Video Transcript: Vitamin D and Bone Health
http://www.umm.edu/video_podcasts/mht/vitamind_bonehealth_streeten.htm
Part One:
* What is Vitamin D
* Role of Sun exposure for Vitamin D
* Risks from Vitamin D deficiency
* Foods with Vitamin D
* Sunscreen vs. vitamin D needs
* Vitamin Supplements
* Illnesses associated with Vitamin D deficiency
Part Two:
* Osteoporosis
o Risk factors
o Symptoms
* Common fracture sites
* Bone density scans
* Osteoporosis medicines
* Osteoporosis prevention
* Osteopenia
* Calcium: Food sources and supplements
Part One: May 2010
Questions by Ellen Beth Levitt
Welcome to "Maryland Health Today." I'm Ellen Beth Levitt. Vitamin D the "sunshine vitamin" as it is sometimes called plays an important role in protecting our bones and many vital organs. And Vitamin D deficiency has been linked to heart disease, cancer, diabetes and other serious health problems. On the show today, we will discuss the role of Vitamin D in protecting us from disease. My guest is Dr. Elizabeth Streeten. She is an endocrinologist and medical geneticist at the University of Maryland Medical Center. Dr. Streeten is also an associate professor of medicine pediatrics at the University of Maryland School of Medicine. Welcome to the show. First of all, tell us about Vitamin D. What is it and what is its role?
Elizabeth Streeten, M.D.: Vitamin D is a vitamin which means that the body needs it for normal functioning. And it is also a hormone which means it is made in one place in the body and travels other places to do its job. And it is in the hormone area, it is a steward hormone which means it is made from building block of cholesterol. It is made in the skin, when the sun shines on the skin, the sun causes cholesterol precursors that are present in the skin to change into Vitamin D.
Q: That's amazing that something like sunlight could actually cause our body to create Vitamin D.
Elizabeth Streeten, M.D.: Yes, it really is amazing but that's the main source for Vitamin Department for most people is the sun.
Q: And then, what is the importance of Vitamin D in our body?
Elizabeth Streeten, M.D.: As you mentioned, Vitamin D is important for many organs, it is very important for preventing osteoporosis, we'll talk about it in a little bit. And for preventing heart disease, diabetes, important for the immune system, and as well as others.
Q: And how much Vitamin D do we need, do we need a daily dose from the sun?
Elizabeth Streeten, M.D.: So this is a source of some controversy. The official RDA recommended daily allowance is currently being redone for Vitamin D. It has not been announced yet but it will likely be in the range of a thousand units at least. Some people need more than that. Those who have more fat need more Vitamin D.
Q: Why would that be?
Elizabeth Streeten, M.D.: Because it is a fat soluble vitamin so when you take in Vitamin D, it has to diffuse or go to all of the different places of the body including the fats, the more fat there is, the more Vitamin D it takes to tank up the stores. So anywhere from a thousand to 4,000 units a day is what most adults need, and up to 10,000 units a day has been shown to be safe.
Q: Are many people in this country deficient in Vitamin D?
Elizabeth Streeten, M.D.: Yes, Vitamin D deficiency has been termed an epidemic.
Q: Really.
Elizabeth Streeten, M.D.: Yes. Not only in the U.S. but actually all over the world. We're becoming more Vitamin D deficient than we were a couple of decades ago. About twice as many people today are deficient in Vitamin D compared to 15 to 20 years ago.
Q: Is that because we're slathering sunscreen on every time we go out in the sun, and it is not getting to us and what kind of rays of the sun are important — rays of the sun are important for Vitamin D?
Elizabeth Streeten, M.D.: The Ultraviolet B rays are what causes the skin to make Vitamin D. There are also a rays, a rays can increase tanning but don't help to make Vitamin D. And, the reason that we think people are more Vitamin D deficient compares to past years is bart partly the obesity epidemic, and partly, the people are not getting outside as much as they used to children are playing inside on the computers as we adults are. And when we're out in the sun, we're using more sunscreen.
Q: Can you get Vitamin D from certain foods? You can get Vitamin D from some foods but not really enough for our needs. So, dairy products, are a good source — Vitamin D is supplemented to our milk. It is not naturally. And each cup of milk has about 100 units.
Elizabeth Streeten, M.D.: And you were saying we need about a thousand.
Q: Yes. So it is only one tenth of what we need.
Elizabeth Streeten, M.D.: Exactly. So you have to drink two and a half quart as day to get enough. Cereals are fortified and some yogurts are now fortified and some orange juice. And then, naturally, small amounts of Vitamin D occur in some fish, fatty fish, the likes of which we don't have every day, most people, salmon and swordfish and things like that and a little bit of other foods like mushrooms.
Q: Do people who live in cloudier northern climates have more risk of Vitamin D defficiency than people who live in more tropical environments or in the south, for example?
Elizabeth Streeten, M.D.: Yes. Exactly. The closer you live to the equator, the more time of the year that the sun's rays are at the right angle and in fact, every day, of the year, you live at the equator you can make Vitamin D in your skin and the further north you go, the less you make Vitamin D as we enter into the winter months. So it is — this latitude in Baltimore we can only make Vitamin D in the skin efficiently, in June, July and august. And the rest of the year, we can't make enough, we can't make significant amounts in the skin.
Q: So we have to try to get it through our diet and through supplements and so forth.
Elizabeth Streeten, M.D.: Yes. I think for now until our food is supplemented more efficiently, most people should take a supplement.
Q: Now, we're told to wear sunscreen obviously to prevent skin cancer, and wrinkles and all sorts of things. So, is there a sunscreen that would still let those UVB rays come in to get the production of the Vitamin D going or, does even a low SPF sunscreen block out the rays for Vitamin D?
Elizabeth Streeten, M.D.: Even a low SPF, SPF8 and above pretty much abolishes the ability to make Vitamin D. And there are some people more prone to skin cancer than others, so I recommend that for my patients that everybody take a Vitamin D supplement so we don't have to worry about increasing skin cancer, by increasing sun exposure, and someone who may be pre-disposed to skin cancer don't know it
Q:What about people who have light skin versus very dark skin. Is there a difference in the absorption of the sunlight for production of Vitamin D?
Elizabeth Streeten, M.D.: Yes. There is. And more pigment in the skin, the more sun is required to make Vitamin D. So the melanin absorbs the ultraviolet light. The older a person is 60 or so the less we'll make Vitamin D. We need more sun to make Vitamin D. And the reason for that is that the cholesterol precursors that are going to turn into Vitamin D decrease in amount in the skin as we age.
Q: Is there a risk of getting too much Vitamin D, like if you're taking supplements or eating a lot of fortified foods?
Elizabeth Streeten, M.D.: Theoretically there is a risk of too much Vitamin D, but it is very hard to get too much Vitamin D from foods, and from over-the-counter supplements. I mentioned, earlier, up to 10,000 units a day has been shown to be safe. So we don't see Vitamin D toxicity very often and when we do see it, it is in people taking a high amount of prescription strength Vitamin D.
Q: Well, should people be tested for their Vitamin D levels at a certain age or point in life?
Elizabeth Streeten, M.D.: I think that's a very good question. And I don't have the answer to that. That's a public health issue because testing everybody would be exorbitantly expensive. I would say that people who have osteoporosis should be tested. Vitamin D sufficiency is important for osteoporosis, and for most of other people I would recommend that they take a supplement, and that they don't need to be tested necessarily.
Q: What about children. Do they sometimes become Vitamin D deficient?
Elizabeth Streeten, M.D.: Yes, we're seeing actually more childhood rickets than we were in the past. Rickets is Vitamin D deficiency. Which leads to bowing of the bones because the bones are soft, as we see in this picture here.
Q: Yes.
Elizabeth Streeten, M.D.: Yes.both these children have bowing of the legs. And Vitamin D deficiency rickets was pretty uncommon in the past few decade as the knowledge about the importance of Vitamin D became available but we're seeing a resurgence of it now, taking a daily multi-vitamin is enough from a children to be Vitamin D replete. And not deficient.
Q: Why is there a resurgence? Is it because of what you are mentioning earlier that kids aren't playing outside that much, or they are getting a lot of sunscreen or they are just staying inside playing on the computer or whatever?
Elizabeth Streeten, M.D.: I think it is a combination of factors. Partly, we're seeing it in women who breast-feed their children. Tend to have more Vitamin D deficiency in the children. Not that there not plenty of Vitamin D in breast milk, but if the mother's Vitamin D deficient not enough gets into the breast milk.
Q: It can start then. 36
Elizabeth Streeten, M.D.: Yes.
Q: And then how early can you diagnose the bowing out of the bones?
Elizabeth Streeten, M.D.: Generally we can't diagnose that until the child begins to bear weight on the bones so when walking starts, when children start pulling themselves up, nine, ten months or a year old.
Q: I think then it would be arrested to correct.
Elizabeth Streeten, M.D.: It is actually pretty easy to treat.
Q: Really.
Elizabeth Streeten, M.D.: With Vitamin D supplements and once the bowing has occurred, we can't reverse it without surgery. But, we can prevent it from getting worse.
Q: What are some of the other health problems that are linked to Vitamin D deficiency? We mentioned a few of them already, but it is pretty amazing to think that this whole list, osteoporosis, of course, that's the weakening or thinning of bones but cancer could be related?
Elizabeth Streeten, M.D.: Yes, I should mention that most of the studies that show that these conditions listed here are associated with Vitamin D deficiencies what we call epidemiological study, studies looking across a population of people, and some of the studies looking back in time, to with Vitamin D levels looking at how many people have had cancer or cardiovascular disease or diabetes. What we really need to absolutely nail down and prove these associations is prospective studies, large prospective studies where people are put on Vitamin D and followed for a number of years. There are few of those but not many.
Q: It is an association.
Elizabeth Streeten, M.D.: At this point, and one of the mechanisms that explains association is that Vitamin D, is what we refer to as the differentiating factor. It keeps cells in their mature state. For example, in the pancreas the cells that beta cells are more likely to stay in a good ability to make and secrete insulin.
Q: They stay healthy.
Elizabeth Streeten, M.D.: They stay healthy and performing at their best, and less likely to turn into malignant cells. So the epidemiological data show that at least twice as many people who have cancer are Vitamin D deficient than those who don't have cancer, and twice as many die of their cancer when they are Vitamin D deficient compared to when they have enough in the system.
Q: Is Vitamin D used sometimes to treat cancer?
Elizabeth Streeten, M.D.: So there have been studies of the years particularly in the 70s of using high doses of Vitamin D to treat particularly prostate cancer, and leukemiaâ??s. And they do work, Vitamin D supplements to some degree, but, the doses required are too high to be really feasible. The doses required to treat cancer is the primary way of treatment, cause other problems like high blood calcium. But, adding the usual amounts of supplements, a thousand to 4,000 units a day, does seem to reduce the risk of dying of certain cancers, particularly colon, breast, and prostate, and decreases the diagnosis.
Q: Getting back to sunlight, is there a place on the body where if you got some sun exposure there on a regular basis, it would be absorbed better and help your body make more Vitamin D, than other places?
Elizabeth Streeten, M.D.: Yes. So the trunk and the legs make Vitamin D the best. And the face and arms make it less well.
Q: And those are the places that are more likely to be exposed a little bit.
Elizabeth Streeten, M.D.: Yes. Generally for most people, those are the areas most likely to be exposed.
Q: Interesting. Well, we have to take a break. But when we come back, we'll talk about bone loss, and osteoporosis. So stay with us. We'll be right back.
Part Two:
Q: Welcome back to "Maryland Health Today." I'm Q. On the show today, we're talking about osteoporosis and bone health. My guest is Dr. Elizabeth Streeten. She is an endocrinologist and a medical geneticist. And also director of bone and mineral health program at the University of Maryland medical center. Dr. Streeten is also an associate professor of medicine in pediatrics at the University of Maryland School of medicine. Before the break we were talking about the importance of Vitamin D and keeping our bones strong and also, preventing some other serious health problems but let's focus on the bones now. I was interested to learn with the bones they are constantly thinning and rebuilding. It is kind of a dynamic process always going on. Can you tell us a little bit about that?
Elizabeth Streeten, M.D.: Sure. So our bones as you mentioned are very active metabolic issue. We replace five to ten percent of our skeleton, and that process is called bone turnover. There are cells that break the bone down and cells that make new bone.
Q: How does that happen? Or where does the bone go when it breaks down?
Elizabeth Streeten, M.D.: Well, the bone is some of the products are recycled. Calcium is recycled. Some are excreted. A lot of the collagen protein in bone is actually excreted out of the urine and you can measure it, the byproducts of collagen and these are indexes of bone turnover.
Q: Interesting. But the process is very complicated and involves the work of many different hormones and including insulin and the sex hormones estrogen, testosterone, parathyroid hormone, Vitamin D. It is fairly complicated process it sounds like it. Tell us about osteoporosis. Really what is the definition of that?
Elizabeth Streeten, M.D.: So osteoporosis is defined as a disorder of the whole skeleton, that's characterized by reduced bone strength, and increased susceptibility to fracture.
Q: How common is osteoporosis.
Elizabeth Streeten, M.D.: It is very common. It affects about 10 million Americans of which about two-thirds are women and about one-third are men.
Q: Do we know why it is disproportionately affects women?
Elizabeth Streeten, M.D.: We don't know completely. That's the source of ongoing study. But, one of the major reasons is that, as we all know women lose their estrogen when they go through menopause, at approximately age 50, and we know that the sex hormones estrogen and progesterone are very important for bone health and men really don't go through the same process.
Q: But men still can get osteoporosis.
Elizabeth Streeten, M.D.: Absolutely. Very important i think men get neglected in the field of osteoporosis a bit. Men get osteoporosis, they get just get it at a lower rate than women. But, as we get older, the gender gap narrows. So those age 80 and older, the incidences almost even. It is closer. Men equal to women.
Q: Let's look at the risk factors. I know there is a whole list of risk factors for osteoporosis, you mentioned older age, family history. If your mom or dad had osteoporosis are you more likely to also get it?
Elizabeth Streeten, M.D.: Yes. Absolutely. We know that our bones strength at its best, peak bone strength is largely controlled by genes. Just like height is. About 85% of your bone dense you the or bone strength at peak in the 20s, to 30s, is controlled by genes.
Q: Oh, okay.
Elizabeth Streeten, M.D.: And somewhere around a third or so, of bone loss is controlled by genes. And, also listed on there is the lack of exercise, Vitamin D, being very thin, and early menopause, i should mention a also of testosterone in men. Many men do with various diseases get low levels of testosterone, and that can affect the bones at adversely. And many medications can affect the bones.
Q: Such as?
Elizabeth Streeten, M.D.: Such as the prednisone, an immune drug used for all kinds of problems such as asthma, to prevent transplants from being rejected. Various other medications and some of the medications used to treat cancers, particularly the breast and prostate which lower the estrogen and testosterone levels can be associated with osteoporosis.
Q: I notice on the list excessive alcohol use and also smoking--
Elizabeth Streeten, M.D.: Yes.
Q: — can contribute.
Elizabeth Streeten, M.D.: Yes. For these purpose, excess alcohol is over two servings of alcohol per day. Causes bone loss.
Q: And then certain ethnic background as well. Which ones are people at most risk of osteoporosis?
Elizabeth Streeten, M.D.: So those that are at highest risk are Caucasian, and those at least risk are African Americans. And those from Africa.
Q: All right. What is osteopenia? I have heard that term but Ii don't know that means.
Elizabeth Streeten, M.D.: Osteopenia is now being called low bone mass, that's really the preferred term but basically, osteopenia, low bone mass and osteoporosis are the same process, it is just that low bone mass is less severe. And if a had a fracture, we always call it osteoporosis, because it is demonstrated bone weakness, regardless of any other information.
Q: All right. And then Vitamin D, what is the role of Vitamin D in preventing osteoporosis.
Elizabeth Streeten, M.D.: Vitamin D is very important for bone health. Vitamin helping calcium from our diet get absorbed from the GI tract, and provides nice high levels of calcium normal, normal levels of calcium for the bone, in its normal turnover process. To make the new bone after the old bone is broken down.
Q: What are the symptoms of osteoporosis? You mentioned somebody having a fracture, but are there some other symptoms that one might be aware of?
Elizabeth Streeten, M.D.: Yes. So, pain is associated with osteoporosis only if there has been a fracture. So, although bone pain and tenderness are listed here generally we see this only if there has been a fracture. A also of height leading to a stooped posture, and soreness in the neck if there are fractures there but most people have no symptoms. And don't know that they have it until they are tested.
Q: What is the compression fracture? And how does that differ from a regular fracture in a bone?
Elizabeth Streeten, M.D.: So, when the long bones break, we see that the two pieces on either side of the break are separate. For the spine, compression fractures occur, it is more as if the beautiful square that the vertebra is supposed to be, is squashed down. And compression fracture typically forms a triangular shape, and the engineers will know that when you add up triangles you get a curve.
Q: Okay.
Elizabeth Streeten, M.D.: This is what leads to the stooped posture from multiple compression fractures of the spine. And these compression fractures can occur very slowly over time, and a person with a very stooped posture may not have pain at all.
Q: Well, how do you diagnose osteoporosis, and I know there is something called a bone scan or a dexiscan.
Elizabeth Streeten, M.D.: There are two ways to diagnose it. For the a person has a fracture from very mild trauma such as from falling from just standing up, as opposed to falling out of a tree, that person has osteoporosis. But we prefer, of course, the diagnosis, before fracture, and we use dexa which stands for dual energy x-ray absorb, bone density that's how we do it today. And this is a very simple task that has a very tiny amount of radiation; anyone who had a bone density may have noticed the technician performing the test doesn't even wear any protection because the amount of radiation is so small. Takes about ten minutes, and it gives us a quite accurate predicter of likelihood to fracture.
Q: Should women get this test when they reach a certain age?
Elizabeth Streeten, M.D.: So, yes, everyone pretty much agrees that all women overage 65, should have a dexa test and many people agree that all men over 70 should have a dexa test. And, in addition, those who are at high risk should for women should have one sooner. Any time after the menopause, when the estrogen level goes down is reasonable to do dexa.
Q: We only have a couple of minutes left but i wanted to ask you about treatment for osteoporosis. Are there some good treatments out there that can help to build up the bones a little bit and make them stronger?
Elizabeth Streeten, M.D.: Yes, we're very fortunate today that we have many treatments that are very effective in treating osteoporosis. Most of the treatments are, we have Fosomax and also called Elendronate available by generic, Boniva, and we have another called Forteo, and these are the mainstays of treatment and they work very well to improve the bone strength. They all help improve bone strength and reduce fractures by about 50%.
Q: So there are probably a lot of people now taking these and are they free of side effects generally speaking?
Elizabeth Streeten, M.D.: As medications go, the drugs for osteoporosis are very safe. Most people take are not taken up by any organ tissue so they are not toxic to the heart, the liver or the kidneys. And they are generally well tolerated.
Q: All right. And what about eating more high calcium foods. Is that something that is important for people who are at risk of osteoporosis.
Elizabeth Streeten, M.D.: Yes, absolutely. Calcium and Vitamin D are extremely important for treating osteoporosis in addition to medication.
Q: What are some of the foods that are high in calcium?
Elizabeth Streeten, M.D.: Primarily dairy products. Each cup of milk has about 300 grams of calcium. Some fish listed there, leafy green vegetables, such as collard greens, rich source of calcium. And primarily those are really the only good sources. So for those people who aren't getting enough calcium, supplement should be taken.
Q: What about exercise. I have heard that certain weight bearing exercises can help you keep your bones strong, is that something that is more a preventive measure or can somebody who has weaker bones also benefit from getting some exercise?
Elizabeth Streeten, M.D.: Well, exercise is probably the fountain of youth. If there is one. And it is very, very important for the bones as well. It should be weight bearing, which includes such activities as bike riding, in addition to.
Q: Really.
Elizabeth Streeten, M.D.: In addition to walking and climbing and other activities that can be fun as well as just being exercise.
Q: And lifting weights as well.
Elizabeth Streeten, M.D.: Lifting weights is excellent for the bones. For those who can tolerate impact, meaning jumping, such as.
Q: Or running, jogging.
Elizabeth Streeten, M.D.: Running, jogging, jump rope, this type of exercise is the best for the bones.
Q: Wonderful. Well, thank you very much.
Elizabeth Streeten, M.D.: My pleasure.
Q: My guest has been Dr. Elizabeth streeten. She is an endocrinologist and medical geneticist at the University of Maryland Medical center who specializes in treating osteoporosis and other metabolic bone and mineral disorders. She's also an associate professor of pediatrics at the medicine at University of Maryland School of Medicine. If you have any comments or questions about this program, please contact me by e-mail at eblevitt@umm.edu. If you would like to reach Dr. Streeten or any other University of Maryland physician, call 1-800-492-5538. Or visit the web site, where you'll find a great amount of health information and be able to see other "Maryland Health Today" programs: the address is www.umm.edu. Take good care of yourself - we'll see you next time on "Maryland Health