Posted on Mar 24, 2017, 6 a.m.
Cognitive impairment risk is reduced by 50 percent and as much as 86 percent for those who are genetically at risk of Alzheimer's.
A recent study by Chinese researchers shows that drinking as little as one cup of tea daily significantly reduces risk of cognitive decline in older adults. Those who are genetically predisposed to developing dementia-related conditions showed an even more significant decrease in risk.
The study was published in December 2016 in The Journal of Nutrition, Health & Aging.
The study, a part of the more comprehensive Singapore Longitudinal Aging Study, was conducted by researchers from the National University of Singapore’s Yong Loo Lin School of Medicine Department of Psychological Medicine. Assistant Professor of Psychological Medicine Feng Lei led the team.
Data was collected from 957 Chinese seniors over a seven-year period. All participants were at least 55 years old and were cognitively intact at the beginning of the study. Every two years, participants were physically examined and provided information on things like lifestyle habits, medical conditions, and physical and social activities. This information was used to create more accurate statistical models from the research data.
Study participants were not asked to alter their diets or daily activities in any way.
Final analysis of study data shows that participants who consumed at least one cup of tea daily were 50% less likely to have experienced signs of cognitive degeneration when compared to their non-tea drinking peers. Those who carry the APOE e4 gene, which has been connected to cognitive disorders like Alzheimer’s and dementia, were 85% less likely to show signs of degeneration.
The type of teas consumed did not seem to affect the outcome, if it was brewed from whole tea leaves, like black, green, or oolong teas. Assistant Professor Feng states that bioactive compounds found in the tea leaves contain anti-inflammatory, antioxidant, and other properties that naturally protect the brain from vascular damage and neurodegeneration. While the exact mechanism is not yet known, bioactive compounds like catechins, theaflavins, thearubigins and L-theanine have been positively linked to better overall brain health.
Effects on Public Health
Per Assistant Professor Feng, the study is significant because of the relatively low cost of teas. Neurocognitive disorders are difficult and expensive to treat with existing drug therapies. Other prevention strategies are not yielding desired results. Drinking a cup of tea each day is affordable and does not require difficult lifestyle changes. Tea therapy can substantially reduce future health and social spending for individuals, families, and governments.
While the study only involved Chinese seniors, researchers believe the results should apply to other races as well.
The study team is planning more comprehensive studies that explore the impact of traditional Asian diets on cognitive health in aging populations. The team is also considering a more rigorous assessment of the tea trial. Researchers hope to identify the chemical processes and mechanisms that make tea an effect brain protectant. The new trial would include randomized control groups.
L. Feng, M. -S. Chong, W. -S. Lim, Q. Gao, M. S. Z. Nyunt, T. -S. Lee, S. L. Collinson, T. Tsoi, E. -H. Kua, T. -P. Ng. Tea consumption reduces the incidence of neurocognitive disorders: Findings from the Singapore longitudinal aging study. The Journal of Nutrition, Health & Aging, 2016; 20 (10): 1002 DOI: 10.1007/s12603-016-0687-0