The relationship between green tea consumption and happiness

Although it has been suggested that green tea or its components may reduce psychological stress, the relationship between green tea intake and well-being has not been investigated in large-scale studies. In addition, no previous studies have simultaneously reported the relationships between green tea intake, social capital, and happiness. This study aimed to demonstrate the association between tea consumption and well-being after adjusting for its relationship with social network size. We analyzed cross-sectional data from the Japan Gerontological Evaluation Study conducted between October and December 2016. Green tea consumption questionnaires were mailed to 34,567 functionally independent community-dwelling residents aged 65 and older in 39 municipalities. Participants rated their well-being on a scale of 1-10, with 10 indicating the happiest and 1 indicating the least happy. The scores were treated as continuous variables and used as dependent variables in the multivariate linear regression analyses. When the number of friends one meets per month was 1-9, the proportion of those with a happiness level of 9-10 accounted for 10-20% of the total number of friends. The percentage of older adults who rated their happiness as 9-10 and had a social network size of ≥ 10 was 46.2%. When social network size (indicated by number of friends) was controlled for, along with tea consumption, gender, age, education, and income, there was a statistically significant correlation, indicating that an increase in number of friends was associated with increased happiness. Higher green tea intake was associated with higher happiness scores: Compared to non-tea drinkers, those who drank 4 or more cups of tea per day had a 0.23 point increase in happiness (95% CI 0.02-0.45, p = 0.032). This study found that even after adjusting for social network size and other confounding factors, higher green tea consumption was associated with increased happiness.