Do Vitamin D Supplements Reduce the Risk of Dying from Cancer?


it all started with this famous study published in 1980 Johns Hopkins researchers were trying to figure out why states like New Mexico and Arizona had only about half the colon cancer rates of states like New York New Hampshire and Vermont maybe it’s because they got so much Sun and so they proposed that maybe the sunshine environment vitamin D is a protective factor against colon cancer since then sun exposure has been associated with lower rates of 14 other types of cancer – vitamin D may also affect cancer survival higher blood levels of vitamin D were associated with lower mortality of patients with colorectal cancer how much lower like nearly half the mortality and the higher the D levels the lower the death rate appeared to fall this may explain why the survival rate from colon cancer may depend on part on the season of diagnosis the reason the risk of rapid death is lowest if you’re diagnosed in the fall after you’ve spent the summer building up your vitamin D stores but look there are other risk factors that could be seasonal – maybe people are taking advantage of the fall harvest and eating healthier maybe that’s why lower risk in the fall season or maybe there’s more drinking in the winter and in the summer running around outside not only you’re getting more Sun you’re running around outside getting more exercise which may itself be protective so these kind of studies just provide circumstantial evidence establishing a cause and effect relationship between colon cancer vitamin D deficiency using observational studies is challenging because of confounding factors like the exercise so-called lurking variables for example there may be a tight correlation between ice cream sales and drowning death but that doesn’t mean icecream causes drowning a more likely explanation is that there’s a lurking third variable like hot weather summertime that explains white drowning deaths are highest when ice cream consumption is highest it’s kind of a trivial example but this actually happened with hormone replacement therapy women taking drugs like premarin appeared to have 50% less risk of heart disease and so doctors prescribe it to women by the millions but if you dig a little deeper into the data yes women taking estrogen had 50% lowered risk of dying from heart disease but they also had a 50% lower risk of dying from accidents and homicide so it probably wasn’t the drug see the only way to know for sure is to put it to the test and a randomized clinical trial where you give half the women the drugs see what happens and a decade later they did and instead of having a 50% drop in risk within a year of being given the hormone pills heart attack and death rates shot up 50% in retrospect the lurking variable was likely socioeconomic class or poor women are less likely to be scribed be prescribed hormone replacement therapy and more likely to be murdered and die of heart disease because of the lurking variable a drug we now know to be dangerous had appeared protective besides lurking variables there’s also the possibility of reverse causation maybe low vitamin D levels didn’t worsen the cancer maybe the cancer worsened the vitamin D levels and this may be unlikely since tumors don’t appear to directly affect vitamin D levels but cancer treatment might even simple knee surgery can dramatically drop vitamin D levels within hours thought to be because of just the inflammatory insult of cutting into somebody so maybe that could help explain the link between lower D and lower survival and he if you got cancer maybe you’re spending less time running around at the beach so yes higher vitamin D levels are associated with improved survival in call rectal cancer and in breast cancer in fact about double the risk of breast cancer recurrence and death in women with the lowest vitamin D levels and vitamin D levels also associated with longer survival with ovarian cancer and other cancers like lymphoma but bottom line as we learned with hormone replacement is that you have to put it to the test but there weren’t a lot of randomized controlled trials on vitamin D supplements and cancer until now we now have a few randomized controlled trials and vitamin D supplements do indeed appear to reduce the risk of dying from cancer what dose the researchers suggest may be getting blood levels up to at least around 75 nanomoles per liter levels not reached by as many three-quarters of women with breast cancer or a striking 97% of colon cancer patients getting up to these kind of levels 75 or perhaps even better a hundred might require about two to four thousand international units of vitamin D a day levels of intake for which there appeared to be no credible evidence of harm regardless with the exact level is the findings of these kind of studies may have a profound influence on future cancer treatment you

31 Replies to “Do Vitamin D Supplements Reduce the Risk of Dying from Cancer?”

  1. Been taking 10000iu a day of Vitamin D3 for little over 10 years. I was ridiculed and laughed back then when I told my doctor, friends and family how much I was taking and advised them to take at least 4000/5000iu day together with a capsule of Vitamin K complex. They all advised me to stop as I could die been a Vitamin D a Hormone and been the daily max amount suggested by the government only 200iu at that time. I am still alive and well and still taking 10000iu daily. Thank you Dr. Greger again for your marvelous job in letting people know the truth.

  2. Dr Gregor, what is your opinion on the blood group diet? Mainly, it says if you're blood group O then you should eat meat, I am vegan but at the back of my mind I hear that little quote. So frustrating. Thanks for all your videos and information. It is appreciated.

  3. Thanks for watching! We have several other Vitamin D videos, also. You can find them on the playlist here or over on the website, under Health Topics–Vitamin D Supplements. And while our awesome medical moderator volunteers try their best to answer questions on YouTube, you may get a quicker answer over the website. -NF Team

  4. So people get cancer from lack of vitamin d pills ? Do we not largely avoid cancer with whole food vegan diet ? It's the dairy and meat and oils right ?

  5. I've recently started taking a chewable vegan D3 supplement. I'll get another blood panel taken in a few months to see if my levels have come up.

  6. If a person (like us) lives on simple raw foods, there is no need for any supplements. For the average person, supplements are a waste of money and can actually be harmful.

  7. I live in England where the summer this year was poor, to say the least. A few really hot days with most weeks being cloudy a lot of the time. D3 supplements are essential!

  8. yo greger ive a question
    uve made some videos about raw veganism
    and u said some things r better eaten raw (like paprika for example) and some r better cooked (like carrots/sweet potatoes)
    however i find it strange that something that seems to be "oh so healthy" like legumes (i mean things like peas/lentils) is something u cant digest if eaten raw (ur stomach will hurt)
    doesnt that sound a bit strange since raw is like "the basic" state of food (which should generally be considered best…since human ancestors grew up in an environment in which fire/cooking still wasnt used evolutionary speaking)

    so my question: why isnt raw vegan the best? (i know u have showed us studies that alledgedly show that it isnt – but i cant find one big conclusion that u draw from all the research u did about it that explains the "WHY")
    im asking this because it just seems utterly illogical to me how raw veganism could possibly NOT be the best way of eating

  9. This explanation about correlation and not causation remembers me of The China study… I can't wait to see more of those randomized controlled trials to know better

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