There is a perception amongst healthcare professionals that alcohol and caffeine should be limited as part of a healthy diet. This advice is based on the possible detrimental effects of both drinks. Caffeine is associated with the release of adrenaline, a stress hormone, and in this regard frequent consumption is thought to create an internal condition similar to that of constant stress. This may fatigue the adrenal glands and lead to long-term physiological changes regarding the adaptability of the individual to stress. Alcohol is perceived as damaging to the health because in high concentrations can be toxic to the liver. This is true and alcoholism leads to alcoholic fatty liver and cirrhosis of the liver if intakes are not tempered. In addition, both alcohol and caffeine are diuretics and this may dehydrate the body and cause changes in electrolyte balance. This ability of these drinks to affect electrolyte balance has lead to speculation that they may increase the risk of sudden cardiac events and thus increase the risk of sudden death.
Studies that have investigated the ability of caffeine and alcohol to increase risk of sudden cardiac death have generally looked at very high intakes of alcohol associated with binging or unrealistic intakes of caffeine not possible through consumption of tea or coffee. Increasingly, normal habitual consumption of caffeine and alcohol is associated with a lower risk of many diseases, particularly cardiovascular disease. Therefore there is scope to investigate the effects of more reasonable intakes of caffeine and alcohol with the risk of sudden death. In a recent study published in the American Journal of Clinical Nutrition, this is exactly what authors set out to do1. Using data from the Women’s Health Initiative Observational Study, associations between alcohol and caffeine intake with the risk of sudden cardiac death were investigated in postmenopausal women. The results of the study showed no association between caffeine intake and sudden cardiac death. For alcohol, moderate consumption of one drink per day was actually protective.
These results support previous studies that show a protective effect for both caffeine and alcohol on the risk of mortality, when consumption is moderated. Both alcohol and caffeine can increase plasma levels of high density lipoprotein (HDL) cholesterol suggesting they have a favourable effect on lipoprotein metabolism and confer beneficial metabolic effects. Another interesting finding in this study was the fact that those women with the highest alcohol and caffeine intakes also had the lowest waist to hip ratios. It has been shown previously that both caffeine and alcohol are associated with weight loss, and one of the protective effects of these drinks may be their ability to moderate body weight. As weight gain is associated with an increased risk of cardiovascular disease and an increase in mortality this may explain the associations seen in this research. As with previous studies, a ‘U-shaped’ relationship between alcohol and health was observed, such that heavy drinkers and teetotallers had a higher risk of sudden death compared to moderate drinkers.
RdB
