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.

AIMS: The aim of this review was to focus on the knowledge of the cardiovascular benefits of moderate alcohol consumption, as well as to analyze the effects of the different types of alcoholic beverages. METHODS: Systematic revision of human clinical studies and meta-analyses related to moderate alcohol consumption and cardiovascular disease (CVD) from 2000 to 2012. RESULTS: Heavy or binge alcohol consumption unquestionably leads to increased morbidity and mortality. Nevertheless, moderate alcohol consumption, especially alcoholic beverages rich in polyphenols, such as wine and beer, seems to confer cardiovascular protective effects in patients with documented CVD and even in healthy subjects. CONCLUSIONS: In conclusion, wine and beer (but especially red wine) seem to confer greater cardiovascular protection than spirits because of…
RATIONALE: Experimental studies have shown a potential blood pressure (BP) lowering effect of red wine polyphenols, whereas the effects of ethanol and polyphenols on BP in humans are not yet clear. OBJECTIVE: The aim of the present work was to evaluate the effects of red wine fractions (alcoholic and nonalcoholic) on BP and plasma nitric oxide (NO) in subjects at high cardiovascular risk. METHODS AND RESULTS: Sixty-seven men at high cardiovascular risk were studied. After a 2-week run-in period, subjects were randomized into 3 treatment periods in a crossover clinical trial, with a common background diet plus red wine (30g alcohol/day), the equivalent amount of dealcoholized red wine, or gin (30g alcohol/day), lasting 4 weeks each intervention. At baseline and…
BACKGROUND: Moderate alcohol intake is associated with lower risk of coronary heart disease (CHD), but the association with sudden cardiac death (SCD) is less clear. In men, heavy alcohol consumption may increase risk of SCD, whereas light-to-moderate alcohol intake may lower risk. There are no parallel data among women. OBJECTIVE: The purpose of this study was to assess the association between alcohol intake and risk of SCD among women and to investigate how this risk compared to other forms of CHD. METHODS: We conducted a prospective cohort study among 85,067 women from the Nurses' Health Study who were free of chronic disease at baseline. Alcohol intake was assessed every 4 years through questionnaires. Primary endpoints included SCD, fatal CHD, and…
ISSUES: Alcohol has been implicated in both the popular press and scientific literature as having a protective effect for at least a dozen conditions including coronary heart disease (CHD). APPROACH: Epidemiological evidence for an apparent protective effect of alcohol on CHD is now being challenged on a number of fronts. This paper is a synopsis of those various challenges as they currently stand. KEY FINDINGS: The argument that systematic misclassification of ex-drinkers and occasional drinkers to 'abstainer' categories among epidemiological studies might explain apparent protective effects of moderate alcohol consumption on CHD has recently been supported by new meta-analyses and independent research. The influence of uncontrolled or unknown factors on the relationship between alcohol and disease cannot be ruled out.…
BACKGROUND: Alcohol has been reported to be a common and modifiable risk factor for hypertension. However, observational studies are subject to confounding by other behavioural and sociodemographic factors, while clinical trials are difficult to implement and have limited follow-up time. Mendelian randomization can provide robust evidence on the nature of this association by use of a common polymorphism in aldehyde dehydrogenase 2 (ALDH2) as a surrogate for measuring alcohol consumption. ALDH2 encodes a major enzyme involved in alcohol metabolism. Individuals homozygous for the null variant (*2*2) experience adverse symptoms when drinking alcohol and consequently drink considerably less alcohol than wild-type homozygotes (*1*1) or heterozygotes. We hypothesise that this polymorphism may influence the risk of hypertension by affecting alcohol drinking behaviour.…
Page 64 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.