STiR coffee and tea magazine

30 STiR coffee and tea / Issue 3, 2022 (June / July) n April, experts in a variety of disciplines convened for the Sixth Interna- tional Symposium on Tea and Human Health. During the virtual event, cognitive and cardiovascular benefits of tea consumption emerged as key themes. Three symposium speakers followed up with STiR coffee and tea mag- azine to share insight into the evidence behind the benefits of drinking tea. Short-term cognitive benefits Louise Dye, PhD, professor of nutrition and behavior at the University of Leeds, spoke about how tea and its components, including caffeine and L- theanine, have the potential to positively impact attention during periods of stress. Researchers explored how the amino acid L-theanine present in tea impacts alertness. One study 1 found that L-theanine reduces both physiologi- cal and psychological stress responses. When given an arithmetic problem, study participants who consumed L-theanine demonstrated responses such as decreased heart rate compared to the study's placebo group. Another study 2 measured alpha activity, which plays a role in attention, in the brain via EEG. Researchers concluded that dietary levels of L-theanine help to relax the brain without contributing to drowsiness. While research like this is promising, Dr. Dye hopes to see more studies supporting the positive relationship between tea and short-term cognition. "The potentially beneficial effects of tea and tea components on attention espe- cially under conditions of stress require further validation in different samples and using different stressors, e.g., induced versus real-life," says Dr. Dye. The L-theanine molecule present in tea decreases heart rate and reduces stress without inducing sleepiness. The Head and the Heart: How Tea The Head and the Heart: How Tea Can Affect Cognitive Function Can Affect Cognitive Function and Cardiovascular Health and Cardiovascular Health I By Carrie Pallardy During the Sixth International Symposium on Tea and Human During the Sixth International Symposium on Tea and Human Health, a variety of experts explored the evidence of the cognitive Health, a variety of experts explored the evidence of the cognitive and cardiovascular benefits of consuming tea. and cardiovascular benefits of consuming tea. Long-term cognitive benefits While drinking tea might help people to focus dur- ing a task at-hand, what kind of cognitive effects does tea consumption have over time? During the symposium, Jonathan Hodgson, PhD, PhD, professor at the Institute for Nutrition Research at Edith Cowan University, spoke about the po- tential for tea consumption to reduce the risk of dementia. "The past three years has seen publica- tion of several high-quality studies, which indicate that easily achievable tea intakes and intakes of the flavonoids found in tea could reduce dementia risk," he says. A single cup of tea (200 milliliters) is rich in a multitude of flavonoids, including catechins, flavonols, flavones, thearubigins, and theaflavins, according to a study 3 published in QJM: An Inter- national Journal of Medicine. Dr. Hodgson points to a number of studies that support the positive link between flavonoid intake and decreased risk for cognitive decline. Flavonoids are the subject of a number of studies exploring their correlation with dementia, stroke, and cognitive decline. One study that followed nearly 50,000 men and women in the United States concluded that higher flavonoid intake is associ- ated with a lower risk of subjective cognitive de- cline 4 . Other studies have demonstrated a promis- ing link between flavonoid intake and decreased risk of Alzheimer's disease and related dementias 5 , as well as a lower risk of stroke and dementia 6 . "Because the evidence is almost entirely from observational studies, we cannot infer causality," says Dr. Hodgson. "However, we can say that tea is a healthy beverage that is likely to provide ben- efits to the health of your blood vessels. The as- sociations with dementia, and particularly vascular dementia, are consistent with this evidence. Ideal- ly, I would like to see large long-term randomized controlled trials investigating the causal effects of flavonoid-rich foods and beverages such as tea." Cardiovascular benefits Tea may be good for heart as well as the head. Taylor Wallace, PhD, principle and c.e.o. at the Think Healthy Group and a professor in the De- partment of Nutrition and Food Studies at George Mason University, examined the cardiovascular benefits of consuming black and green tea. "I think the most exciting aspect is how consistent the data is across all research designs. It all points to [approximately] 2 cups of unsweet tea per day for cardiovascular health," he explains. Tea may not immediately impact cardiovas- cular health, according to one study. Researchers concluded that short-term consumption 7 (four to 24 weeks) does not have a notable effect on blood pressure or blood lipids. The study concluded that more randomized controlled trials of a longer du-

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