Guzzling fizzy or fruit drinks or drinking more than four coffees a day have been linked to higher risk of a stroke.
Frequent fizzy drinks doubles the risk of stroke and more than four cups of coffee a day increases chances of a stroke by a third. However, the new research has found drinking water and tea may actually reduce the risk of stroke.
A stroke occurs when the blood supply to part of the brain is cut-off and damages brain cells. It can either be ischemic stroke, which is usually due to a blood clot, or when there intracerebral haemorrhage, which is bleeding into the brain tissue.
The new findings have come from INTERSTROKE – global research studies co-led by University of Galway, in collaboration with McMaster University Canada and an international network of stroke researchers. The research is one of the largest international studies of risk factors for stroke, involving almost 27,000 people, in 27 countries, including almost 13,500 people who experienced their first stroke.
The study found fizzy drinks – including both sugar-sweetened and artificially sweetened such as diet or zero sugar – were linked with a 22% increased chance of stroke and the risk increased sharply with two or more of these drinks a day.
The research noted that many products marketed as fruit juice are made from concentrates and contain added sugars and preservatives, which may offset the benefits usually linked with fresh fruit, and actually increase stroke risk
Fruit just two juice drinks a day there is a 37% increase in chance of stroke due to bleeding.
However, drinking more than seven cups of water a day was linked with reduced odds of stroke caused by a clot
Lead researcher on both studies Professor Andrew Smyth, Professor of Clinical Epidemiology at University of Galway and Consultant Physician at Galway University Hospitals, said: “Freshly squeezed fruit juices are most likely to bring benefits but fruit drinks made from concentrates, with lots of added sugars and preservatives, may be harmful.
“Our research also shows that the chance of stroke increases the more often someone consumes fizzy drinks.
“As a doctor and as someone who has researched the risk of stroke, we would encourage people to avoid or minimise their consumption of fizzy and fruit drinks and to consider switching to water instead.”
A separate study which focused on people’s consumption of coffee and tea found drinking more than four cups of coffee a day increased chance of stroke by 37% but there was no associated stroke risk for lower intakes
Drinking tea, however, was linked to a reduced chance of stroke by 18-20% but only if it is drunk without milk,
Drinking three or four cups of black tea – including Breakfast and Earl Grey teas, but not green tea or herbal teas – a day was linked with a 29% lower chance of stroke
Drinking 3-4 cups per day of green tea was linked with a 27% lower chance of stroke.
Professor Martin O’Donnell, Executive Dean of College of Medicine, Nursing and Health Sciences at University of Galway and Consultant Stroke Physician at Galway University Hospitals, said: “While hypertension is the most important risk factor, our stroke risk can also be lowered through healthy lifestyle choices in diet and physical activity.
“The current study adds further information on what constitutes healthy choices on daily intake of beverages.”