Cardiovascular System

Is the “J-Curve” Real?

  

  1. J-curve - Lower risk for light to moderate drinkers compared to abstainers

For many decades, epidemiological studies have consistently shown that light-to-moderate  consumers of alcoholic beverages have a lower risk of cardiovascular disease (CVD) and a lower risk of death from all causes (including total cancer) compared with non-drinkers or those who drink heavily. It is not limited to alcohol-related causes of death, but instead captures all deaths combined (Brien et al 2011, Ronksley et al 2011, di Castelnuovo et al 2006, Roerecke et al 2012, Ferrari et al 2014, Jayasekara et al 2014, Xi et al 2017, Wood et al 2018, Colpani et al 2018).

  • Such a J-shaped relationship (J-curve) has been shown in many different populations and dozens of observational studies. In different degrees, it is also seen in men and women and with other types of alcoholic beverages (Corrao et al 2000, di Castelnuovo et al 2006, Gronbaek et al 2000).
  • Observational studies cannot prove causality but the observed association is considered  biologically plausible (see below). However, there is a scientific debate at which level of consumption the nadir of this curve lies.

 

  1. Comparison to Smoking

WHO and other institutions have repeatedly declared the risks of alcohol consumption equivalent to smoking. However, no benefit of “moderate smoking” has ever been found (de Gaetano et al 2017).

 

 

Fig. 2 Dose response analysis of smoking and all-cause mortality

(De Gaetano et al, 2017)

 

  1. J-shape also for other diseases

In addition to CVD and total mortality, a J-shaped curve exists for the risk of other diseases, for example for type-2 diabetes and dementia (Koppes et al 2006, Neafsey et al 2011, Koloverou et al 2014, Xu et al 2017, Lao et al 2020). 

 

  1. Correlation or cause?

Observational studies can only provide statistical associations/correlations and present absolute or relative risks of developing certain diseases. For example, moderate wine consumption can be correlated with a lower risk of heart attack. However, such a correlation does not necessarily mean that moderate wine consumption is the cause of a lower risk of heart attack. Only studies with a different design, such as randomized controlled trials, can prove cause and effect. In such a trial one group of participants would have to consume wine moderately every day with the meals and another (control) group would consume placebo wine. After several years of follow-up, the researchers determine whether in any of the two groups fewer heart attacks occur. If the wine group has fewer heart attacks, there is a proof that wine contributes to a lower risk of heart attack. For obvious reasons, such a study is not possible and observational studies are the second best option.

To get more certainty about a correlation, the researchers examine, if the observed effect is biologically plausible (Hill AB 1965). Does it make sense biologically/physiologically sense that wine drinkers have fewer heart attacks? Many controlled experiments have proven the beneficial physiological effects of light to moderate drinking of wine/alcoholic beverages.

 

What is biologically plausible: How does the protection of wine work?

These controlled experiments (Brien et al 2011) have shown that alcohol:

  • Improves the “good” cholesterol level (HDL increases) and decreases the „bad“ LDL cholesterol
  • Lowers the blood viscosity (blood becomes „thinner“)

 The phenolic, non-alcoholic compounds of wine:

  • Improve the endothelial function and maintain the elasticity of the blood vessels
  • Act as antioxidants and scavenger of free radicals

 

  1. Wine versus other alcoholic beverages

An increasing number of both animal experiments and human trials demonstrate that non-alcoholic substances (polyphenols) in wine provide additional protective effects against risk factors and diseases indicating that light to moderate wine consumption may be more beneficial than consuming other alcoholic beverages (Costanzo et al 2011, Gronbaek et al 2000). 

These observed positive health effects of light to moderate wine consumption may be - at least in part - linked to the protective effects of those specific bioactive ingredients in the wine as well as in the foods consumed with higher abundance in the Mediterra­nean diet.  Although these polyphenols are very poorly absorbed, recent scientific evidence suggests that wine polyphenols exert their effects through the gut microbiota. They seem to change the microbiota and at the same time, are metabolized by the intestinal bacteria (microbiota) into metabolites that are more bioavailable and can be absorbed more easily by the humans (Cueva et al 2017). 

 

  1. Influencing factors

Most epidemiological studies have only used the average amount of alcohol consumed (over a week or month) as the measure of exposure, however, other factors play an important role in the health outcome. i.e. Regular moderate consumers of alcoholic beverages had considerable health advantages compared to binge drinkers, even though they consumed on average the same amount.

  • Drinking pattern (moderate, regular vs. binge drinking) (Bagnardi et al 2008, Morland 2016, Saito et al 2018)
  • Drinking with the meals (Boban et al 2016, Giacosa et al 2016)
  • Alternate wine with water
  • The famous advice of Serge Renaud is: “You drink water, but you sip wine”.

 

  1. Underreporting

An important problem of observational studies is “under-reporting” of alcohol intake. This subsequently affects the J-curve. When “under-reporters” are removed from the study analysis, the curve shifts to the right, which means that the lowest risk of moderate drinkers is actually related to a higher amount of alcohol intake and the increased risk starts at a higher dosage (Klatsky et al 2014).

 

  1. Moderate wine consumption within a healthy lifestyle

Light to moderate consumption of wine/alcoholic beverages should be considered only one component of lifestyle factors related to health (Ruidavets et al 2004, Muller et al 2016). The most important aspects are:

  • Don’t smoke
  • Maintain a normal body weight (avoid becoming obese)
  • Exercise regularly
  • Eat a healthy diet (e.g., a Mediterranean-type diet)
  • Consume alcoholic beverages moderately and regularly with food, unless contraindicated

These lifestyle factors contribute not only to a longer life expectancy but also a longer life free of chronic diseases (Li et al 2018, Li et al 2020).

 

  1. Sick-quitters

Earlier studies included ex-drinkers in the non-drinking reference/control group that may have artificially increased the risk of disease for “current abstainers”, thus, confounding the J-shaped curve and negating a protective relationship with moderate drinking. However, more recent studies have corrected this flaw and when including only lifetime abstainers in the non-drinking category, a similar J-shaped curve was found and disproved the so called “sick-quitters” hypothesis (Shaper et al 1988, Rehm et al 2008, Mukamal et al, NIH).

 

Conclusion

According to the scientific evidence, wine drinkers seem to have a lower risk of cardiovascular and other diseases as well as a lower risk of death from all causes compared to non-drinkers when consuming wine moderately and regularly as part of a meal and within a healthy lifestyle. 

 

Back to top

 

More information and a glossary of terms may be found on the Wine Information Council website: www.wineinformationcouncil.eu

Ursula Fradera, Nicolai Worm (Chair, Wine Information Council)

For more information about the references of this summary, we invite you to take a look at the bibliography.

BACKGROUND: Based on civil registries, 26,000 people died from alcoholic cardiomyopathy (ACM) in 2015 globally. In the Global Burden of Disease (GBD) 2017 study, garbage coded deaths were redistributed to ACM, resulting in substantially higher ACM mortality estimates (96,669 deaths, 95% confidence interval: 82,812-97,507). We aimed to explore the gap between civil registry and GBD mortality data, accounting for alcohol exposure as a cause of ACM. METHODS: ACM mortality rates were obtained from civil registries and GBD for n = 77 countries. The relationship between registered and estimated mortality rates was assessed by sex and age groups, using Pearson correlation coefficients, in addition to comparing mortality rates with population alcohol exposure-the underlying cause of ACM. RESULTS: Among people aged 65…
BACKGROUND: This study investigated the dose-response relationship between alcohol consumption and CVD incidence, conducting a meta-analysis of studies focusing on residents from local communities. Further, we examined whether light to moderate alcohol consumption had a protective effect on CVD incidence through a sub-group analysis. METHODS: This study conducted a meta-analysis of the relationship between alcohol consumption and CVD incidence, selecting journals published up to December 2017. The alcohol consumption level was classified into non-consumers, light (0.01-10.0 g/day), light to moderate (10.1-20.0 g/day), moderate (20.1-40.0 g/day), moderate to high (40.1-60.0 g/day), and high (> 60.0 g/day) groups. The sub-group analysis was conducted according to the number of comorbidities and age. RESULTS: Seven articles were selected in total for the meta-analysis. The…
BACKGROUND: Although it is well established that heavy alcohol consumption increases the risk of hypertension, little is known about the effect of a reduction of alcohol intake on blood pressure. We aimed to assess the effect of a reduction in alcohol consumption on change in blood pressure stratified by initial amount of alcohol consumption and sex in adults. METHODS: In this systematic review and meta-analysis, we searched MedLine, Embase, CENTRAL, and ClinicalTrials.gov from database inception up to July 13, 2016, for trials investigating the effect of a change of alcohol consumption on blood pressure in adults using keywords and MeSH terms related to alcohol consumption, blood pressure, and clinical trials, with no language restrictions. We also searched reference lists of…
The National Institutes of Health stopped the worldwide Moderate Alcohol and Cardiovascular Health (MACH) trial in 2018 because of institutional failings that led to the biased design of this major study. Drawing on e-mail correspondence among officials, researchers, and alcohol companies, we provide the first, to our knowledge, detailed analysis of alcohol industry involvement in the MACH trial.Alcohol companies agreed to fund the MACH trial to advance their commercial interests rather than to help answer a major scientific question. Alcohol industry executives seized opportunities presented by discussions of the MACH trial to try to influence this study and wider public health, research, and policy decision-making.The process of soliciting research funding from corporations, which included convincing alcohol companies that the study…
Page 2 of 69

Disclaimer

The authors have taken reasonable care in ensuring the accuracy of the information herein at the time of publication and are not responsible for any errors or omissions. Read more on our disclaimer and Privacy Policy.