White tea has a positive effect against prediabetes

Research carried out at the Universidad de Beira Interior on rats with high levels of blood glucose show that white tea helps to protect the heart

José Pichel Andrés/DICYT A study carried out at the Health Science Research Centre (CICS) of the Universidad de Beira Interior (UBI) in Covilhã reveals that white tea consumption may be good for people with prediabetes, a condition in which individuals have high levels of blood glucose but not high enough to be considered diabetics. The research was carried out on rats and it was also discovered that this drink has a cardioprotective effect.

The research team of Branca Silva, a lecturer at the Faculty of Health Science of the Universidad de Beira Interior, is studying the chemical composition of foods deriving from plants and of medicinal plants so as to check their antioxidant, anti-diabetic, and anti-carcinogenic biological activities. For this work the scientists chose an infusion that has hardly been studied up to now, white tea from the leaf buds and young leaves of the plant Camellia sinensis, which differs from other better known infusions such as green tea in both its chemical composition and its sensory properties (taste, aroma, and colour).

“A preliminary study showed us that it exceeds green tea in its amount of catechins, substances with a marked antioxidant activity that prevent the damage caused by free radicals; the latter trigger several diseases including cardiovascular and neurodegenerative disorders as well as several types of cancers and diabetes”, Branca Silva commented to DiCYT.

For this reason the research group decided to study in greater depth its properties in relation to diabetes, a disease that has become a world pandemic and causes a series of complications to produce an overwhelming statistic: every six seconds a person somewhere in the world dies from causes related to excess blood glucose. The heart is a particularly sensitive organ where this problem is concerned.

In the experiments the researchers induced the condition of prediabetes in a group of rats. The consumption of white tea did not reduce the glucose levels but it reduced intolerance to this substance and increased sensitivity to insulin, which regulates the amount of glucose in the blood as is stated in an article recently published by Branca Silva and her team in the Journal of Functional Foods.

It improves the antioxidant capacity of the heart

Moreover, “taking into account that some 80% of all diabetic deaths are due to cardiovascular problems, we decided to assess the precise effect of white tea consumption on the heart”, the researcher points out. Important metabolic differences were found between the animals that drank white tea and the control group that drank water. The levels of some substances returned to normal to contribute towards improved cardiovascular protection against alterations characteristic of excess glucose. “Our results clearly show that regular white tea consumption improves the antioxidant capacity of the heart”, Branca Silva emphasises.

The researchers believe that the results are transferrable to humans, but further study is needed to establish the recommended white tea consumption for prediabetic and diabetic patients. In theory this would also be beneficial for healthy people as no adverse effects have been found.

In the near future this team of the Health Science Research Centre of the Universidad de Beira Interior hopes to continue with these studies that are assessing the effect of white tea on other organs of prediabetic animals. As research published by this group in international journals indicates that consumption of this drink can also be positive for the brain, the scientists hope shortly to achieve the necessary financing for a new project to corroborate this.

Bibliographical references

Alves MG, Martins AD, Teixeira NF, Rato L, Oliveira PF, Silva BM (2015) White tea consumption improves cardiac glycolytic and oxidative profile of prediabetic rats. Journal of Functional Foods. 14: 102–110.

Nunes AR, Alves MG, Tomás GD, Conde VR, Cristóvão AC, Moreira PI, Oliveira PF, Silva BM (2015) Daily consumption of white tea (Camellia sinensis (L.)) by prediabetic Wistar rats improves cerebral cortex metabolic and oxidative profile. British Journal Nutrition 26:1-11.

Nunes AR, Alves MG, Moreira PI, Oliveira PF, Silva BM (2015) Can tea consumption be a safe and effective therapy against diabetes mellitus-induced neurodegeneration? Current Neuropharmacology. 12(6): 475-489.

Dias TR, Tomás G, Teixeira N, Alves MG, Oliveira PF, Silva BM (2013) White tea (Camellia sinensis (L.): antioxidant properties and beneficial health effects. Int. J. Food Sci. Nut. Diet. 2(2):1-15.