Wine Consumption and Health: Study Suggests Protective Effect of Polyphenols Against Metabolic Syndrome

A recent study investigated the relationship between the consumption of polyphenols, found in foods and beverages such as wine, in the diet and the risk of metabolic syndrome in Brazilian adults. The findings indicate that higher intake of polyphenols is associated with a lower chance of developing metabolic syndrome, suggesting that diets rich in these substances may play a protective role against cardiometabolic risk factors.

A study (1) conducted using data from the Longitudinal Study of Adult Health (ELSA-Brazil) analyzed the association between polyphenol intake (found in foods such as fruits, coffee, chocolate, and wine) and the incidence of metabolic syndrome, considering cardiometabolic risk factors. Metabolic syndrome is a cluster of risk factors, such as abdominal obesity, hypertension, altered cholesterol levels, and high blood glucose, that increase the likelihood of heart disease, type 2 diabetes, and other health problems. Treatment and prevention are based on lifestyle changes, such as healthy eating, physical activity, and weight management.

The research evaluated 6,387 participants, with a mean age of 49.8 years, of whom 65% were women. Dietary intake was estimated using a semi-quantitative Food Frequency Questionnaire, and polyphenol intake was calculated using the Phenol-Explorer database.

Key Findings
Metabolic syndrome was defined according to the Joint Interim Statement criteria, and associations between polyphenol intake and cardiometabolic risk factors were assessed using logistic regression. During a median follow-up of 8.19 years, 2,031 participants developed metabolic syndrome. Individuals in the higher tertiles of total polyphenol intake had a lower risk of metabolic syndrome compared to those in the lowest tertile. After adjusting for sociodemographic factors, lifestyle, and diet, the risk was 22% lower in the second tertile and 23% lower in the third tertile of polyphenol intake (T2 vs. T1: OR 0.78 [95% CI: 0.68-0.90]; T3 vs. T1: OR 0.77 [95% CI: 0.66-0.90]).

Additionally, inverse associations were observed between the risk of metabolic syndrome and the consumption of phenolic acids, lignans, stilbenes, and other polyphenols. Although total flavonoid intake did not show a significant association, subclasses such as flavan-3-ols (monomers and polymers) demonstrated a protective effect. Total polyphenol intake was also inversely associated with waist-to-hip ratio, systolic and diastolic blood pressure, HOMA-IR, triglycerides, and C-reactive protein, while showing a positive association with total cholesterol, LDL, and HDL.

Implications and Limitations of the Study
The findings reinforce the importance of polyphenol-rich diets, such as those based on fruits, vegetables, and other natural foods, in reducing cardiometabolic risk. Adopting dietary habits that prioritize sources of polyphenols may contribute to strategies for preventing metabolic syndrome and promoting cardiovascular health. Furthermore, these results could support nutritional recommendations and public policies aimed at improving the food quality of the Brazilian population.

However, some caveats should be considered:

• The study assessed dietary habits at a single point in time, which may not reflect changes over time.
• Individuals with higher cardiometabolic risk may have adopted healthier diets during the study, influencing the results.
• Consumption of these foods should follow a nutritional profile: fruits can be consumed in larger quantities, while chocolates and wines should be consumed in moderation.
• The analysis used Odds Ratio (OR) in a longitudinal study, whereas Relative Risk (RR) or Hazard Ratio (HR) would be more appropriate, as OR tends to inflate results for common outcomes.

Conclusion
The findings suggest that the consumption of polyphenols, including those present in red wine, may be associated with a lower risk of metabolic syndrome and its components. However, the role of wine in health should be evaluated within the context of a balanced diet and within the limits of moderate alcohol consumption.

References:

1. Carnauba RA, Sarti FM, Coutinho CP, Hassimotto NMA, Marchioni DM, Lotufo PA, Bensenor IM, Lajolo FM. Associations between polyphenol intake, cardiometabolic risk factors and metabolic syndrome in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). J Nutr [Internet]. 2024 Nov 26. Disponível em: https://doi.org/10.1016/j.tjnut.2024.11.016.

Study Suggests Wine's "Matrix Effect" Enhances Polyphenol Benefits Beyond Isolated Alcohol

A recent scientific review proposes a paradigm shift in how wine and health are studied, advocating for a holistic approach that considers the "matrix effect" rather than focusing solely on isolated compounds. The study highlights how the interaction between polyphenols, alcohol, and other wine components can significantly influence both the bioavailability and biological effects of these compounds, raising questions about the effectiveness of supplements based on isolated ingredients or dealcoholized wine.

A Shift Toward the Matrix Effect

A review study¹ published in the International Journal of Molecular Sciences critically examined current methodologies in wine and health research and introduced the matrix effect concept—a complex interaction between various molecules within plant-based matrices that can trigger specific responses, often different from those observed with isolated constituents.

The study focused on three major polyphenols found in wine: tyrosol, hydroxytyrosol, and resveratrol, emphasizing how their lipophilic properties make them readily soluble in hydroalcoholic solutions, unlike most other polyphenolic compounds. This solubility difference is one reason for their higher bioavailability.

Key Findings on the Matrix Effect

The study demonstrates that wine has the most unique matrix among alcoholic beverages and can significantly impact the bioavailability of its phytocomplex formed during fermentation. The wine matrix plays a dual role: enhancing the absorption of beneficial compounds and inhibiting the carcinogenicity of alcohol metabolites.

The researchers identified at least thirteen polyphenols in wine as “potent inhibitors of pathways related to ethanol metabolism into acetaldehyde.” Additionally, three other polyphenols—epicatechin, epicatechin gallate, and epigallocatechin—were shown to attenuate acetaldehyde-induced double-strand DNA breaks by eliminating acetaldehyde.

Limitations of Alternative Products

The review provides evidence of the limitations of wine alternatives:

• Grape juice: Found ineffective as a matrix for quercetin and resveratrol absorption in both animals and humans. In contrast, adding 10% ethanol or whisky to the juice enabled effective absorption.
• Dealcoholized wine: Experiments in postmenopausal women yielded disappointing results, while regular red wine showed a reduced risk of cardiovascular disease.
• Red wine extracts (RWE): Showed inconsistent results in human studies, especially in terms of flow-mediated dilation (FMD) outcomes.

Implications and Recommendations

The findings suggest that ignoring the full wine matrix and focusing solely on isolated compounds (such as polyphenols) may lead to misleading conclusions—as is the case with dealcoholized wine or wine-based supplements. Alternatively, this narrow focus may also place undue emphasis on the toxic effects of a single component (alcohol), while overlooking the specific protective effects of other compounds (polyphenols) found in the same matrix.

Limitations and Considerations

• The holistic approach still requires more clinical trials for full validation;
• The specific nature of the wine matrix should be taken into account by public health authorities;
• The interaction among various matrix components demands further investigation;
• Consumption should always adhere to guidelines for moderate alcohol intake.

Conclusion

The study concludes that research on wine and health must move beyond classical molecular models toward concepts like the matrix effect and phytocomplexes. The wine matrix plays a crucial role in enhancing the bioavailability of beneficial compounds and/or inhibiting the carcinogenic effects of alcohol metabolites. This confirms the WHO Scientific Group’s recommendation to “investigate the potential protective effects of ingredients other than alcohol in alcoholic beverages.”

References:

1. Miraldi E, Baini G, Biagi M, Cappellucci G, Giordano A, Vaccaro F, Bertelli AAE. Wine, Polyphenols, and the Matrix Effect: Is Alcohol Always the Same? Int J Mol Sci. 2024 Sep 10;25(18):9796. DOI: 10.3390/ijms25189796.