values in Figure 1a. (Hartvigsen et al. in Denmark Crossover To determine the effect of isolated AX alone or in combination with whole grain rye kernels on postprandial glucose, insulin, FFA, gut hormones, SCFA and appetite in subjects with MetS. 15 non-smokers and non-diabetic subjects with MetS as defined by the International Diabetes Federation (8 men and 7 postmenopausal women) of average age 63.5± 5 years, BMI 31.3± 2.7 kg/m2 and fasting blood plasma glucose 5.9±0.4 mmol/L. 12 subjects were treated with blood pressure medication and 7 with medication. Power calculation was conducted a priori. 4 test each providing 50 g of digestible carbohydrate were given in random order after 12h- fasting period as follows: semolina porridge with concentrated arabinoxylan (AX) has 3.5 g AX, rye kernels (RK) has 4.7 g AX or concentrated arabinoxylan combined with rye kernels (AXRK) has 4.4 g AX and semolina porridge as control (SE) which has 0.9 AX. Total fibre from wheat in the included strata (AXRK) was 19 g, containing 23.1% w/w total AX and therefore delivering 4.4 g of AX per eating occasion. Venous blood samples were drawn before the intervention and at frequent intervals within 270 min following the intake of test bread meals. Plasma glucose was measured by a glucose oxidase method (GOD-PAP glucose kit, Roche). ANOVA was used to examine the effect of test breads and time on the postprandial glucose responses. Reduced by crossover design, sufficient washout period combined with compliance to dietary and exercise instructions before and during the Glucose: Only AXRK meal has significantly (P = 0.003) reduced the peak postprandial glucose compared with SE. Mean difference between the included strata and the control was mmol/l. Insulin: significantly (P <0.001) lower in the included stratum (AXRK) compared with the control at the peak. No increase or significant difference in insulin concentrations were observed in the Postprandial blood glucose measurements from the AXRK versus the SE control have been used in the Other outcomes assessed in this trial (e.g. satiety) are not relevant to this review. -
strata at the peak. et al. 2013) in Finland Crossover To investigate whether bioprocessed rye bran in can improve postprandial glucose and insulin responses. Also to investigate phenolic acids absorption after ingestion of bread with rye bran. 15 healthy subjects (9 females and six males) with average age of 52 years and average BMI of 26 kg/m2 started and finished the study. wheat breads providing 50 g of carbohydrates and fortified with bioprocessed (BRB+WW) or native rye bran (RB+WW), and wholegrain rye bread (R) and white wheat bread (WW) as controls. Soluble AX was 3.8 g/portion in BRB+WW, 1.5 g/portion in RB+WW, 1.7 g/portion in R and 0.8 g/portion in WW. Total fibre from rye in the included strata (BRB+WW) was 17 g, containing 50% w/w total AX and therefore delivering 8.3 g of AX per eating occasion. Venous blood glucose was drawn before the intervention and at frequent intervals up to 240 min following the intervention. Plasma glucose was measured using the glucose dehydrogenase photometric method (Konelab System Reagents and KoneLab 20XTi Clinical Chemistry Analyser, Thermo Fisher Scientific). GLM was used to compare the effects of the intervention. Minimised by crossover design, sufficient washout period and the subjects’ compliance to dietary instructions before and during the trial. Glucose: Postprandial blood glucose responses, including at the peak, were similar between the test breads. Mean difference between the included stratum and the control was -0.40±0.21 mmol/l. Insulin: no significant difference between the included stratum (BRB+WW) and the control (WW) at the peak. No increase or significant difference in insulin concentrations were observed in the strata at the peak. Peak postprandial blood glucose in BRB+WW was compared with that in WW as a control. trial
(Lu et al. 2000) in Australia Crossover To compare the effect of meals containing AX-rich fibre on postprandial glucose and insulin responses in healthy subjects. 14 adults completed the study (5 men and 9 women) aged 32.0±6.6 years, with BMI of 22.7±4.3 kg/m2. isoenergetic breakfasts, comprising bread, margarine, and jam, and contained 0, 6, and 12 g AX-rich fibre. The meals provided 75 g available carbohydrate. Total fibre from wheat in the included strata was 6 g, containing 62.8% w/w total AX and therefore delivering 3.7 g of AX per eating occasion. Venous blood glucose was drawn before the intervention and at frequent intervals up to 120 min following the intervention. Plasma glucose was measured with an automatic analyser (Hitachi 705) and colorimetric reagents (Boehringer Mannheim). GLM was used to compare the effects of the intervention. Reduced by crossover design. Glucose: Peak postprandial glucose concentration in control meal was significantly (P < 0.001) higher than with 6 g AX-rich fibre and meals with 12 g AX-rich fibre. Mean difference between the included stratum and the control was -0.80±0.27 mmol/l. Insulin: no significant difference between the included (6 g) or the (12 g) strata and the control (0 g) at the peak. A significant (P <0.05) reduction in postprandial insulin concentration was observed Intervention delivering 6 g of AX-rich fibre has been used in the trial
Appendix 1: database search strategy PubMed: on 01/08/2016 Search Items found #1 (arabinoxylan[Supplementary Concept]) OR arabinoxylan[Text Word] 867 #2 (("randomized controlled trial"[Publication Type] OR "controlled clinical trial"[Publication Type] OR randomi*ed[Title/Abstract] OR placebo[Title/Abstract] OR randomly[Title/Abstract] OR trial[Title/Abstract] OR groups[Title/Abstract])) 2291997 #3 #1 and #2 105 #4 ((animals[MeSH Terms] NOT "humans"[MeSH Terms])) 4236012 #5 #3 NOT #4 80 Embase: on 29/07/2016 Search Query Items found exp *arabinoxylan/ 196 arabinoxylan.mp. or exp *arabinoxylan/ 1012 arabinoxylan.mp. abstract, heading word, drug trade name, original title, device manufacturer, drug manufacturer, device trade name, keyword] 1012 1 or 2 or 3 1012 4 to (human and (randomized controlled or controlled clinical trial)) 27 Cochrane trials (CENTRAL): on 01/08/2016 ID Search Hits #1 "arabinoxylan" in Trials (Word variations have been searched) 36
Appendix 3: Risk of bias of strata included in the systematic review Study Random sequence generation (selection bias) Allocation concealment (selection bias) Blinding of participants and personnel (performance bias)* Blinding of outcome assessors (detection bias) Incomplete outcome data (attrition bias) Selective reporting (reporting bias) Other (dietary and exercise instructions; testing interval in cross-over studies) Hartvigsen 2014a Low Subjects were randomly assigned to the sequence of the test breads by the study coordinator by use of a Latin-Square design. Low The sequence for each subject was kept in a closed numbered envelope until interventions were assigned. Low Crossover design. Subjects complied to instructions before and during the trial. Low Not stated Low All 15 subjects completed the test according to the protocol. Low Relevant results from performed analyses were reported. Low Reduced by overnight fasting, sufficient (1 week) washout periods combined with compliance to dietary and exercise instructions before and during the trial. Hartvigsen 2014b Low Subjects were randomly assigned to the sequence of the test meals by the study coordinator by the use of a Latin-Square design. Low To conceal the sequence until interventions were assigned, the sequence for each subject was kept in a closed numbered envelope. Low Crossover design. Subjects complied to instructions before and during the trial. Low Not stated Low All 15 subjects completed the test according to the protocol. Low Relevant results from performed analyses were reported. Low Sufficient (1 week) washout periods combined with compliance to dietary and exercise instructions before and during the trial.
blind the assessors. Möhlig 2005 Unclear Crossover design but no details are given on the randomisation method. Low Not stated. Low Not stated. Low Not stated Low All of the normoglycaemic sub-cohort completed the test Low Relevant results from performed analyses were reported. Low Sufficient washout period combined with compliance to dietary and exercise instructions before and during the trial.
Appendix 4: summary of findings tables Question: Does the dietary intake of arabinoxylan (AX) reduce peak postprandial glucose concentration? Source: FSANZ systematic review of evidence. Quality assessment of body of evidence Participant numbers Mean difference mmol/L [95% CI] Quality (degree of certainty in relationship) Number of studies Design Risk of bias Inconsistency Indirectness Imprecision Considerations Parallel Changes in postprandial glucose concentration are related to consuming AX-rich fibre 5 RCT Low None None Serious None 0 70 -0.56 Moderate Changes in postprandial blood glucose concentration are related to consuming pure AX 0 NA Not assessable Not applicable Not applicable Not applicable Not applicable 0 0 Not assessable Not assessable