Nutrition: Green tea may affect starch digestion

Green tea may limit digestion and absorption of dietary starch according to a preliminary study published in Scientific Reports this week.

Jaroslaw Walkowiak and colleagues enrolled 28 participants between the ages of 19-28 years old in a randomised, placebo controlled, crossover trial. After fasting for 12 hours prior to the test, participants were asked to eat a meal consisting of cornflakes (a source of starch) and either a digestible wafer containing green tea extract, or a placebo. A CO2 starch breath test was then used to assess the breakdown of carbohydrates during digestion. The authors found that a single dose of green tea extract decreased starch digestion and absorption when compared to the placebo group.

The authors note that the dose of green tea extract used in the study was equivalent to at least several cups of green tea and, as normal daily intake is generally smaller, potential effects may not be as pronounced as those in the test. Further studies are required to determine the mechanism involved and the clinical significance of the chemical components of green tea.