Migraines triggered by ‘sudden rush’ caused by eating processed foods

MIGRAINES are triggered by surges in a brain chemical used in processed food, according to new research.

Huge plumes of glutamate flood grey matter – setting off blinding headaches that blight the lives of eight million Brits.

Its salty component monosodium glutamate (MSG) has flavoured and preserved meaty and savoury products for decades.

Experiments on mice found an abnormal release of glutamate in spaces between neurons spark a tsunami-like wave of activity.

Drugs targeting it could nip migraines in the bud. The phenomenon could also lead to better therapies for other conditions – including stroke and head injury.

Co-corresponding author Professor Kevin Brennan, of Utah University in the US, said: “This is something new under the sun.

“Glutamate plumes are a completely new mechanism of migraine – and it’s a good bet they are players in other diseases of the nervous system.”

The severe, long-lasting headaches affect 12 per cent of people. Some can have a warning visual disturbance – called an aura. Many have nausea and sensitivity to light.

Lead author Patrick Parker, a graduate student in the lab, stumbled on the discovery by chance.

He was was studying abnormalities in glutamate signalling in rodents carrying a human gene that leads to a form of the condition that runs in families.

Known as FHM2, a gene mutation slows the rate of glutamate removal from the brain – sending neurons into overdrive.

But, surprisingly, large puffs of glutamate appeared spontaneously – and seemed to spread from a central location.

Mr Parker added: “Everything I’d read about neural glutamate signalling told me the plumes shouldn’t be there. It wasn’t exactly a ‘eureka’ moment. More like, ‘what the heck was that?’”

Glutamate is an essential neurotransmitter that helps cells communicate. Too much can damage them – so the brain has evolved ways to limit its effects.

In Asian cuisine, MSG is widely used. It’s the main ingredient in soy sauce. Food authorities have labelled it safe – despite controversy over its long-term effects.

Many people have reported suffering headaches or migraines after consuming MSG although there have been no scientific studies into the alleged link. Deeper analysis tracked the “chemical cascade” to a dysfunctional interaction between neurons and astrocytes – specialised cells that control glutamate levels.

Either too much glutamate – or too few astrocytes – could lead to plumes, said the researchers.

Prof Brennan said: “The common denominator is an imbalance between release and re-uptake and an excess of glutamate in the extracellular space.”

The study published in Neuron suggests migraines are caused by a chain reaction in which a nerve cell fires massively.