Green tea may reduce the absorption of starch

Scientists from two universities in Poznań: University of Medical Sciences and the University of Life Sciences, under the supervision of Prof. Jarosław Walkowiak from the University of Medical Sciences, confirmed this in a study of 28 people aged 19-28 years. The participants refrained from eating for 12 hours, and then ate cornflakes, which were a source of starch. Some of them also received green tea extract in an easily digestible form, and the others - placebo.

Then, using a special test that allows to determine amount of natural carbon isotope 13C (the product of metabolism after eating cornflakes) in exhaled air, the researchers assessed the degree of digestion and absorption of carbohydrates. After comparing the results of the group receiving the tea extract and the control group it turned out that even a single dose of green tea extract limited digestion and absorption of starch.

The common perception that green tea is very beneficial for health, and it is a recommended drink during the diet. Already in previous studies Prof. Walkowiak and his team found that green tea also reduces fat absorption. Do the new study results mean that it is beneficial for people struggling with obesity?

Professor reserved that such conclusions should be drawn with caution. "Theoretically, we are dealing with a situation in which one could reduce or slow down the absorption of sugar from starch, and thus prevent hyperglycemia or excessive absorption of sugar" - he said in an interview with PAP. Potentially, it means "a chance to address the issues of obesity, which now has pandemic proportions" - he added.

He noted, however, that the properties of green tea depend on the type of tea and method of making, and the dose of the extract used in the study is the equivalent of at least few glasses of the drink. Since most people would not drink this much green tea, its possible impact on starch digestion might not be as pronounced as the result obtained in the study. "You would have to drink a lot of green tea to get the amount of active substances, which was present in the green tea extract used in the study" - he emphasised.

The expert added that the effect of the extract on the absorption of starch requires further research. "Starch which has not been absorbed in the small intestine, will remain in the gastrointestinal tract, where it will be subject to processing, fermentation involving bacteria. It can also cause some problems" - he said.

The intestinal microflora is now the subject of many studies and an object of interest of scientists - noted Prof. Walkowiak. The bacteria living in the human digestive tract are on the one hand necessary for the proper functioning of the immune system. On the other hand, disorders within the microflora may cause various health problems, for example, small intestinal bacterial overgrowth, one of the symptoms of which is abdominal pain.

"I think that both balanced and varied diet, and a similarly sensible approach to life in its other aspects are important for the long-term maintenance of good health by healthy persons" - said Prof. Walkowiak.

PAP - Science and Scholarship in Poland, Anna Ślązak

zan/ agt/ mrt/

tr. RL