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Zurbau A, Noronha JC, Khan TA, Sievenpiper JL, Wolever TMS. The effect of oat β-glucan on postprandial blood glucose and insulin responses: a systematic review and meta-analysis. Eur J Clin Nutr 2021; 75:1540-1554. [PMID: 33608654 PMCID: PMC8563417 DOI: 10.1038/s41430-021-00875-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 01/18/2021] [Accepted: 01/28/2021] [Indexed: 12/26/2022]
Abstract
To determine the effect of oat β‑glucan (OBG) on acute glucose and insulin responses and identify significant effect modifiers we searched the MEDLINE, EMBASE, and Cochrane databases through October 27, 2020 for acute, crossover, controlled feeding trials investigating the effect of adding OBG (concentrate or oat-bran) to carbohydrate-containing test-meals compared to comparable or different carbohydrate-matched control-meals in humans regardless of health status. The primary outcome was glucose incremental area-under-the-curve (iAUC). Secondary outcomes were insulin iAUC, and glucose and insulin incremental peak-rise (iPeak). Two reviewers extracted the data and assessed risk-of-bias and certainty-of-evidence (GRADE). Data were pooled using generic inverse-variance with random-effects model and expressed as ratio-of-means with [95% CIs]. We included 103 trial comparisons (N = 538). OBG reduced glucose iAUC and iPeak by 23% (0.77 [0.74, 0.81]) and 28% (0.72 [0.64, 0.76]) and insulin by 22% (0.78 [0.72, 0.85]) and 24% (0.76 [0.65, 0.88]), respectively. Dose, molecular-weight, and comparator were significant effect modifiers of glucose iAUC and iPeak. Significant linear dose-response relationships were observed for all outcomes. OBG molecular-weight >300 kg/mol significantly reduced glucose iAUC and iPeak, whereas molecular-weight <300 kg/mol did not. Reductions in glucose iAUC (27 vs 20%, p = 0.03) and iPeak (39 vs 25%, p < 0.01) were significantly larger with different vs comparable control-meals. Outcomes were similar in participants with and without diabetes. All outcomes had high certainty-of-evidence. In conclusion, current evidence indicates that adding OBG to carbohydrate-containing meals reduces glycaemic and insulinaemic responses. However, the magnitude of glucose reduction depends on OBG dose, molecular-weight, and the comparator.
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Affiliation(s)
- Andreea Zurbau
- INQUIS Clinical Research Ltd. (formerly GI Labs), Toronto, ON, Canada.,Toronto 3D Knowledge Synthesis and Clinical Trials Unit, Clinical Nutrition and Risk Factor Modification Centre, St. Michael's Hospital, Toronto, ON, Canada.,Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Jarvis C Noronha
- INQUIS Clinical Research Ltd. (formerly GI Labs), Toronto, ON, Canada
| | - Tauseef A Khan
- Toronto 3D Knowledge Synthesis and Clinical Trials Unit, Clinical Nutrition and Risk Factor Modification Centre, St. Michael's Hospital, Toronto, ON, Canada.,Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - John L Sievenpiper
- Toronto 3D Knowledge Synthesis and Clinical Trials Unit, Clinical Nutrition and Risk Factor Modification Centre, St. Michael's Hospital, Toronto, ON, Canada.,Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Department of Medicine, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Division of Endocrinology and Metabolism, Department of Medicine, St. Michael's Hospital, Toronto, ON, Canada.,Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada
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Rivers CR, Kantor MA. Psyllium husk intake and risk of type 2 diabetes: an evidence-based scientific and regulatory review of a qualified health claim conducted by the US Food and Drug Administration. Nutr Rev 2021; 78:787-797. [PMID: 31968119 DOI: 10.1093/nutrit/nuz103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The US Food and Drug Administration (FDA) received a petition from a company requesting that FDA issue an authorized health claim for the relationship between psyllium husk and a reduced risk of type 2 diabetes. After an initial assessment of the available scientific evidence, FDA determined that significant scientific agreement was lacking for this substance-disease relationship, whereupon the company agreed to have its petition reviewed as a qualified health claim. This article describes the process FDA used in conducting an evidence-based review of the science underpinning the proposed claim and addresses certain safety issues associated with psyllium husk that FDA considered in its review of the petition. Of the 6 studies from which scientific conclusions could be drawn, as identified through FDA's review, psyllium husk significantly improved plasma glucose levels and insulin sensitivity in only 1 study. Therefore, FDA's enforcement discretion letter for this qualified health claim stated: "Psyllium husk may reduce the risk of type 2 diabetes, although the FDA has concluded that there is very little scientific evidence for this claim."
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Affiliation(s)
- Crystal R Rivers
- Office of Nutrition and Food Labeling, Center for Food Safety and Applied Nutrition, US Food and Drug Administration, College Park, Maryland, USA
| | - Mark A Kantor
- Office of Nutrition and Food Labeling, Center for Food Safety and Applied Nutrition, US Food and Drug Administration, College Park, Maryland, USA
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Wolever TMS, Gibbs AL, Chiasson JL, Connelly PW, Josse RG, Leiter LA, Maheux P, Rabasa-Lhoret R, Rodger NW, Ryan EA. Altering source or amount of dietary carbohydrate has acute and chronic effects on postprandial glucose and triglycerides in type 2 diabetes: Canadian trial of Carbohydrates in Diabetes (CCD). Nutr Metab Cardiovasc Dis 2013; 23:227-234. [PMID: 22397878 DOI: 10.1016/j.numecd.2011.12.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 11/18/2011] [Accepted: 12/22/2011] [Indexed: 10/28/2022]
Abstract
BACKGROUND AND AIMS Nutrition recommendations for type 2 diabetes (T2DM) are partly guided by the postprandial responses elicited by diets varying in carbohydrate (CHO). We aimed to explore whether long-term changes in postprandial responses on low-glycemic-index (GI) or low-CHO diets were due to acute or chronic effects in T2DM. METHODS AND RESULTS Subjects with diet-alone-treated T2DM were randomly assigned to high-CHO/high-GI (H), high-CHO/low-GI (L), or low-CHO/high-monounsaturated-fat (M) diets for 12-months. At week-0 (Baseline) postprandial responses after H-meals (55% CHO, GI = 61) were measured from 0800 h to 1600 h. After 12 mo subjects were randomly assigned to H-meals or study diet meals (L, 57% CHO, GI = 50; M, 44% CHO, GI = 61). This yielded 5 groups: H diet with H-meals (HH, n = 34); L diet with H- (LH, n = 17) or L-meals (LL, n = 16); and M diet with H- (MH, n = 18) or M meals (MM, n = 19). Postprandial glucose fluctuations were lower in LL than all other groups (p < 0.001). Changes in postprandial-triglycerides differed among groups (p < 0.001). After 12 mo in HH and MM both fasting- and postprandial-triglycerides were similar to Baseline while in MH postprandial-triglycerides were significantly higher than at Baseline (p = 0.028). In LH, triglycerides were consistently (0.18-0.34 mmol/L) higher than Baseline throughout the day, while in LL the difference from Baseline varied across the day from 0.04 to 0.36 mmol/L (p < 0.001). CONCLUSION Low-GI and low-CHO diets have both acute and chronic effects on postprandial glucose and triglycerides in T2DM subjects. Thus, the composition of the acute test-meal and the habitual diet should be considered when interpreting the nutritional implications of different postprandial responses.
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Affiliation(s)
- T M S Wolever
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada.
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Brouns F, Bjorck I, Frayn KN, Gibbs AL, Lang V, Slama G, Wolever TMS. Glycaemic index methodology. Nutr Res Rev 2012; 18:145-71. [PMID: 19079901 DOI: 10.1079/nrr2005100] [Citation(s) in RCA: 599] [Impact Index Per Article: 49.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The glycaemic index (GI) concept was originally introduced to classify different sources of carbohydrate (CHO)-rich foods, usually having an energy content of >80 % from CHO, to their effect on post-meal glycaemia. It was assumed to apply to foods that primarily deliver available CHO, causing hyperglycaemia. Low-GI foods were classified as being digested and absorbed slowly and high-GI foods as being rapidly digested and absorbed, resulting in different glycaemic responses. Low-GI foods were found to induce benefits on certain risk factors for CVD and diabetes. Accordingly it has been proposed that GI classification of foods and drinks could be useful to help consumers make 'healthy food choices' within specific food groups. Classification of foods according to their impact on blood glucose responses requires a standardised way of measuring such responses. The present review discusses the most relevant methodological considerations and highlights specific recommendations regarding number of subjects, sex, subject status, inclusion and exclusion criteria, pre-test conditions, CHO test dose, blood sampling procedures, sampling times, test randomisation and calculation of glycaemic response area under the curve. All together, these technical recommendations will help to implement or reinforce measurement of GI in laboratories and help to ensure quality of results. Since there is current international interest in alternative ways of expressing glycaemic responses to foods, some of these methods are discussed.
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Affiliation(s)
- F Brouns
- Cerestar- Cargill R&D Center, Vilvoorde, Belgium
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New perspectives on nutritional interventions to augment lipid utilisation during exercise. Br J Nutr 2011; 107:339-49. [PMID: 22136984 DOI: 10.1017/s0007114511006684] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The enhancement of fat oxidation during exercise is an aim for both recreational exercising individuals and endurance athletes. Nutritional status may explain a large part of the variation in maximal rates of fat oxidation during exercise. This review reveals novel insights into nutritional manipulation of substrate selection during exercise, explaining putative mechanisms of action and evaluating the current evidence. Lowering the glycaemic index of the pre-exercise meal can enhance lipid utilisation by up to 100 % through reduced insulin concentrations, although its application may be restricted to specific training sessions rather than competition. Chronic effects of dietary glycaemic index are less clear and warrant future study before firm recommendations can be made. A flurry of recent advances has overthrown the conventional view of l-carnitine supplementation, with skeletal muscle uptake possible under certain dietary conditions and providing a strategy to influence energy metabolism in an exercise intensity-dependent manner. Use of non-carbohydrate nutrients to stimulate muscle l-carnitine uptake may prove more beneficial for optimising lipid utilisation, but this requires more research. Studies investigating fish oil supplementation on fat oxidation during exercise are conflicting. In spite of some strong putative mechanisms, the only crossover trial showed no significant effect on lipid use during exercise. Ca may increase NEFA availability although it is not clear whether these effects occur. Ca and caffeine can increase NEFA availability under certain circumstances which could theoretically enhance fat oxidation, yet strong experimental evidence for this effect during exercise is lacking. Co-administration of nutrients to maximise their effectiveness needs further investigation.
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Wallace AJ, Eady SL, Willis JA, Scott RS, Monro JA, Frampton CM. Variability in measurements of blood glucose response to foods in human subjects is not reduced after a standard breakfast. Nutr Res 2009; 29:238-43. [PMID: 19410974 DOI: 10.1016/j.nutres.2009.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Revised: 03/02/2009] [Accepted: 03/05/2009] [Indexed: 01/10/2023]
Abstract
Measurements of blood glucose response to food are highly variable. We determined whether within-individual variability in data for blood glucose responses were reduced if individuals consumed a standard meal 2 hours before testing and investigated the effect of serving size. Blood glucose responses to muesli and macaroni cheese were determined in 13 individuals by taking 2 fasting capillary blood samples. Food was then consumed, and capillary blood samples were taken every 15 minutes for the first hour and every 30 minutes for the second hour. The incremental area under the blood glucose response curve was determined, and glycemic glucose equivalents (GGEs) were calculated. The GGE values were not significantly different whether the muesli and macaroni cheese were fed fasting or after a standard breakfast (29.2 vs 34.5 g for muesli and 11.0 vs 14.6 g for macaroni cheese). Within-individual coefficients of variation were not significantly different whether the food was consumed fasting or after a standard breakfast (24.9% and 32.5% for muesli and 38.1% and 59.4% for macaroni cheese). Differences in GGE between measured and estimated half serving size for macaroni cheese were 0.8 g (P = .6) and for muesli, 3 g (P = .2); for the double serving size for macaroni cheese, 1.7 g (P = .7); and for muesli, 6.7 g (P = .06). The GGE values for foods and variability in blood glucose response within individuals were not significantly different whether individuals fasted or consumed a standard breakfast before testing. However, blood glucose levels tended to differ significantly after consumption of the double serving size of muesli compared with other serving sizes.
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Affiliation(s)
- Alison J Wallace
- New Zealand Institute for Plant and Food Research Limited, Private Bag 4704, Christchurch 8140, New Zealand.
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Reilly T, Waterhouse J. Altered sleep–wake cycles and food intake: The Ramadan model. Physiol Behav 2007; 90:219-28. [PMID: 17081572 DOI: 10.1016/j.physbeh.2006.09.004] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Accepted: 09/04/2006] [Indexed: 12/28/2022]
Abstract
In this review the effects of diurnal fasting on normal physiological processes are considered. Ramadan is placed in a circadian context, food and fluid ingestion being displaced to the pre-sunrise and post-sunset hours. Over the holy month, negative energy balance is often experienced, though this deficit is not a universal finding. Responses to exercise during the day show influences consistent with hypohydration and an increased reliance on fat as a source of fuel for exercise. Muscle performance and psychomotor performance are impaired as the month of fasting progresses but it is not clear how circadian rhythms in responses to activity are altered. For some measures at rest there is a reduction in amplitude and a delay in acrophase. Health-related benefits are reflected in a rise in high-density lipoprotein cholesterol and individuals with predispositions for coronary heart disease are not at increased risk of cardiovascular disorders due to fasting. The physiological adjustments during the month have some similarities to the disturbances in circadian rhythms experienced in different circumstances. The Ramadan model provides an alternative to those for ageing, nocturnal shift-work and time-zone transitions in understanding the links between behaviour and endogenous circadian rhythms.
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Affiliation(s)
- Thomas Reilly
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Henry Cotton Campus, 15-21 Webster Street, Liverpool, L3 2ET, United Kingdom.
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de Assis MAA, Nahas MV, Bellisle F, Kupek E. Meals, snacks and food choices in Brazilian shift workers with high energy expenditure. J Hum Nutr Diet 2003; 16:283-9. [PMID: 12859710 DOI: 10.1046/j.1365-277x.2003.00448.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To describe the food intake of garbage collectors, who works in three shifts, in terms of meal and snack frequency, content, time distribution and the contribution of various popular foods to the total diet. METHODS Sixty-six Brazilian garbage collectors, who work in morning, afternoon, and night shift, participated in the present study. The quantitative methods used were a combination of one 24-h recall and two 24-h records during three nonconsecutive work days. The qualitative method used was the food-based classification of eating episodes model modified in order to define meals or snacks in three categories of events: meals with three food groups of high nutrient density (three HND meals), meals with two food groups of high nutrient density (two HND meals) and snacks, composed of only one food category of high nutrient density. RESULTS The total number of eating events per day was significantly higher for night shift workers. Over 24-h, 'two HND meals' were the most common events and contributed the most energy, in all three shifts. Night shift workers ate more at dawn and less in the morning than other shifts. In all three shifts, meat was the most important food contributing to energy intake. CONCLUSION Different work schedules did not affect the relative frequency of meal types and snacks or their contribution to daily energy intake, but affected the daily distribution of eating events, with a redistribution of intake from day to night in night shift workers.
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Affiliation(s)
- M A A de Assis
- Departamento de Nutrição, Universidade Federal de Santa Catarina, Florianopolis, Santa Catarina, Brazil.
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Wahlqvist ML. The place of carbohydrates in newer food formulations: Opportunities for nutritional advancement and their safety. Asia Pac J Clin Nutr 2002. [DOI: 10.1046/j.1440-6047.11.s.6.4.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Waterhouse J, Minors D, Atkinson G, Benton D. Chronobiology and meal times: internal and external factors. Br J Nutr 1997; 77 Suppl 1:S29-38. [PMID: 9155492 DOI: 10.1079/bjn19970102] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Although homeostatic mechanisms remain of utmost importance, rhythmic changes are present also. The main ones have a period of 24 h (circadian) or about 2-3 h (ultradian). Circadian rhythms are derived from a body clock, found in the base of the brain, and from the pattern of our sleep-wake cycle, including activity and meal times. These rhythms promote the regular changes between an active wake period and a recuperative sleep period. Ultradian rhythms are also widespread and reflect external (lifestyle) and internal factors. The internal factors include biochemical need and some sort of oscillator; but details of how many oscillators, and exactly where they are, remain to be established. Food intake, appetite, digestion and metabolism have been shown to illustrate these principles. Moreover, these principles become important when special circumstances exist as far as meal times are concerned; the particular difficulties of night workers is a good example.
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Affiliation(s)
- J Waterhouse
- School of Human Sciences, Liverpool John Moores University
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