A study shows that the green tea extract EGCG blocks fat weight gain in metabolic syndrome mice.
I have previously posted on some of the benefits of green tea as an addition to the type 2 diabetes diet and for the management of prediabetes metabolic syndrome.
A new study using mice looked at the ability of the green tea extract EGCG to reverse metabolic syndrome by modulating fat absorption and body weight gain in high-fat fed obese mice.
The study, published in Obesity (June 2011), reports that mice given EGCG in addition to a high-fat diet gained weight 45% more slowly than the control group of mice eating the same diet without the EGCG green tea supplement.
Obese mice were supplemented with EGCG for 6 weeks, while on a high fat diet. The mice given EGCG with the high-fat diet reduced body weight gain by 44% compared to mice just given a high-fat diet.
The research suggests that green tea extract epigallocatechin gallate (EGCG) may slow weight gain by limiting fat absorption as indicated by the almost 30% increase in fecal lipids found in these mice.
The authors propose this decrease in fat absorption occurred through the inhibition of the fat digestion enzyme pancreatic lipase. This enzyme is secreted by the pancreas, and is responsible for breaking down dietary fat in the intestine. If the enzyme is inhibited, the fat doesn’t get broken down and is passed in the stool.
Green tea is rich in flavonoid polyphenols, The four primary polyphenols found in fresh tea leaves are epigallocatechin gallate (EGCG), epigallocatechin, epicatechin gallate, and epicatechin. Black tea is green tea that has been oxidized by fermentation and also contains beneficial polyphenol compounds.
This research may not translate to humans in any meaningful way, but it appears that green tea (and probably tea in general) may block some aspects of digestion. I have posted on the apparent blockage of protein absorption by green tea. Fats and protein are a necessary part of a proper prediabetes diet, and one may not want to block these nutrients. For some this fat blocking property may be beneficial. For others perhaps it is best to drink tea or take a green tea extract supplement without a meal in order to best gain the benefit of its polyphenol phytonutrients without potentially blocking the absorption of others?