Summary: New research has found that frequent consumption of fizzy drinks and fruit juice significantly increases the risk of stroke. The study, which analyzed data from nearly 27,000 participants across 27 countries, showed a 22% increased risk of stroke from drinking fizzy drinks, with the risk rising further with multiple servings per day.
Additionally, drinking more than four cups of coffee daily raised stroke risk by 37%, while tea consumption was associated with a reduced stroke risk. The findings highlight the importance of making healthier beverage choices to reduce the risk of stroke, with researchers urging people to replace sugary drinks with water.
Key Facts:
- Fizzy drinks and fruit juice increase stroke risk by 22% and 37%, respectively.
- Drinking more than four cups of coffee a day raises stroke risk by 37%.
- Tea, especially black tea, reduces stroke risk by 18-29%, but milk may negate this benefit.
Source: University of Galway
Frequent drinking of fizzy drinks or fruit juice is associated with an increased risk of stroke, according to new findings from global research studies co-led by University of Galway, in collaboration with McMaster University Canada and an international network of stroke researchers.
The research also found that drinking more than four cups of coffee per day also increases the risk of stroke.
The findings come from two analyses of the INTERSTROKE research project which have been published – the effects of fizzy drinks, fruit juice/drink and water was reported in the Journal of Stroke; and the findings related to tea and coffee in the International Journal of Stroke.
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.
INTERSTROKE 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.
Those who took part in the study came from a broad range of geographical and ethnic backgrounds, with different cardiovascular risk profiles, including Ireland and the UK.
The study which focused on people’s consumption of fizzy drinks and fruit juice 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 link between fizzy drinks and chance of stroke was greatest in Eastern/Central Europe and Middle East, Africa, and South America
- 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 juice drinks were linked with a 37% increase in chance of stroke due to bleeding (intracranial haemorrhage). With two of these drinks a day, the risk triples
- Women show the greatest increased chance of stroke due to bleeding (intracranial haemorrhage) linked to fruit juice/drinks
- Drinking more than 7 cups of water a day was linked with a 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: “Not all fruit drinks are created equal – 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.”
The 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 not associated with stroke risk for lower intakes
- Drinking tea was linked with a reduced chance of stroke by 18-20%
- Drinking 3-4 cups per day of black tea – including Breakfast and Earl Grey teas, but not green tea or herbal teas – 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
- Adding milk may reduce or block the beneficial effects of antioxidants that can be found in tea. The reduced chance of stroke from drinking tea was lost for those that added milk
- There were important geographical differences in the findings – tea was linked with lower chance of stroke in China and South America but higher chance of stroke in South Asia
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, co-leads the INTERSTROKE study in partnership with Professor Salim Yusuf of the Population Health Research Institute at McMaster University, Canada.
Professor O’Donnell said: “A key goal of the INTERSTROKE study is to provide usable information on how to reduce one’s risk of stroke. 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.”
About this diet and stroke research news
Author: Sheila Gorham
Source: University of Galway
Contact: Sheila Gorham – University of Galway
Image: The image is credited to Neuroscience News
Original Research: Closed access.
“Carbonated Beverage, Fruit Drink, and Water Consumption and Risk of Acute Stroke: the INTERSTROKE Case-Control Study” by Andrew Smyth et al. Journal of Stroke
Open access.
“Tea and coffee consumption and risk of acute stroke: The INTERSTROKE Study” by Andrew Smyth et al. International Journal of Stroke
Abstract
Carbonated Beverage, Fruit Drink, and Water Consumption and Risk of Acute Stroke: the INTERSTROKE Case-Control Study
Background and Purpose
Cold beverage intake (carbonated drinks, fruit juice/drinks, and water) may be important population-level exposures relevant to stroke risk and prevention. We sought to explore the association between intake of these beverages and stroke.
Methods
INTERSTROKE is an international matched case-control study of first stroke. Participants reported beverage intake using food frequency questionnaires or were asked “How many cups do you drink each day of water?” Multivariable conditional logistic regression estimated odds ratios (OR) and 95% confidence intervals (CI) for associations with stroke.
Results
We include 13,462 cases and 13,488 controls; mean age was 61.7±13.4 years and 59.6% (n=16,010) were male. After multivariable adjustment, carbonated beverages were linearly associated with ischemic stroke (OR 2.39 [95% CI 1.64–3.49]); only consumption once/day was associated with intracerebral hemorrhage (ICH) (OR 1.58 [95% CI 1.23–2.03]).
There was no association between fruit juice/drinks and ischemic stroke, but increased odds of ICH for once/day (OR 1.37 [95% CI 1.08–1.75)] or twice/day (OR 3.18 [95% CI 1.69–5.97]). High water intake (>7 cups/day) was associated ischemic stroke (OR 0.82 [95% CI 0.68–0.99]) but not ICH. Associations differed by Eugeographical region—increased odds for carbonated beverages in some regions only; opposing directions of association of fruit juices/drinks with stroke in selected regions.
Conclusion
Carbonated beverages were associated with increased odds of ischemic stroke and ICH, fruit juice/drinks were associated with increased odds of ICH, and high water consumption was associated with reduced odds of ischemic stroke, with important regional differences. Our findings suggest optimizing water intake, minimizing fruit juice/drinks, and avoiding carbonated beverages.
Abstract
Tea and coffee consumption and risk of acute stroke: The INTERSTROKE Study
Background:
Stroke is a leading global cause of death and disability. Daily tea/coffee intake is consumed by > 50% of populations and may represent an important population-level exposure. Therefore, it is first essential that we better understand the associations between the tea/coffee intake and stroke.
Aims:
This research aims to generate hypotheses about the global associations between tea and coffee intake and stroke. These insights will identify interventions for stroke prevention that can be further explored using alternative study designs.
Methods:
INTERSTROKE is a large international matched case–control study of first stroke from 32 countries. Participants were asked “how many cups do you drink each day?” of coffee, green tea, black tea, and other tea. Multivariable conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for associations between intake and stroke.
Results:
We included 13,462 cases and 13,488 controls from INTERSTROKE; mean age was 61.7 (13.4) years and 59.6% (n = 16,010) were male. Overall, 19.4% (n = 5239) did not consume tea/coffee, 47.0% (n = 12,666) consumed tea only, 14.9% (n = 4024) consumed coffee alone, and 18.6% (n = 5021) consumed both, with significant regional variations.
After multivariable adjustment, there was no association between low/moderate coffee intake and stroke, but high consumption (> 4/day) was associated with higher odds of all stroke (OR = 1.37 (95% CI = 1.06–1.77)) or ischemic stroke (OR = 1.32 (95% CI = 1.00–1.74)). Tea consumption was associated with lower odds of all (OR = 0.81 (95% CI = 0.69–0.94) for highest intake) or ischemic stroke (OR = 0.81 (95% CI = 0.68–0.98) for highest intake).
Conclusions:
High coffee consumption was associated with higher odds of all or ischemic stroke; low–moderate coffee had no association with stroke. In contrast, tea consumption was associated with lower odds of stroke. These associations suggest that individuals consider avoiding high coffee consumption (⩾ five cups/day) to impact future stroke risk.
