In a world bitterly divided into pro and anti-Marmite factions, lovers of the tangy British sandwich and toast spread have found support from an unexpected quarter: brain science.
Experiments found that volunteers who ate a daily spoonful of the dark-brown yeast extract seemed to have higher levels of a vital neurone chemical associated with a healthy brain.
The reason could lie in Marmite’s high levels of vitamin B12, the investigators say.
In a study published on Wednesday, psychologists at the University of York in northern England recruited 28 volunteers and divided them into two groups.
One group ate a teaspoon of Marmite each day for a month; the other ate a daily teaspoon of peanut butter.
The volunteers wore non-invasive skullcaps fitted with electrodes to monitor brain activity while they looked at a screen with a visual stimulus – a large stripy pattern that flickered at a regular rate.
The Marmite group showed a substantial reduction of around 30 per cent in response to the stimulus compared with the peanut butter group.
The work, published in the Journal of Psychopharmacology, sheds a powerful light on how diet can affect brain activity, the researchers say.
How Marmite worked was not clinically investigated.
But the presumption is that it boosts levels of an important neurotransmitter called gamma-amino-butyric acid (Gaba).
Gaba acts as a kind of brake on over-excited brain cells. It binds to neurons and reduces their activity, helping to provide balance in the brain.
Scientists have previously theorised that Gaba helps to dampen fear or anxiety, which happens when neurons are over-stimulated.

Source: The National