scholarly journals Dose-dependent effects of insoluble fibre on glucose metabolism: a stratified post hoc analysis of the Optimal Fibre Trial (OptiFiT)

Author(s):  
Stefan Kabisch ◽  
Caroline Honsek ◽  
Margrit Kemper ◽  
Christiana Gerbracht ◽  
Ayman M. Arafat ◽  
...  

Abstract Aims As the first long-term RCT on insoluble cereal fibre, the optimal fibre trial demonstrated glycometabolic benefits, confirming cohort studies. The combined study intervention of lifestyle recommendations and supplementation with insoluble oat hulls fibre allows to clarify, which amount of fibre is required for a beneficial effect. Methods One hundred and eighty participants with impaired glucose tolerance underwent the one-year PREDIAS lifestyle programme and received a blinded, randomized fibre or placebo supplement for two years. We conducted a regression analyses and cut-off-based tertile comparisons in subjects with full data on dietary compliance (food records and accounted supplement; n = 120) after one year, investigating effects on fasting blood parameters, oral glucose tolerance test and anthropometry. Results We found a nonlinear inverse relation between fibre intake and change in postprandial 2-h glucose levels, showing a metabolic benefit beyond 14 g and a plateau beyond 25 g of total insoluble fibre per day. 2-h glucose levels improved significantly stronger in both upper tertiles (−0.9 [−1.6;−0.2] mmol/l, p = 0.047, and −0.6 [−1.6;0.3] mmol/l, p = 0.010) compared to the lowest tertile (0.1 [−1.2;1.1] mmol/l), also when adjusted for changes in bodyweight. Subjects with the highest fibre intake showed superior effects on fasting and postprandial insulin resistance, hepatic insulin clearance, leucocyte count and fatty liver index. Conclusions Extending the knowledge on the benefits of insoluble oat hulls fibre, our post hoc analysis demonstrates a dose effect for glycaemia and associated metabolic markers. Further research is needed in order to replicate our findings in larger trials.

Nutrients ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2726 ◽  
Author(s):  
Stefan Kabisch ◽  
Nina Marie Tosca Meyer ◽  
Caroline Honsek ◽  
Christiana Gerbracht ◽  
Ulrike Dambeck ◽  
...  

Obesity does not modulate the glycometabolic benefit of insoluble cereal fibre in subjects with prediabetes—a stratified post hoc analysis of the Optimal Fibre Trial (OptiFiT). Background: OptiFiT demonstrated the beneficial effect of insoluble oat fibres on dysglycemia in prediabetes. Recent analyses of OptiFiT and other randomised controlled trials (RCTs) indicated that this effect might be specific for the subgroup of patients with impaired fasting glucose (IFG). As subjects with IFG are more often obese, there is a need to clarify if the effect modulation is actually driven by glycemic state or body mass index (BMI). Aim: We conducted a stratified post hoc analysis of OptiFiT based on the presence or absence of obesity. Methods: 180 Caucasian participants with impaired glucose tolerance (IGT) were randomised in a double-blinded fashion to either twice-a-day fibre or placebo supplementation for 2 years (n = 89 and 91, respectively). Once a year, they underwent fasting blood sampling, an oral glucose tolerance test (oGTT) and full anthropometry. At baseline, out of 136 subjects who completed the first year of intervention, 87 (62%) were classified as OBESE (BMI >30) and 49 subjects were NONOBESE. We performed a stratified per-protocol analysis of the primary glycemic and secondary metabolic effects attributable to dietary fibre supplementation after 1 year of intervention. Results: Neither the NONOBESE nor the OBESE subgroup showed significant differences between the respective fibre and placebo groups in metabolic, anthropometric or inflammatory outcomes. None of the four subgroups showed a significant improvement in either fasting glucose or glycated haemoglobin (HbA1c) after 1 year of intervention and only OBESE fibre subjects improved 2 h glucose. Within the NONOBESE stratum, there were no significant differences in the change of primary or secondary metabolic parameters between the fibre and placebo arms. We found a significant interaction effect for leukocyte count (time × supplement × obesity status). Within the OBESE stratum, leukocyte count and gamma-glutamyl transferase (GGT) levels decreased more in the fibre group compared with placebo (adjusted for change in body weight). Comparison of both fibre groups revealed that OBESE subjects had a significantly stronger benefit with respect to leukocyte count and fasting C-peptide levels than NONOBESE participants. Only the effect on leukocyte count survived correction for multiple comparisons. In contrast, under placebo conditions, NONOBESE subjects managed to decrease their body fat content significantly more than OBESE ones. Intention-to-treat (ITT) analysis resulted in similar outcomes. Conclusions: The state of obesity does not relevantly modulate the beneficial effect of cereal fibre on major glycometabolic parameters by fibre supplementation, but leukocyte levels may be affected. Hence, BMI is not a suitable parameter to stratify this cohort with respect to diabetes risk or responsiveness to cereal fibre, but obesity needs to be accounted for when assessing anti-inflammatory effects of fibre treatments. Targeted diabetes prevention should focus on the actual metabolic state rather than on mere obesity.


2015 ◽  
Vol 10 (2) ◽  
pp. 326 ◽  
Author(s):  
Emordi Jonathan Emeka ◽  
Agbaje Esther Oluwatoyin ◽  
Oreagba Ibrahim Adekunle ◽  
Iribhogbe Osede Ignis

<p>The purpose of this study is to evaluate the hypoglycaemic properties and preliminary phytochemical screening of <em>Uveria chamae</em>. The hypoglycaemic properties of <em>Uveria chamae</em> was assessed on normoglycaemic rat that received single dose of the extract at 250 and 500 mg/kg body weight and blood glucose levels estimated at 2, 4, and 6 hours (single dose study). The hypoglycaemic property of the extract was also evaluated in normoglycemic rats by oral glucose tolerance test. Phytochemical screening of the extract for the presence of secondary metabolites was performed with standard methods. The extract showed a significant (p&lt;0.05) reduction in blood glucose levels at 2h and 6h compared to control.  The oral glucose tolerance test  result also showed a significant decrease (p&lt;0.05) in blood glucose levels . The study showed that the extract, <em>Uveria chamae</em> has hypoglycaemic properties which may be accounted for by the presence of the phytochemicals.</p><p> </p>


2006 ◽  
Vol 155 (4) ◽  
pp. 623-632 ◽  
Author(s):  
G Neil Thomas ◽  
C Mary Schooling ◽  
Sarah M McGhee ◽  
Sai-Yin Ho ◽  
Bernard M Y Cheung ◽  
...  

Background: The use of fasting and post-prandial glucose levels in the classification of hyperglycaemic states often identifies distinct subjects, but the factors determining these intermediate-isolated glucose intolerant states are yet to be clearly elucidated in Chinese subjects. Methods: Representative subjects (n = 2769) were randomly recruited from the Hong Kong Chinese population and glycaemic status was determined using both fasting and 2h 75 g oral glucose tolerance test glucose levels. The relationship between the groups with isolated glucose intolerance and vascular risk factors was investigated using ANOVA and logistic regression analyses. Results: Using either criterion, diabetes was identified in 265 (9.6%) subjects and glucose intolerance in 568 (20.5%) subjects. Of those 568, isolated impaired glucose tolerance (IGT) using the post-load criterion was identified in 49.5% and isolated impaired fasting glucose (IFG) in 30.5%. Ageing and hyperinsulinaemia were common determinants of IGT and IFG; with small hip circumference a marker of poorer early life development and being born in China rather than Hong Kong, a possible low birth weight marker was also associated with IFG. Hypertension, hypertriglyceridaemia and poor education were also associated with IGT. When we looked for factors differentially associated with these glucose intolerant states, female sex, greater hip circumference, high triglyceride levels, low fasting insulin levels, and not being born in China were independently associated with isolated IGT compared with isolated IFG. Conclusion: Despite common antecedents to the glucose intolerant states, isolated IFG appeared to be particularly associated with early life development, and isolated IGT was more strongly associated with obesity-related determinants such as hypertriglyceridaemia.


1998 ◽  
Vol 158 (2) ◽  
pp. 191-196 ◽  
Author(s):  
U Totzke ◽  
A Hubinger ◽  
F Bairlein

Substrate utilization and regulatory mechanisms of metabolism were studied in migratory garden warblers by measuring plasma levels of glucose, free fatty acids (FFAs), beta-hydroxybutyrate, insulin and glucagon in response to oral glucose loads. Three different physiological states were examined: (a) the autumnal migratory period on a high and (b) on a fasted low body mass level, and (c) the postmigratory period with low body mass. Glucose tolerance was better in the postmigratory lean than fat condition. However, total food deprivation of 5-7 days with fat birds reaching their lean body mass further reduced the glucose utilization rate. Initial levels of FFAs were highest in the starved, intermediate in the fat and lowest in the lean condition. Changes in plasma FFAs during glucose tolerance tests were opposite to those of the glucose levels. Ten minutes after the glucose load plasma glucagon levels decreased and insulin increased. These effects were larger in the fat than in the postmigratory lean condition. There were no differences between sexes. It appears that during premigratory and migratory periods glucose utilization may be inhibited by a more favorable oxidation of fatty acids as would be predicted by the glucose fatty acid cycle. However, the inhibition of glucose utilization seems to be counterregulated by stronger responses of insulin and glucagon. These results may be important also in the consideration of food selection during premigratory periods and refueling abilities of birds crossing ecological barriers.


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