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. 

 

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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.

Although, three decades have pasted from the introduction of "French Paradox", is still an issue for debate. Epidemiology supports the J-shaped relationship between wine consumption and vascular events as well as cardiovascular mortality with a maximum protection at 21 g of alcohol consumption in the form of wine per day. Nevertheless, the aforementioned studies have used an observational design that raises concerns about potential confounding. Randomized clinical studies may provide data to end the controversy and in parallel with in vitro experiments to elucidate the mechanisms by which wine affects cardiovascular disease. In this concept, this review aims to address the presence of bioactive wine micro constituents, their potential mechanisms of action and also to summarize the cardio-protective effects of…
Existing data have described benefits and drawbacks of alcohol consumption on cardiovascular diseases (CVD), but no research has evaluated its association with the cardiovascular health (CVH) score proposed by the American Heart Association. Here, we conducted a cross-sectional analysis on the Kardiovize cohort (Brno, Czech Republic), to investigate the relationship between alcohol consumption and CVH. We included 1773 subjects (aged 25-64 years; 44.2% men) with no history of CVD. We compared CVD risk factors, CVH metrics (i.e., BMI, healthy diet, physical activity level, smoking status, blood pressure, fasting glucose, and total cholesterol) and CVH score between and within several drinking categories. We found that the relationship between drinking habits and CVH was related to the amount of alcohol consumed, drinking…
BACKGROUND & AIMS: Managing alcohol consumption may be an effective way of preventing hypertension, which is an important modifiable risk factor for cardiovascular diseases. However, there is little evidence on the temporal relationship between alcohol consumption and incidence of hypertension. We investigated the prospective association between repeated measures of alcohol consumption and hypertension incidence among Korean adults aged 40 and over. METHODS: This study included a total of 4989 participants that were not taking antihypertensive drugs and had normal blood pressure (BP) (systolic
BACKGROUND: Observational studies have documented lower risks of coronary heart disease and diabetes among moderate alcohol consumers relative to abstainers, but only a randomized clinical trial can provide conclusive evidence for or against these associations. AIM: The purpose of this study was to describe the rationale and design of the Moderate Alcohol and Cardiovascular Health Trial, aimed to assess the cardiometabolic effects of one alcoholic drink daily over an average of six years among adults 50 years or older. METHODS: This multicenter, parallel-arm randomized trial was designed to compare the effects of one standard serving ( approximately 11-15 g) daily of a preferred alcoholic beverage to abstention. The trial aimed to enroll 7800 people at high risk of cardiovascular disease.…
BACKGROUND: Reductions in World Health Organization (WHO) risk drinking levels have recently been shown to lower the risk of multiple adverse health outcomes, but prior work has not examined reductions in WHO risk drinking levels in relation to cardiovascular disease (CVD), the leading cause of death for men and women in the United States and of global mortality. This study examined associations between reductions in WHO risk drinking levels and subsequent risk for CVD. METHODS: In a US national survey, 1,058 very-high-risk and high-risk drinkers participated in Wave 1 interviews (2001 to 2002) and Wave 2 follow-ups (2004 to 2005). Self-reported CVD history that was communicated to the participant by a doctor or other healthcare professionals included arteriosclerosis, hypertension, angina,…
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