New research has revealed that frequent consumption of carbonated drinks, fruit juice, and more than four cups of coffee per day increases the risk of stroke. The study found a 37% chance of stroke in individuals who consume more than four cups of coffee, but not for those with lower intakes.

The study reported a 22% increased chance of stroke linked to fizzy drinks, including sugar-sweetened and artificially sweetened varieties, with the risk rising sharply for those consuming two or more such drinks daily.

These findings come from two analyses of the INTERSTROKE project, published in the Journal of Stroke and the International Journal of Stroke. The research, co-led by the University of Galway and McMaster University, Canada, involved an international network of stroke researchers.

INTERSTROKE is one of the largest studies on stroke risk factors, involving almost 27,000 people across 27 countries, including nearly 13,500 individuals who experienced their first stroke.

A stroke occurs when blood supply to the brain is cut off, damaging brain cells. It can be ischemic, caused by a blood clot, or hemorrhagic, involving bleeding into brain tissue.

The study focused on participants’ consumption of fizzy drinks and fruit juice, with data collected from various geographical and ethnic backgrounds. The greatest link between carbonated drinks and stroke risk was found in Eastern/Central Europe, the Middle East, Africa, and South America.

The researchers noted that many fruit juices are made from concentrates with added sugars and preservatives, which may negate the benefits of fresh fruit and increase stroke risk. This was associated with a 37% increase in the chance of intracranial haemorrhage, with two such drinks daily tripling the risk.

Lead researcher and clinical epidemiologist at the University of Galway, Andrew Smyth, stressed that freshly squeezed juices are beneficial, but fruit drinks made from concentrates with added sugars can be harmful. “Our research also shows that the chance of stroke increases the more often someone consumes fizzy drinks,” Smyth added.

Smyth advised minimising the consumption of carbonated and fruit drinks and suggested switching to water for better health outcomes.