Vitamin D Supplements

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The Amount of Vitamin D Supplementation I Recommend

Optimal Vitamin D Dose

Randomized, controlled clinical trials have found that vitamin D supplements extend one’s lifespan. What is the optimal dose? What blood level is associated with living longest? In my nine-part video series on vitamin D from 2011, I noted that the relationship between vitamin D levels and mortality appeared to be a U-shaped curve, meaning low levels of vitamin D were associated with increased mortality, but so were levels that were too high, with the apparent sweet spot around 75 or 80 nmol/L based on individual studies. (See Vitamin D and Mortality May Be a U-Shaped Curve for more on this.)

Why might higher vitamin D levels be associated with higher risk? Well, the study I profile in my video How Much Vitamin D Should You Take? was a population study, so we can’t be sure which came first. Maybe the higher vitamin D higher risk, or perhaps higher risk led to higher vitamin D levels, meaning maybe those who weren’t doing as well were prescribed vitamin D. Maybe it’s because it was a Scandinavian study, where individuals tend to take a lot of cod liver oil as a vitamin D supplement, one spoonful of which could exceed the tolerable upper daily limit of intake for vitamin A, which could have negative consequences.

Testing Vitamin D Levels

Anyway, the U-shaped curve is old data. An updated meta-analysis has shown that as population vitamin D levels go up, mortality appears to go down and stay down, which is good because then we don’t have to test to see if we’re hitting just the right level. Routine testing of vitamin D levels is not recommended. Why? Well, it costs money, and, in most people, levels come right up to where you want them with sufficient sun or supplementation, so what’s the point? As well, the test is not very good: Results can be all over the place. What happens when you send a single sample to a thousand different laboratories around the world? You’d perhaps expect a little variation, but results from the same sample ranged anywhere from less than 20 to over 100 nmol/L. Depending on what laboratory your doctor sent your blood sample to, the results could vary dramatically, so one could argue the test isn’t necessarily very helpful.

So, what’s a safe dose that will likely get us to the purported optimal level? A thousand units a day should get most people up to the target 75 nmol/L (which is 30 ng/mL), but by most people, researchers mean 50 percent of people. To get around 85 percent of the U.S. population up to 75 nmol/L would require 2,000 IU a day. Two thousand IU a day would shift the curve so that the average person would fall into the desired range without fear of toxicity. We can take too much vitamin D, however, but problems don’t tend to be seen until blood levels get up around 250 nmol/L, which would take consistent daily doses in excess of 10,000 IU.

Note that if you’re overweight, you may want to take 3,000 IU and even more than that if you’re obese. If you’re over age 70 and not getting enough sun, it may take 3,500 IU to get that same 85 percent chance of bumping up your levels above the target. Again, there’s no need for the average person to test and retest, since a few thousand IU per day should bring up almost everyone without risking toxicity.

Given this, why then did the Institute of Medicine set the Recommended Daily Allowance at 600 to 800 IU? In fact, official recommendations are all over the map, ranging from just 200 IU a day all the way up to 10,000 IU a day. I’ll try to cut through the confusion in my next post.

After all that work plowing through the new science, the same 2,000 IU per day recommendation I made in 2011 remains (for those not getting enough sun):

The other videos in this series include:

I also explore Vitamin D as it relates to specific diseases:

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.

92 responses to “The Amount of Vitamin D Supplementation I Recommend

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  1. I am laughing because I think you already shared that information, but everybody else messed my mind up so much that I needed this blog entry again.

    I am doing the 2000 per day, which you recommended, but this makes me think that I should go up a little because of not being ideal weight and because I get no sun.

    Thank you so much!

      1. Hi Nutrition Nut,

        I am a volunteer for Dr. Greger. Thank you so much for your question.

        The topic of vitamin D is among the most controversial in the field of nutrition. This is because the evidence is mixed, and it is hard to get high-quality data in the form of randomized controlled trials, since the conditions being looked at develop over the course of a lifetime, and most randomized controlled trials on vitamin D are a year to maybe 5-10 years at most.

        Overall, it doesn’t appear that there is much risk for negative health impacts of taking vitamin D supplements. Since there isn’t much of a risk to taking it, and we are unsure as to whether there is a benefit and if so, how much of a benefit there is, research seems to suggest that taking vitamin D supplementation may be best at this time.

        Getting vitamin D from the sun is also a very important way to get vitamin D, and very small amounts of time (10-15 minutes a day between 10am – 3pm) can enable your body to produce plenty of vitamin D. However, there are many places on earth at higher latitudes in which this is not possible for a significant part of the year, due to the low angle of the sun’s rays. In that case, a vitamin D supplement may be beneficial.

        There also may be benefits of getting sunlight aside from vitamin D, such as increasing CoQ10 levels (

        I know this isn’t all that clear, but the answer regarding whether we should take vitamin D supplements or not isn’t all that clear either. I hope this helped!

  2. I still strongly believe that individual testing is important. Use a reputable lab and go with it. I take 8000 i.u./day and that gets me to 45 ng/ml in testing by at least 3 different labs (QuestDiagnostics, ZRT mail in blood spot, and a local village lab in Ecuador).

    From your own 2016 video: The Optimal Dose of Vitamin D Based on Natural Levels

    ” It helps to think of vitamin D as what is truly is—a hormone, not a vitamin. So, if you think of it like that, then it would be reasonable to have normal levels.”

    You would not prescribe a single size dosage of levothyroxine for everyone, I think the same logic applies here.

    1. I agree that testing needs to be done because bodies absorb and process vitamin D differently, and there’s no way to know where you’re at unless you test. Here’s an organization that specializes in vitamin D, and they have all kinds of info on it:

      1. Agreed. One doc said take 800 ius. Another said 10k ius if you get sick often. So Ive been taking 10k ius. The first doc thought that was too high but when my blood tests came back, what I was taking made my Vitamin D levels good. I guess everyone absorps differently. 10k daily is perfect for me.

    2. Geoffrey,
      I agree. BM wife and I have had our levels tested annually for quite a few years. Our routine is very stable as is our supplementation (2000 IU per day vegan D3). Our respective test results are very consistent year after year, each between 45-53 ng/ml. Given the consistency of the results, no doubt we do not need to test annually.

  3. FWIW: 5,000 IU daily (occasionally skip a day) in one liquid droplet, along with supplements
    Boron, MK-7 and Magnesium (Citrate).
    During the warm months I also sunbathe for 10-15 minutes using no sunscreen (but cover the eyes with UV blockers). Been my routine for years.

        1. Except for surgery! Had an emergency prostatectomy (couldn’t pee and ready to burst) 20 years ago which probably saved my life.

    1. The concept of taking a higher dose and skipping days is interesting to me.

      The doctors who don’t think people should take it as a supplement say that the amount stored in the Summer can hold people over through the Winter.

      That isn’t applicable to me, but getting out of taking pills every day would make me happy.

      Can I go up to a mega dose and take one per week?

      I know that I have to go back to the videos.

        1. Deb, you remember right, all right. Mega-D once a week or month was an early theory but turned out to be not such a good idea.
          The concept of on / off rather than daily seems a good idea regarding supplements, if one is going to take them at all.
          The body gets a chance to ‘rest’ and also not get lazy, or dependent, as it were.
          After all, if you drench yourself with supplements every day why would your digestive tract bother keeping the mechanism of absorbing nutrients from food working optimally? This was knowledge a wise chiropractor / nutritionist gave me ages ago and still seems sound today: only 4-5 days a week rather than daily. (Of course this is supplements only. Rx is another subject altogether.

  4. I’m taking 5000 is per day and my blood value was at 44. I’m not sure what other factors play into it. I have felt my vitamin d levels were low because of how I felt. Maybe not a good vitamin source. I’m ideal weight.

  5. I live in the Pacific Northwest and don’t get enough sun from late Fall thru early Spring. I was taking 1000 IU’s per day. In October I started experiencing a lot of ankle and calf pain every day. I upped my dose to 2000 IU’s per day and the pain went away in about a week.

  6. Hello,

    I think the article is outdated… I have seen Dr. Gregger said on one of his live videos that he used to take 2000IU but it was wasn’t enough for him and he began taking 3000IU.
    I personally take D3 5000IU from non animal source, also I pushed a friend to take the same amount as me – she had D3 deficiency and it took her about 3-4 mounts to get to the minimum of 75 nmol/L in her blood tests.

  7. I’m taking 50,000 ui once a week of D2 prescribed by my doctor since my Vitamin D level is 21. The year before my Vit D was at around 15. I know my levels are very low but am I giving my body a toxic dose once a week?

      1. Mega-doses of 600,000 IU/injection in India led to kidney damage in 62 patients. They were 60-ish years old and had 4 to 28 injections.

        Young children, there is a case where 7 kids were given (900 000-4 000 000 U) and they got toxicity, so it isn’t just age.

        Each review states that the toxicity is rare, even in places like India where they are doing that ridiculous amount, but toxicity is jumping as more and more people do that type of process.

        I found one where the majority of 7-year-olds were Vitamin D insufficient in the Fall and Winter in a place where the exposure to sunlight was low at those times of the year, so if those children have problems, then, a much older person who isn’t outside at all should be supplementing.

        (Which was my theory all along.)

        I am going to try the 10,000 once per week. I would love to not have daily supplements.

        1. I don’t know if I made my point clearly enough.

          Many doctors here say that you can get enough sunlight in the Summer and it will carry you through the Winter, but in that study 7-year-olds had already become insufficient by the Fall, so the Summer Vitamin D bank didn’t get them very far.

    1. The D2 form is what doctors prefer only because they can prescribe it.
      But every study I’ve ever read recommends D3 over D2.
      The details are readily searchable.

  8. 6 nmol/L! My dermatologist saw something that prompted him to check my levels. The test came back 6 nmol/L. Reading this blog, I now wonder how accurate that was. But it must be low, because after taking 2,000 iu per day for three months, I was up to 23 nmol/L. And my GP said that is high enough. This blog convinces me that I need to take a lot more Vitamin D3.

    1. The test results and methods vary from lab to lab and can be wildly off.
      Always get a second test – this time from a different lab using a different assay.

      1. Dommy,
        I do not agree. Makes more sense to me to use the newer method(s) that have been shown to be more reliable, viz. liquid chromatography mass spectrometry (LC-MS/MS) assays. Just use a lab that uses LC-MS/MS.
        10 years of 25-hydroxyvitamin-D testing by LC-MS/MS-trends in vitamin-D deficiency and sufficiency

        “Quantification of 25(OH)D in serum is the best indicator of vitamin-D status of individuals. 25(OH)D accurately reflects the body’s vitamin-D stores. At present, LC-MS/MS assays offer the best accuracy for vitamin-D metabolite analysis. “

    1. ‘it is important to remember that excessive intake of any nutrient, including vitamin D, can cause toxic effects. Too much vitamin D can be harmful because it increases calcium levels, which can lead to calcinosis (the deposit of calcium salts in soft tissues, such as the kidneys, heart, or lungs) and hypercalcemia (high blood levels of calcium). The safe upper intake level of vitamin D for adults and children older than 8 years of age is 100 μg per day (4000 IU per day). Toxicity from too much vitamin D is more likely to occur from high intakes of dietary supplements ‘

  9. How is it possible to control for all the variables contributing to longevity? Selecting one thing to account for it is what advertisers do. As Dr. Colin Campbell says it’s an orchestra not just the trumpet player.

    1. Lee,

      You are right about that.

      Still, the reason they ask the question is because of observations, which were interesting.

      For instance, people who live in sunnier places have much lower rates of cancer than people who live in less sunny places.

      At that point, they try to control for variables like obesity and gender and skin color and age and diet, but the process is far from perfect.

      The fact is that they did try to account for those variables and there still has been a statistically significant result of improved mortality rates with D3.

      They can do more studies and longer studies but this is the information we have right now.

      1. I can use the breast cancer studies as an example.

        There are at least 17 studies saying that women who have higher blood levels of Vitamin D are significantly less likely to get cancer.

        An example” Women with 25(OH)D concentrations ≥40 ng/mL had a 67% lower risk of cancer than women with concentrations <20 ng/mL"

        Then, they try to control for everything and they do studies where they get results like this:

        "In 15 646 women (43%) who were not taking personal calcium or vitamin D supplements at randomization, calcium or vitamin D supplements significantly decreased the risk of total, breast, and invasive breast cancers by 14%-20%"

        Each study tells me that it is worth taking.

        1. I got back to the studies I had read last time Vitamin D came up.

          My mother died of breast cancer.

          These studies are why I take it:

          “Low levels of vitamin D were recorded among patients with breast cancer compared with healthy controls.31 Moreover, low vitamin D levels were common at breast cancer diagnosis and were associated with a poor prognosis; about 94% women with vitamin D level less than 20 ng/mL develop metastases and 73% die of the advanced disease.32 The 25(OH)D levels are significantly higher in patients with early-stage breast cancer compared with those with locally advanced or metastatic disease.33 The relationship between vitamin, breast cancer, and prognostic factors such as tumor stage, grade, size, lymph node involvement, and hormone receptors status is contradictory. The 25-hydroxyvitamin D level had a significant inverse association with metastatic breast cancer.34 Low vitamin D levels were associated with advanced stages of the disease, tumor size, and grade in postmenopausal patients,34 as well as in premenopausal women with triple-negative cancer.35 Insufficient and deficient 25(OH)D levels had a higher proportion of tumors with locally advanced and metastatic disease, more positive lymph node, a lower proportion of ER-positive, progesterone receptor–positive tumors, and higher Ki-67.36 Normal vitamin D patients had a higher frequency of luminal A (47.7%) and luminal B (32.2%) tumors when compared with patients with vitamin D insufficiency or deficiency.36 Similar results were reported by a South Korean study, which showed a significant association between low levels of 25(OH)D and poor outcome in breast cancer and triple-negative tumors.37”

          1. Thanks again, Deb, for your response. I’m sorry to learn about your loss. Dr. Greger in one of his annual talks mentioned that in a Harvard nurses’ study those who ate a lot of chicken had a higher incidence of breast cancer. A WFPB diet sounds good. Dr. H Gilbert Welch has youtube talks on mammograms and breast cancer well worth watching.

            1. Thanks, Lee!

              Yes, my mother was my favorite person ever.

              It was devastating losing her so young.

              Yes, I don’t do mammograms.

              Many of the women around me have had surgery for Stage 0 cancers.

              I have already outlived my mother and her father and my father’s parents, who all died young from cancer.

              My mother’s father died of cancer when my mother was less than a year old.

              The fact that I am still alive with how poor my diet has been and with how little Vitamin D I have been getting is already pretty amazing.

              1. Thanks, Deb, for your reply. I searched and like the other person could not find any mention of breast cancer and chicken. Although I don’t have a reference for this, I do remember vividly his mention of a small study that found a 90% reduction in the incidence of breast cancer. The study involved those who ate 15 mushrooms a month and drank 5-6 cups of green tea a day. My wife died 10 years ago from metastatic breast cancer. At the time I had no idea about the effects of nutrition despite my medical “education”. After my wife’s death I spent a couple years reeducating myself and concluded the only sensible diet was a WFPB one. I’ve been on it for 9 years and feel great without taking any meds or supplements. Of coarse, a series of one doesn’t mean much. Best wishes.

                1. Lee,

                  Yes, WFPB has good enough results that it gives peace of mind and decreases fear and those are better for quality of life no matter what the outcome.

                  When I was a young person, the prevailing logic was, “Everybody dies from something.”

                  Now, I have concepts of people reversing the need for kidney and heart transplants and cancer.

                  I am watching so many people go through traumatic end of life processes and I contrast that to watching my grandmother and greatgrandmother dying in their sleep at a more advanced age.

                  They never really had many medicines even.

                  My grandmother had one pill, which she needed every other day at 92.

                  I can’t afford the way everybody else is doing it.

                  I am watching people go 10’s of thousands of dollars into debt every year.

                  My cousin going on dialysis and going in and out of the hospital every other week at 65 has been an eye-opener.

                  I contrast him to my 90-year old aunt and uncle who are slowing down and may have had a little fender bender causing their children to swoop down and question whether they can drive.

                  They are watching the seasons go by. My aunt had a knee replacement, but she isn’t on medicines yet. My uncle is on some, but again, he is 90 years old and it is my 65-year-old relatives who are going to end up in convalescent homes from running out of money for health care.

                  1. My cousin is back in the hospital right now for flu and pneumonia.

                    I really do feel like it is every two weeks he goes back in and every two weeks my dearest friend goes back in.

                    Money for medical care, missing work, losing power, not having food, not having money for medicines and homelessness become the issues and my dear friend already has gone homeless a few times and has lost her electricity when it was 90-something degrees out. Another friend lost her electricity in the middle of the coldest part of Winter. I told her that they can’t do it and she said, “Yes, they can. I make too much money to qualify for not getting my power shut off.” She had her power shut off and then her pipes broke and it all started with medical.

  10. I’m 13-years post-op RNY gastric bypass. I get bloodwork done annually. Until this year, no issues. Now, it looks like I have critically-low vitamin D levels.

    I’m wondering how I should approach correcting this, as I’m certain the malabsorption issue will recur. I’m also curious to hear from from other gastric bypass / malabsorption folks.

    In case it matters, I’m Scotch-Irish; paler than pale with green eyes, middle-aged and living in the oft-gray Midwest.

    Thanks for any sunlight you can shed.

    1. Hello Heather, and thank you for your question,

      I’m a family medicine doc and also volunteer for Dr. Greger on this website. People who have had gastric bypass surgery (and Roux-en-Y is the most common type of bypass surgery) are indeed at risk for nutritional deficiencies. I just did a quick search and found this article from the Journal of the American Osteopathic Association from 2009:

      It says: “The most common deficiencies are vitamin B12, folate, zinc, iron, copper, calcium, and vitamin D and can lead to secondary problems, such as osteoporosis, Wernicke encephalopathy, anemia, and peripheral neuropathy.”

      If (as in your case) you have an extremely low vitamin D level, you need to take 50,000 Units per week, preferably of vitamin D3 (not D2), for 8 weeks. However, my pharmacology source (e-Pocrates) says that for people with malabsorption syndrome, you need to increase that dose by 2- to 3-fold. Maintenance dose is usually 2,000 IU per day, but with malabsorption, you might need 5,000 Units per day. Getting sunlight would reduce your required dose — but a light-skinned person like yourself needs to be careful about getting skin cancer!

      I recommend that you consult with an endocrinologist or gastroenterologist with knowledge about gastric bypass and its complications.

      Good luck with this.
      Health Support Volunteer for

  11. You didn’t mention the genetic factor.
    CYP2R1 rs2060793
    vitamin D
    binding protein
    vitamin D
    binding protein
    rs7041 etc.

      1. Marilyn Kaye:

        Thank you for the link, but:

        Another unreliable study:

        “Excessive consumption of red meat is accompanied by an increased ingestion of dietary fat with low level of polyunsaturated fatty acids (PUFA), and toxic substances formed during thermal treatment of meat.”

        Is it red meat that causes shortened telomeres? or is it excessive consumption of red meat? or is it ingestion of dairy fat? or is it cooking red meat on high heat?

        These “studies” irritate and frustrate me considerably.

    1. The study where Dr. Ornish’s diet lengthened telomeres it was increasing vegetables and fruits and lowering saturated fats.

      He listed the top 5 foods on his website as flax, spinach, mushrooms, berries, and oats, but anti-inflammatory vegetables and spices would be on the list.

    1. Syndey,
      If what the doc meant by the odd phrase “dissolve bones” was “bone resorption”, then there does appear to be that possibility, at least in animal studies. But what level was the doctor talking about?
      High-Dose Vitamin D: Helpful or Harmful?

      “How might high-dose vitamin D increase the risk of fracture? Animal studies suggest that high-dose vitamin D might increase bone resorption.”
      The key issue is what amount might increase adverse outcomes of whatever kind. Dr. Greger has addressed this.

  12. There has been a lot of research done by doctor’s where 50ng- 100ng is optimal for immune system and cancer , I was deficient only 16ng , im 75ng now taking 10,000iu D3 daily with Magnesium Malate 425 mg and vitamin K2 mk-7 145mcg its hard to become toxic when you are taking the cofactors they help absorb and direct calcium to the right places instead of the artiries , that’s how alot have heart attacks to much calcium not to much vitamin D3.

  13. It’s really not easy to find out what to believe. Health authorities don’t agree. Recommendations for D-vitamin in Canada is between 15 mcg (600 IU) and 100 mcg (4000 IU), in Denmark 10 mcg (400 IU) which makes it quite difficult to figure out. I spent many hours and days to find out. Litterature and researchers mostly say 2000 IU to 7000 IU. Surveys on and pubmed mainly agree with Michael Greger that about 2000 IU is a safe dosis, but more might even be better. If you’re working most of your time indoor you probably have D vitamin defiency. Do you life in Northern hemisphere chances of defiency is bigger.

    1. My take: get some reasonable sun exposure (assuming no contraindications), which means no burning, not even tanning required, and if needed take the smallest dose that generally keeps your blood levels to the 30ng/ml – 45 ng/ml ‘sweet spot’. This approach reduces the amount of D supplement needed and helps your body do what it knows how to do. Then stop worrying about it. Loading up on a supplement to reach some speculative optimal level strikes me as foolhardy.

    1. Phil,

      It depends on how you define “waste of time” because what that means is that it didn’t prevent cancer. It did, however, improve the mortality of the cancer patients, particularly the ones who were vulnerable. I believe it even did prevent cancer with dark-skinned patients if we are speaking about the same recent study. To me, that means it might help the Northern Hemisphere people and morbidly obese people and possibly the elderly. Those groups are ones who need so much more sun exposure than they can get most of the year.

      Dr. Fuhrman pointed out that the reviews of the evidence neglected certain things. The first being that studies have been done with D2 and with D3 and those had different results. The second being that some of the studies had the people take mega-doses well above what Dr. Greger is speaking about and some didn’t have the people take enough. The third concept is that the studies haven’t dealt with correcting a deficiency. People in the studies were supplementing whether they had sufficient D levels or not.

      Also, the studies were whether it would prevent cancer or not and it did but not at a statistically significant level, except in the dark-skinned community.

      If you get enough sunlight, you don’t need the supplement and if you can adjust for that, go ahead.

      As a woman, who lives in the Northeast, who is still overweight and whose mother died of breast cancer, I don’t throw out the fact that the results were mildly positive in the first place.

      Plus, Cancer isn’t the only thing Vitamin D is involved in. It has helped in pain studies and has protected DNA in animals and other concepts.

      The concept of calling something useless because it doesn’t prevent cancer would be like calling Green Tea useless (which also didn’t prevent cancer in studies, but it is not worthless.)

    1. Hello Wade,

      While consuming B6 from food has never lead to toxicity (at least in the published research), long term supplementation can cause toxicity, which manifests as neurological symptoms. B6 is a water soluble nutrient, so if you’re only consuming B6 from foods at their natural concentrations, then you will excrete the excess in your urine.

      I hope this helps,

      Matt, Health Support

    2. Wade,

      Dr. McDougall has a video explaining the mechanism of why it can be toxic getting B-6 from supplements other than food. Check YouTube.

  14. Dear Moderators,
    I agree with Ted
    Please include ug equivalents in the article to avoid confusion,especially since recommendations vary in different countries between IU ,IE and RDI it can get confusing.

    1. Great post, YR. I am not surprised as the same is true for e.g. late stage Alzheimer’s disease [LOAD]. At one point the APOES ε4 allele was the only known risk factor for LOAD.

      “Genes associated with Alzheimer’s disease: an overview and current status 2016

      Genome-wide association studies have revolutionized genetic research and have identified over 20 genetic loci associated with late-onset AD. Recently, next-generation sequencing technologies have enabled the identification of rare disease variants, including unmasking small mutations with intermediate risk of AD in PLD3, TREM2, UNC5C, AKAP9, and ADAM10.”

      Science rules. Premature application can be misleading.

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  16. Question I would love someone (especially from to answer): if you’re getting regular sunlight (about 10 min a day, no shirt, shorts, while walking in the dog in Las Vegas), should you reduce your vitamin D intake? It seems from past tests I’m in optimal levels with 2,000 IU of vitamin D when I’m not getting regular sun but I’m OK with 1,000 IU when I am getting regular sun.

      1. You are not the only one, Scott to wonder about that question, yet research hasn’t come up with a convincing answer yet. Considering that Vit D is responsible for important body functions (See ) and reliably obtaining then measuring how much Vit D you are making from sunshine is difficult, most research-based advice errs on recommendations for supplements. There has been no study of individuals who are clearly obtaining adequate sunshine as compared to those who don’t who supplement to see which group lives longer (the primary benefit discovered to date of supplementation.) You can read complex discussions both here and other websites with most experts including Dr. Greger citing potential benefits and minimal risks, recommending Vit D supplementation. See this site for more explanation:

    1. Please see reply below which unfortunately indicates there appears to be no specific research yet to clarify if those obtaining plenty of sunshine can just depend on sunshine alone. As indicated both consistently obtaining then reliably measuring Vit D is challenging –another reason why most experts recommend supplementation despite sun exposure. You are ahead of the curve by testing during times when you are getting regular sun and when you are not, so relying on the testing would indicate the supplement may not be needed. Others would argue that the risks of inadequate Vit D (& possible unreliable testing results) tip the balance toward supplementation.

  17. I live in Canada, have MS, and have been taking 5,000 I.U. D3 for several years now. Are there circumstances – such as having MS – when one might want to supplement with a higher dose than 2,000 I.U.? I know that there’s no science to back up the amount I’m taking beyond suggestions that low Vitamin D might somehow be linked to MS (ergo – is it helpful to supplement with a higher amount?)

    1. I found this article that may be helpful although it concludes as you indicated that the science is not there to recommend a specific higher dose of Vit D to treat MS: (“…evidence isn’t conclusive. Vitamin D supplementation in people with MS appears to be safe but at high doses can lead to changes in calcium levels. More research is needed…”) You want to be aware that very high doses can lead to problems so monitor carefully if you decide to take a higher dose than recommended for general population.

      1. Thank you so much for your response (and research!). I always wear sunscreen – even on rainy days! – and try to minimize time in the sun (I did a lot of sun-damage to my skin in the ‘good old days’). My MS is more benign than active, and I sometimes wonder whether my life-long vegetarian/vegan diet and – for the last 10+ years – high dose intake of vitamin D have helped contribute OR if I’m just very, very lucky.

  18. According to a report ( on a recently published nutrition study (,

    “the team found indications that use of vitamin D supplements by individuals with no sign of vitamin D deficiency may be associated with an increased risk of death from all causes including cancer. Further research on this potential connection is needed.”

    I am surprised that there is not discussion of this recent study regarding vitamin D consumption here. It would be positive if a professional would review the study in the Annals of Internal Medicine and report back to this community. To get more than an abstract online, it appears one has to be a member.

    1. NN,
      Sure it could be more confusing.

      1. If feasible, get some very limited sun exposure per what’s said in the article without sunscreen and ignore the dermatologists. Don’t expose your face or ears. Don’t get burned, You don’t have to even get tan. From that article:

      “The best way to be sure to get enough of the nutrient is to go outside and get some sun. When the sun’s ultraviolet rays hit your skin, that light triggers the production of vitamin D in your body. To benefit, you don’t need to — and, because of skin cancer risk, shouldn’t — sunbathe. Instead, Todorov recommends only 10 to 15 minutes, two to three times a week between 10 a.m. and 3 p.m.

      “Expose yourself, then put on your sunscreen,” she says.”

      2. Else or in addition, take a reasonable supplement as Dr. G recommends.

      3. Optional (but I do it): get tested by a reputable lab to make sure you are between 30 ng/ml and 50 ng/ml.

      4. Then, kick back and stop worrying about.

  19. The update to the Daily Dozen app (2019-12-12) has removed the checkbox for recording Vitamin D supplement intake but retains the Vitamin B12 box. Does that mean that Dr Gregor no longer recommends Vitamin D?

  20. Dear Dr Gregor

    I would like to start taking vitamin D supplements but I also understand that the supplement industry is poorly regulated, dosages can be inconsistent and supplements can have contaminants. What is the best way to protect myself against these risks if I want to take a supplement?


  21. Kamil,

    First the majority of manufactures are very well-run firms with quality controls that oftentimes match or exceed the pharmaceutical industry. That’s not to say that some firms are grossly out of spec and not unlike any other product the buyer needs to beware and do some basic due diligence.

    For a more in-depth take on this see as one example: I think you’d be surprised by the number of supplement firms who do adhere to quality controls that would meet your requirements. Price is one of the driving factors and when you look at the firms that cut corners often times this is one of the issues. The key with vitamin d is two considerations.

    When you take vitamin d with a meal containing fat the absorption is substantially higher and two how much do you need. Testing is inexpensive and can be done via a simple home finger stick test. Clearly for the majority of us we will need some supplementation due to our home and office time that limits sun exposure, etc.

    Dr. Alan Kadish moderator for Dr. Greger

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