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.

BACKGROUND/AIM: The association between alcohol consumption and subclinical atherosclerosis is still unclear. Using data from a European multicentre study, we assess subclinical atherosclerosis and its 30-month progression by carotid intima-media thickness (C-IMT) measurements, and correlate this information with self-reported data on alcohol consumption. METHODS: Between 2002-2004, 1772 men and 1931 women aged 54-79 years with at least three risk factors for cardiovascular disease (CVD) were recruited in Italy, France, Netherlands, Sweden, and Finland. Self-reported alcohol consumption, assessed at baseline, was categorized as follows: none (0 g/d), very-low (0 - 5 g/d), low (> 5 to 10 to 10 to 20 g/d for women, > 30 g/d for men). C-IMT was measured in millimeters at baseline and after 30 months. Measurements…
BACKGROUND: Light-to-moderate alcohol drinking reduces the risk of ischemic heart disease, and this effect of alcohol is mainly explained by alcohol-induced elevation of HDL cholesterol. Hypo-HDL cholesterolemia is a potent risk factor for cardiovascular disease. The aim of this study was to clarify how alcohol relates to cardiovascular risk factors in men with hypo-HDL-cholesterolemia. METHODS: The subjects were middle-aged men with hypo-HDL cholesterolemia (< 40mg/dl), and they were divided into four groups by daily alcohol consumption (non-; light, < 22g ethanol/day; moderate, >/=22g ethanol and /=44g ethanol/day). Each risk factor was compared among the groups after adjustment for age and histories of smoking and regular exercise. RESULTS: Systolic and diastolic blood pressure levels, log-transformed lipid accumulation product and log-transformed cardio-metabolic…
BACKGROUND: The potential impacts of beverage intake during the midlife on future subclinical atherosclerosis among women are unclear. The aim of this study was to evaluate the prospective associations between the intakes of eight beverage groups and subclinical carotid atherosclerosis in midlife women. METHODS: Data came from the Study of Women's Health Across the Nation, a multicenter, multiethnic, and prospective cohort study. A total of 1,235 midlife women had measures of subclinical carotid atherosclerosis and repeatedly beverage intake data collected using a validated food frequency questionnaire. Beverages were aggregated into eight groups, including coffee, tea, sugar-sweetened beverages, artificially sweetened beverages, fruit juices, whole milk, milk with lower fat content, and alcoholic beverages. The associations of beverage intake with common carotid…
OBJECTIVE: To examine how a healthy lifestyle is related to life expectancy that is free from major chronic diseases. DESIGN: Prospective cohort study. SETTING AND PARTICIPANTS: The Nurses' Health Study (1980-2014; n=73 196) and the Health Professionals Follow-Up Study (1986-2014; n=38 366). MAIN EXPOSURES: Five low risk lifestyle factors: never smoking, body mass index 18.5-24.9, moderate to vigorous physical activity (>/=30 minutes/day), moderate alcohol intake (women: 5-15 g/day; men 5-30 g/day), and a higher diet quality score (upper 40%). MAIN OUTCOME: Life expectancy free of diabetes, cardiovascular diseases, and cancer. RESULTS: The life expectancy free of diabetes, cardiovascular diseases, and cancer at age 50 was 23.7 years (95% confidence interval 22.6 to 24.7) for women who adopted no low risk…
Alcohol has a hormetic physiological behavior that results in either increased or decreased cardiovascular risk depending on the amount consumed, drinking frequency, pattern of consumption, and the outcomes under study or even the type of alcoholic beverage consumed. However, the vast majority of studies elucidating the role of alcohol in cardiovascular and in the global burden of disease relies on epidemiological studies of associative nature which carry several limitations. This is why the cardiovascular benefits of low-moderate alcohol consumption are being questioned and perhaps might have been overestimated. Thus, the aim of this review was to critically discuss the current knowledge on the relationship between alcohol intake and cardiovascular disease. Besides new evidence associating low and moderate alcohol consumption with…
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