21 August 2017: 

The Bible says that 'wine makes people happy'. Alcohol seems an inbred constituent of human nutrition, and so many studies have pin-pointed its various health benefits and risks. Usually, the bottom-line recommendation favors alcohol consumption, but limiting it to 'drink in moderation', in order to avoid the potential serious adverse outcomes of heavy and lasting drinking. A new report from the World Cancer Research Fund and the American Institute for Cancer Research addresses 'diet, nutrition, physical activity and breast cancer' [1]. The report states that there is strong evidence that consuming alcohol increases the risk for premenopausal and postmenopausal breast cancer. 

Comment

This has been known, of course, but interestingly, while reviewing the literature, it seems that no threshold has been detected. Dose-response meta-analysis showed that each 10 g of ethanol per day increase the risk of breast cancer by 5% in premenopausal women, and by 9% in postmenopausal women. To note, in the premenopause, only North American studies have demonstrated a statistically significant result, whereas European or Asian studies were in the same direction, but still non-significant. The bottom line of these data means that even just one drink per day, equivalent to 10 g of alcohol, already carries a higher risk for breast cancer. The recommendation was thus clear – 'it is best to avoid alcohol, but if alcohol is consumed, the amount should be limited'.

The adverse health consequences of consuming alcohol have been detailed in thousands of publications, which keep pouring in. For example, a study from the UK which mainly included males, found that higher alcohol consumption over 30-year follow-up was associated with increased odds of hippocampal atrophy in a dose-dependent fashion [2]. Median alcohol consumption for women was 6.4 units (1 unit = 8 g alcohol) a week. Those consuming over 30 units a week were at the highest risk compared with abstainers (OR 5.8, 95% CI 1.8–18.6; p ≤ 0.001); even those drinking moderately (14–21 units/week) had three times the odds of right-sided hippocampal atrophy (OR 3.4, 95% CI 1.4–8.1; p = 0.007). There was no protective effect of light drinking (1 to less than 7 units/week) over abstinence. Higher alcohol use was also associated with differences in corpus callosum microstructure and faster decline in lexical fluency. No association was found with cross-sectional cognitive performance or longitudinal changes in semantic fluency or word recall.

The discrepancy in outcomes between light and heavy drinking is more visible in regard to the cardiovascular effects. Heavy drinking, defined as three or more standard-sized drinks per day, is associated with cardiomyopathy, hypertension, atrial arrhythmias and stroke [3]. However, light-moderate alcohol consumption is regarded as protective since epidemiological studies have demonstrated a reduction in coronary artery disease morbidity and mortality. Thus, the question at what point benefit may turn into risk when the quantity/frequency of ingestion is evaluated becomes very important [4]. Although the traditional quota for women puts the red line at > 14 drinks/week, new data raise concerns that even low-moderate alcohol use may not offer cardio- or cerebrovascular protection.

The degree of drinking determines the risk-benefit balance also in regard to bone parameters. A survey in South Korea showed that femoral bone mineral density (BMD) for light drinkers was significantly greater than that for heavy drinkers and non-drinkers [5]. The mean BMD gradually increased from non-drinkers to the participants who drank two to three times per week. Non-drinkers and heavy drinkers had approximately a 1.7-times greater risk for osteoporosis than light drinkers.

Thus perhaps, while wine makes people happy, its long-term adverse health effects are sometimes undervalued. In biblical times, people did not survive long enough to experience the chronic diseases of old age, but, in the 21st century, the ill effects of drinking must be considered. In real life, drinking within the recommended limits of consumption is highly prevalent all over the world, but well-planned, randomized, long-term trials to enable clear demarcation between safe, enjoyable drinking and risky quantities is much needed [6]. By the way, did you hear the latest news that moderate coffee drinking is associated with reduced risk for death? The EPIC study data (451,743 participants, 16.4 years follow-up, 41,693 deaths) point at 12% lower all-cause mortality in men who drank three or more cups of coffee per day as compared to non-coffee drinkers, as well as 7% lower mortality in women [7].

Amos Pines

Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel

References

1. World Cancer Research Fund and American Institute for Cancer Research. Analysing research on cancer prevention and survival. Diet, nutrition, physical activity and breast cancer.
   http://www.aicr.org/continuous-update-project/reports/breast-cancer-report-2017.pdf
2. Topiwala A, Allan CL, Valkanova V, et al. Moderate alcohol consumption as risk factor for adverse brain outcomes and cognitive decline: longitudinal cohort study. BMJ 2017;357, j2353
   http://www.ncbi.nlm.nih.gov/pubmed/28588063
3. Klatsky AL. Alcohol and cardiovascular diseases: where do we stand today? J Intern Med 2015;278:238-50
   http://www.ncbi.nlm.nih.gov/pubmed/26158548
4. Toma A, Paré G, Leong DP. Alcohol and cardiovascular disease: how much is too much? Curr Atheroscler Rep 2017;19:13
   http://www.ncbi.nlm.nih.gov/pubmed/28210975
5. Jang HD, Hong JY, Han K, et al. Relationship between bone mineral density and alcohol intake: A nationwide health survey analysis of postmenopausal women. PLoS One 2017;12:e0180132
   http://www.ncbi.nlm.nih.gov/pubmed/28662191
6. Mukamal KJ, Clowry CM, Murray MM, et al. Moderate alcohol consumption and chronic disease: the case for a long-term trial. Alcohol Clin Exp Res 2016;40:2283-2291
   http://www.ncbi.nlm.nih.gov/pubmed/27688006
7. Gunter MJ, Murphy N, Cross AJ, et al. Coffee drinking and mortality in 10 European countries: a multinational cohort study. Ann Intern Med 2017 Jul 11. Epub ahead of print
   http://www.ncbi.nlm.nih.gov/pubmed/28693038