Drinking Coffee and Tea May Reduce Risk of Stroke, Dementia

One of the most common pieces of health advice we give involves what to drink: water, tea, or coffee as opposed to fruit juices, sodas, or "energy drinks."

(Yes, alcohol is part of a Mediterranean-style diet, but we are talking about what you drink most of the time, not what you have in moderation with dinner.)

The question often is, which is better: tea or coffee?

It seems that the answer might be both.

The Research

An ongoing, prospective study known as the UK Biobank recruited participants in England, Scotland, and Wales between 2006 and 2010.¹ At the start of the study—along with demographic, dietary, and health information—the participants estimated their weekly intake of coffee and tea, further specifying whether these were certain types, including ground, instant, green vs black, etc.

The participants were contacted regularly through 2020, at which time the authors of this study determined which, if any, of the participants had been diagnosed with stroke (alone), dementia (alone), or post-stroke dementia (any type of dementia specifically experienced after a stroke).

After excluding participants who were under 50 years of age at the start of the study, as well as those who had already been diagnosed with stroke or dementia, there were more than 365,000 participants in the study.

Using inpatient health records from England, Scotland, and Wales, the authors could track which participants were diagnosed with stroke (ischemic stroke or hemorrhagic stroke), dementia (Alzheimer disease or vascular dementia), and outcomes related to both.

Additionally, the authors considered demographic variables, which included age, sex, ethnicity, education, as well as education level, income, rates of smoking or drinking alcohol, intake of sugar-sweetened beverages, clinical history, and diet. The use of diabetes medications or high blood pressure medications as well.

In their analysis for intake of coffee, the authors also considered tea intake, and vice versa. In their analysis for tea, they considered coffee intake.

In this group, almost 21% of participants did not drink coffee while nearly 14% did not drink tea. Just over 16% reported that they drank between 1/2 cup and 1 cup of coffee per day and at least 4 cups of tea per day, while a little over 12% said they drank equal amounts of coffee and tea per day (2 to 3 cups each).

The Results

Compared to those who did not drink coffee at all, those who consumed at least 1/2 cup of coffee per day—up to 3 per day—were about 10% less likely to experience a stroke and those who drank 2 to 3 cups per day were 20% less likely to develop dementia.

Compared with those who did not drink tea at all, those who drank 2 to 4 cups of tea per day were about 16% less likely to experience a stroke. (These results were limited to ischemic but not hemorrhagic stroke). Yet, tea intake did not affect the risk of dementia of any type.

Compared with those who drank neither coffee nor tea, those who drank 2 to 3 cups each per day were 32% less likely to experience a stroke, those who drank at least 1/2 cup to 1 cup of coffee per day as well as 2 to 3 cups of tea per day saw their risk of poststroke dementia fall by 50% although no effect was seen on vascular dementia or Alzheimer disease.

For the various types of coffee, from decaffeinated to instant, to ground coffee, the authors note that overall, drinking coffee made from ground, caffeinated beans appeared to be more protective than decaf or instant.

What’s the Take Home?

The basic advice still applies: your best choice of everyday beverage is water, followed by coffee (regular or decaf) and tea (regular or decaf). This study suggests that drinking both might be more protective than one or the other; perhaps coffee at breakfast and iced tea at other meals, with water in-between.

Reference:

1. Zhang Y, Yang H, Li S, Lie WD, Wang Y. Consumption of coffee and tea and risk of developing stroke, dementia, and poststroke dementia: a cohort study in the UK Biobank. PLOS Medicine. 18(11):e1003830. doi:10.1371/journal.pmed.1003830

Dr. Gourmet is the definitive health and nutrition web resource for both physicians and patients with evidence-based resources including special diets for coumadin users, patients with GERD/acid reflux, celiac disease, type 2 diabetes, low sodium diets (1500 mg/d), and lactose intolerance.

Timothy S. Harlan, MD, is a board-certified internist and professional chef who translates the Mediterranean diet for the American kitchen with familiar, healthy recipes. He is an assistant dean for clinical services, executive director of The Goldring Center for Culinary Medicine, and associate professor of medicine at Tulane University in New Orleans.