I came across this article yesterday and wanted to share!
B vitamins, particularly vitamin B-12 (which comes from animal sources), can be difficult for vegetarians and vegans to get adequate amounts of in their diets. Overtime, deficiencies in B-12 can lead to cognitive decline, nerve damage and are thought to be a main contributing factor in the development of Alzheimer’s disease, which explains why supplements of this nutrient are popular.
A large-scale trial (22,000 participants) recently found that this may not be true. In fact, even after ~2 years, individuals taking the supplements did not demonstrate improvements in their cognitive function. Keep in mind, this study only looked at supplements and didn’t get into dietary B-12, so it is unclear whether or not this would have made a difference in cognitive outcomes.
However, the results showed consumption of the supplements did lead to a signification decrease in homocysteine levels (as compared to the placebo group). Since elevated homocysteine causes inflammation, this suggests the supplements aren’t necessarily without value.
Vegan B-12 sources are a bit controversial, but aside from supplements, nutritional yeast and fortified non-dairy milks and cereals may be helpful in reducing deficiency risk. As with all supplements, actual vs. advertised vitamin/mineral content may not align, so make sure you do your research and pick a trusted brand.