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Fancy a spot of tea? According to a first-of-its-kind study on tea and brain health, saying "Yes!" may help your brain work better and stay younger, longer
A pioneering study led by researchers from the National University of Singapore (NUS) has shown that drinking tea may lead to better interregional brain organization as compared to non-tea drinkers.[i]
In a collaboration with scientists from the universities of Essex and Cambridge in the UK, researchers used neuroimaging data to reveal the role of tea drinking on brain organization. The results offer the first evidence of positive contribution of tea drinking on brain structure, imbuing a potentially protective effect against age-related decline.[ii]
The study's novel approach differed from previous tea studies that relied primarily on neuropsychological measures rather than neuroimaging techniques for investigating interregional connections in the brain. Their findings were published in the scientific journal Aging in June 2019.
More Evidence of Tea's Neuroprotective Properties
The research team, led by Feng Lei, an assistant professor from NUS's Department of Psychological Medicine, investigated the functional and structural brain networks in a group of 36 adult participants. Study recruits were healthy, with a mean age of 71 years; the majority were female.
Recruits were grouped into either "tea drinking" or "non-tea drinking" groups, based on their history of tea drinking for around 25 years prior, with criteria set to consumption of 4 to 6 cups per week or more, on average, of green, black or oolong tea.
Researchers sought to understand tea's effects on regional brain connectivity, as well as global or comprehensive effects on the brain. Structural and functional imaging was performed to unveil differences in regional connectivity and brain organization between the tea-drinking and non-tea-drinking groups.
Researchers also explored interregional connectivity within the default mode network (DMN) since previous studies have suggested that it is predominantly involved in cognitive disease and normal brain aging. Finally, researchers included an assessment of hemispheric asymmetry due to prior studies by the group demonstrating leftward asymmetry in structural connectivity to be associated with brain aging.[iii]
A Cup of Tea Each Day Keeps Cognitive Decline at Bay
Based on prior research by Feng showing tea's neuroprotective effects for Alzheimer's disease,[iv] researchers hypothesized that habitual tea drinking has positive effects on brain organization and structures, reduces leftward asymmetry in structural connectivity and improves the strength of connections in the DMN.
The results of their study validated their hypotheses and added more peer-reviewed, scientific evidence to the literature showing the benefits of plant-based foods. In the comparisons of neuropsychological and cognitive measures, one out of 12 measures, the Block Design test, was significantly different between the tea-drinking and the non-tea drinking groups.
No significant differences were found between the tea-drinking group and the non-tea drinking group in either the global or regional functional network measures, however, six regions were significantly different in the structural network, which primarily reside in the frontal cortex.
Hemispheric asymmetries were significantly different between the groups in the structural network, exhibiting greater asymmetry between hemispheres in the non-tea drinking group.
Analysis of strengths of connections within the default mode network revealed consistently increased strength of functional connectivity and the coexistence of increased and decreased strengths for the structural connectivity in the tea-drinking group compared to the non-tea drinking group. Specifically, 11 functional connections exhibited a significant enhancement in strength in the tea drinking group.
Overall, results showed that tea drinking gave rise to more efficient structural organization of the brain and suppression of hemispheric asymmetry in the structural connectivity network. In addition, functional connectivity strength within the DMN was greater for the tea-drinking group.
"Take the analogy of road traffic as an example -- consider brain regions as destinations, while the connections between brain regions are roads. When a road system is better organized, the movement of vehicles and passengers is more efficient and uses less resources. Similarly, when the connections between brain regions are more structured, information processing can be performed more efficiently," explained Feng.[v]
The research team intends to build on these and prior results by continuing to examine the neuroprotective properties of tea, as well as the bioactive compounds in tea, on cognitive decline.
Food-Based Medicine: All the Benefits, Fewer Side Effects
Whole-plant medicine, such as that you receive when you enjoy a cup of tea, contains synergistic healing capabilities that are difficult to isolate in laboratory conditions. While individual constituents of tea such as catechin, L-theanine and caffeine have been isolated as active ingredients, Feng's research supports the assertion that whole-leaf tea is better than tea extracts when it comes to brain benefits.[vi] So skip the green tea extract pills and enjoy whole leaf, organic tea in its natural form.
Tea has been scientifically validated as a therapeutic substance, with benefits ranging from lowered serum cholesterol[vii] to reduced risk of cancer[viii] and heart disease,[ix] among other substantiated benefits. With regard to brain health, tea has demonstrated exciting antiaging potential , supporting its role as an important component of an overall healthy diet for seniors.
[i] Junhua Li, Rafael Romero-Garcia, John Suckling, Lei Feng. Habitual tea drinking modulates brain efficiency: evidence from brain connectivity evaluation. Aging, 2019; 11 (11): 3876 DOI: 10.18632/aging.102023
[ii] National University of Singapore. "Drinking tea improves brain health, study suggests." ScienceDaily. ScienceDaily, 12 September 2019. www.sciencedaily.com/releases/2019/09/190912100945.htm.
[iii] Junhua Li, Rafael Romero-Garcia, John Suckling, Lei Feng. Habitual tea drinking modulates brain efficiency: evidence from brain connectivity evaluation. Aging, 2019; 11 (11): 3876 DOI: 10.18632/aging.102023
[v] National University of Singapore. "Drinking tea improves brain health, study suggests." ScienceDaily. ScienceDaily, 12 September 2019. www.sciencedaily.com/releases/2019/09/190912100945.htm.
[vi] Junhua Li, Rafael Romero-Garcia, John Suckling, Lei Feng. Habitual tea drinking modulates brain efficiency: evidence from brain connectivity evaluation. Aging, 2019; 11 (11): 3876 DOI: 10.18632/aging.102023
[vii] Yimin Zhao, Sailimuhan Asimi, Kejian Wu, Jusheng Zheng, Duo Li. Black tea consumption and serum cholesterol concentration: Systematic review and meta-analysis of randomized controlled trials. Clin Nutr. 2015 Aug ;34(4):612-9. Epub 2014 Jun 13. PMID: 24972454
[viii] Lanfang Wang, Xingwei Zhang, Jing Liu, Li Shen, Zhiqiang Li. Tea consumption and lung cancer risk: a meta-analysis of case-control and cohort studies. Nutrition. 2014 Oct ;30(10):1122-7. Epub 2014 Mar 12. PMID: 25194612
[ix] Louise Hartley, Nadine Flowers, Jennifer Holmes, Aileen Clarke, Saverio Stranges, Lee Hooper, Karen Rees. Green and black tea for the primary prevention of cardiovascular disease. Cochrane Database Syst Rev. 2013 Jun 18(6):CD009934. Epub 2013 Jun 18. PMID: 23780706