Dear Nathan,
I just received this great interview that Dr Chris Mohr did with leading Vitamin D researcher Dr Robert Heaney.
I asked Chris permission to share it with my list, here it is...
This is Dr. Chris Mohr back again for another monthly update and this month I am so excited to share with you an interview on one of the most popular vitamins in the entire world. Its popularity has grown tremendously over the last several years with the growing body of research and we’re all fortunate to have access to one of the leading vitamin D researchers in the entire world, Dr. Robert Heaney.
Dr. Heaney completed his undergraduate and medical degrees at Creighton University in Nebraska and Dr. Heaney serves or has served on the editorial boards of all the major scientific publications in the field of bone biology and chaired the Scientific Advisory Panel on Osteoporosis of the Office of Technology Assessment which is part of US Congress.
Dr. Heaney has worked for over 50 years in the study of osteoporosis, vitamin D, and calcium physiology. He’s authored three books, published over 400 papers, chapters, and reviews in scientific and educational fields. At the same time, he’s helped redefine the context for estimating nutrient requirements. Specifically he has shown that nutrient deficiencies produce long-latency disease as well as their classical acute disorders and has focused attention on the inadequacy of drug based research designs for the evaluation of nutrient efficacy. So without further ado, I want to introduce Dr. Robert Heaney who I’m very excited to learn from and listen to. Dr. Heaney welcome to the call today.
Dr. Heaney: I’m happy to chat with you about this, Chris.
Dr. Chris: Alright, great. So let’s get right into it. First of all, vitamin D, we keep hearing a lot about that it’s an epidemic, a worldwide deficiency and just in your practice as a researcher and a scientist what have you seen with your research subjects in terms of rates of deficiency?
Dr. Heaney: Well, most of the adults that we work with are vitamin D deficient, at least by my standards, and although I don’t personally work with children or young people, it’s worth noting that an article in the Journal of Pediatrics just about a year ago found that between 60 and 98 percent of teenage girls, for example, both black, Hispanic, and white, were vitamin D deficient. So between 60 and 98 percent. That would be consistent with what we seem to see in adults as well. Probably pushing toward the high end of that. But, of course, if you define vitamin D adequacy by a very low 25-hydroxy D level, then fewer people are g oing to show up as deficient by that criteria.
Dr. Chris: Right. Great point. And for those who don’t know, you’re located in Nebraska, so you’re pretty far north.
Dr. Heaney: Yes, we’re at 41 degrees north latitude. Just about halfway between the Canadian border and the gulf. So it’s not that far north, but we don’t get useful sun exposure for about six months of the year.
Dr. Chris: And that actually brings me – I actually saw you present one time at a conference – and it brings me to my next point. One thing that was mentioned was that if you’re north of Atlanta you wouldn’t be able to make sufficient vitamin D from the sun. If you could just clarify that a little bit, that would be great. If I’m on the mark with that or what.
Dr. Heaney: Well, it’s useful to bear in mind that the human organism evolved in equatorial east Africa wearing no clothing. We got sun exposure, tropical sun exposure, 365 days a year for all practical purposes over our whole body. And we don’t begin to approach that now. In the summer here at Omaha at 41 degr ees north, about the same as Boston as a matter of fact, we can make vitamin D. We can make substantial quantities, but it doesn’t last us through the year. By the time we get to February, even outdoor summer workers are now down to a level that I would consider deficient. So anybody living north of Atlanta certainly, even though they may get out in the sun substantially in the summer, really needs year round vitamin D supplementation. Now from Atlanta or Dallas, farther south, if you’re outdoors a lot then you may not need much vitamin D. But actually studies of middle aged and older women, particularly those with osteoporosis, have shown that the prevalence of vitamin D deficiency is low in any part of the country. Florida, Arizona, Texas, you name it. And that’s largely because the women concerned actually don’t spend much time outdoors. And when that’s the case, of course, it doesn’t make any difference at which latitude you may live, you need to get the ultraviolet rays in order to make the vitamin D. And if you’re not getting them, then you may as well live in Alaska as far as that’s concerned.
Dr. Chris: Great point. And that makes me think of something else... for people who do spend time outdoors, which unfortunately are not many, if people are putting sun block on or suntan lotion, does that affect vitamin D? Or are you still able to make it even with suntan lotion.
Dr. Heaney: Sunblock, to the extent that it’s applied according to the manufacturer’s directions, sunblock blocks vitamin D synthesis entirely. Just as it blocks the damage that those same UV rays might be producing in the skin.
Dr. Chris: Right.
Dr. Heaney: So you can’t really have it both ways. But it’s important to understand that sunblock came into widespread use just in the past 25 years. If the absence of sunblock had b een so deleterious to us, the human race might have died out thousands of years ago. But it didn’t. I mean my parents, my grandparents, your grandparents surely got a lot of sun exposure unprotected and I don’t know whether any of them died of skin cancer, but I can tell you I have no relatives that did. So I think the principal problem with excessive sun exposure is drying and wrinkling and other cosmetic problems. Now yes, you can get squamous cell carcinoma and basal cell carcinoma and I don’t think those are anything to be laughed at but they’re not as serious and life threatening as many of the problem diseases caused by vitamin D deficiency might be.
Dr. Chris: So would you recommend then people either not wear suntan lotion or at least get a little sun exposure on a daily basis without it?
Dr. Heaney: Well the good news is that much of the vitamin D we make in our skin is probably made in the first few minutes after sun exposure. The timing on this is still uncertain so I can’t put a precise time number in terms of how many minutes. But let’s just say for the sake of argument that if you’re going to be out in the sun, stay out there for 15 minutes and then put your sunblock on. That would probably protect you just as well from most of the damage that might be produced by ultraviolet, but at the same time it will allow you to get some and maybe much of the vitamin D you would otherwise have gotten. You see, the longer you’re out in the sun without sunblock protection, what the UV radiation does is not only make vitamin D in the skin, but it also degrades it before it can leave the skin. So you reach a point where there’s kind of a diminishing return there. And that’s why the first few minutes are probably where you’re going to get the best benefit with the least damage.
Dr. Chris: Ok. Great points. Interesting. And now, kind of going back, if someone was outside – so, for example, I’m based in Louisville, Kentucky – if someone was outside a little north of Atlanta, but training all summer, maybe an endurance athlete outside for a long period of time, or working outdoors, would that be... is it still that you would recommend maybe vitamin D supplementation in the winter months because even that long period of time outdoors wouldn’t carry them through?
Dr. Heaney: It won’t carry them through. That’s quite right. Our bodies were designed by the good Lord to get vitamin D essentially year round and stocking up the summer, although it may be the best we can do, is not really good enough. And, furthermore, even if you could get some vitamin D in Louisville on December 25, you’d have to be outdoors naked in order to get it. And, you know, a few of us in mid-winter, however sunny it may be, won’t be exposing much skin. So there’s no doubt about the fact that during winter at least, and I think it’s easier to recommend year round because most of us, I mean, I’m sitting in front of a computer screen and I’m getting no UV radiation, day in and day out. And if I am outdoors, it tends to be in the morning before I go to work or in the evening after I get home and at that point, the amount of UV radiation reaching the earth’s surface where I live is negligible. It may be hot and it may be uncomfortable, but there’s not much UV there, so I can’t make much vitamin D at that time. So you have to bear in mind – I can’t stress too much – that if we’re going to depend upon the sun to do this, it’s got to be midday and if we’re not out substantially at midday with a lot of skin exposure most of the year, then we’re going to need supplements.
Dr. Chris: Ok. So that brings me to my next point. Do you think that... would you recommend that everyone get tested, go to their physician, get tested for their vitamin D status or just certain populations that are at greater risk than others?
Dr. Heaney: Well the answer to that is yes and yes. Certain populations are at greater risk. People of color clearly are at greater risk because the melanin in their skins whether they’re
from South India or from Central Africa, doesn’t make any difference, the melanin in their skins is sunblock. And it will protect against UV transformation of 70-hydrocholesterol into cholecalciferol or vitamin D, the other name for that. So people of color need to be outdoors longer and to expose a lot of skin in order to make vitamin D at our latitudes. And they don’t do it. And so as a result, when you look at the vitamin D status of people of color it’s always low. The pediatric figure that I quoted for you a few moments ago had 98 percent of black teenage girls deficient. 98 percent.
Dr. Chris: Wow. That’s unbelievable.
Dr. Heaney: I contrast white teenage girls on the other end of the color spectrum. Even there, better than 60 percent were deficient. So clearly people of color just aren’t going to be able to count on the sun. In large part because there has been this tremendous migration over the last 75 years from the rural south to the urban north of much of the black population of the U.S. and so we’ve got people who work indoors and once again skin color is of now help or harm at that point, because you’re not getting any vitamin D. So we’re going to have to rely on supplements.
Dr. Chris: Ok. So now when people do get tested, what do you feel are the optimal plasma values? I know that some of the standards sometimes seem to differ from what many experts believe. For example, I got mine tested about two years ago and my physician said oh you’re perfect everything’s fine, but my plasma values were a little bit lower than some experts believe. They were around 32 which falls into the standards, but again lower than that level the lot recommends. What are your recommendations for plasma values?
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