Drinking tea socially is uplifting, but researchers report tea drinking by older adults is clinically beneficial as well.
A peer-reviewed analysis of more than 13,000 elders living in China reveals a strong association between consistent and frequent tea drinking and fewer symptoms of depression. The results, published in the journal BMC Geriatrics, were based on the Chinese Longitudinal Healthy Longevity Survey (CLHLS), which was conducted between 2005 and 2014.
Researchers divided respondents into four groups based on the frequency, and the type of tea they drank, those 60 and older demonstrated “a significant benefit in mental health.”
Those who drank the most tea shared several characteristics, including:
- They were more likely to be educated, married, and pensioners.
- Tea drinkers also exhibited higher cognitive and physical function.
- They were older, male, and urban residents.
- They were more socially involved and more likely to drink alcohol and smoke.
Depression is one of the most common mental disorders for the elderly, often causing great suffering in later life, according to the study’s authors. About 7% of individuals older than 60 worldwide suffer from ‘major depressive disorder.’
As the number of older people increases globally, several studies of risk factors ranging from biomarkers, behavioral characteristics, socioeconomic status, marital status, urban vs. rural home life, and community involvement pointed to tea drinking. A 2012 study found one-third of elderly Chinese aged 75 and over suffered severe depressive symptoms.
Health professionals who study mental health are aware of tea’s popularity with the elderly, but they have long debated whether benefits result from biochemical components of tea or the social context of tea drinking.
Researchers in this study focused on biochemical mechanisms. One hypothesis, advanced in an earlier study published in the journal Aging, is that tea catechins, especially epigallocatechin gallate (EGCG), could exert antidepressant-like effects and prevent a reduction in brain dopamine concentration. Another theory is that theanine, one of the major amino acid contained in green tea leaves, could block the binding of L-glutamic acid and lead to lower post-stress cortisol and greater subjective relaxation, according to the article published by Dr. Junhua Li.
A team led by researcher Feng Qiushi, an associate professor at NUS Sociology (National University Singapore) and Associative Professor Shen Ke from Fudan University in Shanghai, examined gender, education, residence, marital and pension status and also factored in lifestyle habits and health details such as smoking, drinking alcohol, daily activities, level of cognitive function and degree of social engagement.
Assoc Prof Feng and his team controlled for covariates that could have significant associations with elderly depression.
The team found “consistent and frequent tea consumption, according to our study, was associated with significantly fewer depressive symptoms for old Chinese individuals, even adjusting for their socioeconomic status, lifestyle, health status, and social engagement.”
“In addition, the protective role of tea consumption was particularly strong for the males and younger elderly,” wrote Feng.
The correlation between tea drinking and depression is yet to be proven causative, but Feng said, “The promotion of the traditional lifestyle of tea drinking could be a cost-effective way towards healthy aging for China.”
The study expands the work of Assistant Professor Feng Lei at NUS Psychological Medicine, who systematically investigated the positive effect of tea-drinking on brain function, mental health, and mortality in old age.
Assoc Prof. Feng and his team are now collecting new data from the CLHLS about tea-drinking. “This new round of data collection has distinguished different types of tea such as green tea, black tea, and oolong tea so that we could see which type of tea really works for alleviating depressive symptoms,” according to the Science Blog.