About six weeks ago, I extensively revised the articles on nutritional supplements on my mcmanweb site. There was very little in the way of new information I added. Nor do I profess any deep understanding on the topic. But there were a number of general themes I needed to underscore loud and clear. With your help here, maybe we can explore them in more depth in future posts, but first a few broad outlines:
The Evidence for Supplements for Treating Mental Illness is Weak
In the first of the supplements articles on mcmanweb, I turn to what we know about the eye to contrast what we don't know about the brain. In particular, I make note of the evidence that supports lutein as a treatment to prevent age-related macular degeneration. The findings in favor are hardly conclusive, but are nonetheless convincing. A lot of this has to do with a phenomenon we can pinpoint. We understand the condition and we can identify its causes and effects, including the eye’s physical mechanics. Moreover, we can link lutein to both the mechanics and a clinical benefit.
We can’t come close to this with mental illness. What we call depression and bipolar and anxiety and the like are at best approximations and at worst totally misleading. We are only scratching the surface of our understanding of the brain, which means we can only theorize what goes wrong. Whether it’s a med we’re talking about or a supplement, we have yet to link any agent to both mechanics and a clinical benefit.
So, imagine testing omega-3 for bipolar. A 1999 pilot study showed promising results, but larger trials failed. Consider: Bipolar is a highly complex illness, with many many different causes and effects, manifesting in a countless variety of shapes and sizes. The experts can’t even agree on the dimensions of the illness. Moreover, we can only make wild guesses how omega-3 works on the brain.
Undoubtedly, there is a population of bipolar patients who would benefit enormously from omega-3. But we have no way of identifying these people in advance and separating them out from those likely to fail. Thus, a clinical trial is doomed from the start.
Bio-individuality enters into the picture. Low folate (vitamin B9) levels have been linked to depression. But a clinical trial to measure for folate treatment for depression (we haven’t had one) would include people with normal and high folate levels, as well. So the failures (only about 30 percent of the population has low folate) would mask the successes.
As I point out in my article:
Thus, if you are skeptical of meds for psychiatric conditions, be equally skeptical of supplements for psychiatric conditions. No matter what you may hear - from any source - we have no credible evidence remotely approaching what lutein does for macular degeneration, nor are we likely to for decades to come.
Absence of evidence, of course, does not mean evidence of absence.
You may get a good result trying Vitamin X for bipolar or Supplement Z for depression, but you might want to shift your focus away from the illness, namely: