Study: Vitamin D Boosts Survival For Some Colon Cancer Patients

When it comes to vitamins, much of the recent news has been grim.  "Enough is enough: Stop wasting money on vitamin and mineral supplements" was the headline of a medical journal  editorial not so long ago.

One exception may be Vitamin D, aka the sunshine nutrient.

Vitamin D is no silver bullet, according to the research. But studies have shown that when your levels are too low, it can be bad for your health.

Now, a new study by researchers at the Dana-Farber Cancer institute finds that high levels of vitamin D increase survival in certain patients with colon cancer.

From the Dana-Farber news release:

... clinical trial patients with metastatic colorectal cancer who had high levels of vitamin D in their bloodstream prior to treatment with chemotherapy and targeted drugs, survived longer, on average, than patients with lower levels of the vitamin. Those findings were reported today at the 2015 American Society of Cancer Oncology (ASCO) Gastrointestinal Cancers Symposium in San Francisco.

...The research, based on data from more than 1,000 patients with metastatic colorectal cancer who enrolled in a phase 3 clinical trial of chemotherapy plus biologic therapies, adds to vitamin D’s already impressive luster as a potential cancer-inhibiting agent. In the study, patients with the highest blood levels of vitamin D survived for a median period of 32.6 months, compared to 24.5 months for those with the lowest levels...

The study's lead researcher Kimmie Ng, MD, MPH, a medical oncologist at Dana-Farber said in an email to me:

"There is a lot of debate about what can be concluded from observational studies of vitamin D and colorectal cancer survival, with many believing that higher vitamin D levels may just be a proxy for better health or less aggressive disease. But this is where our study truly stands out from the rest – we had very detailed and comprehensive data on patient and tumor characteristics, survival, response to chemotherapy, and diet and lifestyle factors. Even after controlling for all of these variables in our analysis, our results did not change – higher plasma vitamin D was still associated with significantly better survival.

Moreover, we showed that colorectal cancer patients with higher vitamin D levels had delayed progression of their disease, which strongly suggests that vitamin D may have direct effects on the tumor and/or tumor microenvironment.

Another very important finding from our study is that patients may not necessarily need to have supratherapeutic levels of vitamin D to see a potential beneficial effect on survival. In fact, our results suggest that simply repleting vitamin D to normal ranges that are recommended to maintain bone health may be associated with better cancer outcomes.

Headshot of Rachel Zimmerman

Rachel Zimmerman Reporter
Rachel Zimmerman previously reported on health and the intersection of health and business for WBUR. She is working on a memoir about rebuilding her family after her husband’s suicide. 



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