Saturday, January 7, 2012

New Study on Vitamin D and Depression

Quite a bit of feedback on my rant from yesterday.  In truth I would probably keep these rants to myself, except I keep getting asked about what I think about certain matters, so I'm assuming there is wider interest in these opinions.  The rants garner big audiences, for what it is worth.  If you don't like them but enjoy the more sciencey stuff, you can stick to my Psychology Today blog, as I doubt the rants will get cross-posted over there.

To answer and clarify some general questions from the comments: (Sleeper Agent Get Burned)

I'm not expecting to rain on anyone's parade.  There is an inevitable pull to the side of quasi-scientific posturing in the paleosphere.  Sometimes I just like to yank back.  The even-tempered bloggers (Paul Jaminet and Stephan Guyenet) have large blogrolls.  I do not.  Like Kurt Harris, I'm a bit more on the cranky side, and I consider my blogroll to be something of an endorsement, meaning I often find valuable information and interesting ideas on those blogs without a huge amount of garbage.  Of course nearly all of those on the blogroll have published something I vehemently disagreed with.  That's pretty cool, of course.  Differing opinions open the mind.  When it goes too far into the land of obvious pseudoscience and woo or dangerous advice or the endorsement of that, it is no longer my cup of tea, and I drop the blog.  I've dropped several blogs in the past but I just haven't mentioned it.  Sometimes, though, not mentioning or pointing out something is taken as tacit approval.

As to Gary Taubes' petition, I merely have a problem with the very specific nature of the treatise. He basically asks us to sign a petition endorsing his particular theory of obesity, which involves insulin and the adipose tissue as the main regulating mechanism.  It should be obvious to anyone reading my blog that I don't agree with that theory and feel it has been disproven.  That doesn't mean I don't think insulin is involved, or that low carb diets aren't helpful, or that I'm eating a 90% carb diet of unsalted potatoes.  I just wish Gary had been a tad less specific - more of a "let's study low carb diets and not be afraid of fat" petition, and "let's not give up on obesity just because most people fail at diets."  I'm 100% in favor of not giving up on obesity.

As to supplements, I take some myself and have written extensively about them.  However, I don't think they are the be-all, cure-all, and used pharmacologically, a risk-benefit analysis ought to be taken, though the full data will never be known.  In addition, supplements won't cure a crappy diet, crappy sleep hygiene, and complete other lack of self-care or stress reduction.  I like Stumptuous' rant for that reason.  It's a step back.  Let's evaluate as best we can the safety and efficacy, and more often than not the shiny new supplement with the promising data becomes the harmful supplement when more data is gathered.   The same is true for prescription pharmaceuticals.

Speaking of supplements, vitamin D is a tricky one.  It was the paleosphere darling for a while.  The unheralded sunshine vitamin the dermatologists wanted to take from us with their creams and sun hats.  And while getting a certain amount of D to keep from being deficient is clearly helpful, and it seems there is decent data to show that "deficient" for the IOM may be too low when one considers cancer data and being prudent,  it is also clearly problematic to go for the gold and have the highest vitamin D level around (not that anyone recommends that).  In the past year or so, the promising pro-Vitamin D papers have been followed by some disappointing findings.  Some very thoughtful editorials have been written in JAMA and Nature on the subject (not even by dermatologists).

I've posted on vitamin D and depression before (here and here).  It seemed very promising when I read the articles at the Vitamin D Council.  But when I looked up the actual scientific studies, there wasn't much at all.  I could honestly pull together a sober recommendation that there are plausible reasons to think D levels would effect mood, and since it also plausibly could prevent cancer and help bones, seems reasonable to stay in a nice healthy range.

But of course, I keep an eye out.  And this week on twitter a new paper came to my attention from my own alma mater (1).  This paper is a population study of vitamin D levels and depression scores.  5 previous population studies have been done, with 3 showing correlations between low levels and depression, and two showing no correlation.

As I've explained before, the brain needs vitamin D for neuronal repair.  As depressive disorders can be progressively neurodegenerative, in a similar way but with far less global neuron damage as dementia, it is very plausible that low vitamin D levels could hasten or worsen an existing depression, or perhaps even cause depressive symptoms.  Indeed, low levels of vitamin D have been associated with increased inflammatory markers, and inflammation is associated with depression.

The current study is the largest population-based study to date, of 12,600 some odd relatively healthy patients at the Cooper Clinic in sunny Dallas, Texas between 2006 and 2010.  The sample was 68% men with a mean age of 52.  All participants had baseline 25 (OH) vitamin D (actually D2+D3, though D2 levels are typically negligible in my experience unless someone is taking a prescribed D2 supplement) and had level of depression tested with a standard 10 item questionnaire.

Patients with a history of depression were analyzed separately.  There were significantly more women in that group, as well as a significantly higher number of people with history of diabetes, cardiovascular disease, and cancer.  Those with a history of depression had a lower education level, were less likely to exercise, and had a higher BMI.  Age, smoking history, and vitamin D levels were not significantly different in the patients with a history of depression compared to those without.

Among these 12,600 folks, low vitamin D (less than 20 ng/ml) was very common - 50.7% of the sample was affected.  Those who exercised regularly were much more likely to have normal vitamin D levels than those who did not.  Those with high levels of vitamin D were significantly less likely to have current depression symptoms than those who had deficient vitamin D.  The effect was stronger in the group with prior history of depression, and was also stronger in October to March than in the sunnier times of the year.

The study was limited by the observational nature and the relatively brief screening tool used to diagnose depressive symptoms.  But the findings are interesting, and certainly it is still reasonable not to be deficient in Vitamin D, whether you are depressed or not.

22 comments:

  1. The Institutes of Medicine about a year ago reviewed the RDA for vitamin D, and didn't recommend the much higher intake level that I and others had predicted.

    I'm not sure who's right.

    -Steve

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  2. You incorrectly said " data is gathered." Instead of "data are gathered." Oh boy, now you've done it! I'm dropping your sloppily-written, rant-ridden blog!


    Just kidding.

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  3. Couldn't it be that some people need more vitamin D than others, and that some people with "depression" don't have the same problem that other people have, and only some are helped with vitamin D? There are probably some people who are greatly helped by getting proper levels of vitamin D, and others not helped so much, if at all. On the other hand, given the various benefits of proper levels of Vitamin D, even if it doesn't help depression, it may help with other health issues.

    My favorite study, as presented by the Vitamin D Council, was the reduction of cancer with proper levels of Vitamin D, particularly the various internal cancers. Getting cancer could depress you, and taking vitamin D after that might not cure that depression.

    And we could propose that unlimited sun exposure is not altogether a good thing, considering the tanning and protection that generally occurs in individuals after repeated heavy doses and localized increased skin pigmentation in various populations near the equator. So there seems to be a point of diminishing returns even for Vitamin D?

    It gets too close to magical thinking for me to believe that all depression will be alleviated by taking Vitamin D. Maybe some depression will be reduced. Modest doses are probably a good thing, if you cannot get regular sun exposure.

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  4. Rant on, Dr. Deans. Rant on.

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  5. I'll take my science with a dose of reality and a few rants sprinkled on top over the pseudoscience bunk any day. LOL @ the Stumptuous' rant. That's a good one :-)

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  6. @Richard - I don't know enough about the whole vitamin D metabolism pathway to make any authoritative comment but it might not just be the amount of vitamin D required that is different but rather whether the vitamin D receptors are able to do their job also: http://www.ncbi.nlm.nih.gov/pubmed/15854747
    I do remember a while back Chris Masterjohn wrote a post about vitamin D synthesis and cholesterol which I don't know would be relevant or not i.e. did the participants actually have low cholesterol levels which subsequently impacted on vitamin D status?
    As for the rant Dr D, perhaps another famous Kaiser Chiefs record might have been more appropriate - "I predict a riot". Molotovs at the ready...

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  7. The "Vitamin D for depression" idea does sound like someone may be mistaking correlation for causation again. I must read this blog more often.

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  8. Hi Emily
    Thanks for the great blog.

    Speaking about supplements, my 6 yo son has just been prescribed "SAMe"(S-adenosylmethionine) and zinc to counter behavioural issues (tantrums etc). The doctor is also speaking of a condition called Pyroluria which, after a bit of research, does not appear to covered in many mainstream medical publications.

    Do you think it is sensible and safe to be giving these supplements to a 6yo?

    Many Thanks

    Matt

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  9. Steve - I feel the IOM was a bit conservative (I'm thinking 35-50 is a good range for most people). But I did not read their 450 page report, either.

    Aaron - thank goodness I can always count on you for grammar policing! I never took any English after high school…

    Paul - you definitely picked the more appropriate song

    Anarchic teapot - In my clinical experience, I find a lot of vitamin D levels that are in the TOILET. We're talking 4s, 6s, 11s, etc. Just repleting the D doesn't seem to help, but over time, if the D is off, it seems to make everything harder to fix, and those who are repleted seem to very gradually get better more easily than those who don't follow through with the supplements. It is a subtle effect, and the "noncompliance" of the others is also an obvious confounder.

    Matt - SAMe has several dozen clinical trials showing efficacy but I'm not aware of any in children. In addition, it can raise homocysteine which could be a long term problem. It's important to make sure you are getting the other B vitamins if you take SAMe in order to make sure the homocysteine is being recycled back into methionine. As to zinc, it can interfere with copper absorption at high amounts but as long as you aren't overshooting the RDA by a huge amount I think it's probably okay. Unfortunately, without copper, one can die of heart arrythmia and children are more sensitive to these heart problems even than adults.

    I feel it might be more of a marker of inflammation and problems than the cause, though for those who don't absorb zinc well, who don't get enough in the diet, or who waste it especially fast (as has been seen in kids with ADHD) might need supplements.

    Pyroluria is a bit of an alt med term. Most of the research/papers were done by one guy, and the urine test for it seems a bit sketchy. However, it certainly seems plausible that some people aren't able to utilize zinc/B6 well due to certain genetic issues.

    In general I am more of a fan of making sure one gets food sources of zinc (eggs and shellfish are good sources - beef liver will provide copper). MEat, green leafy veggies and organ meats and eggs are great sources of the B vitamins. The vitamins are more of an insurance policy especially if kids are picky eaters.

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  10. I've been eating a Paleo diet (modified to include healthy starches, like sweet potatoes, yams, potatoes, bannana and some rice) for about three years. I've been doing CrossFit and occasional yoga for the same period of time. After experimenting with various supplements, I've settled on three: a multi-vitamin, some probiotics and Vitamin D. If I can't eat enough fish, I'll kick in some fish oil once in a while too. I suspect that I'm doing it right because I don't get sick, even though I have two small children.

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  11. Chris Masterjohn has written about different cultures having possibly different "normal" values of calcidiol and calcitriol.

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  12. Emily let me ask you this, say you have two people both depressed to equal amounts that you have been following for three years. One has a HS CRP of 16 and the other has a HS CRP of 3, and both have low D levels consistently and live in Boston year round. What would you do clinically with respect to the HS CRP and the D in each case for their depression. Assume that this is a consistent finding over say nine months. Bring your theory to practice for us.

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  13. I would be more aggressive repleting and checking D with the high CRP, sign of obvious ongoing inflammation (autoimmune, infectious or whatever the cause). Would try nail down the cause. Would also be more aggressive in eliminating trans fats and other nasties from the diet.

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  14. Since everyone is ranting and grammar is being corrected, why not typography...

    I've noticed recently on the blogosphere that the two spaces after the period has become very popular (here I think of Masterjohn, Guyenet and others...)

    I wonder why :)

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  15. Dr Deans' last post was a 'rant'? Well I'll be...

    I'd like to see a rant from Paul Jaminet. It would probably start like this: "I'm sorry to say I have several points of disagreement with my esteemed colleague..."

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  16. There are so many vitamin Ds around. Some are sulphated and water-soluble, some travel their long journey with lipoproteins attached. I wonder which really manage to go through the blood-brain barrier. Any idea? Apparently if a mother wants to deliver vitamin D to a baby through milk it has to sulphate it. Same applies to placental absorption. Chances are if you oversupply the raw form absorbed through the gut via cholesterol you decrease the other one. It is a very neglected area unfortunately.

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  17. Hey there, I love your blog. I came across it after discovering B-12 and Vitamin D deficiencies via bloodwork.

    In an old post you said that the posts regarding Schizophrenia were popular and ADHD were unpopular. I was wondering if you could write up something on OCD? I'm quite curious to know your thoughts about it in regards to Evolutionary Biology.

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  18. Emily, have you seen this video? It gives a possitive view of supplements:

    Aging slowed in mice with supplement mix
    http://www.cbc.ca/news/health/story/2011/12/28/aging-longevity-chasing-cures.html

    Incredible effect on mouse.

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  19. I agree with scorp2780. OCD baffles me to no end - and why high dose SSRIs help, too.

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  20. Could it be a problem in synthesizing the active form due to low magnesium status? If many people are deficient in magnesium, and if people with depression are generally more deficient (not sure if this is true but I don't need to convince you that magnesium is a brain's best friend), then we should expect to see less efficacy of vitamin d in these people.

    Vitamin d council says that magnesium is important for vitamin d metabolism http://www.vitamindcouncil.org/about-vitamin-d/vitamin-d-cofactors/magnesium/ and Stephan G wrote a post about it once. If I knew that the general population had tons of magnesium available then I wouldn't criticize 25 (OH) levels as a marker for vitamin d status, but because of the circumstances I have to.

    Also excessive inflammation can interfere with vitamin d metabolism, I think. And that is prevalent in depressed people for sure.

    What do you think?

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  21. Lack of vitamin D can't help in building nutrients needed in our brains. We need to take vitamin D for the proper stimulation of our brain.

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