Vitamin D supplements

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How Much Do Vitamin D Supplements Affect Lifespan?

Living Longer With Vitamin D?

In 1822, a Polish physician was the first to publish that sunlight could cure the vitamin D deficiency disease rickets. His work was ignored by mainstream medicine for a century, not coming into widespread use until the 20th century, when wire cages were actually affixed to tenement buildings so babies could benefit from the sun. In my video Will You Live Longer If You Take Vitamin D Supplements?, I explore whether we’re in a similar situation now, where the medical profession has just not caught up with the science.

Researchers have documented correlations between higher vitamin D levels and all sorts of positive outcomes like decreases in cardiovascular disease, weight gain, infectious diseases, and declining cognitive function, and even tested whether vitamin D supplementation might reduce the adverse effects of earthquakes. It seems to help with everything else, so why not? It’s actually not as silly as it sounds because traumatic events like natural disasters can have a significant psychological impact that might be affected by vitamin D status.

Putting Vitamin D to The Test

But when researchers put supplements to the test, the purported links often didn’t pan out. This lack of effect may exist in part because low vitamin D levels may just be a marker for things like aging, obesity, smoking, and inactivity. Or, maybe low vitamin D didn’t lead to disease, but disease led to low vitamin D, because inflammation can drop D levels within the body. So, just because low D levels and disease seem to be correlated, it doesn’t mean that vitamin D deficiency is the cause.

While the majority of observational studies may show a link, where you simply measure vitamin D levels and disease rates, in only a handful of conditions have interventional studies—where you give people D supplements or placebos then see what happens—proven vitamin D to be effective. One of the conditions for which vitamin D supplements appear to genuinely work, however, is helping to prevent premature death.

Fifty-six randomized clinical trials involving nearly 100,000 people (mostly women) between the ages of 18 and 107 were randomized to four years of vitamin D supplements or sugar pills. Putting all the studies together showed those given vitamin D supplements lived longer and specifically had a lower risk of dying from cancer. This effect appeared limited to vitamin D3, though, which is the type derived from plants and animals, not vitamin D2, which is the type derived from yeast and mushrooms.

Is Supplementing Vitamin D Worth It?

How large an effect was it? It would take 150 people taking vitamin D supplements for five years to save one life. If we were talking about a drug, we’d need to weigh that against the cost and side effects of dosing so many people. But when we’re talking about something as safe and cheap as vitamin D supplements, it seems like a bargain to me. A similar analysis pegged the benefit at 11 percent in terms of reduction of total mortality, which is pretty substantial, potentially offering a life extension benefit on par with exercise. Though, no, it does not seem to reduce the adverse impacts of earthquakes.

The only concern is that it may give people license to order an extra doughnut or something. We still have to eat healthfully because any longevity benefit from vitamin D would just be a small adjunct to a healthy lifestyle. But, for those of us who want all the help we can get, the question then becomes how much should we take? I address that in my videos How Much Vitamin D Should You Take? and The Optimal Dose of Vitamin D Based on Natural Levels.

For an exploration of the purported links between vitamin D and obesity, diabetes, and hypertension, see my video Do Vitamin D Supplements Help with Diabetes, Weight Loss, and Blood Pressure?.

The “extra doughnut” effect can explain How Diet Soda Could Make Us Gain Weight.

You may also be interested in:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

82 responses to “How Much Do Vitamin D Supplements Affect Lifespan?

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  1. Has anyone seen the recent research on vitamins that includes vitamin D? According to that study, taking vitamin D if you aren’t deficient can promote cancer. Thoughts?

    1. Yes, I just read about that study in the New York Times Science section on April 16th. Would also like your thoughts on this most recent research about the dangers of supplementing with Vitamin D.

      1. No, that says vitamin D enhances CD31 which hinders T-cells from freaking out in those with autoimmune diseases. Then point of the study at the bottom:
        “Low vitamin D status has long being implicated as a significant risk factor for the development of several autoimmune diseases. Our study reveals one way in which vitamin D metabolites can dramatically influence the immune system.”

    2. It gets confusing. I was told this week by a doctor (who I thought was going to be great as her website states she specialises in nutrition)to go off my D supplements. But then she also said soy is bad for my hypothyroidism, that I should take cod liver oil for retinol because vitamin A is not converted well from plants and a c2+salts supplement is good for adrenal health. She is not a fan of vegan diet clearly, but not wanting to throw the baby out with the bath water has me investigating my beliefs about D again. Oh dear.

      1. Kerry,

        Start with the basics.

        Do your Vitamin D tests show that you have sufficient levels?

        If so, then her advice may not be contradictory.

        If not, then how low are your numbers?

        When this process gets confusing, slow down and don’t make decisions right away.

        Diet still trumps all of it, as far as I can see.

        Dr. Ornish and Dr. Barnard and Dr. Esselstyn all reversed conditions in studies based on dietary changes alone. If you look at the studies, you won’t find and paragraph where Dr. Ornish says, “Change your diet and while you are at it, could you get rid of your Vitamin D?” Nor did he say, “Could you take more Vitamin D so this health study can work?”

        As for the thyroid and soy issues, start with Dr. Greger’s soy videos since you are here. Then, look up Dr. Fuhrman or Dr. Barnard and search for a video from either of them on the topic.

        You can go to PubMed yourself. The studies are difficult to read, but if you start at the results and conclusion sections. Then, if the results are good, move up to the methodology.

        Note which type of study and who funded it.

        Then, go back to the doctors and look for their take on it.

        Stick with doctors you know because topics like soy are ridiculously confusing and using too many unknown doctors makes it worse.

  2. Follow-up- I went and found an article about the study. It reports that all-cause mortality and cancer risk is increased by supplementation of vitamin D in people who aren’t deficient.

    My two theories are that either we shouldn’t have excessive levels of any hormone in our body OR the causation is reversed. It could be that sicker people and/or people with worse lifestyle habits and diets take the vitamin D as “insurance” against getting sick which would cause a correlation between the two. The article study also looked at several other supplements.


      1. I understand that they feel like they have helped the situation when they threw out all of the people eating healthy foods and who had healthy lifestyles.

        But I don’t like having them be the population which I am learning from.

        I wish they could have done an analysis of the people who have healthy eating habits and healthy lifestyles and then compare the healthy people who supplemented versus the ones who didn’t.

        1. Also, we know that taking mega-doses can be toxic and I have multiple friends who have been taking mega-doses because of their doctors or naturopaths.

          That already confounds things.

          Dr. Fuhrman felt that correcting for dose already took away some of the risks. This one doesn’t seem to be mentioning dosage.

            1. Sydney

              I am not sure that this is true. Eskimoes (or whichever politically correct term is currently in fashion) and other sub-Arctic hunter gatheres are relatively dark-skinned. So were the first Europeans.

              There is a theory that those of us who have white skin do so as an adaptation to high cereal/grain diets.

              The dietary explanation may also account for why many North Asians eg Koreans are white skinned.

          1. Blair,

            Dr. McDougall’s point that mankind did survive without it for so many years is an idealistic one.

            For me, people used to work outside and used to have food scarcity more than food plenty. They were not nearly as obese as the current populations are.

            Dr. McDougall is giving good advice for young, thin, healthy people who get sunlight.

            Obese people who are not getting sunlight at all is what half of America might be right now.

        2. Hello,
          I absolutely agree with you. Do the healthy people suffer because of lack of vit.D.
          Indeed this should be checked too.

    1. My two theories are that either we shouldn’t have excessive levels of any hormone in our body OR the causation is reversed.
      Had my labs done a few days ago and was reading them earlier today. When looking at my D levels, they were Low at 16.4.

      The range for D at the VA is 30 – 80. From 10 to 30 is not considered dangerously low, but anything above 80 is considered toxic. Still, I’m doubling up on my D intake to try and get it in the lower end of range.

      1. Here is Dr. Fuhrman’s input. He recommends taking a modest amount.

        I am posting it because of his sentences:

        “This analysis did not take into account D2 vs. D3, and also did not group studies by the dose of vitamin D. A previous pooled analysis, which analyzed studies based on the dose of vitamin D, established that dose matters. This analysis took into account the actual intake of vitamin D, not just whether or not the person had been assigned to the supplement group. In this analysis, there was a 30 percent reduction in hip fracture rate at the highest level of vitamin D intake (792-2000 IU) in the supplement groups compared to the control groups.6-7 An earlier meta-analysis supports this idea, recommending 800 IU as the minimum effective dose.8”

      2. I am starting to doubt the testing of Vitamin D, it is a known fact that in Australia outdoor workers still show low Vitamin D levels, go figure.

  3. The information presented in the previous NF video “The Optimal Dose of Vitamin D Based on Natural Levels” is the kind of data that appears to be be very useful. In that study, researchers looked at what levels of vitamin D are found in people living in a natural equatorial environment where humans first evolved, and they found that the level was around 110 nmol/L or 45 ng/ml. That approach to determining what levels a person should have seems very reasonable to me, regardless of all the other studies showing benefits or harms. The human body and the interactions amongst all the nutrients are so complex, studying isolated nutrients is very tricky, to say the least!

    I do have my D levels checked every so often (hopefully, they are accurate) and adjust the supplementation accordingly. So far, I’m able to keep my D levels near the 45 ng/ml.

    1. Hal,

      Yes, the fact that the tests are not accurate makes it so important to have the standards.

      Ryan, if I got any sunlight at all, I might skip the supplements. The fact that I don’t, and the fact that they don’t have studies involving only people who are deficient, I don’t see any guideline other than Dr. Greger’s of whether it is better to stay deficient or not.

  4. So disappointed to see Dr. Greger going negative on vitamin D. Is this why the powers that be continue to allow him to get traction online? Might want to check in with the MS patients of the world before you embarrass yourself any further.

    1. Perhaps you should forward the randomized double-blind placebo-controlled long term scientific studies in support of that to Dr. Greger which, like the things he presents to us here, give irrefutable evidence of the claims he’s reporting on.

          1. Dabhar,

            Yes, but more accurately might be “This much we still don’t know now and there is nothing we can do about that part.”

      1. Tom, this is one topic where I have looked at so many PubMed articles and watched so many doctors’ videos and I don’t see that there is any consensus yet and it is hard to tell which evidence to believe.

  5. Studies I’ve read over the years suggest that D3 not be taken alone. It should be taken along with K2, Boron and Magnesium. These all work together synergistically to enhance D3’s health benefits.

  6. As a dialysis patient I would be interested in how you relate kidney failure to Vitamen D3 or Calcitroil intake and its effectiveness in supplementing normal D3 production that is no longer occurring in kidney failure patients.

    1. It is impossible for northerners to produce enough vitamin D from sunlight to get the optimal 45ng/ml level in their blood for much of the year. Are we all supposed to move south? Geography sometimes affects health in ways that require supplements. I live in an area that was rife with goiters before iodine supplementation.

    1. The NYT article is irrelevant to almost people as the poor woman also had no D binding protein in her blood, a very rare condition.

      I agree with McDougall that rational amounts of sunlight (no burning, even tanning unnecessary) is healthy. I am not confident in the advice never to supplement (it’s easy for him to get sunshine since he lives in california). I do think people have been scared into thinking getting any sun is risky. In my view, sunscreen itself is risky. dermatologists and sunscreen marketers live off of the public’s fear. People need to be reasonable about their activities.

      1. Gengo,

        Yes, when I lived in California, I got sun. Plus, I was young and flexibly employed and lived in a house with so many people that I didn’t have bills and we went camping every weekend and exposed more skin on our young bodies.

        I haven’t worn shorts or sun-bathed in decades. Where I live it is hot and it is wet heat so it is hard to breathe even. This past Summer there were weeks when it was too hot and too humid to go outside at 9 at night.

        I don’t feel comfortable using sunscreens and my walking path and patio are covered with shade by trees and I am inside by necessity during the daylight hours.

        Trying to go someplace to get sunlight at 6 or 7 at night I end up eating dinner at 9 PM and that throws everything off.

        1. I know that those are a list of excuses, but I can’t tolerate the heat in the Summer or trying to stand outside in the cold in the Winter trying to get 5 minutes of the sun just on my face.

          Plus, I am older and that means you have to spend longer to get the same effects. Plus, I am still not thin. Getting better, but it still would mean longer still.

          In the Spring, like now, I have long sleeves and long pants so again, it is just my face getting sun and in the Fall, it is just my face getting sun and in the Summer, I go back inside after 3 minutes, unless it is after direct sun and I think you need the sun to hit you for it to happen.

      2. “In my view, sunscreen itself is risky. dermatologists and sunscreen marketers live off of the public’s fear. People need to be reasonable about their activities.”
        – – – – – –

        I agree. I’ve never used the stuff. You just have to wear a hat and sunglasses, and avoid long exposures during the hours when the sun is at its highest. And forget sunbathing…who does that anymore?

        “Mad dogs and Englishmen go out in the noon-day sun.”


        1. YR,
          I recall that when a teenager, we’d grab a bottle of baby oil, slather it on and burn to a crisp. But that was so long ago, doctors were recommending smoking for relaxation, Still I have neighbors who trot out their lawn chairs etc and sunbath. Some people do not learn.

          1. Laughing, yes I had friends who used to do that on purpose.

            We used Coppertone. I can still smell it in my memory even though I haven’t used any sunscreens in years.

    2. Robert,

      Dr. McDougall said an interesting sentence.

      He said that 5 minutes in the sun with just face, arms and hands is enough for 3 seasons of the year and that you can skip getting it during the Winter because it is stored.

      Can we just get it through our car windshield while we drive?

      I only have a half mile commute, but I do drive to the grocery store most days.

      I don’t know what study that is based on. Are people who do that testing not deficient?

      I go back to the fact that I do know overweight night shift workers. Can they just drive to work and the sunset hitting their face through the windshield, is that enough?

      Or walking out to the car going to work and getting from the parking lot at work into the building?

      1. He said that 5 minutes in the sun with just face, arms and hands is enough for 3 seasons of the year and that you can skip getting it during the Winter because it is stored.
        Hadn’t heard about D storage for a season, anyway.

        But I would really like to know more about naturally getting enough. For a while in the winter I would enter my clear plastic sauna wearing a robe. When inside, I would open the robe and sit for roughly 30 minutes (about as long as I could stand the sometimes 110+ degree heat. That should have driven my D numbers up… unfortunately I wasn’t scheduled for lab work during that time and my recent numbers came in pretty low, even though I have been supplementing.

        So, does the plastic filter out the D producing rays?… does a tanning bed produce D?… do different parts of the body produce D in greater amounts?

        So many questions.

        1. Personally, I’d skip the face and get more sunshine on the legs and lower arms. Face and ears are the number one areas for melanoma, as I recall.

          1. Gengo,

            Not gonna happen.

            I wear long pants and sensible shoes.

            I work in a factory and cuts and welding burns and grease and oil and metal slivers are all part of the scenery.

            No shorts. Short sleeves only in July and August.

            But then, it is sweltering hot outside and cold in the air conditioning inside, so I sometimes have 3/4 sleeves even then.

      2. No, you cannot get it through the windshield because glass blocks UVB (what you want) and lets in UVA (what you don’t want). Dr Gregor has a video about it here somewhere.

  7. I would like Dr Greger to comment on this study that claims:

    “New study links excessive amounts of vitamin D to onset of atrial fibrillation”

    I believe that is exactly what had happend to me — I end up in emergency twice in February (february 4th and February 13th) of this year. For the first time ever I was diagnosed with Paroxysmal Atrial Fibrillation. I attribute my condition to two possible causes: 1. High dose of vitamin D. For the past few years I have been taking quite high dose of vitamin D3 – I also was on Mag Malate as well as on occasionally I would take other supplements too – such as B12 and low dose of calcium (around 300 mg with other minerals in the capsule). 2. For some reason I developed heartburns just a month or so before the onset of the Afib. So I sensed the Afib to be triggered by the heartburn… just a correlation, of course.

    Well, I stopped taking all supplements, except vitamin C ( I use it only when I feel a cold/flu in vicinity) at the beginning of March this year. So far I havn’t had Afib since Feb. 13th.

    There is a great deal of promotion for vitamin D supplementation – but, I believe we ought to be very careful about megadoses of any substance, including the vitamin D. For the similar argument, we ought to be careful about advice to drastically reduce intake of salt – – – we know that sodium and chloride (i.e., salt) are essential electrolytes, as are others electrolytes, such as potassium, calcium, magnesium — Our neurons would not be able to communicate without balanced level of electrolytes, nor would our heart would be able to beat (pump)…


    1. Dr. Greger has two videos on why Calcium supplements are harmful. Also, Magnesium supplements could cause low estrogen, which in turn would cause other health issues. Megadosing is never a good idea, and B12 and D3 are no exception. Dr. Greger has videos on that, too.

      1. Alexandra, you state that magnesium can cause low estrogen. I haven’t been able to find any studies that say that. Do you have reliable sources that show that?

        Most studies show that estrogen causes magnesium to be used more efficiently, and therefore more dietary magnesium is needed by postmenopausal women to avoid heart disease and bone loss.

    2. Mary,
      Sorry to hear you have had afib. I’ve had one episode of afib and atrial flutter, which was fortunately apparently cured by an atrial flutter ablation 7 years ago (apparently the afib episode was ‘parasitic’ on the flutter, which can be more reliably fixed by catheter ablation).

      How high were your D levels? According to that study, only participants with levels excessive levels, defined to be over 100 ng/ml had increased in risk.

      “In patients with low, low-normal, normal and high-normal levels of vitamin D there was no increased risk of atrial fibrillation. However, in those with excess levels of vitamin D there was a significant increased risk of atrial fibrillation. Atrial fibrillation risk was two and a half times greater in patients with excess levels of vitamin D compared to those with normal levels.”
      Few people jack their levels up over 100 ng/ml, which is independently known to be risky

      To me the moral is not to do anything in excess and when possible, rely on modest amounts of sunshine.

    3. I think taking supplements for long term is not healthy, you need to get all you need through diet. There are some foods that have Vitamin D too. But unless you have good gut bacteria it is possible that you do not absorb all your nutrients.

  8. Is there a list of recommended levels of things that one can check their blood tests against? Are the recommended levels that get returned with blood work (for things like folate, vitamin d, omega3/6, etc) good recommendations or just “normal” i.e. average i.e. typical unhealthy American levels?

    I’d like to see a list of Dr. Greger’s recommended levels for all these typical things.

    1. MSA- I remember from one of Dr. Greger’s videos that “normal” WBC count is higher than you want it to be unless you’re sick. WFPB individuals usually come in at the low end of normal or a bit under which seems to be ideal from a wellness perspective (unless it’s acting as an indicator that you have cancer)

    1. Yeah, I was reading about Vitamin D and autoimmune.

      Boy, the human studies not being specific enough is messing things up.

      They need to do one starting with overweight, night shift in Vermont who test low or something like that.

      I know that they can’t make the control group not supplement, but it just makes the whole issue have way too many shadows of doubt.

  9. “This effect appeared limited to vitamin D3, though, which is the type derived from plants and animals, not vitamin D2, which is the type derived from yeast and mushrooms.”

    What plants is D3 derived from?

    What about D3 from mushrooms?

  10. I take 20,000 IU’s of D3 a day together with magnesium L-threonate and K2 to treat my MS. I have my levels tested every 6 months and have never exceeded 92.

  11. I find it interesting if not difficult to believe that the researchers had someone 107 years old they could study for 4 years. And who didn’t or did have health issues to complicate results.

    1. There are over 180 people who have been verified to have lived long enough

      They verified 100 women and almost 100 men who lived over 111.

      There were 13 more who almost lived that long. Those died after passing 110 years and all of them lived over 310 days of the 111th year.

      I just don’t see the 18-year-olds being included in the same study as being helpful.

  12. How does this connect and influence (my understanding of what I’ve heard/read thus far) the suggestion of (taking 2,000 IU a day if you’re not going outside that much or have sunblock because you burn easily) vitamin D (like vitamin D and B12 are listed in the Daily Dozen App)

    1. Hi, Lisa Mathews! What you eat may affect how easily you burn in the sun. Foods such as seeded watermelon (eat the seeds!) may help with this. The lighter your skin, the less sun exposure you are likely to need to produce vitamin D. Other factors include the time of year and how far you live from the equator. It is best to get your vitamin D from sensible sun exposure, but supplements may be needed if that is not enough. You can find everything on this site related to vitamin D here:
      I hope that helps!

  13. Fifty-six randomized clinical trials involving nearly 100,000 people (mostly women) between the ages of 18 and 107 were randomized to four years of vitamin D supplements or sugar pills. Putting all the studies together showed those given vitamin D supplements lived longer and specifically had a lower risk of dying from cancer. This effect appeared limited to vitamin D3, though, which is the type derived from plants and animals, not vitamin D2, which is the type derived from yeast and mushrooms.


  14. This blog leaves me confused. I stopped taking Vitamin D supplements after listening to Dr. McDougall who is dead set against Vitamin D supplements. I do trust Dr. Mcdcougall and the difference of opinion here between him and Dr. Greger concerns me.

  15. Arun,

    Totally appreciate your confusion, and welcome to medicine. The field of Vitamin D in particular has seen its proponents make it out to be” the answer to everything”, it’s not. Unfortunately, this is much to the detriment of those who do benefit from some supplemental intake.

    With that said in testing “healthy” people we consistently see a lack of adequate vitamin d. Why, it’s a combination of lifestyle, genetic issues, the amount of food intake of fortified foods. In clinic we have urged our patients to get some additional sun exposure with limited results, generally due to time constraints and limited changes in the vitamin d levels for those who did get additional sun. Yes I’m in Oregon….

    My suggestion is to have your blood tested, be that by yourself, you don’t need permission from a health care provider unless you’re in NY, NJ or RI. The simple finger blood draw is both adequate and accurate.

    If the levels are less than 40 ng/ml you’re probably needing a bit more vitamin d. How much depends on multiple issues and only by using vitamin d3 and then retesting can you actually be certain what you need to raise your levels. What’s the optimal level….not sure the data’s in yet, but between the mid 40’s to 60’s seems to be the current sentiment.

    Dr. Alan Kadish moderator for Dr. Greger

  16. While nothing in the field of health medicine is absolutely proven to be true in all cases, I so appreciate Dr. Greger’s rigorous investigation of health-promoting ideas. For me, in my late 60’s, obese, and with a history of very poor sleep, no major medical issues aside from low thyroid (take meds), finding Vitamin D was a great help. I relax more deeply and my sleep (chronic early-wakefulness) has greatly improved. I now manage to fall back to sleep and routinely get seven hours, sometimes even eight! I take 2,000 a day of Vitamin D3.

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