A vitamin B-rich diet is highly recommended for optimal cognitive and physical function, and insufficient B vitamin intake has been linked with elevated levels of oxidative stress and neural inflammation, indicated by increased blood plasma homocysteine.
At the same time, however, little is known about neural biomarkers of oxidative stress — as quantified via proton magnetic spectroscopy (1H-MRS), and the association between such blood and neural biomarkers has not been widely studied.
To B or not to B
Based on this, researchers at Swinburne University and Austin Hospital in Melbourne conducted an RCT to assess the direct impact of six months of high-dose B vitamin supplementation on metabolic blood and neural biomarkers.
They recruited 32 healthy adults (12 male, 20 female) between the ages of 30 and 65, who were given either Blackmores' Executive B Stress Formula tablets, or placebo that contained a small amount of glucose and riboflavin (2mg of B2).
Each participant took two tablets daily — one at breakfast and one at lunch — for six months. The researchers performed a series of blood tests, including tests for vitamins B6 and B12, folate and homocysteine levels at baseline and after the trial.
They also performed 1H-MRS of the posterior cingulate cortex (PCC) and dorsolateral prefrontal cortex (DLPFC) in the study participants before and after supplementation.
Subsequently, they reported that the supplemented group experienced an increase in blood plasma vitamin B6 and B12 levels, as well as a decrease in blood plasma homocysteine. There was, however, no change in the group’s folate levels.
Additionally, the researchers observed significant relationships between vitamin B6 and N-acetylaspartate (NAA, the second-most concentrated molecule in the brain), creatine and choline, as well as between vitamin B12 and creatine.
They also found that within the supplemented group, NAA in the PCC increased, though not in a statistically significant manner.
Furthermore, they noted that although vitamins B6 and B12, along with folate, usually worked together to maintain cardiovascular, neural and psychological health by regulating homocysteine, the results suggested that the higher levels of blood plasma vitamin B6 and B12 was responsible for lowering blood plasma homocysteine levels.
They added that since the vitamin B6- and B12-dependent enzymes — cystathionine B-synthase and methionine synthase, respectively — drove homocysteine catalysis, supplementation with a high-dose vitamin B multivitamin could "promote the breakdown of homocysteine to a greater extent than folate".
However, many food products sold in Australia, such as bread and milk, are already fortified with folate, and this could explain why participants experienced minimal change in their levels of red cell folate.
More B-grade research required
The researchers acknowledged that the study's small sample size was a limitation and therefore, said the results would be better interpreted as "preliminary findings that warrant further investigation with a larger sample".
They stated that this was the first study to have assessed the efficacy of high-dose vitamin B multivitamin supplementation in regulating the relationship between blood and neural biomarkers of oxidative stress.
In conclusion, they wrote: "Blackmore's Executive B Stress Formula was shown to reduce blood markers for oxidative stress (homocysteine) and increase brain markers for oxidative metabolism and myelination, but not energy or cellular membrane metabolism.
"Increasing levels of blood high-dose B-group vitamins were also associated with increased neural metabolism. These findings suggest that high-dose B-group vitamin supplementation might be effective in reducing oxidative stress and inflammation through increasing oxidative metabolism, and may promote myelination, cellular metabolism, and energy storage.
"Together, these findings highlight the importance of B-group vitamins in the maintenance of brain health in healthy adults, and may have important implications in the prevention and alleviation of disease and disability."
"The Effect of a High-Dose Vitamin B Multivitamin Supplement on the Relationship between Brain Metabolism and Blood Biomarkers of Oxidative Stress: A Randomized Control Trial"
Authors: Talitha C. Ford, et al.