How does geography and climate impact wine quality and its health benefits?

By Hugo Francisco de SouzaReviewed by Benedette Cuffari, M.Sc.Jan 22 2024

In a recent study published in Foods, researchers review the health benefits and quality of wines and their phenolic derivatives.

Study: New Labeling Rules for Wine: Wine Alcohol-Derived Calories and Polyphenol Consumption on Health. Image Credit: Stokkete / Shutterstock.com

How is wine quality determined?

Wines are alcoholic drinks produced by the yeast-mediated fermentation of fruits, mainly grapes. Wines are known to significantly differ in quality from region to region based on their phenolic content and the stringency of their manufacturing protocols.

Novel labeling rules introduced in the European Union, which were enforced on December 8, 2023, as well as the five-tier Spanish regulatory wine classification system, are intended to equip wine consumers with the quality and calorific information needed to make informed purchasing decisions.

Each category represents an incrementally higher level of quality and geographic specificity, offering valuable information about the wine's origins and characteristics. Considerations of caloric intake become particularly important when consuming wine, especially for individuals managing conditions such as metabolic syndrome. This is attributed to the potential impact on overall caloric intake and metabolic health."

Conventionally, wine quality was determined by its phenolic content, specifically of proanthocyanins and anthocyanins. Research has investigated the health benefits of these phenolics, in which in vitro studies have revealed their remarkable antioxidant and anti-cancer properties.

However, in vivo studies highlight the poor bioavailability of anthocyanins, despite observable increases in serum antioxidant levels. This has led the medical scientific community to doubt the real-world benefits of wines' biomolecules.

Recent research, in tandem with the growing global interest in 'healthy diets' and low-calorie foods, has prompted regulatory agencies, especially in the EU, to evolve their manufacturing requirements to enhance consumer information and transparency. Given that the alcohol concentration, phenolic content, pH, and 'fullness of taste' of wines can differ significantly based on geographic region and manufacturing practices, understanding the factors influencing wine's quality and health benefits would provide these regulatory agencies the information to ultimately aid consumers.

About the study

In the present study, age- and bush-density-matched wines across five geographically and climatically distinct regions in the Priorat region, Spain, were compared to evaluate the impacts of these factors on their quality and nutritional content.

Methodologies to evaluate wine quality indices were derived from those of the International Organization of Vine and Wine (OIV) and include alcohol by volume (ABV), pH, total anthocyanins, total tartaric acidity (ATT), total tannins, and flavan-3-ol by derivatization with p-dimethylaminocinnamaldehyde (DMACA).

High-performance liquid chromatography (HPLC) coupled with mass spectrometry (MS) was used to identify and quantify anthocyanidins. Procyanidins were analyzed using rapid resolution liquid chromatography (RRLC). Statistical analyses comprised analysis of variance (ANOVA) for wine quality assessment.

Site 1 and Site 2 regions represent wines derived from the warmest areas (early ripening, E), while wines from Site 3, Site 4, and Site 5 are obtained from the coldest areas (late ripening, L). The wines are designated as Site 1 (El Molar, early region, uphill), Site 2 (El Molar, early region, downhill), Site 3 (Porrera, late region, downhill west-exposed), Site 4 (Porrera, late region, downhill east-exposed), and Site 5 (Porrera, late region, uphill)."

For estimations of human bioavailability, the Atwater factor of seven kcal/g alcohol was applied to evaluate alcohol-derived energy. The Harris-Benedict equation was used to calculate total calorie requirements for men and women in the study regions.

Study findings

Wines from the study sites exhibited significant differences in all measured parameters, thus highlighting the profound impact of geography and climate on wine quality.

Site 1, for example, was found to contain substantially higher tannin at 109.9 mg/L, lower anthocyanin at 251.1 mg/L, and higher alcohol content at 16.1% alc. vol than the other four sites. HPLC analysis revealed 15 anthocyanins and 15 procyanidins, with ANOVA results identifying high malvidin content (anthocyanins) and gallic acid (procyanidins).

The recommended amounts for daily alcohol intake are 30-40 g for men and 10-20 g for women. Therefore, three levels of g alcohol/day were considered: 30, 35, and 40 for men; and 10, 15, and 20 for women."

Bioavailability estimates revealed that wines across the five study sites varied in their daily recommended total procyanidin from 2.9-17.1% and total anthocyanin from 9.8-57.7% content. Thus, despite their low bioavailability, these phenolics should be considered when evaluating wine quality.

What does this mean for the consumer?

Not all wines are equal. Geography, soil type, and climate can profoundly affect the phenolic content and alcohol concentration of different wines. This emphasizes that close attention should be paid to nutritional content labels when choosing which wines to consume.

Depending on the healthy recommended servings of wine for either women or men, different wines can be selected to obtain similar amounts of procyanidins and anthocyanins in the diet. In addition, the selection of specific wines may avoid additional alcohol intake."

The study findings serve as a foundation for future research on the impacts of geographically unique wines on human health. The importance and consumer-centric benefits of the rules newly implemented by EU and Spanish regulatory bodies are also evident, especially those mandating nutritional content labels.