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article imageEssential Science: Can taking yeast extract boost brain function?

By Tim Sandle     Apr 10, 2017 in Science
York - A new study suggests that yeast extract (as sold in the form of popular consumer products like Marmite) could boost brain function and lower the chances of a person developing dementia in later life.
The study has received particular attention in parts of the world where eating the product Marmite (or the equivalent Vegemite) is common. The savory spreads are not so popular in North America. With the term ‘popular’, a product like Marmite divides opinion – a ‘love it or hate it’ reaction.
What is Marmite?
Marmite is the brand name for two similar food spreads. One is the original British version and a modified version produced in New Zealand. Marmite is produced from yeast extract, as a by-product of beer brewing (which is how the product was developed, as a means to reduce waste and recover costs).
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Yeast extract is a sticky, dark brown food paste. It has a distinctive, powerful flavor, which is extremely salty. The word Marmite is taken from the French term for a large, covered earthenware cooking pot. Marmite was invented unintentionally by a German chemist, Baron Justus von Liebig (who also invented beef extract products like Oxo). This serendipitous discovery occurred in the late 19th century.
A shot of the Oxo Tower on London s south bank.
A shot of the Oxo Tower on London's south bank.
The product contains additives of nutritional value, such as B vitamins including thiamin (B1), riboflavin (B2), niacin (B3), folic acid (B9) and vitamin B12. However, the high sodium content makes the product unsuitable for people on a low salt diet. Some of the vitamins are part of the natural manufacturing process and some are added in the food production process. The manufacturing process begins with yeast sludge, collected after the microbe has been used to brew beer. To this a blend of herbs and spices is added. A process called autolysis begins. Here the natural enzymes in the yeast act to develop the Marmite flavor. The resultant mix is then concentrated to create a product of suitable viscosity for spreading on bread.
B12 and brain function
This is all very interesting, but how does this relate to brain function? According to the Daily Telegraph, scientists based at York University in the U.K. have found that the high concentration of vitamin B12 in Marmite leads to an increase in levels of chemicals in the brain that protect an individual against neurological disorders. Research showed that people who eat the equivalent of a teaspoon a day, over the course of a month, showed a 30 percent decrease in their brains’ response to visual patterns (as shown via electroencephalography scans). The chemicals are gamma-aminobutyric acid.
Human brain.
Human brain.
National Institute of Mental Health
In study a test group of subjects who consumed Marmite each day were compared with a control group who were given equivalent quantities of peanut butter. The analysis of the foods found that Marmite contains 116 times more B12 than peanut butter. The vitamin, also called cobalamin, is a water-soluble vitamin that has a key role in the normal functioning of the brain and nervous system, and the formation of red blood cells.
Gamma-Aminobutyric acid is the chief inhibitory neurotransmitter in the central nervous system. The chemical plays the principal role in reducing neuronal excitability throughout the nervous system. It is involved in the regulation of muscle tone. With the neuronal excitability the chemical effectively “turns down the volume” of neural responses. This is seen as important for regulating the balance of activity needed to maintain a healthy brain. Changes in gamma-amino butyric acid levels have been linked with neurological conditions, such as Alzheimer’s and Parkinson’s disease.
Evaluating the results
Commenting on the research, lead scientist Anika Smith stated in a research brief: "These results suggest dietary choices can affect the cortical processes of excitation and inhibition - consistent with increased levels of gamma-aminobutyric acid - that are vital in maintaining a healthy brain.” Highlighting the positive influence of Marmite, the researcher added: "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.”
A second researcher, who was involved with the study - Dr Daniel Barker- told The Independent about the next phase of the research: "In our next study we plan to give participants vitamin B12 supplements in pill form or a placebo to attempt to isolate whether this is the substance driving the effect."
It is possible that a more refined type of diet could have some medical or therapeutic applications in the future. The research has been published in the Journal of Psychopharmacology, in a paper titled “Dietary modulation of cortical excitation and inhibition.”
Essential Science
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Test tubes and other recipients in chemistry lab
Horia Varlan
This article is part of Digital Journal's regular Essential Science columns. Each week Tim Sandle explores a topical and important scientific issue. Last week we also covered a food related topic and weighed in on whether a medicinal diet could help to combat type 1 diabetes. The week before we considered a new material capable of producing low-cost electricity. The electricity is generated by exposing the material to variations in temperature.
More about Dementia, brain function, Yeast, Vitamins, vitamin B12
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