Apple and blackcurrant polyphenol-rich drinks decrease postprandial glucose, insulin and incretin response to a high-carbohydrate meal in healthy men and women

Abstract

Postprandial glycemic responses to meals are inhibited by polyphenol-rich plant foods. Combinations of polyphenols may be particularly effective through complementary mechanisms. A randomized, controlled, double-blinded cross-over trial was conducted in healthy volunteers to test the hypothesis that apple and blackcurrant polyphenol-rich drinks would reduce postprandial blood glucose concentrations. Secondary outcomes included insulin and glucose-dependent insulinotropic polypeptide (GIP) secretion. Twenty men (mean age 26 y, SD 8) and 5 postmenopausal women (mean age 57 y, SD 3) consumed a placebo drink (CON) and 2 polyphenol-rich drinks containing fruit extracts: either 1200 mg apple polyphenols (AE), or 600 mg apple polyphenols+600 mg blackcurrant anthocyanins (AE+BE), in random order with a starch and sucrose meal. Incremental areas under the curve (iAUC) for plasma glucose concentrations were lower following AE+BE over 0-30 and 0-120 min compared with CON; mean differences (95% CI) -32 mmol/L·min (-41, -22, P<.0005) and -52 mmol/L min (-94, -9, P<.05), respectively. AE significantly reduced iAUC 0-30 min (mean difference -26 mmol/L min, -35, -18, P<.0005) compared with CON, but the difference over 120 min was not significant. Postprandial insulin, C-peptide and GIP concentrations were significantly reduced relative to CON. A dose response inhibition of glucose transport was demonstrated in Caco-2 cells, including total and GLUT-mediated transport, and SGLT1-mediated glucose transport was strongly inhibited at all doses in Xenopus oocytes, following 10 min incubation with 0.125-4 mg apple polyphenols/ml. In conclusion, ingestion of apple and blackcurrant polyphenols decreased postprandial glycemia, which may be partly related to inhibition of intestinal glucose transport.

Glycaemic regulation, appetite and ex vivo oxidative stress in young adults following consumption of high-carbohydrate cereal bars fortified with polyphenol-rich berries

“…In contrast, the polyphenol-rich and reference bars used in the present study contained no soluble fibre and did not differ in viscosity. Indeed similar to the present study, Castro-Acosta (8,9) removed fibre as a potential confounding variable (i.e. by testing apple and blackcurrant extracts) and observed that the fruit extract modulated the glycaemic response to fruit juice and white bread with apricot jam.…”

“…In support, some studies have shown that whole berries, berry extracts, apple extract or juice and a mixture of polyphenol and fibre-rich foods (e.g. green tea, apple peel and freeze-dried berry powders) modulate the glycaemic response following consumption of sugar water or starch-based food items (8)(9)(10)(11)(12)(13)(14) . For example, Torronen et al (13,14) demonstrated that consuming polyphenol-rich berry nectars or berry purees with a high-carbohydrate food favourably modulated postprandial glycaemia in healthy adults by slowing glucose absorption and enhancing insulin and glucagon-like peptide-1 (GLP-1) secretion.…”

Fermented pumpkin-based beverage inhibits key enzymes of carbohydrate digesting and extenuates postprandial hyperglycemia in type-2 diabetic rats

“…Similar trend was also observed in normal rats. Similar fi ndings were reported for apple and blackcurrant polyphenol-rich drinks (CASTRO-ACOSTA et al, 2017). Dietary supplementation with Lactobacillus mali strain also effectively maintained blood glucose level in high-fat diet-induced obese mice (LIN et al, 2016).…”

Modulation of Diabetes by Natural Products and Medicinal Plants via Incretins

“…More recently, Castro-Acosta et al [108] published the results of a randomized, controlled, double-blinded, crossover trial conducted in healthy volunteers to investigate if enriched polyphenol drinks based on apple [Malus sylvestris (L.) Mill., Rosaceae] and blackcurrant (Ribes nigrum L.) could affect postprandial blood glucose concentrations. They analyzed different parameters, including GIP secretion, in 20 men (age average: 26 years old) and 5 postmenopausal women (age average: 57 years old) who consumed two polyphenol-rich drinks containing fruit extracts or placebo.…”