Daily tea fix helps ward off depression in elderly

Tea appears to have potent antidepressive effects among older adults, reducing the risk of developing depression and preventing the worsening of its symptoms, according to a recent Singapore study.

“[T]ea did not appear to have the effect of improving existing depressive symptoms but may have the beneficial effect of preventing the worsening of existing depressive symptoms,” the researchers said.

Drawing from the Singapore Longitudinal Ageing Study, the researchers enrolled 3,177 older adults (mean age, 67 years), of whom 3,044 were free from depression at baseline. The key exposure variable was consumption of Chinese (black, oolong, or green) or Western-style (mixed with milk) tea; change in the Geriatric Depression Scale (GDS) score was set as the outcome.

Most of the participants (n=1,503) were not tea drinkers, consuming no to <1 cup per day. In comparison, 866 drank 1–2 cups per day, while 808 could finish ≥3 cups daily. Baseline scores in the Mini-Mental State Examination (MMSE) were slightly but significantly better with increasing tea consumption (27.4±3.11 vs 27.7±26.5 vs 28.2±2.19, respectively; p<0.001). [J Nutr Health Aging 2021;25:295-301]

While GDS-defined depression did not differ among tea intake groups at baseline, tea drinkers saw a significantly lower prevalence of depression at follow-up, an average of around 4 years later. For instance, 61 percent of participants with no or low tea intake had GDS score ≥5, indicative of depression; in comparison, only 12 percent of elderly adults drinking ≥3 cups per day had such a score (p=0.001).

Moreover, the proportion of participants who saw a deterioration of ≥4 depressive symptoms from baseline significantly decreased with increasing tea consumption (37 percent to 5 percent; p=0.002). No such change was observed in terms of improvements in depressive symptoms.

Stratifying according to the type of tea consumed revealed notable differences in the primary findings. Consumption of ≥1 cup of Chinese tea per day led to a significantly greater drop in GDS score (adjusted mean, –0.13, 95 percent confidence interval [CI], –0.24 to –0.02) and lower odds of worsened symptoms (adjusted odds ratio [OR], 0.47, 95 percent CI, 0.22–1.00; p<0.05 for both) than those with no intake.

Drinking ≥1 cup of Western milk tea daily had no statistical effect on GDS scores (adjusted mean, –0.06, 95 percent CI, –0.19 to 0.08) or the likelihood of worsening symptoms (adjusted OR, 0.78, 95 percent CI, 0.36–1.70) relative to no consumption. Nevertheless, there was a significant within-group drop in GDS score relative to baseline (adjusted mean, –0.24, 95 percent CI, –0.46 to –0.02; p<0.05).

Focusing on participants who did not have GDS depression at baseline, the researchers additionally found that the risk of developing incident depression (GDS ≥5) at follow-up was nearly 70-percent lower among those who drank ≥3 cups of tea per day, as opposed to nondrinkers (OR, 0.34, 95 percent CI, 0.13–0.90).

Analysis by tea time likewise showed that such an impact was significant for Chinese tea (≥1 vs no cups: OR, 0.46, 95 percent CI, 0.21–0.99), but not for Western milk tea (≥1 vs no cups: OR, 0.51, 95 percent CI, 0.20–1.32).

“Our study finding has important implications for population-based preventive measures to promote and maintain the mental health and quality of life of older persons,” the researchers said. “The observed effects of tea consumption on reducing the severity of depressive symptoms are in the subclinical efficacy range, but at the population level, it translates to a potentially nontrivial impact in reducing the societal burden of disease in the general population.”

“Further prospective cohort and interventional studies should investigate the heterogeneous effects of different types and ways of tea consumption on promoting and maintaining mental wellbeing in diverse populations,” they added.