Fascinating and very well written. You’ve turned a literature review into a gripping detective story.
I’m not complaining because you’ve done an amazingly thorough job with what you looked at, but I’ve been supplementing vitamin D purely for mood effects. I saw a couple of small RCT studies on clinical levels of seasonal affective disorder (SAD) which showed very, very large effects of bolus supplementation of vitamin D. This population might very well be self-selected for abnormally low serum levels causing the SAD.
I have never experienced severe SAD, but I did notice that when I moved from cloudy northern Michigan to sunny Colorado, my mood in the winter noticeably improved, even though I hadn’t thought about sunshine or vitamin D levels. Most psychological effects exist on a continuum, so I reasoned, as you have, that our ancestral populations got a lot more sunlight and therefore a lot more vitamin D synthesis than we have.
This was a long time ago, so I didn’t save the references for those studies. I definitely recommend anyone who noticeably suffers from seasonal affective issues to supplement with vitamin D. Doing low-level supplementation, and not in a bolus for the reasons you’ve given, seems wise.
Mood disruptions for a substantial portion of the year should be expected to have knock-on effects in activity levels and, therefore, overall health. This would be expected to show overall health benefits. I think it would be enough alone to account for the modest improvements in all-cause mortality that you arrive at.Given your analysis, I’d probably conclude that the benefits are coming mostly from raising levels in the few people who are very deficient.
Thank you! I didn’t look much at studies looking at the impact of vitamin D on mood, but at a glance, the RCTs seem incredibly inconclusive. This meta analysis found a good looking effect-size, but the funnel plot suggests a horrific amount of publication bias. There’s an ongoing study that looks well-designed but it’s happening in Finland (which already fortifies their food to the sky) and they don’t screen for low baseline levels and the sample is small, so it seems unlikely to be definitive...
Fascinating and very well written. You’ve turned a literature review into a gripping detective story. I’m not complaining because you’ve done an amazingly thorough job with what you looked at, but I’ve been supplementing vitamin D purely for mood effects. I saw a couple of small RCT studies on clinical levels of seasonal affective disorder (SAD) which showed very, very large effects of bolus supplementation of vitamin D. This population might very well be self-selected for abnormally low serum levels causing the SAD. I have never experienced severe SAD, but I did notice that when I moved from cloudy northern Michigan to sunny Colorado, my mood in the winter noticeably improved, even though I hadn’t thought about sunshine or vitamin D levels. Most psychological effects exist on a continuum, so I reasoned, as you have, that our ancestral populations got a lot more sunlight and therefore a lot more vitamin D synthesis than we have. This was a long time ago, so I didn’t save the references for those studies. I definitely recommend anyone who noticeably suffers from seasonal affective issues to supplement with vitamin D. Doing low-level supplementation, and not in a bolus for the reasons you’ve given, seems wise. Mood disruptions for a substantial portion of the year should be expected to have knock-on effects in activity levels and, therefore, overall health. This would be expected to show overall health benefits. I think it would be enough alone to account for the modest improvements in all-cause mortality that you arrive at.Given your analysis, I’d probably conclude that the benefits are coming mostly from raising levels in the few people who are very deficient.
Very nice work.
Thank you! I didn’t look much at studies looking at the impact of vitamin D on mood, but at a glance, the RCTs seem incredibly inconclusive. This meta analysis found a good looking effect-size, but the funnel plot suggests a horrific amount of publication bias. There’s an ongoing study that looks well-designed but it’s happening in Finland (which already fortifies their food to the sky) and they don’t screen for low baseline levels and the sample is small, so it seems unlikely to be definitive...