MDedge|Neurology
Megan Brooks
A growing body of research explores the link between stroke risk and regular consumption of coffee, tea, soda, and alcohol. This research roundup reviews the latest findings, highlighting both promising insights and remaining uncertainties to help guide discussions with your patients.
Coffee and Tea: Good or Bad?
In the INTERSTROKE study, high coffee consumption (> 4 cups daily) was associated with an significantly increased risk for all strokes (odds ratio [OR], 1.37) or ischemic stroke (OR, 1.31), while low to moderate coffee had no link to increased stroke risk. In contrast, tea consumption was associated with lower odds of all strokes (OR, 0.81 for highest intake) or ischemic stroke (OR, 0.81).
In a recent UK Biobank study, consumption of coffee or tea was associated with reduced risk for stroke and dementia, with the biggest benefit associated with consuming both beverages.
Specifically, the investigators found that individuals who drank two to three cups of coffee and two to three cups of tea per day had a 30% decrease in incidence of stroke and a 28% lower risk for dementia versus those who did not.
A recent systematic review and dose-response meta-analysis showed that each daily cup increase in tea was associated with an average 4% reduced risk for stroke and a 2% reduced risk for cardiovascular disease (CVD) events.
The protective effect of coffee and tea on stroke risk may be driven, in part, by flavonoids, which have antioxidant and anti-inflammatory properties, as well as positive effects on vascular function.
“The advice to patients should be that coffee and tea may protect against stroke, but that sweetening either beverage with sugar probably should be minimized,” said Cheryl Bushnell, MD, MHS, of Wake Forest University School of Medicine in Winston-Salem, North Carolina, and chair of the American Stroke Association (ASA) 2024 Guideline for the Primary Prevention of Stroke.
Taylor Wallace, PhD, a certified food scientist, said, “most people should consume a cup or two of unsweetened tea per day in moderation for cardiometabolic health. It is an easy step in the right direction for good health but not a cure-all.”
When it comes to coffee, adults who like it should drink it “in moderation — just lay off the cream and sugar,” said Wallace, adjunct associate professor at George Washington University, Washington, DC, and Tufts University, Boston, Massachusetts.
“A cup or two of black coffee with low-fat or nonfat milk with breakfast is a healthy way to start the day, especially when you’re like me and have an 8-year-old that is full of energy!” Wallace said.
The Skinny on Soda
When it comes to sugar-sweetened and diet beverages, data from the Nurses’ Health Study and Health Professionals Follow-Up Study, showed a 16% increased risk for stroke with one or more daily servings of sugar-sweetened or low-calorie soda per day (vs none), independent of established dietary and nondietary cardiovascular risk factors.
In the Women’s Health Initiative Observational Study of postmenopausal women, a higher intake of artificially sweetened beverages was associated with increased risk for all stroke (adjusted hazard ratio [aHR], 1.23), ischemic stroke (aHR, 1.31), coronary heart disease (aHR, 1.29) and all-cause mortality (aHR, 1.16).
In the Framingham Heart Study Offspring cohort, consumption of one can of diet soda or more each day (vs none) was associated with a nearly threefold increased risk for stroke and dementia over a 10-year follow-up period.
A separate French study showed that total artificial sweetener intake from all sources was associated with increased overall risk for cardiovascular and cerebrovascular disease.
However, given the limitations of these studies, it’s hard to draw any firm conclusions, Wallace cautioned.
“We know that sugar-sweetened beverages are correlated with weight gain and cardiometabolic dysfunction promotion in children and adults,” he said.
Yet, “there really isn’t any convincing evidence that diet soda has much impact on human health at all. Most observational studies are mixed and likely very confounded by other diet and lifestyle factors. That doesn’t mean go overboard; a daily diet soda is probably fine, but that doesn’t mean go drink 10 of them every day,” he added.
Alcohol: Moderation or Abstinence?
Evidence on alcohol use and stroke risk have been mixed over the years. For decades, the evidence was suggestive that a moderate amount of alcohol daily (one to two drinks in men and one drink in women) may be beneficial at reducing major vascular outcomes.
Yet, over the past few years, some research has found no evidence of benefit with moderate alcohol intake. And the detrimental effects of excessive alcohol use are clear.
A large meta-analysis showed that light to moderate alcohol consumption (up to one drink per day) was associated with a reduced risk for ischemic stroke. However, heavy drinking (more than two drinks per day) significantly increased the risk for both ischemic and hemorrhagic stroke.
A separate study showed young adults who are moderate to heavy drinkers are at increased risk for stroke — and the risk increases with more years of imbibing.
In the INTERSTROKE study, high to moderate alcohol consumption was associated with increased stroke risk, whereas low alcohol consumption conferred no increased risk.
However, Bushnell pointed out that the study data was derived from based on self-report, and that other healthy behaviors may counteract the risk for alcohol consumption.
“For alcohol, regardless of stroke risk, the most important data shows that any alcohol consumption is associated with worse cognitive function, so generally, the lower the alcohol consumption the better,” Bushnell said.
She noted that, currently, the American Heart Association (AHA)/ASA recommend a maximum of two drinks per day for men and one drink per day for women to reduce stroke risk.
“However, the data for the risk for cognitive impairment with any alcohol is convincing and should be kept in mind in addition to the maximum alcohol recommended by the AHA/ASA,” Bushnell advised.
“We know excessive intake puts you at major risk for CVD, cancer, cognitive decline, and a whole host of other health ailments — no question there,” said Wallace.
The impact of moderate intake, on the other hand, is less clear. “Alcohol is a highly biased and political issue and the evidence (or lack thereof) on both sides is shoddy at best,” Wallace added.
A key challenge is that accurate self-reporting of alcohol intake is difficult, even for scientists, and most studies rely on self-reported data from observational cohorts. These often include limited dietary assessments, which provide only a partial picture of long-term consumption patterns, Wallace noted.
“The short answer is we don’t know if moderation is beneficial, detrimental, or null with respect to health,” he said.
Bushnell reports no relevant disclosures. Wallace (www.drtaylorwallace.com) is CEO of Think Healthy Group; editor of The Journal of Dietary Supplements, deputy editor of The Journal of the American Nutrition Association (www.nutrition.org), nutrition section editor of Annals of Medicine, and an advisory board member with Forbes Health.
A version of this article appeared on Medscape.com.
