What is better for your health: coffee or tea?
Both claim to have a host of health benefits, including boosting energy, reducing inflammation and reducing the risk of heart disease.
But when it comes to your risk of heart attack or stroke, one seems to dominate.
An international study of more than 25,000 people found that drinking more than four cups of coffee a day increased the risk of stroke by almost 40 percent.
Meanwhile, the same amount of tea reduced the risk by almost a fifth.
Experts have long debated whether coffee or tea has more health benefits. However, a new study suggests that coffee may increase the risk of stroke, while tea lowers the risk
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The researchers suggested this could be because frequent coffee drinkers are more likely to have heart problems such as high blood pressure, which increases the risk of stroke.
In the study, published in July in the International Journal of Strokeresearchers recruited 26,950 adults from 32 countries, including Britain and Canada, about half of whom had survived a stroke in the past few days.
On average, patients were recruited approximately two and a half days after stroke.
The average age of participants was 61 years, and most were men. Most patients were also overweight, a risk factor for stroke.
Participants completed questionnaires about their medical history, diet, physical activity and other risk factors for stroke, such as smoking and high blood pressure.
They were also asked how many cups of coffee, Chinese/Japanese green tea, black tea and other types of tea they drank per day.
About one in five participants drank neither drink, while almost half stuck to tea alone. About 15 percent drank only coffee, while almost one in five drank both.
The team found that drinking four or more cups of coffee per day increased the risk of stroke by 37 percent. However, drinking the same amount of any type of tea lowered the risk by 19 percent.
Black tea, including Earl Gray and Breakfast tea, had the lowest overall risk of stroke at 29 percent, while green tea led to a reduced risk of 27 percent.
There was no link between drinking three or fewer cups of coffee and having a stroke.
The researchers noted that drinking coffee in excess could have such a harmful effect because those who drank that much coffee were more likely to suffer from problems such as high blood pressure and high heart rate.
Coffee has a higher caffeine content than tea, with about 80-100 milligrams per 8-ounce cup compared to 50 in tea.
Caffeine has been shown to promote the release of adrenaline, which increases heart rate and blood pressure.
Over a longer period of time, these effects can damage the blood vessels in the brain, increasing the risk of clots and stroke.
However, the researchers noted that adding milk to any type of tea negated any potential benefits associated with stroke.
The team did not look at the impact of sugar, syrups, spices or other additives to coffee or tea.
The team said this could be because milk blocks antioxidants, disease-fighting molecules found in both coffee and tea that have been shown to reduce inflammation that can lead to stroke.
There were several limitations to the study. The researchers noted that the findings may be subject to recall bias because participants suffered a stroke just days before they were interviewed.
Furthermore, participants from China and South Asia formed the largest demographic group. Because tea is particularly popular in these areas, there may be potential bias.