Green tea extract decreases starch digestion and absorption from a test meal in humans: a randomized, placebo-controlled crossover study

Abstract

Green tea is known worldwide for its beneficial effects on human health. However, objective data evaluating this influence in humans is scarce. The aim of the study was to assess the impact of green tea extract (GTE) on starch digestion and absorption. The study comprised of 28 healthy volunteers, aged 19 to 28 years. In all subjects, a starch 13C breath test was performed twice. Subjects randomly ingested naturally 13C-abundant cornflakes during the GTE test (GTE 4 g) or placebo test. The cumulative percentage dose recovery (CPDR) was significantly lower for the GTE test than for the placebo test (median [interquartile range]: 11.4% [5.5–15.5] vs. 16.1% [12.7–19.5]; p = 0.003). Likewise, CPDR expressed per hour was considerably lower in each point of the measurement. In conclusion, a single dose of green tea extract taken with a test meal decreases starch digestion and absorption.

Health effects of resistant starch

“…Other factors that affect the resistance of starch include the size and type of starch granules; the physical form of grains and seeds; plant genotype and mutations [genetic engineering can be used to increase RS content (Wei et al 2010;Carciofi et al 2012)]; crop-growing location; associations between starch and other food components [i.e. lipids, proteins, sugars, gums, other fibre types and plant bioactives that inhibit a-amylase (Lochocka et al 2015)]; and food processing methods such as milling, cooking, annealing (physical modification of starch in water at temperatures below gelatinisation), high-pressure processing, autoclaving, cirradiation, extrusion and storage time (Seneviratne & Biliaderis 1991;Englyst et al 1992;Muir & O'dea 1992;Chung et al 2009;Chung & Liu 2010;Rohlfing et al 2010;Singh et al 2010;Pollak et al 2011;Linsberger-Martin et al 2012;Dundar & Gocmen 2013). Grinding of grains during processing can reduce RS1, due to the breakdown of cell walls, and cooking starchy foods in water can lead to gelatinisation, which reduces resistance to digestion.…”

“…lipids, proteins, sugars, gums, other fibre types and plant bioactives that inhibit α‐amylase (Lochocka et al . )]; and food processing methods such as milling, cooking, annealing (physical modification of starch in water at temperatures below gelatinisation), high‐pressure processing, autoclaving, γ‐irradiation, extrusion and storage time (Seneviratne & Biliaderis ; Englyst et al . ; Muir & O'dea ; Chung et al .…”

The Role of Dietary Phenolic Compounds in Protein Digestion and Processing Technologies to Improve Their Antinutritive Properties

“…Due to the generally low absorption of polyphenols after food intake, most of the consumed polyphenols remain in the gastrointestinal tract (GIT), where they may influence the activity of digestive enzymes (Karaś and others ; Renard and others ). Polyphenol compounds have been found to inhibit crucial enzymes involved in starch and lipid digestion, such as α‐amylase, α‐glucosidase, and pancreatic lipase (Boath and others ; Sakulnarmrat and others ; Lochocka and others ), as well as protein digestion, such as pepsin and trypsin (He and others ).…”

Perspectives of lupine wholemeal protein and protein isolates biodegradation

“…Regarding the influence of phenolic compounds on the digestibility of other nutrients, after food intake, most of the consumed polyphenols remain in the GIT, where they can then exert inhibitory effects on enzymes involved in the degradation of saccharides, lipids and proteins (Cirkovic Velickovic & Stanic‐Vucinic, ). Polyphenol compounds have been shown to inhibit crucial enzymes involved in the digestion of starch and lipid (Boath et al ., ; Sakulnarmrat et al ., ; Lochocka et al ., ), as well as protein (He et al ., ). The effects of phenolic compounds on protein digestibility are consequences of their binding to endogenous proteins, mainly digestive proteases (inhibition, activation, none), as well as protein substrates, which further influences protease activity and protein substrate accessibility (Cirkovic Velickovic & Stanic‐Vucinic, ).…”