US scientists at the The Children's Hospital of Philadelphia have found that a protein drink described as a ‘cocktail’ of amino acids can help heal brain damage in mice.

The Press Association reports that lead researcher Dr Akiva Cohen and colleagues fed a mixture of amino acids to the mice in their drinking water. The team found that those given the branched chain amino acids (BCAAs) leucine, isoleucine and valine, together with glutamate and gamma-aminobutyric acid (GABA), responded to an electric shock in the same way as normal mice after drinking the cocktail for a few weeks.

Brain damaged mice fail to respond to anticipated electric shocks with the normal ‘freeze response’, say researchers, because they are unable to remember the fear response that develops in normal mice who have experienced a shock and anticipate another. Normal mice exhibited the freeze response when placed in the same surroundings in which they had experienced the electric shock previously, whereas the brain damaged mice did not.

BCAAs are vital for creating two brain chemicals which play a vital role in nerve function, while the two neurotransmitters glutamate and GABA work antagonistically to balance brain activity – glutamate causes brain neurons to ‘fire’, while GABA inhibits them. If the neurons become overstimulated or are not stimulated enough, brain responses do not work properly.

Doctors say that traumatic brain injury (TBI) sustained either on the battlefield or in serious car accidents can follow this pattern of neurons ‘misfiring’ – and previous studies have found that injecting BCAAs into patients who have sustained brain injuries can help improve their mental responses.

When the team examined slices of brain tissue from the memory centre of the mice – called the hippocampus – they found the amino acid protein cocktail has restored neural activity in the brain damaged mice.

Dr Cohen said: ‘We have shown in an animal model that dietary intervention can restore a proper balance of neurochemicals in the injured part of the brain, and simultaneously improves cognitive performance.’

He added that supplying amino acids through diet rather than injecting them might be more effective and the therapy could be delivered in the form of a drink, as injecting them straight into the bloodstream might ‘flood’ the brain and have less effect.

The findings of the study are published online in the journal the ‘Proceedings of the National Academy of Sciences’.

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