Moderate coffee consumption is not associated with the development of heart conditions.
The most recent report on cardiovascular disease from the Department of Health’s Committee on Medical Aspects of Food Policy concluded that `coffee drinking as practised in the United Kingdom does not appear to affect coronary heart disease risk’. (1)
The British Heart Foundation also says up to six cups of coffee per day will not significantly affect a person’s risk of coronary heart disease or stroke. (2)
From data taken from studies in humans we know that, in the general population, consumption of coffee in moderate amounts does not modify cardiovascular functions and does not cause or exacerbate cardiac rhythm anomalies, myocardial infarction or high blood pressure.
Because there are individual sensitivities to coffee, healthcare professionals can advise people on the amounts of coffee they can consume. Moderate coffee consumption, of 4-5 cups per day, is perfectly safe for the general population and may confer health benefits.
Coronary heart disease (CHD)
Many retrospective and prospective epidemiological surveys have tried to evaluate the relationship between coffee or caffeine consumption and prevalence of coronary heart disease or death caused by CHD.
In a recent cohort study of 38,000 Norwegian men (Scandinavia is the highest consumer of coffee in the world), only men who drank nine or more cups of coffee daily displayed a slightly increased risk of death from CHD after 12 years of follow-up (3). While in a cohort of Scottish men, followed up for 21 years, there were no associations between coffee consumption and CHD. (4)
Moderate consumption of coffee does not lead to coronary insufficiency or infarction. Indeed some studies have argued that coffee drinking may be a marker for a lifestyle characterised by known atherogenic factors – such as smoking – and is not a causal factor in itself (5, 6, 7).
Effects on cardiac rhythm
There is little evidence to support the idea that drinking coffee causes cardiac arrhythmias. In intervention trials neither 300mg nor 450mg of caffeine increased the occurrence or severity of ventricular arrhythmias in patients recovering from a heart attack (8, 9).
In a prospective cohort study of 128,934 adults over eight years there was no association between consumption of coffee and risk of death attributed to cardiac arrhythmia without specified cause (10).
A review of intervention trials and epidemiological studies concluded that `moderate ingestion of caffeine does not increase the frequency or severity of cardiac arrythmias in normal persons, patients with ischaemic heart disease, or those with pre-existing serious ventricular ectopy’ (11).
Research published in the early 1990s indicated that regular consumption of caffeine in the UK does not lead to raised blood pressure in people with blood pressures in the normal range (12, 13)
These studies also found that while ingestion of caffeine after a period of abstinence may cause a small transient rise in both diastolic and systolic blood pressure, tolerance develops with regular consumption and blood pressure returns to baseline in 2-3 days, with no long-term effects.
A more recent critical review of over 100 published studies concluded that coffee or caffeine may have a negative effect on people prone to hypertension, but only if consumed in large doses – although the authors did not specify what constituted `a large dose’ (14)
The effects of drinking different types of coffee on blood lipid levels including total, low density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol have been reviewed (15). The authors said that the diterpenes cafestol and kahweol are the cholesterol-raising factors. Filtered coffee and instant coffee contain low levels of diterpenes.
An intervention trial has shown that consumption of decaffeinated coffee did not lower total or LDL-cholesterol levels (16) and a cross-sectional study showed no link between caffeine intake and total, LDL- or HDL- cholesterol (17)
However, heavy consumption of boiled coffee elevates blood total and LDL-cholesterol levels (18). Although more common in Scandinavia and the Middle East drinking boiled coffee is comparatively rare in the UK.
Homcysteine is a naturally occurring amino acid found in the blood and tissues. It has been suggested that elevated levels of homocysteine can increase the risk of cardiovascular disease (19), although some large cohort studies have found no link (20, 21)
It is unclear whether elevated blood homocysteine levels cause cardiovascular disease or whether cardiovascular disease causes elevated homocysteine levels.
It has further been suggested that coffee consumption raises homocysteine levels – but there is no conclusive proof for this. An effect of coffee consumption on cardiovascular disease risk mediated by homocysteine levels is therefore unlikely.
Cardiovascular Health References
- Department of Health, Committee on Medical Aspects of Food Policy. Report on Health and Social Subjects 46, 143. HMSO: London, 1994
- British Heart Foundation Statement June 1, 2001
- Stensvold, I. et al. British Medical Journal, 312, 544-545, 1996
- Hart, C. and Davey Smith, G. Journal of Epidemiology and Community Health, 51 461-462, 1997
- Puccio, M. et al. American Journal of Public Health, 80, 1310-1313, 1990
- Jacobsen, B.K. and Thelle, D.S. Acta Medica Scandinavica, 222, 215-221, 1987
- Gyntelberg, F. et al. Journal of Internal Medicine, 236, 1-7, 1994
- Myers, M.G. et al. American Journal of Cardiology, 59, 1024-1028, 1987
- Myers, M.G. et al. Canadian Journal of Cardiology, 6, 95-98, 1990
- Klatsky, A.L. et al. Annals of Epidemiology, 3, 375-381, 1993
- Myers, M.G. et al. Annals of Internal Medicine, 114, 147-150, 1991
- Rosmarin, P.C. et al. Journal of General Internal Medicine, 5, 211-213, 1990
- Myers, M.G. et al. American Journal of Hypertension, 4, 427-431, 1991
- Nurminem, N.L. et al. European Journal of Clinical Nutrition, 53, 831-839, 1999
- Urgert, R. and Katan, M.B. Annual Review of Nutrition, 17, 305-324, 1997
- Wahrburg, U. et al. European Journal of Clinical Nutrition, 48, 172 -179, 1994
- Carson, C.A. et al. American Journal of Epidemiology, 138, 94-100, 1993
- Jee, S.H. et al. American Journal of Epidemiology, 153, 353-362, 2001
- Hankey, G.J. and Eikelboom, J.W. Lancet, 354, 407-413, 1999
- Folsom, A.R. et al. Circulation, 98, 1-7, 1998
- Fallon, U.B. et al Heart, 85, 153-158, 2001