Low-to-Moderate Coffee Intake in Midlife Tied to Heart Benefits

Among middle-aged people without heart disease, drinking up to 3 cups of coffee per day was associated with a lower risk for stroke or death over the next decade, along with better heart structure and function, in a large, observational study.

Specifically, light-to-moderate coffee drinking, defined as 0.5 to 3 cups per day, was associated with a 21% lower risk for stroke, a 17% lower risk for death from cardiovascular disease (CVD), and a 12% lower risk for death from all causes, as well as more favorable cardiac MRI findings, compared with nondrinkers (<0.5 cup per day) during a median 11-year follow-up.

Heavy coffee drinkers, defined as those consuming more than 3 cups per day, on the other hand, likewise had more favorable cardiac MRI findings, but with similar (not lower) rates of stroke and CVD or all-cause mortality compared with nondrinkers.

Judit Simon, MD, presented these findings, from close to 500,000 participants in the UK Biobank study, at a press conference before an e-poster session at the virtual European Society of Cardiology (ESC) Congress 2021.

"To our knowledge, this is the largest study to systematically assess the cardiovascular effects of regular coffee consumption in a population without diagnosed heart disease," Simon, a PhD student at the Heart and Vascular Centre, Semmelweis University, Budapest, Hungary, said in an ESC press release.

The results "suggest that regular coffee consumption is safe, as even high daily intake was not associated with adverse cardiovascular outcomes and all-cause mortality after a follow-up of 10 to 15 years," she said.

The imaging analysis showed that "compared with participants who did not drink coffee regularly, daily consumers had healthier sized and better functioning hearts," Simon continued, "consistent with reversing the detrimental effects of ageing on the heart."

"The observed benefits might be partly explained by positive alterations in cardiac structure and function," she speculated, adding that further studies are needed to explain the underlying mechanisms.

Instant Coffee Most Popular

In this population, the coffee drinkers mostly drank instant coffee (55%), followed by filtered/ground (23%), decaffeinated (20%), or other types of coffee (2%), Simon told theheart.org | Medscape Cardiology.

Risk for myocardial infarction (MI) or heart failure did not significantly differ for different categories of coffee intake, she added. The researchers did not study the effect of coffee consumption on atrial fibrillation (AF), she noted.

Study limitations, Simon acknowledged, include that it was observational, so it cannot show causation, and that coffee consumption was self-reported in a questionnaire.

Invited to comment, Alice H. Lichtenstein, DSc, who was not involved with the research said, "Consistent with prior data, this new study indicates there is no adverse effect of coffee consumption on cardiovascular health and there may be a benefit."

However, "because of the nature of the data, it would not be recommended that an individual starting drinking coffee to improve cardiovascular health," added Lichtenstein, director and senior scientist at the Cardiovascular Nutrition Laboratory at Tufts University, Boston, Massachusetts.

But if people already drink coffee, "it is fine to continue, assuming that the coffee drinks are not high in added sugar and cream," she said in an email to theheart.org | Medscape Cardiology.

Coffee Intake, CVD Outcomes, and Heart Structure

To study the relationship between coffee intake and incident myocardial infarction (MI), stroke, and death, as well as heart structure, the researchers examined data from the UK Biobank, which recruited 500,000 people aged 40 to 69 years in 2006-2010 from across the United Kingdom.

They identified 468,629 participants with no signs of heart disease at recruitment and an average age of 56 years, of whom 56% were women.

The participants were divided into three groups based on usual coffee intake: none (22% of participants), light-to-moderate (58%), and high (20%).

Median tea intake was 3 cups per day overall, 4 cups per day in noncoffee drinkers, 3 cups per day in light-to-moderate coffee drinkers, and 1 cup per day in high coffee drinkers.

Compared to not drinking coffee, light-to-moderate coffee consumption was associated with lower risks for all-cause death (hazard ratio [HR], 0.88; P < .001), CVD death (HR, 0.83; P = .006), and stroke (HR, 0.79; P = .037), over a median follow-up of 11 years, after adjustment for sex; weight; height; smoking status; physical activity; high blood pressure; diabetes; cholesterol level; socioeconomic status; and usual intake of alcohol, meat, tea, fruit, and vegetables.

In the 30,650 participants who had cardiac MRI data, the study found that compared with not drinking coffee, both light-to-moderate and high coffee consumption were associated with significantly increased left and right ventricular end-systolic and end-diastolic volumes, and with greater left ventricular mass (all P < .001).

These differences were small but significant, Simon stressed, because this was a cohort of healthy patients who did not have CVD (heart failure, MI, stroke, AF) at baseline, although some had hypertension or diabetes.

Press conference chairperson, Steen Dalby Kristensen, MD, professor and cardiologist, Aarhus University Hospital, Denmark, a coffee lover himself, wanted to know if an amount such as 2, 3, or 4 cups of coffee was optimal to see these heart benefits, and whether there were differences in benefits seen with drinking different types of coffee.

The analysis did not identify an optimal coffee intake, Simon said. Compared with not drinking coffee, she continued, drinking instant coffee was associated with a lower risk for all-cause mortality, but not CVD mortality or stroke.

Drinking filtered coffee was associated with lower risks for all three outcomes, but there was no significant difference in risk for MI. Drinking decaffeinated coffee was associated with a lower risk for all-cause and CVD mortality.

"Decaffeinated coffee contains a small amount of caffeine," Simon pointed out. "Something other than caffeine might have this protective impact," she suggested.

The researchers and Lichtenstein declare they have no relevant financial disclosures.

European Society of Cardiology (ESC) Congress 2021. E-poster presented on August 27, 2021.

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