Effects of whole grain rye, with and without resistant starch type 2 supplementation, on glucose tolerance, gut hormones, inflammation and appetite regulation in an 11-14.5 hour perspective; a randomized controlled study in healthy subjects

Nutr J. 2017 Apr 21;16(1):25. doi: 10.1186/s12937-017-0246-5.


Background: The prevalence of obesity is increasing worldwide and prevention is needed. Whole grain has shown potential to lower the risk of obesity, cardiovascular disease and type 2 diabetes. One possible mechanism behind the benefits of whole grain is the gut fermentation of dietary fiber (DF), e.g. non-starch polysaccharides and resistant starch (RS), in whole grain. The purpose of the study is to investigate the effect of whole grain rye-based products on glucose- and appetite regulation.

Method: Twenty-one healthy subjects were provided four rye-based evening test meals in a crossover overnight study design. The test evening meals consisted of either whole grain rye flour bread (RFB) or a 1:1 ratio of whole grain rye flour and rye kernels bread (RFB/RKB), with or without added resistant starch (+RS). White wheat flour bread (WWB) was used as reference evening meal. Blood glucose, insulin, PYY, FFA, IL-6 as well as breath H2 and subjective rating of appetite were measured the following morning at fasting and repeatedly up to 3.5 h after a standardized breakfast consisting of WWB. Ad libitum energy intake was determined at lunch, 14.5 h after evening test and reference meals, respectively.

Results: The evening meal with RFB/RKB + RS decreased postprandial glucose- and insulin responses (iAUC) (P < 0.05) and increased the gut hormone PYY in plasma the following morning 0-120 min after the standardized breakfast, compared to WWB (P = 0.01). Moreover, RFB increased subjective satiety and decreased desire to eat, and both RFB and RFB/RKB decreased feeling of hunger (AUC 0-210 min). All rye-based evening meals decreased or tended to decrease fasting FFA (P < 0.05, RFB/RKB: P = 0.057) and increased breath hydrogen concentration (0-120 min, P < 0.001). No effects were noted on energy intake at lunch or inflammatory marker IL-6 (0 + 180 min) after the rye-based evening meals, compared to WWB.

Conclusion: Whole grain rye bread has the potential to improve cardiometabolic variables in an 11-14.5 h perspective in healthy humans. The combination RFB/RKB + RS positively affected biomarkers of glucose- and appetite regulation in a semi-acute perspective. Meanwhile, RFB and RFB/RKB improved subjective appetite ratings. The effects probably emanate from gut fermentation events.

Trial registration: The study was registered at: ClinicalTrials.gov, register number NCT02347293 ( www.clinicaltrials.gov/ct2/show/NCT02347293 ). Registered 15 January 2015.

Keywords: Appetite regulation; Dietary fiber; Dietary prevention; Glucose regulation; Gut fermentation; Gut hormones; Obesity; Rye; Type 2 diabetes; Whole grain.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Appetite*
  • Biomarkers / blood
  • Blood Glucose / metabolism
  • Body Mass Index
  • Bread
  • Cholesterol / blood
  • Cross-Over Studies
  • Cytokines / blood
  • Diet
  • Dietary Carbohydrates / administration & dosage
  • Dietary Carbohydrates / analysis
  • Dietary Fiber / administration & dosage
  • Dietary Fiber / analysis
  • Fatty Acids, Nonesterified / blood
  • Female
  • Gastrointestinal Hormones / blood
  • Glucose Tolerance Test*
  • Healthy Volunteers
  • Humans
  • Inflammation / blood*
  • Inflammation / diet therapy
  • Insulin / blood
  • Interleukin-6 / blood
  • Male
  • Peptide YY / blood*
  • Portion Size
  • Postprandial Period
  • Secale / chemistry*
  • Starch / analysis*
  • Treatment Outcome
  • Triglycerides / blood
  • Whole Grains / chemistry
  • Young Adult


  • Biomarkers
  • Blood Glucose
  • Cytokines
  • Dietary Carbohydrates
  • Dietary Fiber
  • Fatty Acids, Nonesterified
  • Gastrointestinal Hormones
  • IL6 protein, human
  • Insulin
  • Interleukin-6
  • Triglycerides
  • Peptide YY
  • Starch
  • Cholesterol

Associated data

  • ClinicalTrials.gov/NCT02347293