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Should You Take A Vitamin D Supplement - Dr Holick transcript Oct 2022

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Should You Take A Vitamin D Supplement? With Dr Michael Holick

YouTube AUDIO 44 minute


Transcript

0:00:08.0 Tucker: Welcome back to season two of What Your GP Doesn't Tell You, the podcast for both doctors and patients with me, Liz Tucker. Today I'm joined by Dr. Michael Holick, a pioneer in vitamin D science. He spent a lifetime researching and exploring what he believes are the vitamin's potential life-changing benefits. As a graduate student, Michael was the first to identify the circulating form of vitamin D in our blood, which doctors now use to measure our vitamin D levels, and he went on to isolate and identify the active form of vitamin D known as 1,25-Dihydroxyvitamin D3.

0:00:48.4 Tucker: Michael argues that across the world, guidelines for the amount of vitamin D we need are simply too low and that many of us, even those of us living in a hot climate, will not be able to get enough of the vitamin we need from sunlight alone. He contends that not only do we need vitamin D for bone health, we also need it for many other critical functions too. Without enough of it, Michael says our immune system can't operate effectively, and that a lack of vitamin D is linked to a wide range of other health conditions from heart disease and depression to autoimmune illnesses and cancer. In this interview, Michael discusses why he believes vitamin D is so essential and reveals the levels he thinks we all need to take for optimal health.

0:01:34.9 Tucker: Before we get to Michael's interview, if you enjoy this podcast and would like to find out more, you can sign up to my Substack account, which is liztucker.substack.com, go to my website to sign up for the podcast mailing list at whatyourgpdoesnttellyou.com and follow me on Twitter @lizctucker. If you would like to financially support the podcast, I'd really appreciate it as a huge amount of work goes into both the research and production of this pod, even a small amount a month makes a huge difference. You can provide support at patreon.com/WhatYourGPDoesntTellYou or via my website, which as I mentioned earlier, is whatyourgpdoesnttellyou.com. And now back to the interview with Michael.

0:02:26.9 Tucker: Dr. Michael F. Holick is a Professor of Medicine, Physiology and Biophysics. He's the Director of the General Clinical Research Unit, Director of the Bone Health Care Clinic, and Director of the Heliotherapy, Light and Skin Research Centre at Boston University Medical Center. Michael and I started off our conversation discussing when doctors first realized that a lack of vitamin D could have very serious consequences for our health. Here's the interview.

0:02:57.0 Tucker: Michael, thank you very much indeed for joining the podcast today.

0:03:01.7 Holick: My pleasure.

Rickets might be caused by lack of sunshine – 1822

0:03:02.8 Tucker: We know that when we don't get enough vitamin D, problems can develop. I think it was originally suggested back in 1822 that a lack of sunlight could cause a bone disease known as rickets.
0:03:15.7 Holick: Yeah, if you go back in history, in the 1600s, children living in Glasgow, Scotland, where coal was being burned heavily and so they had the pall of pollution, and because living so far north and living in very close quarters where the buildings were in close proximity, the children were never exposed to any sunlight and they developed rickets. It was estimated by the turn of the 19th century that probably 80%-90% of children in northern Europe, as well as even in the northern United States, had evidence for rickets.

0:03:51.0 Tucker: Michael, can you explain exactly what rickets is?

0:03:54.4 Holick: Rickets is a bone disease which causes bowing or knock knees in children and it also causes growth retardation. When children are starting to walk, gravity is pushing down, they have hardly any mineral in their bones which is why the bones either bow out or turn inward. And then the other point is that often the wrists are wider at the joints, and the reason is that vitamin D plays a critical role in the maturation of the cells that produce the collagen, and if they don't have vitamin D around, they become very haphazard and as a result they grow outward. That's the classic reason for why they have what's called the Rachitic rosary, so at the costochondral junctions of the rib cage, they're kind of bulging out and around the wrists, all of those are classic signs for rickets.

0:04:48.0 Tucker: Although rickets was first diagnosed in the 19th century, it's another 100 years before we start treating it.

0:04:55.7 Holick: Correct. It's really remarkable, like you said, 1822 is Dr. Śniadecki and it turns out that he was a physician scientist and he realized something, and that is that children living in Warsaw had a high incidence of rickets, but children living in the rural areas outside of Warsaw on the farms, they didn't. And so he made the observation in 1822, it was strong and obvious the influence of sun on preventing rickets. It was Palm in 1890s that started to appreciate what Śniadecki had said, and he also made another interesting observation, which is that living in London compared to living in India, which is an incredibly poor country, children in London were at higher risk of having rickets than very, very poor third world countries. And so he concluded the same thing, recommended sunbathing as a prevention for rickets, and then finally it was Hess and Unger, 1921, took some children, put them on a roof of a New York City hospital and demonstrated marked improvement in the X-ray mineralization and basically curing rickets.

0:06:07.0 Tucker: Now evidence suggests that clearly vitamin D important for skeletal diseases but from a range of illnesses, from MS, infections, blood pressure and even cancers.

Almost every cell needs Vitamin D

0:06:18.8 Holick: Correct. And so we know that essentially every tissue and cell in your body has a vitamin D receptor. Mother nature wouldn't put them there if they weren't having a biologic effect. We and many others had shown that if you grew prostate cancer cells or colon cancer cells or breast cancer cells that have a vitamin D receptor and you add the active form, 1,25-Dihydroxyvitamin D, you inhibited the cancer growth and they began to mature. And so that was the introduction to the concept that vitamin D may be playing a role in reducing risk for deadly cancers.

0:07:00.0 Holick: We also realized that your blood vessels have a vitamin D receptor and there's good evidence that vitamin D can help to maintain blood pressure, keeping it a little bit lower by causing an effect on the vascular system. Your heart has a vitamin D receptor, we think that it also plays a role, and it turns out that the cells that lay down the cholesterol plaque for atherosclerosis, that 1,25-Dihydroxyvitamin D in culture prevents that. The brain has a vitamin D receptor and there's good evidence, association studies, that depression and neurocognitive dysfunction, Alzheimer's disease have been related to vitamin D deficiency.

Immune cells have Vitamin D receptors

0:07:49.0 Holick: Finally, it turns out that the immune cells have a vitamin D receptor. We now know that children living in northern latitudes are more likely to get Type 1 diabetes. So there's a lot of evidence linking vitamin D with immune function. In fact, the recent observation from the VITAL study where 25,000 adults getting 2000 units of vitamin D a day followed for more than five years reduced risk of autoimmune disorders like psoriasis, rheumatoid arthritis by 22%.

0:08:31.5 Tucker: Of course, the problem is when one looks at a lot of these studies, what the critics would say is a lot of them are correlation, not necessarily causation.

0:08:40.0 Holick: Right. The VITAL study did find 25% reduced risk of dying of colorectal cancer. That's pretty impressive. And now the VITAL study is saying that 22% reduced risk of autoimmune disorders.

0:08:57.8 Tucker: That does seem to be a problem for those of us living in the northern hemisphere, that actually, for a large part of the year, it's just not possible for us to get enough vitamin D from the sun.

Vitamin D – from mid-day sun

0:09:07.5 Holick: Correct. We showed many years ago because I wanted to know what time of day, season, latitude, degree of skin pigmentation had on vitamin D production. And so we showed that if you live in Boston, for example, you can't make essentially any vitamin D from November until next March, and if you live in Edmonton, Canada, it's from about end of September until end of April, six months of the year. We did a study in northern Norway and showed exactly the same thing. It has to do with the zenith angle of the sun. What's really remarkable is that we also did a study in Panama, done studies in India, if you got out early in the morning, eight o'clock in the morning with the sun shining brightly at the equator, you make no vitamin D. It's only between about 10:00 AM until 3:00 PM, 2:00-3:00 PM, that's the maximum time that you're making vitamin D. If you're not out there around 9:00, beginning at around nine o'clock, but 10 o'clock to two o'clock, you can't make any vitamin D.

0:10:09.3 Tucker: Of course, for so long, particularly people who are very fair like me, we've been told to stay out of the sun. And so whenever I do go out in the sun, I've got factor 50 plastered on me, so my chance of getting vitamin D from the sun is going to be very reduced.

0:10:24.0 Holick: SPF of 50 applied properly reduces your ability by 99%, and so even the British Dermatology Society does recommend some sensible sun exposure. There was a very nice study done by UK docs, and they showed that very light-skinned people like you, when exposed to sunlight, simulated sunlight in a laboratory, it's true that it does make vitamin D and it will damage your skin, but what they also showed very nicely, after about six weeks, they could not show any additional DNA damage. And so we think that the reason is that mother nature designed us to be exposed to sunlight and that if you are damaging your DNA, you repair it. And so we always recommend sensible sun exposure, definitely protect your face, it's the most sun exposed, most sun damaged, but arms, legs, abdomen and back is not an issue. It does not really significant increased risk for non-melanoma skin cancer. Just an FYI, is that everybody worries about melanoma 'cause it's the most deadly form. Most melanomas occur on the least sun exposed areas and occupational sun exposure decreases your risk for melanoma.

0:11:46.6 Tucker: Michael, what's your recommendation then for what's an appropriate level of sun exposure?

0:11:51.5 Holick: Well, that's the problem. Time of day, season, latitude, degree of skin pigmentation. There's only one thing to do, we developed an app and so you can go to dminder, D-M-I-N-D-E-R.I-N-F-O, it's free, on your Android and on your iPhone. It'll tell you anywhere on this planet when you could begin making vitamin D, how much vitamin D you can make. It takes into account your skin pigmentation and it warns you to get out of the sun so you don't get a sunburn because you can't figure it out. If you know, for example, that you're gonna go outside in June, full sun and you're gonna get a mild pinkness to your skin 24 hours later, it's called the minimal erythema dose. We recommend to be out there for about 50% of the time.

Can get sunburned by UVA, even in October

0:12:38.7 Tucker: Well, I've been sunburnt in London in October, which people didn't believe me till the next day, but it was true.

0:12:43.8 Holick: Right. It also turns out that even though it's UVB that makes vitamin D and is most damaging and causing sunburn, UVA will do the same. And so as you're going into fall, even in the UK, you're getting blasted by UVA radiation and that can definitely cause a sunburn.

0:13:06.0 Tucker: I think one of the complications is, generally speaking, governmental recommendations for the levels of vitamin D we should take seem to be predicated on preventing us getting rickets, whereas a lot of the neurologists I talked to and other groups actually privately will take much higher doses, but they tell me I can't recommend that to my patients because it's not in the government guidelines.

Need at least 30 ng of vitamin D to prevent bone problem in adults

0:13:28.7 Holick: Correct. The bottom line has been that your 25-hydroxyvitamin D should be between 25 and 37 nmol/L but the data, in my opinion, show very clearly, and the Institute of Medicine concluded the same, at a minimum, it should be 50 nmol/L. If you look at all the studies, there was a study done in Germany of 675 healthy German adults that died in an accident, and they took a piece of their bone and they got their blood, and they related their blood level of 25-hydroxy D to evidence of vitamin D deficiency osteomalacia, the counterpart of rickets in children. They showed that to guarantee no vitamin D deficiency in your bones, that you needed to have a blood level of 75 nmol/L or 30 ng/mL, and that's why the Endocrine Society practice guidelines recommends that.

His patients: 3,000-5000 IU ==> 40-60 ng/mL

0:14:30.7 Holick: For all of my patients, I've always had them taking minimum 1500-2000 units of vitamin D a day. That will get your blood level in the range of about 30, and that many of my patients were on 3000-5000 units a day, their levels then are about 40-60 ng/mL. That's in my opinion, the ideal range. I personally take 6000. I use daily. My blood level is in the range of about 170-180 nmol/L.

0:15:05.7 Tucker: And these are international units?

0:15:07.7 Holick: Correct. These are international units.

0:15:10.0 Tucker: Anybody can go to their GP and ask to get their vitamin D level measured so they know what their baseline is before they start taking something?

Obese need 2-3 X more vitamin D

0:15:17.6 Holick: Bottom line is, we do not recommend getting a blood level, and the reason is, A, it's expensive, and B, depending upon who's doing it, may not be reliable. We know from our work and others that if you take 1000 units a day, your blood level will be in the range of about 25-30 ng/mL, but 1500-2000 units a day will get you above that. But if you are obese with a BMI of greater than 30, it dilutes in your body fat, and as a result, you need to take more. The data from a Canadian study showed, 2-3 times more in order to satisfy that requirement.

0:16:04.7 Tucker: You've suggested that there's an unrecognized epidemic of vitamin D deficiency in the over 50s, which has led to people being wrongly diagnosed with a range of illnesses such as fibromyalgia, depression, and even in one case, ALS, or as it's known in the UK, motor neurone disease.

ALS symptoms might result from low Vitamin D

0:16:23.9 Holick: Right. There are two pieces to this puzzle. The first is that it is true, and studies have shown, association studies, if you're really very significantly vitamin D deficient, higher risk of depression, neurocognitive dysfunction. The ALS story is a different story. If you're severely vitamin D deficient, it can cause motor neurone disease that looks like ALS. It was the physician realizing the patient was vitamin D deficient and had this motor neurone disorder, and so...
  ALS fought by vitamin D - many studies

0:16:58.6 Tucker: So a disorder that mimics the symptoms of ALS.

0:17:10.6 Holick: Exactly. When the vitamin D deficiency was corrected, so too were those neuromuscular dysfunction.

0:17:10.7 Tucker: You were suggesting the vitamin D deficiency may actually be increasing.

0:17:14.7 Holick: In my opinion, and based on all the literature, depending upon where you have that numbers, whether it should be 50 nmol/L or 75 nmol/L. At 50 nmol/L, we estimate 40% of the world's population is less than 50 nmol/L, and 60% is less than 75 nmol/L. We think that there's a hierarchy for vitamin D in the sense that lower blood level at around 50 nmol/L probably will help to maintain your calcium metabolism but you need to be above 75 nmol/L or 30 ng/mL to have the function in your immune cells and other cells in the body.

1200 genes changed by 10,000 IU of Vitamin D/day

0:18:07.4 Holick: We did a study several years ago when we showed healthy adults that were vitamin D deficient or insufficient, and gave them either 600, 4000 or 10,000 units a day for half a year. What we did was, we did expression analysis to see how many genes were being influenced at the beginning of the trial and at the end of the trial. What's remarkable is that even on 600 units a day, which is not adequate for maximum bone health, still about 200-300 genes were being influenced. On 4000 units a day, about 300, but on 10,000 units a day, over 1200 genes in your immune system were being influenced. And we did not see any toxicity.

Endocrine society recommendations to get to 30ng level

0:18:58.1 Holick: So we think that vitamin D is much safer than we were all taught because we were taught that it was a fat-soluble vitamin, highly toxic, especially to infants, and it turns out none of that's correct. The recommendation that I have is the Endocrine Society practice guidelines, which make recommendations to physicians around the world, especially endocrinologists. I chair that committee and all the members of the committee were experts in vitamin D, pediatric, adult, geriatric vitamin D. We recommended the following: For infants, 400-1000 units a day, children 600-1000 units a day and adults 1500-2000 units a day. If you're obese, BMI of greater than 30, you need to take 2-3 times more.

0:19:51.4 Tucker: Can I ask, do you have any financial interests in vitamin D? What are your commercial interests in the area?

0:19:58.9 Holick: Right. I'm a consultant for Biogena and basically get very little compensation. I have a grant from Carbogen Amcis, where we've shown very nicely that 25-hydroxyvitamin D is very effective in raising your blood levels. I also am a consultant for Solius. It's a company that's developing a light box for people to actually walk in and to throw, to turn on for a couple of minutes so you can make your vitamin D. It's available now in Canada. It's been approved by Canada Health. We have a study underway here in the United States in the Boston University School of Medicine. Those are the major ones, and then I'm on the speakers bureau for Sanofi and several other companies.

0:20:45.6 Tucker: Thanks for clarifying that. You mentioned at the start the fact that there are vitamin D receptors in cells across the body. What's the potential mechanism for vitamin D, if it does, in terms of reducing the risk of cancer such as colon, breast, and a number of other cancers?

Vitamin D also causes apoptosis (cell death), which fights many diseases

0:21:01.4 Holick: What we think is happening is that the cell has the capacity to activate vitamin D, and if the cell is starting to go nuts and become malignant, it has a couple of choices. 1,25 D can try to help prevent that from happening or if it becomes malignant, we know that the active form of vitamin D causes apoptosis, which means it causes the cell to start to die. We think that that's the major reason why there's these association studies suggesting that improvement in vitamin D status can reduce risk of many deadly cancers, and Dr. Grant has been in the forefront of demonstrating this.
   Cleaning out poor cells (autophagy) is increased by Vitamin D and fasting – Jan 2022

0:21:43.8 Tucker: Basically, vitamin D is causing the cancerous cells to die?

0:21:48.1 Holick: Correct. That's what we think because all of the work that's done in cultured cells suggests that, that it induces genes for apoptosis, for cell death. It'll also take leukemic cells and help make them look normal again. They'll begin to mature. So there's a variety of mechanisms that vitamin D has. One of the other ones, which is interesting, is that if the cancer does start to grow, it needs new nutrition and it needs more blood vessels, and what vitamin D does through its active form is shut that down.

0:22:20.5 Tucker: But so far with research, we're still looking at correlation, not causation, although there are theories about what that causation might be.

A 5 year study found a 25% reduction in Cancer deaths with Vitamin D & Omega-3

0:22:29.8 Holick: Correct. Cancers take usually a while to develop, and even the vital study, Dr. Manson said that, yeah, we did five years, we didn't see any reduced risk of developing cancer, but sometimes these cancers take a longer period of time. What they did find, which I think is remarkable, a 25% statistically significant reduced risk of dying from the cancer.
   2,000 IU of vitamin D and Omega-3 reduced Cancer death rate bv 1.7X (normal weight) – VITAL RCT Nov 2020

0:22:58.6 Tucker: For those who say that the problem is many of the studies are not randomized controlled trials, and that's a big weakness, what's your response?

Some 800 IU vitamin D pills contain 1200 IU to deal with shelf life

0:23:06.9 Holick: Herein lies the problem with most of the studies these days because everybody agrees that you can't have a vitamin D-deficient person remain vitamin D-deficient. As a result, they always have the control group getting vitamin D. The VITAL study, for example, they were permitted, all of the ones in the control group, 800 units of vitamin D a day, but here's the problem. Manufacturers put in 20 up to 50% more vitamin D in the pill to maintain shelf life. So it could be, for the vital study, for example, that they were comparing 1200 units a day versus 2000 units a day. That could be one of the explanations for why so few studies are beginning to show any benefit because you're already giving vitamin D to the control group.

0:24:03.9 Tucker: As an outsider, one of the issues it seems to me with the studies are very different levels of vitamin D are sometimes measured and following your argument that actually the very low levels that are sometimes recommended are not enough to see the significant benefits. If the studies are done at these lower levels then you're not potentially gonna get the benefits?

0:24:25.9 Holick: Correct.

Vitamin D and falling controversy

0:24:27.2 Tucker: Now Michael, one of the points that skeptics of vitamin D have raised is a genetic study of fractures in over half a million people. This found that there was no effect of vitamin D or milk drinking on the risk of a bone break. And that when you factor in poor quality studies, this shows there's not actually an effect on preventing either fractures or falls, and indeed that the overuse of vitamin D supplements has been linked in several trials to increased falls and fractures.

0:24:58.7 Holick: I'm familiar with this. It turns out that studies that have used physiologic doses of vitamin D have not ever demonstrated, in my opinion, increased falls. In fact, we did a study in a nursing home and we took vitamin D-deficient elders, and we gave them 400 and 600 units a day. Those that raised their blood level of 25 hydroxy D reduced risk of falling by 72%, and we followed them. We followed each of the individuals. Unlike a lot of the studies where they simply send it out to them and then they ask them to write it down as to whether you fell or not.

0:25:38.4 Holick: There was one study that was done by a Swiss group where what they did was that they advertised for their study, and they said, if you had fallen in the past year, you're welcome to be part of the study. And so a lot of people signed up. Well, the problem is if 100% of them fell the year before and now less than 100% fell the next year, you have to wonder whether or not you were still having a benefit. Other studies have shown that if you give like 500,000 units of vitamin D, this huge dose, that it increased risk of fractures and falls. My argument is that often patients that are vitamin D-deficient, if they have osteomalacia, they have aches and pains in their bones and muscles. They don't want to move. But when you give them vitamin D, they just feel better. They're more robust and they're now beginning to be more active. As a result, they're falling more likely.

0:26:34.6 Tucker: I suppose one of the issues when looking at these associative studies, and we can see that there appears to be a link with vitamin D and various positive outcomes for health, if I've got higher levels of vitamin D, it could also be I'm fitter, therefore I'm outside more, I'm walking more, I'm jogging, I'm doing more sport, I'm perhaps more social, I'm going out and seeing people. Those could all be factors that might muddy that data.

Family doctor thanked him: Fewer winter-time health problems after patients got vitamin D

0:27:00.5 Holick: Yeah. There's no question about that. I gave a talk at a family doctors conference and the president came up to me and she said to me that I had given her back her life. And I said, what do you mean? She said that my patients had all been complaining to me in the wintertime, I have aches and pains in my bones and muscles, I'm fatigued. And so she had concluded that she had the same and that she was just overworked. And then she realized that in fact, her patients were telling her, but Dr. Holick said in his New England Journal article, that that could be caused by vitamin D deficiency. Sure enough, she took vitamin D and she said dramatic improvement in how she felt. And so I think that it's true that younger people may be more active, but in my opinion, the common denominator has been vitamin D deficiency increases risk for muscle weakness, especially at very low levels.

0:27:55.3 Holick: We did a study in a poor gentleman that had a very severe vitamin D sensitivity problem. He could not get up from a sitting to standing position. He had such severe muscle weakness and severe bone pain.

0:28:11.8 Tucker: Just say, for example, if I go for a walk for at least half an hour a day, every day, which would be good for heart health, all sorts of things, that would probably also increase my vitamin D levels.

0:28:22.5 Holick: It can, if you're not wearing sun protection completely. Yes, it will definitely.

0:28:28.3 Tucker: One disease which does seem to show a particularly strong association is multiple sclerosis. In countries with low levels of vitamin D, there does seem to be higher levels of MS, particularly countries in the Northern Hemisphere, apart from areas of Scandinavia where they have a very high level of oily fish in their diet. What do we know about the connection between vitamin D and MS?

Risk of Multiple Sclerosis reduced 40% by just 400 IU per day

0:28:50.8 Holick: We know that if you live above Atlanta, Georgia, about 35 degrees latitude for the first 10 years of your life, you have 100% increased risk of developing MS for the rest of your life no matter where you live on this planet. There was a study done at Harvard that showed that women that had the highest intake of vitamin D, over 400 units a day, this was like 20 years ago, reduced risk of developing MS by more than 40%. A similar study was done for rheumatoid arthritis in Iowa, and they made the same observation.

Risk of T1 Diabetes reduced 88% by 2,000 IU daily for a year as a child

0:29:24.1 Holick: Just another point about autoimmune disorders, there was a study done in Finland because they worried in Finland about vitamin D deficiency, and it was shown if infants for the first year of life received 2000 units of vitamin D a day and followed them for 31 years, it reduced their risk of getting Type 1 diabetes by 88%. The experts then came in and said, "Wait a minute, you can't give infants 2000 units a day, that's toxic." So they decreased it to 1000, and then down to 400, and the incidence of Type 1 diabetes in Finland was on the rise. If you raise your blood level of 25-hydroxyvitamin D above 30 ng/mL, the immune cells can now activate vitamin D. They can regulate B lymphocyte activity by modulating immunoglobulin synthesis and reducing the production of autoimmune antibodies, reducing risk for rheumatoid arthritis, psoriasis, Type 1 diabetes, multiple sclerosis, and the list goes on.

0:30:34.1 Tucker: Michael, there was this idea, I think, that perhaps some people had a predisposition for MS and that their bodies might get enough vitamin D, but simply weren't able to process it effectively. One of the studies that suggests that's not true is research done looking at MS data on women in Iran, pre and post the cultural revolution, which suggests a lack of vitamin D could be linked to development of the disease. Can you explain a little bit about what that study showed?

8X increase in Multiple Sclerosis in Iranian women after clothing coverup

0:31:06.5 Holick: Yes, if they weren't getting vitamin D supplementation, they wear clothing to completely prevent any of their skin from being exposed to sunlight, extremely high risk of vitamin D deficiency.

0:31:19.0 Tucker: So the argument is that prior to the Iranian cultural revolution, women didn't have to cover up their bodies, but after the revolution, MS rates go up over eight times. And the authors of the study suggested that this is largely because women then had to cover up their bodies so their skin could no longer absorb vitamin D from the sun.
   More hijab clothing may have resulted in 6X increase in Multiple Sclerosis in Tehran – May 2013

Has been using Coimbra protocol on his MS patients

0:31:41.3 Holick: Correct. There's a lot of data out there to show that vitamin D deficiency increases risk for MS. There's a study done by Dr. Coimbra, who I met in Sao Paulo, Brazil. He's giving massive doses of vitamin D to MS patients. I have about four patients like his in my clinic that I was giving very high doses and I was able to control their MS. And so we think that very very high doses, but very carefully watched, the ones that I've had, the ones that Dr. Coimbra's had all making the same observation. The super high doses like 40,000/50,000 units a day can have a dramatic effect on helping to either not have the disease progress or even to have it begin to decline in terms of its activity.

0:32:32.8 Tucker: It seems to me with Dr. Coimbra's work, what we really need some published trials.

0:32:37.6 Holick: Correct.

0:32:38.0 Tucker: Which we don't have yet.

0:32:40.2 Holick: But the problem is that I don't think there ever can be a controlled trial.

0:32:45.4 Tucker: We know that once these autoimmune diseases develop, they're very difficult to treat, so shouldn't there be more focus then on preventing them developing at all? If we appear to have evidence that vitamin D, certainly for MS and potentially other autoimmune disease too is protective, why aren't we recommending higher levels of vitamin D?

The risk is Deficiency if far far bigger than the risk of Toxicity

0:33:04.9 Holick: That's because of this culture that's out there saying that vitamin D is potentially toxic, and we know that that's just not true. That's why for me, when I give my presentations, is I say you need vitamin D from birth until death because it can reduce risk of many chronic illnesses, it'll make you feel better, and as a result, I think it's a good recommendation and you do need to be on adequate calcium and often, having adequate calcium, you'll have stronger bones.

0:33:38.2 Tucker: As I mentioned earlier, a number of neurologists, particularly those with an interest in MS, tell me they take 5000 units a day. But they said to me, but we can't tell our patients this.

0:33:49.2 Holick: Right.

0:33:49.8 Tucker: Going back to this issue of calcium, what I find puzzling is there's parts of the world where people have very low levels of calcium in their diet particularly if you look at parts of Asia, they don't tend to suffer high levels of osteoporosis. In the US where people have the most calcium in the diet, they have the highest levels of osteoporosis. Why does that happen?

0:34:13.3 Holick: It turns out that calcium obviously is very important for your skeleton. We know, for example, in Africa that children with rickets exposed to a lot of sunlight is due to severe calcium deficiency. They see the same in Bangladesh, for example. But when you mean low calcium, you're not talking about very very low calcium. You're talking about calcium in the range of probably 400-600 milligrams a day as opposed to 1000 milligrams a day in the United States. We know that your activity makes a difference. We know 'cause you had said you like to walk and you were giving some examples of the benefits. Well, one of the additional benefits is that it helps to maintain both hip and spine bone density. It's the pounding on the pavement that's translated to your hip and spine.

0:35:02.8 Holick: A lot of these other countries, these people are much more active and as a result that even though that they have lower calcium intake is that they're able to help maintain their bone marrows. In the United States, even though you have adequate calcium intake, if you're vitamin D-deficient, you're not utilizing that calcium. So it's kind of a catch-22. Those in Asia, for example, are more likely eating sun-dried mushrooms, good source of vitamin D, as they're out there, outside all the time, they're making adequate vitamin D. And so the body is very clever is that if you have low calcium intake, but adequate vitamin D, you increase the active form of vitamin D being produced in the kidneys which goes to the intestine to tell the intestine, okay, increase the efficiency of absorption. Normally, if you're vitamin D sufficient, you absorb 30%-40% of your dietary calcium. If you're vitamin D insufficient, only about 10%-15% is being absorbed.

0:36:03.0 Tucker: How much calcium should we all be drinking as adults?

Calcium absorption better if take 3 times per day (consider vegi-calcium)

0:36:06.4 Holick: I tell my patients that I think 1000 milligrams a day, as recommended by the Institute of Medicine, is quite reasonable. You don't wanna take it all at once because if you do, you can't as efficiently absorb it. We prefer that you break it up. Personally, I think dietary calcium is much better. The major dietary source, of course, is dairy. And now of course they have various types of milks, oat milk and almond milk, where they're adding calcium carbonate to it as a source of calcium, but to me, the best source is dairy. I drink three glasses every day.

0:36:42.2 Tucker: Because there's been speculation about a link between breast cancer and dairy, particularly for postmenopausal women, that I think has been a worry.

0:36:51.7 Holick: Yeah, and I think, there are other studies that have shown that's just not true. I think that's still, in my opinion, a very debatable issue just like hormone replacement therapy. We've been taught don't go on hormones because it increases risk of breast cancer by 25%. That's the women's health initiative. So I tell my students, okay, read the paper. What does that really mean? What it means is per 10,000 women on estrogen and progestin versus placebo, that 38 women on estrogen developed breast cancer per 10,000, 30 women without taking estrogen developed breast cancer. The difference was eight and even though 38 and 30, it's a 25% difference. But read the paper even more carefully. And they showed, women with no uterus who were only taking estrogen and not progestin had no increased risk for breast cancer.

0:37:55.3 Tucker: So what does that tell us?

Increase risk of Breast Cancer may be due to progestin, not estrogen

0:37:56.8 Holick: It tells me that it's the high dose of progestin maybe with the estrogen that is the offender because if women with no uterus only taking estrogen didn't increase risk of breast cancer, there has to be another reason, which is the combination. And so now, the dose that they used, which was 0.625 of Premarin and 5 mg of the progestin, I give my patients now 0.3 of the estrogen compound and only 1.5 mg of the progestin, medroxyprogesterone. I've seen maybe 500-1000 postmenopausal women, if they don't have a history of breast cancer, family history of breast cancer, I'm pretty aggressive in using hormone replacement therapy because they feel better, don't have hot flashes and many of the other consequences of being menopausal and not on hormone replacement therapy.

0:38:56.4 Tucker: Linked to that, one of the latest suggestions has been the use of vitamin D for women with postmenopausal breast cancer who were taking Arimidex, who often complain of muscle aches and joint pain, the dose was 7000 international units a day.

0:39:11.9 Holick: I've had plenty of breast cancer patients at my clinic on these anti-estrogen medications, and I make sure that their blood levels of 25-hydroxy D are in the range of 40-60 ng/mL, and I've never had that experience.

0:39:29.3 Tucker: But 7000 units a day would probably be more than you would be giving to your patients.

0:39:33.6 Holick: Twice as much. I'm not familiar with this study particularly, but I always tell my students read these studies carefully. Don't just read the abstract because it's basically...

0:39:44.9 Tucker: So true.

0:39:47.2 Holick: Yeah. Is what the authors want you to believe. It's an advertisement basically for their paper. And so, it's important to deeply read into these to see what's happening because we do know, by the way, that patients who were severely vitamin D-deficient and you give them vitamin D, they can develop aches and pains in their bones and muscles initially, and we don't understand why. It seems to have some effect on trying to remineralize the bone and I've seen it and can't explain it.

0:40:16.2 Tucker: Michael, what do we need to do then for the future with vitamin D to maximize its potential?

0:40:24.2 Holick: Personally, I think the most important thing for the UK and the rest of the world, you've gotta begin to fortify foods. You cannot get enough from sunlight. You cannot get enough from your diet. Even India now, a country that you would think is sunny all the time, they realize that vitamin D deficiency is a major health problem. As a result, the government now permits the fortification not only of dairy, of milk with twice the amount that is available in the United States, but because they're very poor population and they can't afford milk, they decided to put it in cooking oil and that's very clever. Now you may ask the question, well, if you put in cooking oil and you're cooking your food, are you destroying the vitamin D? And the answer is no. Vitamin D is incredibly stable to heat.

0:41:17.9 Tucker: But couldn't we all just take a vitamin D supplement?

Vitamin D till requires a prescription in some countries

0:41:21.1 Holick: Personally, that's my recommendation for all my patients, but there's some places that it's expensive and right now many countries in South America and of course in Europe, you need a prescription to get your vitamin D. You can't just go to your drugstore and purchase it.

0:41:38.2 Tucker: You can buy it online quite easily?

0:41:40.4 Holick: Yes, you can. The problem with that, in my opinion, is you have to be careful because I had one case that we published in New England Journal of Medicine where he went online and he said it was 2000 units in two teaspoons, and I had been recommending 2000 units a day and he became severely toxicated. The reason was the company forgot to dilute it. He was taking 1,000,000 units a day for over a year.

0:42:05.4 Tucker: You can also buy vitamin D over the counter in the UK, but at much lower doses.

Any amounf of vitamin D is better than not taking Vitamin D

0:42:12.0 Holick: Right. But in my opinion, any amount is good.

0:42:16.3 Tucker: Well, Michael, thank you so much for talking. Absolutely fascinating.

Many benefits of Vitamin D for pregnancy

0:42:20.0 Holick: My pleasure. Just to leave you with one more thought, which is we have good evidence that vitamin D deficiency in pregnancy increases risk for preeclampsia, the most serious complication of pregnancy. It reduces risk of requiring a C-section because vitamin D is very important for muscle functioning during birthing, and it reduces risk for premature birthing. And then we also know that in utero, if the fetus is recognizing a higher blood level in the mom, after birth, they have less likelihood of having wheezing disorders and asthma. There is no downside to increasing your vitamin D intake into those levels that we've talked about. If studies eventually show that in fact there is additional benefits, you're on top right away. Rather than have lost all that time being vitamin D-deficient and potentially markedly increasing risk for chronic illnesses later in life.

0:43:24.3 Tucker: Many thanks, Michael. Great talking to you.

0:43:26.4 Holick: Take care. Bye.

0:43:28.7 Tucker: Bye. Hope you enjoyed the latest episode of the podcast. Many thanks for listening. A reminder, you can follow me on Twitter @lizctucker and sign up to the podcast mailing list at whatyourgpdoesnttellyou.com. The podcast will be back after the Christmas break on Tuesday, the 17th of January. In the meantime, I hope you have a very happy Christmas and New Year. Bye for now.


52+ VitaminDWiki pages have HOLICK in the title

This list is automatically updated

Items found: 52
Title Modified
Should You Take A Vitamin D Supplement - Dr Holick transcript Oct 2022 28 Nov, 2023
Vitamin D: 100 year anniversary of discovery – Holick Jan 2023 23 Jan, 2023
Vitamin D and neurocognitive function – Holick April 2014 21 Oct, 2022
Vitamin D and neurocognitive function – Holick Oct 2022 21 Oct, 2022
How Sensible Sun Exposure Benefits Your Health -Holick interview May 2022 30 May, 2022
UV, sunshine, and vitamin D (87 charts) - Holick March 2013 11 Jan, 2022
Vitamin D and COVID-19: a narrative review - Holick - Jan 4, 2022 10 Jan, 2022
Low Vitamin D in infants - video interview of Dr. Holick - May 2017 11 Dec, 2021
Hospital has banned Dr. Holick due to testifying in cases of infants with broken bones- August, 2021 03 Aug, 2021
Vitamin D Is Not as Toxic as Was Once Thought – Holick May 2015 20 Mar, 2021
Vitamin D, Zinc, etc. look promising for COVID-19 (Holick) - Jan 25, 2021 28 Jan, 2021
A call to action: Vitamin D for hip fracture (50,000 weekly for 8 weeks, then bi-weekly – Holick July 2020 11 Dec, 2020
Rate of COVID-19 test positive is 40 pcnt lower if high vitamin D (192,000 people) - Holick Sept 2020 17 Sep, 2020
Immunologic Effects of Vitamin D on Human Health and Disease - Holick July 2020 15 Jul, 2020
The vitamin D deficiency pandemic – Holick May 2017 21 Jan, 2020
Call to action – more Vitamin D for pregnancies, loading doses are OK – Holick Aug 2019 25 Jun, 2019
Diagnosis and treatment of osteopenia – Holick 2010 10 Dec, 2018
Photobiology of Vitamin D – free chapter in book – Holick 2010 17 Nov, 2018
Kaiser Health News wrote a damning article about Dr. Holick and Vitamin D, NYT published it – Aug 2018 20 Aug, 2018
Vitamin D - at least 4,000 IU to achieve 40-60 ng and reduce risk of early death – Holick June 2018 04 Jun, 2018
Role of Vitamin D in the Pathogenesis of Diabetes – Holick July 2017 16 Jul, 2017
The risks and benefits of sun exposure – Holick Oct 2016 05 Jan, 2017
Vitamin D presentation by Dr. Holick Spring 2012 08 Mar, 2016
Holick interview by Mercola on Vitamin D – Dec 2015 17 Jan, 2016
Major review of Vitamin D – Holick Feb 2013 27 Dec, 2015
Vitamin D Global Perspective - Holick June 2013 27 Dec, 2015
Dr. Holick video on vitamin D - March 2013 27 Dec, 2015
Vitamin D from 1940 and into the future – Holick video Nov 2013 28 Nov, 2015
Vitamin D review – Holick Jan 2013 24 Sep, 2015
Go ahead, soak up some sun (but don’t burn) – Holick July 2015 01 Aug, 2015
Chicago Sun Times on vitamin D: Depression, chest pain, fibromyalgia, Holick, 3000 IU without test - May 2010 15 Jul, 2015
Chicago Times on vitamin D: Depression, chest pain, fibromyalgia, Holick, 3000 IU without test - May 2010 15 Jul, 2015
Live Longer with Vitamin D - Holick March 2015 17 May, 2015
Sunlight and Your Health: An EnLIGHTening Perspective - Holick Video Dec 2014 14 Mar, 2015
Less sun means more disease -Grant, Holick, Cannell, et al Feb 2015 05 Mar, 2015
Cancer, Sunlight, and Vitamin D - Holick Oct 2014 06 Oct, 2014
Environmental factors that influence the cutaneous production of vitamin D – Holick 1995 06 Jan, 2014
If You're Low in This Nutrient, It Doubles Your Odds of Many Cancers– Interview Dr. Holick Oct 2013 23 Dec, 2013
Patent application for a skin cream which enhances production of vitamin D – Holick July 2013 24 Nov, 2013
Vitamin D update – Holick Sept 2013 11 Nov, 2013
Vitamin D, Sunlight and Cancer Connection – Holick Jan 2013 11 Aug, 2013
Vitamin D encyc. - 2nd edition, Holick - April 2013 02 Mar, 2013
Major review of Vitamin D – Holick 2013 part II 08 Feb, 2013
Vitamin D: A D-Lightful Vitamin for Health – Holick Dec 2012 07 Jan, 2013
Evidence for vitamin D – Holick June 2012 23 Nov, 2012
VITAMIN D: A D-LIGHTFUL SOLUTION FOR GOOD HEALTH – Holick 2012 30 Oct, 2012
Michael Holick – reduce health care costs 25 percent – interview Sept 2010 07 Oct, 2012
High Prevalence of Vitamin D Inadequacy - Holick Mayo Clinic 2006 14 May, 2012
Professional book on Vitamin D - Editor Holick 2010 27 Aug, 2011
Vitamin D Holick – Jan 2011 29 Mar, 2011
Vitamin D is essential to the modern indoor lifestyle – interview Holick Oct 2010 09 Oct, 2010
Interview of pioneer in Vitamin D research - Holick LEF Sept 2010 08 Sep, 2010

A tiny sample of Dr. Holick's recent Vitamin D videos


VitaminDWiki- Supplementing Vitamin D


VitaminDWiki- 17 reasons why are doctors reluctant to accept vitamin D


VitaminDWiki- Health Problems and D left-hand column of VitaminDWiki


VitaminDWiki- Do not expect your doctor to know about vitamin D


VitaminDWiki- 13 reasons why many seniors need more vitamin D (both dose and level) - July 2023


VitaminDWiki- Can get 50,000 IU Vitamin D anywhere on the globe

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