Moderate Coffee Intake Not Hazardous To Heart Health

Source: Tufts University
January 22, 2001 (Reviewed: February 18, 2003)

Introduction

Coffee consumption is an oft-studied consumer health habit, with much of the research focused on a possible connection between coffee intake and risk of cardiovascular disease. But, in spite of a substantial body of research on the subject, scientists do not yet have a clear picture of what effect, if any, regular coffee has on heart health. A study published in a recent issue of the Archives of Internal Medicine provides more food for thought about the relationship of coffee to heart disease in both men and women.

Assessing coffee consumption in Finland

In this latest analysis, Finnish researchers used information gathered during a national health survey to assess the usual coffee intake, smoking habits, and medical history of more than 20,000 men and women aged 30 to 59. They then followed the subjects for up to ten years, documenting the number of people who suffered a non-fatal myocardial infarction (MI) or died from any cause during that time.

After adjusting for age, smoking status, serum cholesterol level, blood pressure, and history of MI, the researchers found a U-shaped association between coffee consumption and total mortality in men, with the lowest risk among those who consumed 4 to 7 cups of coffee a day. (In this study, one cup was equal to 1.1 dL, or slightly less than 4 oz. Each cup contained 100 mg of caffeine, about the amount in 6 oz. of the type of coffee commonly consumed in the US.) In women, risk of death from all causes decreased as coffee consumption increased. There was no association between coffee intake and non-fatal MI or death from cardiovascular disease in either men or women.

Scores of studies have investigated a possible link between coffee and coronary heart disease (CHD) risk, with mixed results. Most cohort studies do not show a connection between coffee intake and heart disease, but many case-control studies have reported a positive correlation. Why the discrepancy?

Limitations of study designs limit its conclusions

The authors point out that cohort studies are conducted over extended periods of time, and are meant to capture the eventual consequence of a particular behavior on a health outcome. Case-control studies, on the other hand, often capture shorter-term associations. The researchers speculate that coffee intake may be a "triggering event" that precipitates an MI in those with existing CHD. In that instance, a case-control study would pick up on a transient effect that would be missed in a long-range cohort study. Another problem with case-control studies is that those with a diagnosis may tend to exaggerate their recall of events associated with the health problem, while those without the diagnosis may tend to under-report.

Also, in spite of researchers' efforts to control for confounders, it is difficult to separate one particular habit--like coffee consumption--from all the other lifestyle factors that can have an effect on health. This study and others have shown that high coffee consumption is positively correlated with heavy cigarette use and elevated serum cholesterol, both potent risk factors for heart disease. (Lipid-rich components in boiled coffee, once a mainstay of Finnish meals but now largely replaced by filtered coffee, may have contributed to an increase in total and LDL cholesterol levels in earlier studies. It is not known if intake of boiled coffee had a significant impact on the serum cholesterol levels of the people in this study.)

Should recommendations change?

Although interesting to read, these research findings don't warrant any new recommendations about coffee consumption. Rather, they reinforce the current advice that coffee, like all other food and drink, is best consumed in moderation - which in the United States, translates to about 2 to 3 cups of filter-brewed coffee a day.

Source

• Coffee consumption and the risk of coronary heart disease and death. P Kleemola, P. Jousilahti, P. Pietinen, Arch Int Med, 2000, vol. 160, pp. 3383--3400

Related Links
Healthy Lifestyle Can Reduce Women's Heart Disease Risk
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