Recently, a study investigating the impact of tea drinking on the health of European’s reported conflicting findings depending on the region where the data were collected. Remarkably it was found that the discrepancies were related to whether the tea was served with or without milk. These findings led to a recent study published in the European Journal of Nutrition that investigated the influence of dietary proteins on the bioavailability of green tea catechins.
In this randomized cross-over design study, 24 healthy participants consumed an experimental drink containing 1.75g of green tea extract with or without the addition of casein protein, soy protein, or skim milk. Blood samples were taken before and several times after consumption of the experimental drink. Plasma concentrations of catechins were measured by HPLC. The authors reported that total catchins were significantly decreased if subjects took green tea extract with any of the protein sources, with the most significant reduction being in EGCG bioavailability.
Action Point: Past research has shown us that green tea extract supplements (standardized for EGCG) work synergistically with cardio for fat reduction. This current study provides solid evidence that if you take green tea with a protein shake, then you may not be getting what you bargained for. Thus, in order to circumvent protein’s effects on EGCG bioavailability, make sure you take green tea supplements with water, on an empty stomach, and 30 minutes before consuming protein.
Egert S1, Tereszczuk J, Wein S, Müller MJ, Frank J, Rimbach G, Wolffram S. Simultaneous ingestion of dietary proteins reduces the bioavailability of galloylated catechins from green tea in humans. Eur J Nutr. 2013 Feb;52(1):281-8.