Those of us who are now in the depths of winter may be suffering not just from the cold, but the relative lack of light too. Shortened days have the ability to depress the mood and precipitate ‘seasonal affective disorder’ (SAD) or ‘winter blues’. Back in October I wrote about this condition, and in particular some research which suggests that light from the ‘blue’ part of the electromagnetic spectrum can be effective in combating it.
However, very rarely does a particular medical condition have one cause. While lack of ‘blue’ light may indeed be a factor in the development of SAD, it does not mean it’s the only potential factor. One other candidate that’s at least worth considering in this respect is vitamin D deficiency. Last year, I wrote about some evidence which suggests that vitamin D has natural anti-depressant action.
After that post I’d pasted in a previous piece which refers to research in which vitamin D therapy (at relatively low doses, too) appears to have helped improve mood in the winter [1]. Another interesting study assessed the impacted of tanning bed sessions on mood [2]. As part of this study, frequent users of tanning beds were given access to either or two tanning beds, one of which supplied ultraviolet light, while the other didn’t. Overwhelming, individuals showed a preference for the UV-light supplying bed. Exposure to this bed was also associated with greater feelings of relaxation too. The suggestion here is that mood-related benefits associated with UV light exposure may be reinforcing the behaviour of those who regularly use sunbeds. In the UK this year there have been reports of young adults apparently exhibiting signs of ‘tanning’ addiction. Could it be that some of these individuals are using sunbed sessions to ‘self-medicate’ their way to improved mood? This may be important because there is talk here in the UK of banning unsupervised sunbed sessions for those under the age of 18.
Higher vitamin D levels have been associated with a reduced risk of a wide range of conditions, and there have been calls for recommended intakes of this nutrient to be increased (see here for more on this). One of the potential benefits of optimising vitamin D levels may be improved mood, which is likely to have important implications for mental health and quality of life.
Here’s some purely anecdotal information, but I think it’s persuasive.
I recently moved back to the Pacific Northwest (U.S.). When I lived here previously, I had serious problems with SAD, that were only alleviated by using an intense light specifically designed to deal with that. It worked at the time.
I was concerned that I would have to do the same this time. But a couple of years ago, after reading a lot about Vitamin D, I started taking large amounts, generally 50,000 units/week.
I haven’t been ill in that time, which is interesting. But what I find even more interesting is that I have had no problems with SAD over two winters now, and I’m at a higher latitude than I was the last time I was in this area.
This is persuasive to me, because I had no anticipation of this happening. I had not heard that Vitamin D improved mood and helped SAD until recently, long after the time when I expected to become depressed.
So there ya have it.
I am glad to know for sure, patients with severe major depression would have to have baseline 25(OH)D blood levels, be treated with doses of vitamin D adequate to raise their levels to at least 35 ng/mL for several months and be compared to a normal control group treated with placebo. No one has ever published such a study.