Daily Coffee and Tea Linked to Lower Diabetes, Heart Disease, and Stroke Risk

A large cohort analysis drawing on U.K. Biobank data finds that drinking several cups of caffeinated coffee or tea each day is associated with meaningfully lower risks of type 2 diabetes, coronary heart disease, and stroke, with the sweet spot appearing to be two to three cups of coffee or up to three cups of tea daily. The findings, published in The Journal of Clinical Endocrinology & Metabolism, tracked 188,000 participants ages 37 to 73 over roughly 12 years.

Researcher Ke and colleagues based in China and Sweden focused their analysis on about 172,000 of those participants who specifically reported drinking caffeinated coffee or tea on beverage intake questionnaires covering the previous 24 hours. None of that group had a history of cardiometabolic disease at baseline, defined in the study as a diagnosis of at least two of three conditions: type 2 diabetes, coronary heart disease, or stroke.

The results carry particular weight for people already living with type 2 diabetes. A separate U.K. Biobank cohort study examining macrovascular complications in a T2DM population found that those who drank 0.5 to 1 cup of coffee daily had the lowest stroke risk compared with non-drinkers, with a hazard ratio of 0.67 (95% CI 0.518 to 0.856). Among tea drinkers, consuming 2 to 4 cups daily produced a nearly identical stroke benefit, with an HR of 0.66 (95% CI 0.524 to 0.839). For heart failure specifically, the most protective combination was 2 to 4 cups of coffee paired with 0.5 to 1 cup of tea per day, yielding an HR of 0.55 (95% CI 0.379 to 0.790) compared with those who drank neither beverage.

A meta-analysis published in Frontiers in Nutrition on June 2, 2025, by Li Ding, Hai-Peng Wang, Jun-Yu Zhao, Xin Zhao, Yu Sha, Li-Qiang Qin, and Khemayanto Hidayat added further granularity by pooling prospective observational studies of people with diabetes mellitus. Searching PubMed, Web of Science, the Cochrane Library, and Embase, the authors found that the highest coffee consumption category was associated with lower risks of all-cause mortality, CVD mortality, CHD mortality, CVD incidence, and CHD incidence compared with the lowest category. Tea's highest intake levels were similarly tied to lower all-cause and CVD mortality. On a per-cup basis, each additional daily cup was linearly associated with a 5% lower risk of CVD mortality, a 6% lower risk of CHD mortality, and a 3% lower risk of CVD incidence.

A cardiovascular review published on ScienceDirect adds useful texture on mechanisms and the heart failure picture specifically. The review notes that coffee consumption reduces the risk of coronary heart disease, heart failure, arrhythmia, stroke, CVD, and all-cause mortality, and that green tea confers similar cardiovascular benefits, with 3 cups per day associated with improved survival in population-based studies. One meta-analysis cited in the review identified a J-shaped relationship between coffee and heart failure risk, with the strongest protective effect, an 11% risk reduction, observed at 4 cups per day. The same review flags that the effects of coffee on glucose homeostasis are complex: caffeine can reduce insulin sensitivity through adrenaline release, adenosine A1 receptor antagonism from acute intake can reduce skeletal muscle glucose uptake within one to three hours, and coffee can also increase secretion of gastric inhibitory polypeptide while decreasing glucagon-like peptide-1, reducing intestinal glucose absorption. The review also notes that while 2 to 3 cups per day is associated with benefits for metabolic syndrome including hypertension and diabetes, coffee may elevate lipid levels.

Experts urge caution about reading too much into the data. "It can give us an idea, but we can't draw any conclusions," said Laffin, an expert not involved in the research, speaking to NBC. "Everything in moderation is probably the best way to do it. If someone is having a couple cups of coffee a day, this suggests that dose might be protective." He also stressed that too many cups can raise blood pressure in people who already have hypertension, and that some types of heart disease make caffeine intake more dangerous.

Dr. Iluyomade framed the broader significance this way: "This study adds to the growing evidence that moderate coffee or tea consumption, particularly when caffeinated, may reduce the risk of cardiometabolic diseases. The findings highlight the potential for coffee and tea to play a role in disease prevention, specifically targeting major conditions like type 2 diabetes, coronary heart disease, and stroke. The results are important because they emphasize the value of dietary habits in managing and reducing cardiometabolic risk, particularly as the global burden of these diseases continues to rise."

All studies involved here are observational, meaning they identify associations rather than proving that coffee or tea directly causes better outcomes. Reported optimal intake ranges also vary depending on the population studied and the outcome measured, a point worth keeping in mind before treating any single cup count as a universal prescription.