Tea began as a medicine and grew into a beverage, these are the words of Okakura Kakuzo, the author in 1906 of the first book about Japanese green tea ceremony. And he was right, according to the latest results of a scientific study performed on the neuroprotective properties against Alzheimer shown by two substances contained in green tea and carrot, combined together. The research was performed by a team of scientists of the University of Southern California and was published a few days ago in the Journal of Biological Chemistry (Mori et al, JBC, March 2019).
The researchers have focused their attention on the epigallocatechin gallate (EGCG), a powerful antioxidant of green tea, and on ferulic acid that may be found in carrots but also in tomatoes, rice, wheat and oat. The study has shown that, in presence of Alzheimer’s-like symptoms, 30 mg per body weight of a supplement obtained by combining EGCG and ferulic ancid is able to restore, in animals, some deteriorated cognitive functionalities, by allowing again orientation and the movement in a space in a more efficient way than the same substances taken alone. The reason of this behavior is explained by the senior author of the study, Professor Terrence Town. According to Professor Town, these two substances are able, first of all, to reduce neuroinflammation and the oxidative stress in the brain.
Moreover, it is considered that these substances act to prevent the amyloid precursor protein from breaking up into smaller proteins, the so called amyloid beta. The amyloid beta proteins may form aggregates that are toxic for the brain tissues by causing the Alzheimer disease. This is of course an amazing result since the study shows that a supplement may reverse a process initiated by a degenerative illness. However, other studies are required in order to understand deeply the mechanisms and to observe whether the benefits can be found also in humans. But the strength of the research is that, as pointed out by professor Town, the results are obtained with a dosage that is easily consumed as a part of a healthy diet and is also well tolerated by humans. We don’t have to wait 10-12 years for a drug to put it to the market, but it is possible to perform some changes in lifestyle now. A little consideration, the green teas aren’t all the same and the content in EGCG varies on the basis of the preparation and the type of tea. Indeed, to maximize the release of beneficial substances, it is needed an infusion time of the leaves of about 8-10 minutes at a temperature of 60-70°C. For what concerns the type of green tea, in general, Japanese green teas are richer in EGCG than Chinese tea, with the exception of Pilo Chun. The Japanese varieties that present a higher amount of beneficial substances are Gyokuro, Sencha and Matcha (Richard Beliveau and Denis Gingras, Foods to fight cancer, Sperling and Kupfer Editori).