A set of mutations in the gene for the vitamin D receptor are more common in patients with severe eczema than they are in controls or patients with moderate eczema, a group of German researchers has found.
In a paper in press at the British Journal of Dermatology, the scientists explain that this set of mutations, or "haplotype," likely does not cause eczema but combines with other factors to make the disease more severe.
Vitamin D is widely touted on the internet as a miracle cure for many conditions including eczema. Clinical data on links between eczema and vitamin D is spotty. However, it's known that vitamin D plays an important role in inflammation--and eczema is nothing if not an inflammatory disease.
The mutations of interest occur not in the coding region of the gene, but in an upstream regulatory region, which means that the structure of the vitamin D receptor is not changed, but the amount of the receptor that the body produces is probably reduced. That would indicate to me that consuming excessive vitamin D could be of little help in treating severe eczema, since the body would simply not have the receptors present to react to the supplements
The scientists, led by Margitta Worm at Charité - Universitätsmedizin Berlin, sampled DNA from two groups of adults: a control group of 259, and a group of 265 eczema patients, 142 of whom were classified as severe cases. The scientists found that the odds of the severe group having any one of three particular mutations was about 50% higher than for the control group.
Showing posts with label vitamin D. Show all posts
Showing posts with label vitamin D. Show all posts
Friday, October 5, 2012
Friday, June 8, 2012
Scots could benefit from vitamin D in the winter
A moderate dose of ultraviolet light during the winter months increases the levels of vitamin D in the blood and appears to put a brake on the T-cell arm of the immune system--which could reduce the severity of autoimmune disease, a new small-scale study on a group of Scottish patients has shown.
The research was led by Mark Vickers and Anthony Ormerod, a professor and clinical reader in dermatology, respectively, at the University of Aberdeen. It was reported in the Journal of Allergy and Clinical Immunology.
The trial was conducted between December and March, 2012. Before and after exposing 24 subjects repeatedly to the equivalent of a quarter of a day's worth of summer sunlight, the scientists measured blood levels of vitamin D; the fraction of white blood cells comprised of "regulatory" T cells; and the degree to which T cells expanded their numbers when stimulated.
Regulatory T cells are a subset of T cells known to suppress the activity of other T cells. According to Wikipedia, "Mouse models have suggested that modulation of Tregs can treat autoimmune disease and cancer, and facilitate organ transplantation." Eczema with an allergic component qualifies as an autoimmune disease.
The scientists found that, after two weeks' exposure to UV, vitamin D levels increased by 50%; after four weeks, by 100%. The fraction of regulatory T cells increased threefold, and other classes of T cells reacted less vigorously to stimulation.
While I am always interested in the connection between vitamin D, T cells, and eczema--I wonder whether this study really tells us anything new. The American Academy of Dermatology says there is no safe recommended level of exposure to UV (because of the risk of skin cancer).
The connection between vitamin D and regulatory T cells appears to be well-established, according to a PubMed search I just did. And everyone knows that regulatory T cells suppress other T cells.
Having spent several years in the north of Scotland myself, I well know how little sunlight the Scots get in the winter. Were the subjects' vitamin D levels low to begin with? I bet they were. Could they benefit from supplements? Almost certainly.
Especially since, as I recall, the Scottish diet consists largely of chips, lager, and cigarettes!
The research was led by Mark Vickers and Anthony Ormerod, a professor and clinical reader in dermatology, respectively, at the University of Aberdeen. It was reported in the Journal of Allergy and Clinical Immunology.
The trial was conducted between December and March, 2012. Before and after exposing 24 subjects repeatedly to the equivalent of a quarter of a day's worth of summer sunlight, the scientists measured blood levels of vitamin D; the fraction of white blood cells comprised of "regulatory" T cells; and the degree to which T cells expanded their numbers when stimulated.
Regulatory T cells are a subset of T cells known to suppress the activity of other T cells. According to Wikipedia, "Mouse models have suggested that modulation of Tregs can treat autoimmune disease and cancer, and facilitate organ transplantation." Eczema with an allergic component qualifies as an autoimmune disease.
The scientists found that, after two weeks' exposure to UV, vitamin D levels increased by 50%; after four weeks, by 100%. The fraction of regulatory T cells increased threefold, and other classes of T cells reacted less vigorously to stimulation.
While I am always interested in the connection between vitamin D, T cells, and eczema--I wonder whether this study really tells us anything new. The American Academy of Dermatology says there is no safe recommended level of exposure to UV (because of the risk of skin cancer).
The connection between vitamin D and regulatory T cells appears to be well-established, according to a PubMed search I just did. And everyone knows that regulatory T cells suppress other T cells.
Having spent several years in the north of Scotland myself, I well know how little sunlight the Scots get in the winter. Were the subjects' vitamin D levels low to begin with? I bet they were. Could they benefit from supplements? Almost certainly.
Especially since, as I recall, the Scottish diet consists largely of chips, lager, and cigarettes!
Thursday, May 31, 2012
Hormone works in tandem with vitamin D to fight skin infections
A certain hormone works in tandem with vitamin D to control how skin cells produce a natural microbe-fighting agent, and can compensate for a lack of vitamin D, scientists have found.
The new results help explain something that has confused researchers for a long time: although it is known that vitamin D plays a role in the immune defense, there are very few clinical trials that show that taking supplemental vitamin D helps prevent infection.
The work was led by Richard Gallo, a professor of medicine and pediatrics and chief of the Division of Dermatology at the University of California, San Diego. It was published this week in the journal Science Translational Medicine.
The skin makes natural antimicrobial compounds (protein fragments called peptides) to kill unwanted bacteria, fungi, and viruses. Eczema patients produce these compounds at lower levels than normal; psoriasis patients, at higher levels. Vitamin D initiates production of cathelicidin, a broad-spectrum antimicrobial.
Gallo and colleagues showed that human skin cells produce parathyroid hormone (PTH) when treated with a bacterial compound known to trigger the immune system. The same cells, stimulated with vitamin D, manufactured copies of the receptor for PTH. And the skin cells produce far more cathelicidin when they are treated with parathyroid hormone and vitamin D than with either compound alone.
The results suggest a model in which, in humans, vitamin D can stimulate cathelicidin production by itself—but PTH is doing so by a parallel pathway, which vitamin D can amplify.
The scientists also showed that PTH helps reduce the severity and extent of Streptococcus skin infections in mice—but it does so much more strongly in normal mice, compared to mice genetically engineered to be unable to convert vitamin D to its active form. (Apparently it is very difficult to make a mouse deficient in vitamin D.)
What this means for eczema patients is not clear yet. The research gets us further toward understanding how vitamin D and other factors participate in the skin’s immune response. If I were a doctor, it would make me hesitant to recommend that patients with normal vitamin D levels should take supplements.
The new results help explain something that has confused researchers for a long time: although it is known that vitamin D plays a role in the immune defense, there are very few clinical trials that show that taking supplemental vitamin D helps prevent infection.
The work was led by Richard Gallo, a professor of medicine and pediatrics and chief of the Division of Dermatology at the University of California, San Diego. It was published this week in the journal Science Translational Medicine.
The skin makes natural antimicrobial compounds (protein fragments called peptides) to kill unwanted bacteria, fungi, and viruses. Eczema patients produce these compounds at lower levels than normal; psoriasis patients, at higher levels. Vitamin D initiates production of cathelicidin, a broad-spectrum antimicrobial.
Gallo and colleagues showed that human skin cells produce parathyroid hormone (PTH) when treated with a bacterial compound known to trigger the immune system. The same cells, stimulated with vitamin D, manufactured copies of the receptor for PTH. And the skin cells produce far more cathelicidin when they are treated with parathyroid hormone and vitamin D than with either compound alone.
The results suggest a model in which, in humans, vitamin D can stimulate cathelicidin production by itself—but PTH is doing so by a parallel pathway, which vitamin D can amplify.
The scientists also showed that PTH helps reduce the severity and extent of Streptococcus skin infections in mice—but it does so much more strongly in normal mice, compared to mice genetically engineered to be unable to convert vitamin D to its active form. (Apparently it is very difficult to make a mouse deficient in vitamin D.)
What this means for eczema patients is not clear yet. The research gets us further toward understanding how vitamin D and other factors participate in the skin’s immune response. If I were a doctor, it would make me hesitant to recommend that patients with normal vitamin D levels should take supplements.
Monday, February 27, 2012
New path discovered by which vitamin D reduces inflammation
Scientists have identified a new path by which vitamin D reduces inflammation.
According to a group led by Elena Goleva at National Jewish Health Center in Denver, vitamin D binds to a receptor in monocytes, a type of white blood cell. The receptor then binds to DNA in the cells and directs the cells to make more of an enzyme that shuts down inflammatory signaling.
The researchers found that vitamin D at or above a concentration of 30 nanograms per milliliter was enough to do the job. 30 ng/ml is a widely accepted lower limit for vitamin D in blood serum. (I recently had my own vitamin D level assayed and found it was 32 ng/ml.)
The research was published in the Journal of Immunology. [paper] [media summary] The authors say that vitamin D not only is important in maintaining calcium levels and bone health, but also plays an important role in the immune response.
That’s what I’ve found in my reading, although there’s also a lot of people on the internet who would like you to believe that taking vitamin D supplements—sometimes to an extreme degree—is a good idea for your health and in particular for relieving eczema. I remain wary. If vitamin D is so important then you need to maintain a proper level, not overdose yourself. All drugs are toxic when ingested beyond ranges established to be safe in clinical trials.
What I like about this paper is that the authors have gone out of their way to conduct their experiments in an environment that is similar to the human body, as far as concentrations of various substances go (including vitamin D). They also used monocytes taken from human donors instead of cells from some purified, genetically altered strain, as is so often the case with cell biologists dabbling in medical applications. So their results mean something to you and me.
One question that I do have is whether the same kind of inflammation studied here—caused by LPS, a bacterial molecule that triggers an anti-infection response—is at work in chronic eczema. Is there one major inflammatory response, or are there several?
According to a group led by Elena Goleva at National Jewish Health Center in Denver, vitamin D binds to a receptor in monocytes, a type of white blood cell. The receptor then binds to DNA in the cells and directs the cells to make more of an enzyme that shuts down inflammatory signaling.
The researchers found that vitamin D at or above a concentration of 30 nanograms per milliliter was enough to do the job. 30 ng/ml is a widely accepted lower limit for vitamin D in blood serum. (I recently had my own vitamin D level assayed and found it was 32 ng/ml.)
The research was published in the Journal of Immunology. [paper] [media summary] The authors say that vitamin D not only is important in maintaining calcium levels and bone health, but also plays an important role in the immune response.
That’s what I’ve found in my reading, although there’s also a lot of people on the internet who would like you to believe that taking vitamin D supplements—sometimes to an extreme degree—is a good idea for your health and in particular for relieving eczema. I remain wary. If vitamin D is so important then you need to maintain a proper level, not overdose yourself. All drugs are toxic when ingested beyond ranges established to be safe in clinical trials.
What I like about this paper is that the authors have gone out of their way to conduct their experiments in an environment that is similar to the human body, as far as concentrations of various substances go (including vitamin D). They also used monocytes taken from human donors instead of cells from some purified, genetically altered strain, as is so often the case with cell biologists dabbling in medical applications. So their results mean something to you and me.
One question that I do have is whether the same kind of inflammation studied here—caused by LPS, a bacterial molecule that triggers an anti-infection response—is at work in chronic eczema. Is there one major inflammatory response, or are there several?
Friday, February 10, 2012
Eczema occurrence increases from north to south in Australia. Is sunshine responsible?
An Australian/British study connecting eczema and exposure to sunshine (in press) in the Journal of Allergy and Clinical Immunology has been getting a lot of media attention of late. [media summary] [paywall link to paper, which I mysteriously got for free a few days ago]
The media coverage has been misleading, at least in the titles. Makes it sound like you should send your kids out in the sun. "Playing in the sun ‘reduces risk of eczema and food allergies in children.'" "Sunlight may help ward off allergies." Irresponsible, really, when Australia faces an epidemic of melanoma caused by exposure to UV through the ozone hole.
That doesn't mean the results aren't interesting. The authors of the paper analyzed data from a national database, for two cohorts of 3312 and 4331 children (aged 4-5 and 8-9) so the number of subjects isn't a concern. They stratified the kids by geographical location from north to south and found that the incidence of eczema and allergy to peanut and egg increased from north to south. (Asthma showed no correlation.)
Strangely, the authors don't quantify how much sunlight children might be exposed to in these regions, even in crude average numbers. You'd think that if they are going to make the claim, as they do, that their numbers provide support for the hypothesis that kids are developing eczema and allergies because they aren't getting enough sunlight--or to go further and say that the lack of sunlight is reducing vitamin D levels in these kids and THIS is what is causing the eczema and allergies--that they might make some effort to refer to how much sun kids are exposed to. But no.
This leaves me wondering what other factors might account for the incidence of eczema and allergies increasing as you go southward through Australia. Also, I wonder whether it might be true that sunlight helps keep eczema down (I have no personal experience with this) by some other mechanism than vitamin D production. Perhaps exposure to long-wavelength--safer--UV radiation affects skin cells in some beneficial way that I'm not aware of.
I had my own vitamin D level measured last week. According to Kaiser Permanente, the normal range for 25-hydroxy vitamin D in the blood is 25-79 ng/ml. My level is 32 ng/ml. Relatively low, but in the normal range. So it's unlikely that for me personally a lack of vitamin D is what's causing my eczema.
Once I'm done with my habit-reversal trial, it might be worth taking some supplemental vitamin D to see whether it has any effect.
The media coverage has been misleading, at least in the titles. Makes it sound like you should send your kids out in the sun. "Playing in the sun ‘reduces risk of eczema and food allergies in children.'" "Sunlight may help ward off allergies." Irresponsible, really, when Australia faces an epidemic of melanoma caused by exposure to UV through the ozone hole.
That doesn't mean the results aren't interesting. The authors of the paper analyzed data from a national database, for two cohorts of 3312 and 4331 children (aged 4-5 and 8-9) so the number of subjects isn't a concern. They stratified the kids by geographical location from north to south and found that the incidence of eczema and allergy to peanut and egg increased from north to south. (Asthma showed no correlation.)
Strangely, the authors don't quantify how much sunlight children might be exposed to in these regions, even in crude average numbers. You'd think that if they are going to make the claim, as they do, that their numbers provide support for the hypothesis that kids are developing eczema and allergies because they aren't getting enough sunlight--or to go further and say that the lack of sunlight is reducing vitamin D levels in these kids and THIS is what is causing the eczema and allergies--that they might make some effort to refer to how much sun kids are exposed to. But no.
This leaves me wondering what other factors might account for the incidence of eczema and allergies increasing as you go southward through Australia. Also, I wonder whether it might be true that sunlight helps keep eczema down (I have no personal experience with this) by some other mechanism than vitamin D production. Perhaps exposure to long-wavelength--safer--UV radiation affects skin cells in some beneficial way that I'm not aware of.
I had my own vitamin D level measured last week. According to Kaiser Permanente, the normal range for 25-hydroxy vitamin D in the blood is 25-79 ng/ml. My level is 32 ng/ml. Relatively low, but in the normal range. So it's unlikely that for me personally a lack of vitamin D is what's causing my eczema.
Once I'm done with my habit-reversal trial, it might be worth taking some supplemental vitamin D to see whether it has any effect.
Friday, January 21, 2011
Most definitely no definite answer for vitamin D and eczema
As with most of the posts on this blog, I wrote the last one in a hurry--there's only so much free time if you've got a job and a commute and two kids. Being in a rush makes blogging unsatisfying as a writing exercise, both for the strength of argument and the quality of prose. A blog is nothing more than a series of first drafts, and the expression "shitty first drafts" (Google it) exists for a reason.
So I thought perhaps I'd been too quick to diss vitamin D as potentially having benefit for patients with eczema. A PubMed search turned up this review paper, which I am inclined to trust as credible for several reasons:
That's not enough to make me rush out and buy barrels of vitamin D though, especially since there are multiple side effects of an overdose, including kidney damage. As Caroline commented after my last post, the issue is really whether you're deficient or not, not that it's a good idea to take an excessive dose. (I sent her a copy of the paper so we can look forward to learning her perspective.)
A reading of the paper turns up a bewildering number of studies in cells and mice that produced conflicting results. E.g. mice deficient in vitamin D had helper T cell responses greatly slanted toward type 1 instead of type 2; but it's known that, in humans, eczema patients have overactive type 2 helper T cells. If you were to take that one paper as gospel, you'd try to deprive yourself of vitamin D to cure your eczema.
Another paper shows that adults who received vitamin D supplements as infants were more likely to develop atopy and allergy. But then opposing papers balance this out. Dosage and timing could be crucial.
So, as with most science, the conclusion is the familiar "more research needed."
So I thought perhaps I'd been too quick to diss vitamin D as potentially having benefit for patients with eczema. A PubMed search turned up this review paper, which I am inclined to trust as credible for several reasons:
- one of the two authors is Donald Leung, head of pediatric allergy and immunology at National Jewish Health Center in Denver; editor-in-chief of the Journal of Allergy and Clinical Immunology; and principal investigator for the Atopic Dermatitis Research Network
- the authors cite 73 papers instead of just one or two selected to support their cause; they present a balanced view with opposing data
- they don't use scary headings like "Is This Nutritional Deficiency Ruining Your Heart?" or provide a convenient link to an online store with products such as krill oil, vitamin spray, and bidets.
That's not enough to make me rush out and buy barrels of vitamin D though, especially since there are multiple side effects of an overdose, including kidney damage. As Caroline commented after my last post, the issue is really whether you're deficient or not, not that it's a good idea to take an excessive dose. (I sent her a copy of the paper so we can look forward to learning her perspective.)
A reading of the paper turns up a bewildering number of studies in cells and mice that produced conflicting results. E.g. mice deficient in vitamin D had helper T cell responses greatly slanted toward type 1 instead of type 2; but it's known that, in humans, eczema patients have overactive type 2 helper T cells. If you were to take that one paper as gospel, you'd try to deprive yourself of vitamin D to cure your eczema.
Another paper shows that adults who received vitamin D supplements as infants were more likely to develop atopy and allergy. But then opposing papers balance this out. Dosage and timing could be crucial.
So, as with most science, the conclusion is the familiar "more research needed."
Wednesday, January 19, 2011
Vitamin D isn't the answer
In a recent conversation with Caroline over at Fighting Eczema, she mentioned that she wanted to look into whether having low levels of vitamin D might be correlated with risk of developing eczema. The theory was her own, but she mentioned "a strong advocate for the benefits of vitamin D on the internet, Dr. Mercola." I thought I'd check the man out, since I'd seen another article or two by Mercola in the general health news.
I was seriously unimpressed. Joseph Mercola is a self-appointed "expert" on "natural health" who, in short, is a scaremonger peddling fears of modern technology and the drug industry. Natural cures are best, he says; and just in case you were wondering where to get them, you need only visit his extensively stocked online store.
He's big on vitamin D, for sure; has an entire section devoted to it. According to him, it cures just about everything. Count me a skeptic. Every doctor I've asked, and a few I haven't, has told me that anyone eating a balanced diet has no need of any vitamin supplements at all. Vitamin C, and perhaps a few others, are flushed out of your body in your urine, but the rest accumulate in your tissues. Too much of a vitamin or mineral is a bad thing, just like too little. No way would I take an excessive dose of one particular substance unless I'd been diagnosed with a severe deficiency.
(Amusing aside: in my 20s, for a short while, I took several multivitamins a day, in the belief they would make me super-healthy. I developed a remarkable case of hemorrhoids that cleared up when I stopped taking the pills.)
Caroline, I mean no offense--in the search to cure eczema for our children and ourselves, we ought to explore every avenue. But vitamin D isn't going to be the answer.
If you're interested--I recommend it--the blog Science-Based Medicine has a comprehensive and entertaining takedown of Mercola. Here's one segment. The FDA has served Mercola with two warning letters concerning unwarranted claims for seven of his products.
I was seriously unimpressed. Joseph Mercola is a self-appointed "expert" on "natural health" who, in short, is a scaremonger peddling fears of modern technology and the drug industry. Natural cures are best, he says; and just in case you were wondering where to get them, you need only visit his extensively stocked online store.
He's big on vitamin D, for sure; has an entire section devoted to it. According to him, it cures just about everything. Count me a skeptic. Every doctor I've asked, and a few I haven't, has told me that anyone eating a balanced diet has no need of any vitamin supplements at all. Vitamin C, and perhaps a few others, are flushed out of your body in your urine, but the rest accumulate in your tissues. Too much of a vitamin or mineral is a bad thing, just like too little. No way would I take an excessive dose of one particular substance unless I'd been diagnosed with a severe deficiency.
(Amusing aside: in my 20s, for a short while, I took several multivitamins a day, in the belief they would make me super-healthy. I developed a remarkable case of hemorrhoids that cleared up when I stopped taking the pills.)
Caroline, I mean no offense--in the search to cure eczema for our children and ourselves, we ought to explore every avenue. But vitamin D isn't going to be the answer.
If you're interested--I recommend it--the blog Science-Based Medicine has a comprehensive and entertaining takedown of Mercola. Here's one segment. The FDA has served Mercola with two warning letters concerning unwarranted claims for seven of his products.
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