Summary: A study from the University of York suggests that regular consumption of Marmite may alter brain activity by increasing levels of the inhibitory neurotransmitter GABA.
Source: University of York.
Researchers at the University of York report a possible connection between daily Marmite consumption and changes in cortical activity, linked to an apparent rise in a chemical messenger important for healthy brain function.
In the study, participants who ate a teaspoon of Marmite each day for one month were compared with a control group that consumed peanut butter. Using steady-state electroencephalography (EEG) to measure electrical responses to visual patterns, the Marmite group showed a pronounced reduction — roughly 30 percent — in the brain’s responsiveness to visual stimuli relative to controls.
Investigators propose that this change may result from Marmite’s high content of vitamin B12 and other nutrients that support the production of gamma-aminobutyric acid (GABA). GABA is the brain’s primary inhibitory neurotransmitter and functions to reduce neuronal excitability, effectively “turning down the volume” of cortical responses when appropriate. Proper balance between excitation and inhibition is essential for normal brain function.
Because Marmite consumption appears to be associated with increased markers of inhibition, this work is notable as one of the first controlled demonstrations that a short-term dietary intervention can influence cortical excitation–inhibition balance in humans. Imbalances in GABA signaling have been implicated in a number of neurological conditions, which is why dietary modulation of these processes could be of scientific interest.
Anika Smith, a PhD student in the Department of Psychology and the study’s first author, commented that the results indicate dietary choices can affect cortical mechanisms of excitation and inhibition in ways consistent with elevated GABA. She also noted that effects persisted for an extended period: participants continued to show altered responses for around eight weeks after stopping the Marmite regimen, suggesting that dietary changes may produce longer-lasting shifts in brain function than expected.
Dr Daniel Baker, Lecturer in the Department of Psychology and senior author of the paper, said the high concentration of vitamin B12 and related nutrients in Marmite is the most likely explanation for the observed change in visual responsiveness. He emphasized that while the findings reveal a link between diet and neural processes involving GABA, they do not constitute medical advice or a therapeutic recommendation. People with medical conditions should consult their general practitioner for treatment.
Funding: This research was supported by the American Federation for Aging Research.
Source: Saskia Angenent — University of York
Image source: NeuroscienceNews.com image credited to WestportWiki (illustrative).
Original research: Abstract for “Dietary modulation of cortical excitation and inhibition” by Anika K. Smith, Alex R. Wade, Kirsty E.H. Penkman, and Daniel H. Baker, Journal of Psychopharmacology. Published online April 4, 2017. DOI: 10.1177/0269881117699613
Abstract
Dietary modulation of cortical excitation and inhibition
The balance between excitatory and inhibitory neurotransmitters influences both neural responses and behavior across species. This study tested whether a dietary intervention intended to increase levels of the inhibitory neurotransmitter GABA could alter neural responses to basic sensory input. Using a steady-state EEG paradigm, researchers found that neural responses to visual patterns were reduced in individuals who consumed a yeast-extract product rich in substrates linked to GABA production (such as glutamate and B vitamins), but not in a placebo control group. The experiment included 14 participants per group. These results indicate that the cortical balance of excitation and inhibition can be influenced by diet, and suggest potential avenues for further research into dietary strategies for conditions where inhibition is disrupted (for example, certain forms of epilepsy). The authors stress that clinical implications remain speculative and require further study.
“Dietary modulation of cortical excitation and inhibition” by Anika K. Smith, Alex R. Wade, Kirsty E.H. Penkman, and Daniel H. Baker. Journal of Psychopharmacology. Published online April 4, 2017. DOI: 10.1177/0269881117699613
This report summarizes published research and statements from the study authors. Results highlight a potential relationship between specific dietary components found in yeast-extract spreads and measurable changes in cortical activity as recorded by EEG. The study does not prove clinical benefit, and further research is required to replicate findings, clarify mechanisms, and determine whether dietary modulation of GABA can be translated into safe, effective therapeutic approaches.