By Stephenie Overman
Polyphenols in white tea are promising candidates to test for protection against neurodegeneration associated with diabetes, according to Dr. Branca Maria Silva, an associate professor at the University of Beira Interior, Covilhã, Portugal.
Silva spoke on “Polyphenols as protective agents against neurotoxicity and neurodegeneration: the case of tea polyphenols,” at the 10th World Congress on Polyphenols Applications. The conference was held in Porto, Portugal, under the auspices of the International Society for Antioxidants in Nutrition and Health (ISANH).
“Compelling evidence has shown that dietary phytochemicals, particularly polyphenols, have properties that may suppress neuroinflammation and prevent toxic and degenerative effects in the brain. The mechanisms by which polyphenols exert their action are not fully understood, but it is clear that they have a direct effect through their antioxidant activities,” according to a paper co-authored by Silva: “Are polyphenols strong dietary agents against neurotoxicity and neurodegeneration?”
Neurodegenerative diseases include Alzheimer’s, Parkinson’s, and amyotrophic lateral sclerosis.
At the conference, Silva also discussed papers she has co-authored on diabetes and neurodegeneration, including: “Daily consumption of white tea (Camellia sinensis (L.)) improves the cerebral cortex metabolic and oxidative profiles of prediabetic Wistar rats.”
In that paper, published by the British Journal of Nutrition, she and her co-authors noted that “diabetes mellitus (DM) is a major public health problem and its incidence is rising dramatically. The brain, particularly the cerebral cortex, is very susceptible to glucose fluctuations and hyperglycaemia-induced oxidative stress.”
“We hypothesized that regular consumption of white tea can ameliorate the brain cortical glycolytic and oxidative profile,” the authors wrote, adding that they chose white tea because it has higher catechins content and stronger antioxidant potential than green tea.
The authors found that a prediabetic state induced undesirable alterations in glycolytic and oxidative profiles of the brain cortex and that impaired glucose metabolism induced oxidative stress that contributed to cortical brain damage.
White tea consumption, they concluded in their study of rats, restored glucose tolerance and insulin sensitivity; modulated the glycolytic and oxidative profiles of prediabetic brain cortex; and prevented cortical brain damage promoted by the mild hyperglycemia.