Scientists at the University of York have discovered that Marmite may influence brain activity in a positive way via the increase of a chemical messenger associated with healthy brain function.
The normal functioning of your brain is dependent on a delicate balance of excitation and inhibition, carefully controlled by neurotransmitters such as gamma-aminobutyric acid (GABA). Previous research has shown that an imbalance in the level of GABA is linked to disorders such as anxiety, depression, autism and epilepsy.
GABA inhibits the excitability of neurons in the brain – fine tuning neural responses which help to maintain the correct balance of activity needed to keep the brain healthy. Although products containing GABA are available commercially the success of these supplements is limited due to its inability to cross the blood-brain barrier effectively.
Researchers at The University of York hoped to determine whether consumption of food containing the pre-cursors associated with the production of GABA would help to balance excitation and inhibition in the brain and therefore maintain healthy brain function.
In the trial, one group of participants ate a teaspoon of Marmite daily for a month whilst the other group consumed peanut butter. The researchers recorded the participants’ response to visual stimuli before and after the trial using electroencephalography (EEG) to measure electrical activity in the brain.
Their results showed that dietary intervention had a significant effect on the brain’s response to visual stimuli, compared with consumption of a placebo. The individuals who ate Marmite showed a substantial reduction of around 30 % in their brain’s response to stimuli.
The researchers think that the high level of vitamin B12 in Marmite was the primary factor responsible for increasing GABA production in the brain. Vitamin B12 is a co-factor needed for the production of the myelin sheath which acts as an insulator for nerve axons – increasing the speed of nerve transmissions.
This is the first trial of its kind that proves dietary intervention can affect neural processes in the brain – consistent with raising levels of GABA – that are essential for maintaining a healthy brain.
The positive effects of Marmite took about 8 weeks to wear off following cessation of the study which suggests that dietary changes could possibly have long-term consequences to brain health and could be of clinical benefit in conditions where neuronal responses are abnormal e.g. epilepsy.
*Individuals with mental health conditions should always consult with their GP for medical treatment.
Baker, Penkman, Smith et al. Dietary modulation of cortical excitation and inhibition. Journal of Psychopharmacology 2017, 1-9.