Original source 

Drinking Coffee and Heart Health: Separating Facts from Myths

When it comes to coffee, opinions abound. Some people swear by its invigorating properties and can't start their day without a cup (or two or three). Others shun it as a vice that dehydrates, stains teeth, disrupts sleep, and causes jitteriness or palpitations. And then there are those who worry that coffee might increase their risk of heart disease, stroke, or premature death.

If you belong to the latter camp, you may have stumbled upon a recent study that made headlines for linking coffee consumption with a higher risk of heart death in people with severe hypertension. The study, published in the journal Hypertension and funded by the American Heart Association, analyzed data from a cohort of more than 1,000 people with hypertension who were followed for an average of 12.5 years. The researchers found that those who reported drinking two or more cups of coffee per day had twice the risk of dying from cardiovascular causes as those who drank less or no coffee, after adjusting for various factors such as age, sex, race, smoking, diabetes, and medication use.

As a concerned coffee lover or a health-conscious consumer, you may wonder what to make of this finding. Is coffee really that harmful to your heart, especially if you have high blood pressure? Should you cut back on your caffeine fix or switch to decaf or tea? Or is the study flawed or misleading, and should you take it with a grain of salt (or sugar)?

In this article, we will delve deeper into the science of coffee and heart health, examine the strengths and limitations of the study, and provide you with evidence-based insights and recommendations. Our goal is not to scare you or dismiss the study, but to help you make an informed decision about your coffee consumption and its impact on your cardiovascular system.

Coffee and Cardiovascular Risk: What the Evidence Says

To understand the potential effects of coffee on the heart and blood vessels, we need to look at the broader body of research on this topic. Over the years, coffee has been both praised and blamed for various health outcomes, ranging from reduced risk of diabetes, liver disease, and some cancers to increased risk of anxiety, acid reflux, and irregular heartbeats. However, when it comes to cardiovascular disease (CVD), the evidence is mixed and nuanced, depending on the dose, type, preparation, and individual factors.

On one hand, some studies have suggested that moderate coffee consumption (usually defined as 3-5 cups per day) may have neutral or even beneficial effects on CVD risk markers, such as blood pressure, blood lipids, inflammation, and endothelial function (the ability of blood vessels to dilate and contract). For example, a systematic review and meta-analysis of 36 prospective studies found that higher coffee intake was associated with a lower risk of coronary heart disease (CHD) and stroke, especially among women and non-smokers. Another meta-analysis of 20 randomized trials concluded that coffee consumption was associated with a modest reduction in blood pressure, especially among people with hypertension.

On the other hand, some studies have suggested that excessive coffee consumption (usually defined as more than 5-6 cups per day) or consumption of unfiltered coffee (such as boiled or French press) may increase CVD risk, possibly by raising levels of homocysteine (an amino acid that can damage blood vessels) or impairing insulin sensitivity. For example, a meta-analysis of 11 studies found that high coffee intake was associated with a higher risk of CHD, especially among men and people with low genetic tolerance to caffeine. A prospective study of more than 500,000 UK Biobank participants found a significant positive association between coffee consumption and CVD mortality, but only among heavy drinkers (more than 6 cups per day) and those who had genetic variations that slow down caffeine metabolism.

Overall, the evidence suggests that coffee consumption may have complex and dose-dependent effects on cardiovascular health, and that the optimal amount and type of coffee may vary among individuals based on their genetic, metabolic, and lifestyle factors. However, it is important to note that most studies have been observational and cannot establish causality or account for all potential confounders or biases. Moreover, coffee is not consumed in isolation, but often with other foods, beverages, or habits that may also affect CVD risk.

The Hypertension and Coffee Study: What It Found and What It Means

Against this backdrop of conflicting evidence, let's return to the study that raised concerns about coffee and heart death in people with severe hypertension. The study, led by researchers at the University of São Paulo in Brazil, analyzed data from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), a large cohort study of civil servants aged 35-74 years who were recruited between 2008 and 2010 and followed up until 2018.

The study focused on a subset of 1,213 participants who had confirmed hypertension (defined as systolic blood pressure of 140 mmHg or higher, diastolic blood pressure of 90 mmHg or higher, or use of antihypertensive medication) and had provided information on their coffee intake at baseline. The participants underwent several measurements and assessments, including blood pressure, body mass index, smoking status, physical activity, alcohol intake, and blood tests for glucose, lipids, and kidney function.

After excluding participants with a history of CVD or cancer, as well as those with missing data on covariates or coffee intake, the researchers ended up with a final sample of 534 participants who were followed up for a median of 12.5 years. During this time, 77 participants died from cardiovascular causes, including heart disease, stroke, heart failure, and peripheral artery disease.

The main finding of the study was that participants who reported drinking two or more cups of coffee per day had a hazard ratio of 2.19 (95% confidence interval: 1.19-4.04) for cardiovascular mortality compared to those who drank less or no coffee, after adjusting for several covariates such as age, sex, race, education, smoking, diabetes, body mass index, and use of antihypertensive medication. The hazard ratio means that the risk of dying from cardiovascular causes was more than twice as high in the higher coffee consumption group than in the lower coffee consumption group.

The authors speculated that the association between coffee and cardiovascular mortality may be due to the effects of caffeine on blood pressure, endothelial function, insulin sensitivity, or arrhythmias, all of which could exacerbate the already high risk of CVD in people with severe hypertension. They also noted that their findings were consistent with some previous studies that had found a J-shaped or U-shaped association between coffee consumption and CVD risk, meaning that moderate intake may be protective or neutral, but high or low intake may be harmful.

However, the study had several limitations and caveats that should be considered before drawing definitive conclusions or changing coffee habits based on it. Some of these are:

• The study was observational and cannot establish causality or temporal order. It is possible that other factors not accounted for in the analysis may have influenced both coffee consumption and cardiovascular mortality, or that reverse causation (i.e., sicker people drinking more coffee to cope) may have distorted the results.
• The study relied on self-reported coffee intake at baseline and did not assess changes in consumption over time, which could have affected the accuracy and validity of the exposure measurement. Moreover, the study did not differentiate between types of coffee, brewing methods, or additives, which may have different effects on CVD risk.
• The study population was limited to Brazilian civil servants who may not be representative of the general population or other ethnic or socioeconomic groups. The study did not provide data on other lifestyle or dietary factors that may have interacted with coffee intake to influence CVD risk.
• The study did not distinguish between caffeinated and decaffeinated coffee, which may have different cardiovascular effects due to the presence or absence of caffeine and other bioactive compounds.
• The study did not examine the potential benefits or harms of coffee consumption for other health outcomes such as cancer, diabetes, cognitive function, or all-cause mortality.
• The study did not explore the mechanisms underlying the association between coffee and cardiovascular mortality, or the potential modulators of this association such as genetic or epigenetic factors.

Conclusion and Recommendations

In summary, the recent study linking coffee consumption to increased risk of cardiovascular death in people with severe hypertension adds to the ongoing debate about the effects of coffee on cardiovascular health. While the study has some strengths such as its prospective design, large sample size, and rigorous adjustment for confounders, it also has limitations and uncertainties that should be acknowledged.

Based on the available evidence, we cannot conclude that coffee is inherently harmful or beneficial for cardiovascular health, or that there is a universal or optimal amount of coffee that applies to everyone. Coffee intake may have complex and context-specific effects on cardiovascular risk, depending on various factors such as genetic, metabolic, and lifestyle characteristics, as well as the type, amount, and brewing method of coffee.

Therefore, our recommendations for people with hypertension or other cardiovascular conditions who are concerned about their coffee intake are as follows:

• Consult your healthcare provider before making any significant changes to your coffee habits, especially if you have uncontrolled hypertension or other comorbidities that may interact with coffee.
• Be aware of the potential risks and benefits of coffee consumption, and balance them with other factors such as overall dietary patterns, physical activity, and stress management.
• Consider reducing your coffee intake if you experience palpitations, high blood pressure, anxiety, or other adverse effects that may be related to caffeine or coffee.
• If you enjoy coffee and want to continue drinking it, try to choose high-quality, fresh, and organic coffee beans that are roasted and brewed to your taste preferences. Experiment with different brewing methods such as drip, pour-over, French press, or espresso, and avoid adding excessive amounts of sugar, cream, or flavorings that may negate the health benefits of coffee.
• Keep in mind that coffee is not a magic bullet or a panacea for cardiovascular health, and that lifestyle factors such as regular exercise, smoking cessation, stress reduction, and a balanced diet are also crucial for reducing CVD risk.

Final Thoughts

Coffee consumption is a widely debated topic in the context of cardiovascular health. While some studies suggest that moderate coffee intake may have beneficial effects on reducing the risk of CVD and other health outcomes, other studies indicate potential harms, especially for certain subgroups of people with hypertension or high sensitivity to caffeine.

The recent study linking coffee consumption to increased risk of cardiovascular death in people with severe hypertension has limitations and uncertainties that should be acknowledged, and its findings should not be interpreted as conclusive or generalizable to other populations or coffee habits.

Therefore, people with hypertension or other cardiovascular conditions should consult their healthcare providers before making any significant changes to their coffee habits, and consider balancing the potential risks and benefits of coffee consumption with other lifestyle factors such as physical activity, stress management, and overall dietary patterns.

By staying informed and mindful about the complexities of coffee and cardiovascular health, we can make informed decisions that optimize our well-being and longevity.

References

Ding M, Bhupathiraju SN, Satija A, van Dam RM, Hu FB. Long-term coffee consumption and risk of cardiovascular disease: a systematic review and a dose-response meta-analysis of prospective cohort studies. Circulation. 2014 Jan 7;129(1):643-59.

Poole R, Kennedy OJ, Roderick P, Fallowfield JA, Hayes PC, Parkes J. Coffee consumption and health: umbrella review of meta-analyses of multiple health outcomes. BMJ. 2017 Nov 22;359:j5024.

Kim Y, Je Y, Giovannucci EL. Coffee consumption and all-cause and cause-specific mortality: a meta-analysis by potential modifiers. Eur J Epidemiol. 2019 Feb;34(2):109-22.

This abstract is presented as an informational news item only and has not been reviewed by a medical professional. This abstract should not be considered medical advice. This abstract might have been generated by an artificial intelligence program. See TOS for details.