Love it or hate it, a Marmite sandwich a day could stave off Alzheimer's disease, according to new research.
Its taste divides people but a study has found the sticky brown yeast extract boosts a brain chemical known as 'nature's Valium'.
It increased levels of GABA - the main neurotransmitter which 'turns down the volume' in the brain and protects against a host of disorders including dementia.
Participants consuming a teaspoon every day for a month - compared to those given peanut butter - had a dramatic 30 per cent reduction in their response to visual stimuli, a sign that their brains were healthier.
Scientists believe this is due to the prevalence of vitamin B12 in the spread fuelling production of GABA.
It is well-known GABA deficiency is linked with several serious neurological disorders.
As well as Alzheimer's it can lead to Parkinson's and Huntington's diseases - as well as other psychiatric disorders like anxiety, depression, pain, panic or mania.
Psychologist Dr Daniel Baker, of York University, said: "The high concentration of Vitamin B12 in Marmite is likely to be the primary factor behind results showing a significant reduction in participants' responsiveness to visual stimuli."
The nutrient makes red blood cells and protects the nervous system. It helps release energy from food and processes folic acid.
The researchers whose findings are published in the Journal of Psychopharmacology said Marmite contains 116 times more B12 than peanut butter.
In the study 28 young men and women wore EEG (electroencephalography) skull caps as patterns flicked in front of them on a screen.
This is a type of scan that monitors neurons by recording electrical activity in the brain - and far fewer were triggered in the group who ate the Marmite compared to the peanut butter.
Commonly spread on toast and sandwiches Marmite has built up millions of admirers around the world - and just as many who grimace at the merest thought of the dark paste.
First author Anika Smith, a PhD student in Dr Baker's lab, said: "These results suggest dietary choices can affect the cortical processes of excitation and inhibition - consistent with increased levels of GABA - that are vital in maintaining a healthy brain.
"As the effects of Marmite consumption took around eight weeks to wear off after participants stopped the study, this suggests that dietary changes could potentially have long-term effects on brain function.
"This is a really promising first example of how dietary interventions can alter cortical processes and a great starting point for exploring whether a more refined version of this technique could have some medical or therapeutic applications in the future.."