bright sun shining, sunlight, sunlight boost, boost your mood

Researchers at the American Society of Cancer Oncology report that clinical trial participants with newly diagnosed colorectal cancer fared better if they had higher blood levels of vitamin D.

The patients were enrolled in studies of anti-cancer drugs, and their blood levels of 25-hydroxyvitamin D were measured at the beginning of the studies. Those with the lowest levels, around 8 nanograms/mL, survived for an average of two years. Those with the highest levels, roughly 27 ng/mL, lived an additional eight months, on average.

The research does not show that taking extra vitamin D would have an impact on cancer survival, but it has inspired the investigators to start such a study. The benefit of high vitamin D levels held up even after statistical adjustment for physical activity, diet and obesity.

[ASCO Gastrointestinal Cancers Symposium, San Francisco, Jan. 12, 2015]

To learn more about vitamin D, supplements, sunshine and 25-hydroxyvitamin D levels, see our Guide to Vitamin D Deficiency.


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  1. Don

    I don’t know about using D for cancer but I do know that I feel much better since I started taking 2000 IU of D3, especially in the winter months. I’ve also started using K-2 as it is supposed to aid in D absorption. My mood has also improved in the winter and some research indicates D might also help in that aspect.

  2. Cindy M. B.
    Seattle, WA

    Seems like when you’re trying to determine correct dosage for many supplements, certainly including Vitamin D, instead of a per-day dosage you’re instead given a certain blood level to shoot for. Well, this is just completely useless if you can’t determine that for yourself and rarely see a doctor. And I assume those tests would be expensive — because absolutely everything medical is expensive! So, like I said, the info is useless. I just follow package instructions and hope for the best. I’m aware there’s lots of variation in dosing recommendations on the packages, though.

  3. Helen M

    I don’t use sunscreen; however am outdoors for less than an hour a day. I also take a lot of D3; my last test showed my levels at 49, closer to that considered optimal by many alternative health practitioners. I think that people who are just crossing from their cars to their destinations do not need to use sunscreen. Every bit of sunlight helps with the formation of vitamin D. And the suppression of anxiety and depression. Whenever the weather permits I take some paperwork and sit outside from 15 to 30 minutes. In the summer I usually have a light tan.

    Of course, the lighter the natural coloring of the skin, the greater the risk of skin cancer. But have there been any studies that show just how much sun is safe?

    Personally, my skin coloring is akin to that of people living in Italy or Spain who have dark hair and eyes.

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