Consumption of high-fiber rye bread improves insulin secretion but not insulin sensitivity or glucose effectiveness in postmenopausal women

Katri Juntunen, D.E. Laaksonen, L.K. Niskanen, Kirsi Liukkonen, Kaisa Poutanen, Hannu Mykkänen

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Abstract

It has been shown that the modication of carbohydrate intake affects the postprandial glucose and/or insulin responses, but little is known about the longer-term effects of different cereal products on insulin secretion and sensitivity and glucose effectiveness in peripheral tissues.In the present study the intake of carbohydrates was modified by replacing almost all bread cereals in the diet with high-fiber rye and white wheat breads in a randomized crossover trial.The subjects were 20 postmenopausal women, 59 + 6.0 years old, BMI 27.5 + 2.9 kg/m2 and baseline fS-cholesterol 6.5 + 0.8 mmol/L.Three of the subjects had impaired glucose tolerance as determined by a 2-hour oral glucose tolerance test.After a 2-3-week run-in period the women were divided into two groups and advised to consume either rye bread or wheat bread for 8 weeks.After an 8-week wash-out period, the groups were reversed.Fasting blood samples were collected for the determination of plasma glucose and insulin at the beginning and at the end of both bread periods.The frequently sampled intravenous glucose tolerance test was performed at the run-in and at the end of both bread periods.Acute insulin response (AIR) was calculated from the area under the insulin curve above the baseline level from 0 to 10 minutes. Insulin sensitivity (SI) and glucose effectiveness (SG) were calculated with the Minmod program (Pacini et al., 1986).There were no differences in body weight, intake of energy or reported frequency of exercise among the run-in and bread periods.The rye bread made up 23.4 + 4.3 % and wheat bread 26.7 + 8.2 % from the total intake of energy.The intake of fiber from the breads was 35.5 + 7.3 g and 4.7 + 1.0 g during the rye and wheat bread periods, respectively.The analysis of proportional changes in AIR during the rye bread period compared to run-in (9.9 + 24.2%) and during the wheat bread period compared to run-in (2.8 + 36.3%) tended to be significantly different (P = 0.062).In pairwise comparisons only the consumption of rye bread increased AIR (P = 0.033).The consumption of wheat bread did not affect any of the variables studied.The present study indicates that modification of the carbohydrate intake by high-fiber rye bread may improve acute insulin secretion, but does not alter peripheral insulin sensitivity, glucose effectiveness or fasting concentrations of plasma glucose and insulin in postmenopausal hypercholesterolemic women.
Original languageEnglish
Title of host publicationWhole Grain and Human Health: International Symposium
Subtitle of host publicationAbstracts
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Pages134-135
ISBN (Electronic)951-38-5719-0
ISBN (Print)951-38-5718-2
Publication statusPublished - 2001
EventWhole Grain and Human Health: International Symposium
- Porvoo, Finland
Duration: 13 Jun 200115 Jun 2001

Publication series

SeriesVTT Symposium
Number213
ISSN0357-9387

Conference

ConferenceWhole Grain and Human Health: International Symposium
CountryFinland
CityPorvoo
Period13/06/0115/06/01

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Juntunen, K., Laaksonen, D. E., Niskanen, L. K., Liukkonen, K., Poutanen, K., & Mykkänen, H. (2001). Consumption of high-fiber rye bread improves insulin secretion but not insulin sensitivity or glucose effectiveness in postmenopausal women. In Whole Grain and Human Health: International Symposium: Abstracts (pp. 134-135). VTT Technical Research Centre of Finland. VTT Symposium, No. 213