Food Inhibits the Oral Bioavailability of the Major Green Tea Antioxidant Epigallocatechin Gallate in Humans

Abstract

The bioavailability of the most abundant and most active green tea antioxidant, epigallocatechin gallate (EGCG) remains uncertain. Therefore, the systemic absorption of EGCG was tested in healthy fasted humans. It was administered as capsules with water or with a light breakfast, or when incorporated within a strawberry sorbet. The results for plasma EGCG clearly revealed that taking EGCG capsules without food was better; the AUC was 2.7 and 3.9 times higher than when EGCG capsules were taken with a light breakfast (p = 0.044) or with EGCG imbedded in the strawberry sorbet (p = 0.019), respectively. This pattern was also observed for Cmax and Cav. Therefore, ingesting food at the same time as EGCG, whether it was imbedded or not in food, substantially inhibited the absorption of the catechin. As with some types of medications that are affected by food, it appears that EGCG should be taken without food in order to maximise its systemic absorption. Therefore, based on these findings, ingesting EGCG with water on an empty stomach is the most appropriate method for the oral delivery of EGCG in clinical trials where EGCG is to be investigated as a potential bioactive nutraceutical in humans.

The Effect of Dietary Supplementation of Green Tea Catechins on Cardiovascular Disease Risk Markers in Humans: A Systematic Review of Clinical Trials

“…The studies outlined in this review have demonstrated some of the putative cardiovascular protective properties that GTCs may have on the lowering of body weight, arterial blood pressure, and plasma abnormalities in biomarkers commonly seen in individuals who are prone to developing a serious CVD-related illness in the future. Beneficial effects were observed when GTE was supplemented at levels between 300 and 1500 mg/day (total GTCs 208-1344 mg/day), roughly in line with previous literature, which had suggested that 540 mg of pure EGCG (between 5 and 10 cups of green tea [39]) was the optimal daily requirement for prevention of CVD risk factors [40]. Furthermore, the duration of the studies was also considered in the present systematic review, as significant sustained lowering of the CVD risk biomarkers were more likely to be seen in studies conducted over at least 12 weeks of supplementation [9][10][11][12][13][14][15].…”

“…In addition, GTCs are expected to prevent this vascular inflammation by suppressing leukocyte adhesion ability to the endothelium, thereby indicating the potential to inhibit progression of atherosclerotic lesions and thrombogenesis [38] However, despite these findings, the reviewed studies showed varying degrees of hypocholesterolemic and hypolipidemic activity in participants, with some studies indicating insignificant change for both parameters in the group supplemented with GTCs [11,12,14]. This finding is possibly attributed to the differing health conditions and statuses of the participants recruited, differences in study designs [1], and the effect of food consumption on catechins systemic absorption [39].…”

“…Importantly, the systemic absorption of GTCs incorporated within the GTE and even individual catechins, such as EGCG, is affected by several factors, including the type and quantity of the food consumed at the same time [39] and the exposure to biological fluids (gastric, pancreatic, and biliary fluids) prior to reaching the site of absorption. These factors can significantly influence the absorption and bioavailability of the GTCs in human trials.…”

Sugar and cocoa: sweet synergy or bitter antagonisms. Formulating cocoa and chocolate products for health: a narrative review

“…The product formulation or food matrix also has a number of physical effects that could affect bioavailability. A study in much larger molecular weight green tea polyphenol epigallocatechin gallate has identified that its systemic absorption was reduced when this catechin ingested with food or if it is imbedded in the food matrix if compared to the pure product (Naumovski et al, 2015). From the studies reported, the quality and concentrations of the cocoa powder constituents used were not always reported including its ability to be dispersed in the medium (typically water) (Fogliano et al, 2011).…”

A Randomized Controlled Trial of Green Tea Beverages on the in vivo Radical Scavenging Activity in Human Skin

“…Genetic predisposition [44] and nutrition patterns interacting with polyphenol absorption [40,45] are among the factors that were postulated to contribute to the interindividual variations. The microbiome hypothesis seeks to explain the varying effects of green tea administration through the impact of the gut microbiome [28,42].…”