A recent study published in the Nutrition Journal examined the potential interaction between long-term tea consumption and alcohol intake on the risk of hypertension and mortality among Chinese individuals, shedding light on the protective effects of tea against these health outcomes.

Tea is a widely consumed beverage worldwide, and numerous studies have highlighted its beneficial effects on various medical conditions, including hypertension, cardiovascular disorders, diabetes, stroke, heart attack, and overall mortality.

However, factors such as milk content, smoking habits, coffee consumption, lifestyle factors, and gender may influence the health benefits associated with tea consumption.

The study aimed to address the limited data on the potential interactions between alcohol and tea in relation to hypertension and mortality, providing valuable insights into the combined effects of these factors on health outcomes.

Study Overview:

In this extensive prospective cohort study, researchers aimed to explore the relationship between tea consumption, changes in blood pressure (BP), and mortality in individuals who consume alcohol compared to those who do not in China.

The study involved 6,387 participants from the China Health and Nutrition Survey (CHNS) and spanned the period from 1993 to 2011.

To conduct the analysis, individuals with at least two recorded instances of tea intake, with at least one from 1993, were included. The researchers employed group-based trajectory modeling (GBTM) to identify distinct long-term patterns of tea consumption over the course of 18 years.

Data on tea intake, including the average number of cups consumed per day, were collected through in-person surveys conducted during follow-up rounds between 1993 and 2011. Participants who reported consuming alcohol in the preceding year were categorized as current alcohol consumers. The outcomes of interest were all-cause mortality and changes in blood pressure measurements.

Assessment and Methodology:

To investigate mortality, the study involved conducting interviews with family members of deceased participants. The researchers recorded the last day of life or the date of the final survey, whichever came earlier, to determine the length of the follow-up period.

Cox regression modeling and Kaplan-Meier statistics were employed to examine the cumulative mortality rate. Restricted cubic splines were used to assess potential non-linear associations between average tea consumption and mortality.

Generalized linear mixed-effects modeling (GLMM) was utilized to analyze changes in blood pressure (BP) among different trajectories of tea intake. The hazard ratio (HR) was calculated, adjusting for various covariates such as age, marital status, gender, nationality, place of residence, education level, occupation, annual household income, smoking habits, comorbidities (e.g., diabetes, hypertension, cancer), use of antihypertensive medications, and mean values of body mass index (BMI), waist circumference, and hip circumference.

Data from the China Health and Nutrition Survey (CHNS) were collected through multistage, random-cluster sampling in 12.0 provinces. The CHNS cohort was initiated in 1989 and followed up every two to four years from 1989 to 2015, encompassing a population of over 30,000 individuals.

Findings and Discussion:

The study included individuals with an average age of 54 years, with 50% being male, and 33% reported current alcohol consumption.

Participants were categorized into three groups based on tea consumption: non-tea consumers (zero cups daily), light tea consumers (one cup daily), and high tea consumers (three to four cups daily). Among the participants, 2,838 were light tea consumers, and 1,478 were high tea consumers.

Over a median follow-up period of 18 years, nine percent of participants (n=580) passed away. The association between tea intake and mortality was found to be influenced by alcohol consumption.

The cumulative mortality rate was lower among high tea consumers compared to non-tea consumers (HR 0.8). However, the reduced mortality risk associated with high tea intake was observed only among non-alcohol consumers (HR 0.6).

For current alcohol consumers, a linear relationship between tea intake and mortality was observed, suggesting that the benefits of tea against mortality were overshadowed by alcohol. Similarly, the GLMM modeling demonstrated that alcohol also diminished the blood pressure-lowering effects of tea. These findings were consistent when stratified by gender.

Characteristics of individuals consuming high amounts of tea daily included being older, male, smokers, and residing in urban areas.

Current alcohol consumers were more likely to have unhealthy lifestyles, including smoking, and higher values for BMI, waist circumference, and hip circumference. These factors could potentially diminish the benefits of tea consumption.

The presence of alcohol may diminish the antioxidant activity of tea-derived polyphenols, which could explain the reduced benefits of tea intake. Additionally, the blood pressure-lowering effects of tea might be attributed to its ability to delay arterial stiffness.

In conclusion, this study demonstrated that consuming three to four cups of tea daily was associated with a lower risk of mortality and prevented increases in blood pressure. However, the positive effects of tea consumption were attenuated by alcohol consumption, which could even have detrimental effects on health.

These findings support previous studies highlighting the beneficial effects of tea consumption on mortality and extend the results to a broader population in China. It is important to note that the study sample may not fully represent the entire nation, limiting the generalizability of the findings.

Future research should include national data obtained from randomized controlled trials (RCTs) that examine tea intake, including the specific type of tea consumed, using objective measurement methods.

Steeped in Longevity: Exploring the Link Between Tea Consumption and Lower Mortality