Is wine good for your heart? A critical review

Effects of low ethanol doses on heart rhythm in rabbits

Effects of low ethanol doses on the vagosympathetic mechanisms of heart rhythm regulation were studied in rabbits. Analysis of heart rhythm variability showed that single intragastric administration of 0.5 mg/kg ethanol caused tachycardia in animals with initial predominance of vagal activity and bradycardia in animals with predominating sympathetic mechanisms. This was associated with general activation of all regulatory effects on the heart rhythm and a drastic increase in power spectrum for all frequency ranges, though with a certain deficiency of vagal effects. However, after 24 h the vagal component of the spectrum drastically increased in animals of both groups, while other parameters did not differ from the control. Presumably, this rebound can be used as a physiological marker, ethanol tolerance measure, formation of the abstinence syndrome and liability to alcoholism.

Genetic modification of the effect of alcohol consumption on CHD

The deleterious health effects of high alcohol consumption are numerous and well recognized; however, the effect of moderate alcohol consumption on overall health continues to be a debated issue. Among the more prevalent diseases in Westernized countries, epidemiological research suggests that alcohol in moderation substantially reduces the risk of CHD, while it modestly increases the risk for certain cancers, such as breast and colon cancer. Despite the overwhelming data supporting the beneficial effect of moderate alcohol consumption on the cardiovascular system, some researchers are not convinced. Sceptics argue that the reduction in risk is attributed to a favourable lifestyle factor associated with moderate alcohol consumption, or that it may be attributed to constituents of alcoholic beverages other than ethanol, such as the antioxidants in the grapes. In order to promote overall health for the general public, it is necessary to elucidate these issues. One approach is to study population differences in alcohol metabolic efficiency, which is likely to contribute to an individual's susceptibility to alcohol-associated diseases. Among the population there is substantial variability in the efficiency to metabolize alcohol. Genetic variation among the alcohol-metabolizing genes is known to produce isoenzymes with distinct kinetic properties. Studying genetic differences that potentially influence disease susceptibility among populations may provide insight into the mechanism(s) for the relationship between risk factor and disease, such as alcohol and CHD.

Relationship between Genetic Polymorphisms of Alcohol-metabolizing Enzymes and Changes in Risk Factors for Coronary Heart Disease Associated with Alcohol Consumption

Background: There are large individual variations in the responses of risk factors for coronary heart disease to alcohol consumption. To clarify the factors responsible for these individual variations, we studied the relationship between blood pressure, serum lipids, and uric acid and the genetic polymorphisms of alcohol dehydrogenase (ADH) 2 and aldehyde dehydrogenase (ALDH) 2 in alcohol drinkers.

Methods: We examined 133 male workers who drank >300 g of alcohol per week. Information regarding lifestyle habits was obtained by questionnaire. The ADH2 genotype was determined by PCR and subsequent digestion with MaeIII. The ALDH2 genotype was determined based on amplified product length polymorphisms.

Results: When the workers were divided into three groups: the ADH21/21, ADH21/22, and ADH22/22 groups, the mean triglycerides and γ-glutamyl transpeptidase concentrations were significantly higher in the ADH22/22 group than in the ADH21/21 group. In addition, multiple logistic regression analysis showed that the frequencies of individuals whose systolic blood pressure, triglycerides, and uric acid values were in the highest one third were significantly higher in the ADH22/22 group than in the ADH21/21 group. In contrast, no difference was observed between the ALDH21/21 and (ALDH21/22 + ALDH22/22) groups with regard to the mean value of any variable and to the frequency of individuals with any variable value in the highest one third.

Conclusion: Individuals with the ADH21/21 genotype might suffer fewer negative effects of drinking.