Carob pulp preparation rich in insoluble dietary fibre and polyphenols increases plasma glucose and serum insulin responses in combination with a glucose load in humans

Abstract

Dietary fibre consumption is associated with improved glucose homeostasis. In contrast, dietary polyphenols have been suggested to exert both beneficial and detrimental effects on glucose and insulin metabolism. Recently, we reported that a polyphenol-rich insoluble dietary fibre preparation from carob pulp (carob fibre) resulted in lower postprandial acylated ghrelin levels after a liquid meal challenge test compared with a control meal without supplementation. The effects may, however, differ when a different food matrix is used. Thus, we investigated the effects of carob fibre on glucose, insulin and ghrelin responses in healthy humans in combination with a glucose load. In a randomized single-blind cross-over study involving twenty healthy subjects (aged 22-62 years), plasma glucose, total and acylated ghrelin, and serum insulin were repeatedly assessed before and after the ingestion of 200 ml water with 50 g glucose and 0, 5, 10 or 20 g carob fibre over a period of 180 min. The intake of 5 and 10 g carob fibre increased the plasma glucose by 47 % and 64 % (P,0·001), and serum insulin by 19·9 and 24·8 % (P, 0·001), compared with the control. Plasma acylated ghrelin concentrations did not change significantly after the consumption of carob-enriched glucose solution. Total ghrelin decreased only after 10 g carob fibre (P,0·001) compared with control. In conclusion, we showed that polyphenol-rich carob fibre, administered within a water -glucose solution, increases postprandial glucose and insulin responses, suggesting a deterioration in glycaemic control.

Postprandial hyperglycemia and insulin response are affected by sea buckthorn (Hippophaë rhamnoides ssp. turkestanica) berry and its ethanol-soluble metabolites

“…However, also controversial results have been reported. Gruendel et al (2007) found out that carob pulp preparation rich in polyphenols deteriorated postprandial glycemic control. Evidently, food matrix and other components present can modulate the effect of polyphenols on glycemic response.…”

Hypoglycaemic activity of four plant extracts traditionally used in South Africa for diabetes

“…Tshikalange (2007) isolated various triterpenoides such as lup-20(30)-ene-3,29-diol, (3␣)-(9Cl), lup-20(29)-ene-30-hydroxy-(9Cl), taraxastanonol and ␤-sitosterol and a phenolic derivative and depside namely ataric acid and atranorin from Elaeodendron transvaalense, these substances were however not tested for their anti-diabetic activity, except ␤-sisosterol that demonstrated ␣-glucosidase and ␣-amylase inhibition (Nkobole, 2009). Drewes and Mashimbye (1993) isolated the phenolic compound, elaeocyanidin as well as the gallotannins and ouratea proanthocyanidin A from Elaeodendron transvaalense and it is likely that these compounds are responsible for the hypoglycaemic activity (Gruendel et al, 2007;Gorelik et al, 2008). In literature the use of Schkuhria pinnata as an anti-diabetic agent is numerous but no literature could be found on the chemical analysis and testing for it's hypoglycaemic activity.…”

Fiber intake Inconsistently Alters Gut Hormone Levels in Humans Following Acute or Chronic Intake

“…In contrast, the same doses of carob fiber added to glucose water had no effect on acylated ghrelin, but the 10 g dose decreased total ghrelin compared to control (Gruendel, Otto et al, 2007). In a third study, volunteers consumed calorie and nutrient matched meals with or without 50 g carob fiber, followed by an overnight fast (Gruendel et al, 2007). Ghrelin was measured the next morning following ingestion of a standardized white bread.…”