less sunlight is available, were likelier to be vitamin D-deficient and have higher incidence rates for colon cancer. They carried out subsequent studies and found that vitamin D is also linked to bladder, lung and breast cancers.
For their study, the researchers sought to identify the vitamin D level needed to reduce risks of cancer effectively using 25(OH)D as a marker, which is the main form of the vitamin in the blood. Using the Lappe trial cohort and the GrassrootsHealth prospective cohort, they came up with a bigger sample size as well as a wider range of 25(OH)D serum samples.
The only way to accurately measure vitamin D levels in the body is through a blood test. After analyzing samples from the cohort studies, the researchers saw that cancer incidence rates declined as 25(OH)D increased. In fact, women with 40ng/ml 25(OH)D concentrations in their blood were 67 percent unlikelier to develop cancer compared to those who had serum levels 20ng/ml and lower.
The researchers were not able to determine the optimal daily intake for vitamin D or which source is best but they noted that reduced risks of cancer become measurable once 25(OH)D serum levels were at 40ng/ml and benefits add up the higher the serum levels were.
"Primary prevention of cancer, rather than expanding early detection or improving treatment, will be essential to reversing the current upward trend of cancer incidence worldwide," said the researchers, suggesting that higher vitamin D levels can be an important tool for prevention.
Aside from Cedric Garland, Sharon McDonnell, Robert Heaney, Carole Baggerly, Joan Lappe, Christine French, Edward Gorham and Leo Baggerly also contributed to the study. Their work received funding support from the Vitamin D Society, the Pure North S'Energy Foundation and Bio-Tech Pharmacal.
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