Wine Information Council

The authors of this review state that a strong controversy persists regarding the effects of moderate red wine consumption and health. Guidelines for the prevention of cardiovascular diseases (CVD) and cancers discourage any consumption of alcoholic beverages, but several studies have demonstrated that low red wine intake may have positive effects on CVD risk.

In their review, they assessed the effect of red wine on:

1. antioxidant status,
2. cardiovascular function,
3. coagulation pathway and platelet function,
4. endothelial function and arterial stiffness,
5. hypertension,
6. immune function and inflammation status,
7. lipid profile and homocysteine levels,
8. body composition, type 2 diabetes and glucose metabolism, and
9. gut microbiota and the gastrointestinal tract. 

Red wine consumption resulted mostly in improvements in antioxidant status, thrombosis and inflammation markers, lipid profile, and gut microbiota, with conflicting results on hypertension and cardiac function. Notably, beneficial effects were observed on oxidative stress, inflammation, and nephropathy markers, with a modest decrease in CVD risk in five out of seven studies (with a duration between six months and two years) that evaluated the effect of red wine consumption in patients with type 2 diabetes mellitus (T2DM). Importantly, a longer study duration with red wine consumption has been shown to protect renal and cardiac function parameters in T2DM patients, suggesting that a moderate intake of red wine may serve as a dietary supplement in diabetic patients.

The authors suggested that additional long-term randomised controlled trials are needed to confirm these benefits, and to assess the potential risks associated with red wine consumption. 

Lombardo M, Feraco A, Camajani E, Caprio M, Armani A. Health Effects of Red Wine Consumption: A Narrative Review of an Issue That Still Deserves Debate. Nutrients. 2023 Apr 16;15(8):1921. oi.org/10.3390/nu15081921

Chronic low-grade inflammation (inflammation that fails to resolve or is continuously triggered) can negatively affect tissues and organs over time. It is observed in many chronic non communicable diseases, from obesity to type 2 diabetes mellitus, non-alcoholic fatty liver to cardiovascular disease. While excessive consumption of alcoholic beverages tends to promote the inflammatory process, quite a few studies found lower levels of inflammatory markers with light to moderate consumption of alcoholic beverages. However, is this association "real"? 

Acute inflammation is a vital and adaptive response of the body as defense against pathogens and for wound healing. However, if they do not disappear and become chronic, even mild (low-grade) inflammation is part of a vicious cycle that can stress tissues and organs and damage them. Many of today's common lifestyle diseases are associated with such chronic low-grade inflammation, which can be determined - among other parameters - by elevated hsCRP (high-sensitivity C-reactive protein) levels: a protein that reacts particularly sensitive to inflammatory messenger substances in the body. 

Do alcoholic beverages play a role?

Since many lifestyle factors influence the inflammatory process, the influence of alcoholic beverages has also been investigated. While it is assumed that increased inflammation plays a role in the harmful health effects of excessive consumption, either no effects or lower inflammation markers were found with low to moderate consumption of alcoholic beverages. 

But how robust and how consistent are these findings considering the fact that research about the influence of moderate alcohol consumption is influenced by many factors? This starts with the selection of the comparison group (abstainers, ex-drinkers and/or occasional consumers), includes the drinking guidelines, which vary greatly from region to region, and extends to other influencing factors (covariates) that should be taken into account in the respective studies - but are not always considered. These include also sociodemographic characteristics, physical and mental health, and other lifestyle factors such as smoking, diet, and physical activity. 

To answer this question, an Australian-British research team used the data of  3,100 British individuals who were born in a specific week in 1970. Their consumption data at age 36 and 42 and a measurement of hsCRP at age 46 were available. New statistical methods and modelling (*) were used to calculate all the possible combinations of influencing factors, drinking patterns, time periods and recommendations for moderate consumption. For example, low-to-moderate consumption data (**) and consumption above various international drinking guidelines were compared to an abstinent reference. 

Would they arrive at consistent conclusions in their analysis? If yes, this would mean that there would be a more robust evidence for an association between light to moderate consumption of alcoholic beverages and lower inflammatory markers (here: hsCRP). Although this would not yet prove a causal relationship, it would support a more robust relationship than the observational studies to date allow. 

Moderate consumption: consistently lower inflammation levels

This extensive evaluation of the data led to several insights:

• The best comparison group is not lifelong abstainers and/or ex-users, because there are too few of them. It is better to use the occasional users (here: less than once a week) for comparison.
• No matter which drinking guidelines were used (Spanish, English, American, or Dutch): Light to moderate consumers always had lower hsCRP levels than occasional consumers.
• No matter what kind and how many influencing factors (covariates) were taken into consideration: Light to moderate consumption of alcoholic beverages was always associated with lower hsCRP levels than in occasional consumers.
• Regardless of whether the consumption data were averaged or calculated individually, or whether only the maximum consumption was included in the calculations, lower hsCRP values were always observed in light to moderate consumers than in occasional consumers.
• In contrast, the associations were no longer obvious for consumption above moderate amounts. 

The differences to the group of occasional consumers were not very large, but in most cases significant. Thus, the favorable association between light to moderate drinking levels and lower inflammatory markers in middle-aged individuals may be considered "robust."

(*) (so-called multiverse and effect-vibration analyses)

(**) Definitions:

Low to moderate consumption (drinking guidelines)

• Netherlands: < 70 g aöcphpl/week
• UK: < 112 g alcohol/week
• USA: women < 98, men < 196 g alcohol/week
• Spain (former guidelines): women < 170, men < 280 g alcohol/week

Visontay, R et al.: A comprehensive evaluation of the longitudinal association between alcohol consumption and a measure of inflammation: Multiverse and vibration of effects analyses. Drug and Alcohol Dependence 2023;247:109886

Researchers at the Canadian Institute for Substance Use Research (*) published a new meta analysis about the effects of various levels of alcohol consumption on all-cause mortality and concluded that drinking less than two standard drinks per day (<25g/d) was not associated with protection against heart disease or contributed to a longer life expectancy. Thus, disputing the well-established J curve and that wine is protective against heart disease.

Main findings

• The current meta-analysis of 107 cohort studies involving more than 4.8 million participants did not find a significant reduction in risk of all-cause mortality for “low-volume” drinkers consuming less than 25 g of ethanol per day compared to lifetime abstainers (after adjusting for key characteristics such as age and gender).
• These results seem to be inconsistent with the data presented in the publication’s
• When they separated the underlying (or original) studies into older participants and younger ones, this meta-analysis found no risk associated with any drinking up to 45g/day and
• an increase in risk among heavier drinkers across both age groups compared to abstainers and to occasional drinkers.
• The meta-analysis found that the mortality risk appears to be different for men and women, with an increase for women at drinking levels above 24g/day and for men above 44g/day. But the risk did differ by age (even though the authors did not do an analysis to test the significance of these differences).
• These results as well as larger increases in risk for women compared to men for certain drinking levels are consistent with the findings of previous studies.

What does it mean?

• The current publication is an update of the authors’ 2016 meta-analysis, where 20 new studies (from 2016 to July 2021) were included. Their findings are inconsistent with most other meta-analyses conducted during past two decades.
• The study assumptions appear to be subjective and based on the authors’ previous publications.
• The authors’ conclusion that ”daily low or moderate alcohol intake was not significantly associated with all-cause mortality risk” does not fully reflect the study’s results. There are several limitations to this study’s design, analysis, and interpretation that warrant caution when considering its results and conclusions.

Details:

• The authors adequately acknowledge the study’s main strengths but understate some of its limitations:
• In many studies, the measurement of alcohol consumption is imprecise and was assessed only once
• Underreporting is a problem: individuals report less than they actually consume, which distorts the research results and the associated health risk of alcoholic beverages (ie. if they report 1 glass of wine but they actually consume 2 glasses, the risk appears to be higher than if they would actually only consume 1 glass),
• Few underlying studies included sufficient data on drinking patterns to fully capture their likely effect. For example, a binge drinking pattern affects the risk quite differently, even though the averaged daily drinking volume is low.
• It is important to know that many of the studies that went into the meta-analysis do not assess certain confounding factors such as drinking patterns (only average alcohol consumption), type of alcoholic beverages and lifestyle factors such as diet, smoking, body weight, exercise)
• Despite these limitations, the authors conclude that moderate, “low-volume” alcohol drinking was not associated with protection against death from all cause.
• However, the figures presented in the publication and the J curve in the appendix (eFigure 4) do not support these conclusions. The data clearly show that both the non-adjusted as well as the adjusted data support a J-shaped relation between alcohol consumption and overall mortality. This means that low volume drinking (defined as 1.3 – 24 g alcohol per day, or up to two drinks) is associated with a significantly reduced risk of dying.
• The paper does unfortunately not present any new ideas to support their data interpretation; it is just an extension of previous papers by the same group. The hypothesis put forward by the authors a long time ago (the “sick quitters” hypothesis) has been disproven decades ago, and all studies since the 1990s have excluded those who stop drinking from the non-drinker’s pool. This appears to be just be another attempt to revive their misconceptions.
• Furthermore, the authors deliberately excluded numerous strong epidemiological studies showing a J-shaped association between drinking and mortality. They also did not acknowledge the well-described mechanisms that explain the causal relation between regular light to moderate consumption of alcoholic beverages and reduced risk of coronary heart disease and, therefore, reduced risk of death.

(*) the authors disclose funding from Canadian Centre on Substance Use and Addiction under a Health Canada grant related to the recent review of Canada’s Low-risk drinking guidelines from 2011.

The current prospective study examined the contradictory relation between the intake of alcoholic beverages with waist circumference (WC) and body weight (BMI). 

Alcoholic beverages provide calories, and reducing the consumption is often used as an argument not to put on extra body weight.  An increasing trend in energy consumed from alcoholic beverages coupled with increases in waist circumference (WC) and body weight (BMI) have been reported in the US over the past two decades. But when you examine the scientific evidence, studies of alcohol intake with measures of body weight are inconsistent: positive, negative and no associations of alcohol intake with WC and body weight have been observed. In such inconsistent study findings, the drinking pattern and the preferred type of alcoholic beverage may also play a role, and these habits can change over the years.

 In the mid 80’s, a prospective study was initiated, where 5000 young adults were recruited for the CARDIA study (Coronary Artery Risk Development in Young Adults). These participants were questioned about their eating, drinking, smoking and exercise pattern and their socio-economic status. Every 5 years, these parameters as well as their weight and waist circumference were measured again.

Since the drinking patterns of these CARDIA participants were also assessed every 5 years, the researchers could determine whether changes in WC and body weight differ between individuals who drink and those who do not. They could examine whether changes in drinking habits during these 5-year intervals were linked to a corresponding 5-year change in waist circumference and body weight (BMI, Body Mass Index) and possibly address the knowledge gaps.

Changes in the drinking level (light/moderate and excessive*) and 5-year changes by beverage type were also evaluated. 

Thus, for the first time, data of 4355 American individuals are available, which can be used to assess whether and how a change in drinking patterns over each 5-year interval could affect body weight. This study adds evidence to the existing inconsistent study findings, however, since the study is observational, a causal inference cannot be drawn. It can provide at least an indication for possible associations, which can be further researched. 

Abstainers ("stable non-consumers") served as the control group in this study: They had indicated in all six assessments that they did not consume alcoholic beverages. Both the abstainers and the consumers of alcoholic beverages gained weight over the 25 yr follow up period (increased body weight and waist circumferences).

However, certain changes in drinking habits were found to be associated with smaller increases than with consistent abstinence. 

Changes in men

Thus, among men, a reduced consumption of alcoholic beverages was associated with lower increases in body weight and waistline, and did so when "excessive" consumption was reduced. 

Among women, the relation between the changes in their drinking habits and their body weight was only obvious when drinking patterns were included. The women put on less weight than abstainers, especially when they maintained (or started) a light to moderate consumption of alcoholic beverages. In the current study, this is the equivalent of up to 7 drinks per week, with one drink corresponding to 14 g of alcohol or around 150 ml of wine.

Beverage preference among women

When beverage preference was also included the 5-year intervals, it was shown that women gained less weight than abstainers, when they maintained their wine consumption and reduced their consumption of spirits and mixed drinks. Abstaining from wine, on the other hand, did not provide any benefits. 

The researchers concluded that this was the first study to examine changes in waist circumference and body weight related to changes in alcoholic beverage consumption (by drinking level and beverage type) in US-based participants. They emphasize, however, that the associations of alcohol consumption with obesity/body weight are complex and that the observed magnitude between alcohol intake and body weight changes were small. 

(*) Definitions:

Men:               light drinker = < 7 drinks/week

moderate drinker = 7-14 drinks/week

excessive drinker = > 14 drinks/week

Women:          light drinker =< 4 drinks/week

                        Moderate drinker: 4-7 drinks/week

                        Excessive drinker = > 7 drinks/week

Butler, JL et al.: Associations of 5-year changes in alcoholic beverage intake with 5-year changes in waist circumference and BMI in the Coronary Artery Risk Development in Young Adults (CARDIA) study. PLoS ONE 2023;18:e0281722