In a recent article published within the journal Nutrients, researchers chosen two red wines constituted of Zweigelt grape varietals cultivated in Hokkaido, Japan, in several vintage years, 2015 and 2018, to evaluate their effect on vascular and platelet function in healthy adult men.

Study: The Effect of Hokkaido Red Wines on Vascular Outcomes in Healthy Adult Men: A Pilot Study. Image Credit: futuristman / Shutterstock

Background

Several aspects contribute to the polyphenolic content of wine, especially anthocyanins that impart color and hue to red wines.

Thus, malvidin glucoside (MG) levels, a red wine anthocyanin, are higher in younger wines. Secondly, environmental aspects influence a red wine’s polyphenolic profile, including temperature, humidity, sunlight exposure, and soil conditions. Thirdly, variety and 12 months of harvest contribute to differences within the polyphenolic profiles of red wine vintages. Clearly, red wines constituted of the identical grape varietal cultivated in similar regions but in several years could have substantially variable polyphenolic profiles.

The polyphenolic profile of red wine is the important thing determinant of its useful effects on cardiovascular health. Thus, it makes perfect sense to explore how consuming red wine from the identical grape varietals cultivated in similar geographic areas but in several vintage years could exert various effects on systolic and diastolic blood pressure (SBP and DBP) and vascular and platelet function.

In regards to the study

In the present three-arm, controlled cross-over study, researchers first subjected all eligible participants (healthy men aged 50 to 70 years) to measurements of vascular function, SBP & DBP, and platelet reactivity at baseline. It included augmentation index (AI) measurement at 75 beats/min (AI75), indicating peripheral arterial stiffness.

Next, they randomly assigned them to eat 240 mL each of red wine or sparkling white grape juice (control). They provided beverages with mozzarella string cheese and 16 crackers (snacks) that provided 360 kcal energy, 40% of which was derived from fats. They repeated all of the measurements two and 4 hours after beverage consumption. The washout duration between study arms was seven days. 

Further, they quantified tyrosol (Tyr) and hydroxytyrosol (HT) concentrations in each Hokkaido red wine. Finally, they used a linear mixed model to research changes from the baseline in vascular outcomes, BP, and range-scaled platelet function.

Winter vineyard pruning in Hokkaido, Japan (Image Credit: Hokkaido Wine Co.; Otaru, Hokkaido, Japan).

Results

In comparison with the intake of the control beverage, the 2015 and 2018 Zweigelt red wines (each) lowered AI in healthy adult men. Nevertheless, the only intake of the 2018 wine significantly reduced SBP and DBP within the postprandial period in comparison with the 2015 wine or control intake.

Notably, a postprandial state that typically lasts six to 12 h could last for greater than 16 h under the influence of a high-calorie eating regimen with more saturated fats and carbohydrates, which increases cardiovascular risk via increased exposure to increased plasma glucose, chylomicrons, triglycerides-rich very-low-density lipoprotein (VLDLs) and their remnants.

Induction of unfavorable postprandial responses, including inflammation and oxidative stress, to call a number of, promotes atherosclerosis, leading to increased arterial stiffness, as observed on this study.

Moreover, the authors noted an improved vascular response with red wine, especially the 2018 red wine, which contained almost twice as much HT because the 2015 wine. Notably, HT, a significant phenolic in red wines and olive oil, gets absorbed and metabolized inside 4 to 6 hours, explaining BP-related discrepancies observed in the current study.

Studies have shown that HT is best absorbed and more bioavailable than Tyr in in vitro models. Hokkaido in Japan experiences a shorter and cooler summer season. Yet, interestingly, its Zweigelt red wines produced vascular responses comparable to wines produced in warm climate regions with longer growing seasons, most probably resulting from their higher phenolic concentrations. 

Conclusions

Overall, a single intake of 2015 and 2018 Hokkaido Zweigelt red wines markedly reduced arterial stiffness in healthy adult males, with the effect of 2018 wine being more pronounced on SBP and DBP values.

In the present study, the researchers assessed the consequences of red wines on vascular outcomes for over 4 hours only, which may need minimized the absorption and metabolism of their anthocyanin and ellagitannin constituents. Thus, future studies with larger sample sizes and longer-duration follow-ups should consider a more precise differentiation of major anthocyanin subtypes in red wines of various vintage years while reporting their cardiovascular outcomes.