Recent scholarship into new uses for familiar vitamins and minerals has tracked some surprising and positive correlations. I’ve recently read about Ginseng boosting testosterone, and even common Biotin improving cognitive function.
Unfortunately, not all news in this field is good news. While multiple studies and sources have confirmed the positive effects of Vitamin B1 (Thiamine) on Cognitive Impairment (CI), the literature on B12 and B6 has not been as favorable.
One Study with Positive Results
The only study I could find–either through literature or cross-reference–was a placebo controlled study of healthy, elderly men. Half of participants took a placebo, and half took a B6 supplement. The study tested for the quantitative values of memory and cognitive performance, and the qualitative values of memory, mood, and “mental effort.”
Researchers only found any improvement in memory, and it should be noted that even in this instance, their data is now almost 30 years old.
The Rest of the Field
Following the mixed results of the previous study, and some of the very promising links between Thiamine (B1) and cognitive function, literally dozens of studies of Vitamins B6 and 12 have been conducted, looking for any link between these nutrients and brain functions.
Literature reviews can be a double edged sword. They are not, in and of themselves, direct trials or studies of participants and outcomes. So in some cases, they can mislead a casual observer. But in other cases, when the entirety of the literature review can only find one conclusion, it can save a researcher a lot of time and energy.In this case, I’ve found a literature review from one of the most prestigious publications in medicine–the Journal of the American Medical Association (JAMA).
They searched literally thousands of studies, found 50 that met criteria, and 14 that had rigorous enough results to merit consideration. For B6, they found absolutely no indication of benefit to cognitive performance–not in mood, memory, function, or anything else.
For B12, they found that half of the studies did show improvement–but that the other half showed a decrease in function.
Doing my due diligence, of course, I reviewed as many of the citations as have any public data–the researchers for JAMA didn’t not misrepresent the data. As best as can be described is that some combination of B vitamins tend to have an improvement on memory–in some cases. But there isn’t a good molecular mechanism identified, leading many researchers to theorize that the correlation is not related to the B vitamins individually.
An Example Study
Taking a closer look at a highly targeted study, we find a recent trial of over 7,000 women, over the course of 5 years. Researchers found no associations between Vitamin B6 or B12 and mild cognitive impairment or preventing the early signs of dementia.
There is one research study that didn’t fit neatly into any category, mostly because it was–well, odd. Japanese researchers publishing in Translational Psychiatry found that depriving adult mice of adequate Vitamin B6 impaired their cognitive function as well as their social development.
This research is really very new, and I haven’t seen any other scientists building off of it, yet–though it has already been accessed over 5,000 times and garnered 6 separate citations in other literature.
Most importantly, these scientists may have identified a mechanism–they believe that Vitamin B6 deficiency may result in overstimulation of the system which produces and releases norepinephrine. This hyperactivity, in the opinion of the researchers, may be responsible for the decline in mice.
These data require more study, because so far this has not been observed in humans. It does not mean these processes are not occurring in humans–only that they haven’t been studied for or seen.
The overwhelming scientific data does not support the use of either Vitamin B6 or B12 for CI. There is some outlying data that could provide further study–for instance, why do some B12 studies show an improvement, while others show a decline? Why does B6 affect mice more than people?
Until these outliers are further tested against, and until those studies yield contradictory data, it appears that there is no support for the hypothesis the Vitamins B6 and B12 support cognitive function.