健康与营养科学团队出版物

Sylvetsky, A. C., Hiedacavage, A., Shah, N., Pokorney, P., . . . Dietz, W. H. (2019). From biology to behavior: A cross-disciplinary seminar series surrounding added sugar and low-calorie sweetener consumption. Obesity Science and Practice, 5(3), 203-219. doi:10.1002/osp4.334

Abstract:

Introduction: This report presents a synopsis of a three-part, cross-sector, seminar series held at the George Washington University (GWU) in Washington, DC from February–April, 2018. The overarching goal of the seminar series was to provide a neutral forum for diverse stakeholders to discuss and critically evaluate approaches to address added sugar intake, with a key focus on the role of low-calorie sweeteners (LCS). Methods: During three seminars, twelve speakers from academic institutions, federal agencies, non-profit organizations, and the food and beverage industries participated in six interactive panel discussions to address: 1) Do Farm Bill Policies Impact Population Sugar Intake? 2) What is the Impact of Sugar-sweetened Beverage (SSB) Taxes on Health and Business? 3) Is Sugar Addictive? 4) Product Reformulation Efforts: Progress, Challenges, and Concerns? 5) Low-calorie Sweeteners: Helpful or Harmful, and 6) Are Novel Sweeteners a Plausible Solution? Discussion of each topic involved brief 15-minute presentations from the speakers, which were followed by a 25-minute panel discussion moderated by GWU faculty members and addressed questions generated by the audience. Sessions were designed to represent opposing views and stimulate meaningful debate. Given the provocative nature of the seminar series, attendee questions were gathered anonymously using Pigeonhole™, an interactive, online, question and answer platform. Results: This report summarizes each presentation and recapitulates key perspectives offered by the speakers and moderators. Conclusions: The seminar series set the foundation for robust cross-sector dialogue necessary to inform meaningful future research, and ultimately, effective policies for lowering added sugar intakes.

Wolever, T. M. S., Jenkins, A. L., Yang, J., Nisbet, M., . . . Pan, Y. (2019). An optimized, slowly digested savory cluster reduced postprandial glucose and insulin responses in healthy human subjects. Current Developments in Nutrition, 3(3), nzz006. doi:10.1093/cdn/nzz006

Abstract:

Background: Slowly digested carbohydrates are perceived as beneficial by some consumers, and various regulatory bodies have published specific criteria defining lower postprandial glycemic response. We developed an optimized savory cluster snack containing slowly digested starch. Objective: We compared the glucose and insulin responses elicited by the optimized (test-) cluster, a control-cluster, and an available-carbohydrate-matched portion of white bread in healthy individuals. The primary outcome was blood-glucose peak rise. We tested healthy individuals (n = 25) on 3 occasions using a randomized crossover design. On each occasion, the participants provided fasting blood samples and then consumed 1 serving of test-cluster, control-cluster, or white bread. We then measured the participants’ blood-glucose and serum-insulin concentrations over the next 4 h. Results: The test-cluster elicited a significantly lower blood-glucose peak rise (mean ± SEM: 1.24 ± 0.09 mmol/L) and incremental area under the curve (iAUC; 67 ± 8 mmol × min/L) than the control-cluster (2.27 ± 0.13 mmol/L and 117 ± 10 mmol × min/L, respectively) and white bread (2.27 ± 0.16 mmol/L and 114 ± 9 mmol × min/L, respectively). The serum-insulin peak rise and iAUC elicited by the test-cluster (128 ± 13 pmol/L and 6.10 ± 0.73 nmol × min/L, respectively) and white bread (141 ± 20 pmol/L and 6.47 ± 1.11 nmol × min/L, respectively) were significantly lower than those elicited by the control-cluster (205 ± 26 pmol/L and 9.60 ± 1.31 nmol × min/L, respectively). Conclusion: The test-cluster elicited lower glucose and insulin responses than the control-cluster. The results support the hypothesis that the carbohydrates in the test-cluster are digested and absorbed slowly in vivo.

Ding, J., Johnson, J., Chu, Y. F., & Feng, H. (2019). Enhancement of γ-aminobutyric acid, avenanthramides, and other health-promoting metabolites in germinating oats (avena sativa L.) treated with and without power ultrasound. Food Chemistry, 283, 239-247. doi:10.1016/j.foodchem.2018.12.136

Abstract:

Power ultrasound as an emerging processing technology has been investigated for stimulating seeds to enhance germination and accumulation of health-promoting metabolites, such as γ-aminobutyric acid (GABA) and phenolic compounds. This work was undertaken to evaluate the effects of power ultrasound (25 kHz) on the nutritional properties of germinated oats, and the microstructure of oat groats after treatment. The changes in the external and internal microstructures of the ultrasound-treated oats kernel were investigated using Environmental Scanning Electron Microscopy (ESEM) and 3D X-ray Micro Computed Tomography (Micro-CT). Physicochemical properties of oats including GABA, free sugars, avenanthramides, total phenolic content, and antioxidant capacities were enhanced after germination. Furthermore, the power ultrasound treatment for 5 min after soaking significantly enhanced the GABA (48–96 h), alanine (24–96 h), succinic acid (48–72 h), total phenolic content (24 h), and total avenanthramides (24 h) in the germinated oats.

Volokh, O., Klimenko, N., Berezhnaya, Y., Tyakht, A., . . . Alexeev, D. (2019). Human gut microbiome response induced by fermented dairy product intake in healthy volunteers. Nutrients, 11(3), 547. doi:10.3390/nu11030547

Abstract:

Accumulated data suggests that the gut microbiome can rapidly respond to changes in diet. Consumption of fermented dairy products (FDP) fortified with probiotic microbes may be associated with positive impact on human health. However, the extent and details of the possible impact of FDP consumption on gut community structure tends to vary across individuals. We used microbiome analysis to characterize changes in gut microbiota composition after 30 days of oral intake of a yoghurt fortified with Bifidobacterium animalis subsp. lactis BB-12. 16S rRNA gene sequencing was used to assess the gut microbial composition before and after FDP consumption in healthy adults (n = 150). Paired comparison of gut microbial content demonstrated an increase in presence of potentially beneficial bacteria, particularly, Bifidobacterium genus, as well as Adlercreutzia equolifaciens and Slackia isoflavoniconvertens. At a functional level, an increased capacity to metabolize lactose and synthesize amino acids was observed accompanied by a lowered potential for synthesis of lipopolysaccharides. Cluster analysis revealed that study volunteers segregated into two groups with post-intervention microbiota response that was dependent on the baseline microbial community structure.

Dennis-Wall, J. C., Burns, A. M., Solch, R. J., Ukhanova, M., . . . Langkamp-Henken, B. (2019). A beverage containing orange pomace improves laxation and modulates the microbiome in healthy adults: A randomised, blinded, controlled trial. Journal of Functional Foods, 60. 103438.  doi:10.1016/j.jff.2019.103438

Abstract:

The aim was to assess whether citrus pomace increases stool frequency in healthy adults. In this randomised, blinded, controlled trial, healthy adults (62% females) received a beverage containing pomace (473 mL/day, providing 10 g fibre/day, n = 111) or control (n = 110) for 3 weeks. Stool frequency, Bristol Stool Form Scale (BSFS), and Gastrointestinal Symptom Rating Scale (GSRS) scores were self-assessed. 24-h diet recalls were completed once/week. Stool microbiota were analysed by 16S rRNA sequencing and qPCR. Mean total daily fibre intake was higher with pomace vs. control (P < 0.0001). Mean weekly stool frequency was higher, indicating improved laxation, with pomace vs. control (P = 0.0281) and increased from baseline with pomace (P = 0.0003) but was unchanged with control. Mean BSFS scores were higher with pomace vs. control (P = 0.04). GSRS indigestion syndrome scores, specifically symptoms of gas and bloating, were higher with pomace, suggesting fermentation. Pomace intake increased faecal OTUs corresponding to Lachnospiraceae and Ruminococcaceae.

Liska, D., Mah, E., Brisbois, T., Barrios, P. L., . . . Spriet, L. L. (2019). Narrative review of hydration and selected health outcomes in the general population. Nutrients, 11(1), 70. doi:10.3390/nu11010070

Abstract:

Although adequate hydration is essential for health, little attention has been paid to the effects of hydration among the generally healthy population. This narrative review presents the state of the science on the role of hydration in health in the general population, specifically in skin health, neurological function (i.e., cognition, mood, and headache), gastrointestinal and renal functions, and body weight and composition. There is a growing body of evidence that supports the importance of adequate hydration in maintaining proper health, especially with regard to cognition, kidney stone risk, and weight management. However, the evidence is largely associative and lacks consistency, and the number of randomized trials is limited. Additionally, there are major gaps in knowledge related to health outcomes due to small variations in hydration status, the influence of sex and sex hormones, and age, especially in older adults and children.

Wolever, T. M. S., Johnson, J., Jenkins, A. L., Campbell, J. C., . . . Chu, Y. (2019). Impact of oat processing on glycaemic and insulinaemic responses in healthy humans: A randomised clinical trial. British Journal of Nutrition, 121(11), 1264-1270. doi:10.1017/S0007114519000370

Abstract:

Oats can be processed in a variety of ways ranging from minimally processed such as steel-cut oats (SCO), to mildly processed such as large-flake oats (old fashioned oats, OFO), moderately processed such as instant oats (IO) or highly processed in ready-to-eat oat cereals such as Honey Nut Cheerios (HNC). Although processing is believed to increase glycaemic and insulinaemic responses, the effect of oat processing in these respects is unclear. Thus, we compared the glycaemic and insulinaemic responses elicited by 628 kJ portions of SCO, OFO, IO and HNC and a portion of Cream of Rice cereal (CR) containing the same amount of available-carbohydrate (23 g) as the oatmeals. Healthy males (n 18) and females (n 12) completed this randomised, cross-over trial. Blood was taken fasting and at intervals for 3 h following test-meal consumption. Glucose and insulin peak-rises and incremental AUC (iAUC) were subjected to repeated-measures ANOVA using Tukey’s test (two-sided P<0·05) to compare individual means. Glucose peak-rise (primary endpoint, mean (SEM) mmol/l) after OFO, 2·19 (SEM 0·11), was significantly less than after CR, 2·61 (SEM 0·13); and glucose peak-rise after SCO, 1·93 (SEM 0·13), was significantly less than after CR, HNC, 2·49 (SEM 0·13) and IO 2·47 (SEM 0·13). Glucose iAUC was significantly lower after SCO than CR and HNC. Insulin peak rise was similar among the test meals, but insulin iAUC was significantly less after SCO than IO. Thus, the results show that oat processing affects glycaemic and insulinaemic responses with lower responses associated with less processing.

Joyce, S. A., Kamil, A., Fleige, L., & Gahan, C. G. M. (2019). The cholesterol-lowering effect of oats and oat β-glucan: Modes of action and potential role of bile acids and the microbiome. Frontiers in Nutrition, 6, 171. doi:10.3389/fnut.2019.00171

Abstract:

Consumption of sufficient quantities of oat products has been shown to reduce host cholesterol and thereby modulate cardiovascular disease risk. The effects are proposed to be mediated by the gel-forming properties of oat β-glucan which modulates host bile acid and cholesterol metabolism and potentially removes intestinal cholesterol for excretion. However, the gut microbiota has emerged as a major factor regulating cholesterol metabolism in the host. Oat β-glucan has been shown to modulate the gut microbiota, particularly those bacterial species that influence host bile acid metabolism and production of short chain fatty acids, factors which are regulators of host cholesterol homeostasis. Given a significant role for the gut microbiota in cholesterol metabolism it is likely that the effects of oat β-glucan on the host are multifaceted and involve regulation of microbe-host interactions at the gut interface. Here we consider the potential for oat β-glucan to influence microbial populations in the gut with potential consequences for bile acid metabolism, reverse cholesterol transport (RCT), short-chain fatty acid (SCFA) production, bacterial metabolism of cholesterol and microbe-host signaling.

Vieux, F., Maillot, M., Rehm, C. D., Barrios, P., & Drewnowski, A. (2019). The timing of water and beverage consumption during the day among children and adults in the United States: Analyses of NHANES 2011–2016 data. Nutrients, 11(11), 2707. doi:10.3390/nu11112707

Abstract:

Dietary Guidelines for Americans 2015–20 recommend replacing sugar sweetened beverages (SSBs) with plain water in order to promote adequate hydration while reducing added sugar intake. This study explored how water intakes from water, beverages, and foods are distributed across the day. The dietary intake data for 7453 children (4–18 y) and 15,263 adults (>19 y) came from the National Health and Nutrition Examination Survey (NHANES 2011–2016). Water was categorized as tap or bottled. Beverages were assigned to 15 categories. Water intakes (in mL/d) from water, beverages, and food moisture showed significant differences by age group, meal occasion, and time of day. Plain water was consumed in the morning, mostly in the course of a morning snack and between 06:00 and 12:00. Milk and juices were consumed at breakfast whereas SSBs were mostly consumed at lunch, dinner, and in the afternoon. Children consumed milk and juices, mostly in the morning. Adults consumed coffee and tea in the morning, SSBs in the afternoon, and alcohol in the evening. Relatively little drinking water was consumed with lunch or after 21:00. Dietary strategies to replace caloric beverages with plain water need to build on existing drinking habits by age group and meal type.

Young, H. A., Cousins, A., Johnston, S., Fletcher, J. M., & Benton, D. (2019). Autonomic adaptations mediate the effect of hydration on brain functioning and mood: Evidence from two randomized controlled trials. Scientific Reports, 9(1), 16412. doi:10.1038/s41598-019-52775-5

Abstract:

Dehydration (water loss >2.0% of body weight) has significant negative effects on physical and mental performance. In two studies the effects of minor hypo-hydration (water loss <1.0% of body weight) on CNS function, mood and cardiovascular functioning were measured. Study 1: On two mornings twelve male participants were exposed to a temperature of 30 °C for four hours and either did or did not drink two 150 ml glasses of water during that time. Study 2: Fifty-six (25 M) individuals were exposed to the same 30 °C environment and randomly allocated to either drink (2 × 150 ml) or not drink. When not given water 0.59% (Study 1) and 0.55% (Study 2) bodyweight was lost. Participant’s heart rate variability (HRV) was measured, and they rated their thirst and mood. In study 1, participants participated in an fMRI protocol during which they completed a modified version of the Paced Auditory Serial Addition Test (PASAT), at the end of which they rated its difficulty. Decreases in fMRI BOLD activity in the orbito-frontal cortex, ventral cingulate gyrus, dorsal cingulate cortex, hypothalamus, amygdala, right striatum, post-central gyrus and superior parietal cortex were observed when participants were hypo-hydrated. These deactivations were associated with reduced HRV, greater perceived effort, and more anxiety. In study 2 declines in HRV were found to mediate the effect of hypo-hydration on ratings of anxiety. These data are discussed in relation to a model that describes how autonomic regulatory and interoceptive processes may contribute to the affective consequences of minor hypo-hydration.

Huang, Y., Park, E., Replogle, R., Boileau, T., . . . Edirisinghe, I. (2019). Enzyme-treated orange pomace alters acute glycemic response to orange juice. Nutrition and Diabetes, 9, 24. doi:10.1038/s41387-019-0091-z

Abstract:

The goal of the present study was to determine the impact of the addition of enzyme-treated orange pomace to orange juice on postprandial glycemic response. Ten healthy subjects (aged 27.9 ± 7.7 years, body mass index 22.1 ± 1.1 kg m−2) participated in a randomized, 2-arm, cross-over clinical trial to test the glycemic response to 100% orange juice (OJ) or 100% orange juice with 5 g of enzyme-treated orange pomace fiber (OPF). Blood samples were collected and glucose and insulin concentrations were measured at fasting (0 min) and every 15 min for 2 h after consuming the study juice products. Analysis of the 2 h incremental area under the curve (iAUC0–2h) indicated a significant reduction in blood glucose after ingesting the OPF juice compared to the OJ, p = 0.02. Peak glucose concentrations were also lowered after the OPF juice compared to the OJ, p < 0.05. No significant difference was observed in insulin responses between treatments, p > 0.05. Overall, this study demonstrated that adding 5 g of fiber from orange pomace into a serving of OJ attenuated the postprandial glucose response.

Wolever, T. M. S., Jones, P. J. H., Jenkins, A. L., Mollard, R. C., . . . Chu, Y. F. (2019). Glycaemic and insulinaemic impact of oats soaked overnight in milk vs. cream of rice with and without sugar, nuts, and seeds: A randomized, controlled trial. European Journal of Clinical Nutrition, 73(1), 86-93. doi:10.1038/s41430-018-0329-1

Abstract:

Background/Objectives: Soaking oats overnight in milk renders them ready to eat the next morning, however, it is unknown whether oats prepared this way will retain its relatively low glycaemic and insulinaemic impact. Therefore, we compared the glycaemic, insulinaemic and subjective hunger responses elicited by oats soaked overnight in 110 g skim-milk (ONO) vs. cooked cream of rice cereal (CR), both with and without inclusions. Subjects/Methods: The project was performed at two research centers (Toronto, Winnipeg) as two separate studies each using a randomized, cross-over design with similar methods. The glycaemic and insulinaemic responses of overnight-fasted participants without diabetes (males:females: Toronto, 24:16; Winnipeg, 20:20) were measured for 3 h after consuming CR and ONO fed alone (Toronto) or with added sugar, nuts, and seeds (CRsns and ONOsns) (Winnipeg). Participants rated subjective hunger using visual analog scales. Data were analyzed by paired t-test. The primary endpoint was 0–2 h incremental area under the curve (iAUC) for glucose. Results: Mean glucose iAUC was 33% less, after ONO than CR (mean difference was 39 (51–27) mmol × min/l, p < 0.0001) and 24% less, after ONOsns than CRsns (mean difference was 43 (65–21) mmol × min/l, p = 0.0003). Serum-insulin iAUC was 33% less, after ONO than CR (mean difference 57 (81–40) pmol × hl, p < 0.0001) and 32% less, after ONOsns than CRsns (966 (1360–572) pmol × h/l, p < 0.0001). In both Toronto and Winnipeg, subjective hunger ratings were similar across the two treatments. Conclusions: Oats prepared by soaking overnight in skimmed milk without and with inclusions retain their relatively low glycaemic and insulinaemic impact.

Pavadhgu, P., Bumrungpert, A., Harjani, Y., & Kurilich, A. (2019). Oat porridge consumption alleviates markers of inflammation and oxidative stress in hypercholesterolemic adults. Asia Pacific Journal of Clinical Nutrition, 28(2), 260-265. doi:10.6133/apjcn.201906_28(2).0008

Abstract:

Background and Objectives: Oats contain antioxidant phytochemicals that may help reduce inflammation as well as oxidative stress. In this study we aimed to investigate the effect of oat porridge consumption on inflammatory marker levels and oxidative stress in Thai adults with high blood lipid levels. Methods and Study Design: A randomized crossover study was conducted. Hypercholesterolemic adults were randomly assigned to a 4-week daily consumption of oat or rice porridge. After 4 weeks, they were switched to alternate intervention arms for 4 weeks. At baseline, before and after each intervention period, inflammatory markers including hsCRP, IL-6, IL-8, TNF-α, and MCP-1 and antioxidant status markers including ORAC, FRAP, and MDA of all subjects were measured. Results: Compared to baseline, levels of hsCRP, IL-6, IL-8, and TNF-α were significantly decreased after oat porridge consumption (mean change: -0.6&#177;0.9 mg/L, -26.9&#177;27.6 pg/mL, -56.3&#177;27.6 pg/mL, and - 9.7&#177;11.6 pg/mL, p＜0.05 for all, respectively). In addition, consumption of oat porridge also increased antioxidant capacity; ORAC and FRAP levels (mean change: 2.7&#177;1.0 μmol of Trolox/L and 2.4&#177;0.8 μmol of Fe^(2+)/L, p＜0.001, respectively). However, MCP-1 and MDA levels were not affected. Consumption of rice porridge did not lead to significant changes in these measures. Conclusions: Daily consumption of 70 grams oat porridge containing 3 grams β-glucan for 4 weeks may help reduce markers of inflammation and oxidation in hypercholesterolemic adults. Therefore, oat may be an appropriate dietary recommendation for individuals with hypercholesterolemia.

Van Den Abbeele, P., Kamil, A., Fleige, L., Chung, Y., . . . Marzorati, M. (2018). Different oat ingredients stimulate specific microbial metabolites in the gut microbiome of three human individuals in vitro. ACS Omega, 3(10), 12446-12456. doi:10.1021/acsomega.8b01360

Abstract:

We used a standardized in vitro simulation of the intestinal environment of three human donors to investigate the effect of six oat ingredients, which were produced by the application of different processing techniques, on the gut microbial community. Fructooligosaccharide was used as the positive control. Consistent changes in pH and gas production, on average −0.4 pH units and +32 kPa, indicated the high fermentability of the oat ingredients, and the resulting increased production of metabolites that are considered as beneficial for human health. These metabolites included acetate and lactate, but mostly propionate (+13.6 mM on average). All oat ingredients resulted in increased bifidobacteria levels with an average increase of 0.73 log. Moreover, a decreased production of proteolytic markers was observed, including branched short-chain fatty acids and ammonium. The results were donor-specific and product-specific. The results suggested an association between the total amounts of dietary fiber and the prebiotic potentials of different ingredients. Furthermore, as mechanical processing of oat products has previously been linked to increased extractability of dietary fibers, the obtained results suggest that different processing techniques might have impacted the potential functional properties of the final ingredients.

Rebello, C. J., Johnson, W. D., Martin, C., Johnson, J., . . . Greenway, F. L. (2018). Effect of two oat-based cereal on subjective ratings of appetite. Current Topics in Nutraceutical Research, 16, 113-120.

Abstract

Viscosity generated by oat β-glucan induces gastrointestinal mechanisms that influence appetite. Two oat-based ready-to-eat cereals (RTEC) with similar amounts of β-glucan but differing in their protein and sugar content were compared for their effects on appetite. Forty-seven healthy individuals, ≥18 years old, enrolled in a crossover trial consumed RTEC1 or RTEC2 in random order at least a week apart. Breakfasts contained 250kcals cereal and 105kcals fat-free milk. Subjective ratings of appetite were completed at baseline, and at 30, 60, 120, 180 and 240 minutes after consumption of the breakfast meals. Responses were analyzed as area under the curve (AUC) and per time-point. Significance was set at α=0.05. Fullness (p=0.01) and stomach fullness (p=0.02) were greater with RTEC 1 compared to RTEC 2 at 240 minutes. Stomach fullness (p=0.01) was greater at 30 minutes, and desire to eat (p=0.04) was reduced at 120 minutes with RTEC2 compared to RTEC1. There was no difference in the AUC for hunger, fullness, stomach fullness, desire to eat, or prospective intake. Ready-to-eat cereals containing similar amounts of oat β-glucan differed in the timing of significant differences in fullness or desire to eat, but appetite ratings over a four hour period did not differ.

Marriott, B. P., Hunt, K. J., Malek, A. M., St. Peter, J. V., & Greenberg, D. (2018). Low-calorie sweeteners: Exploring underutilized database resources to understand dietary patterns and obesity. Obesity, 26, S5-S8. doi:10.1002/oby.22261

Abstract

The use and impact of low-calorie sweeteners (LCS) in relation to the national challenges of overweight and obesity are complex and controversial. Most research on LCS have focused on the prevalence of consumption of LCS in beverages. The 2015 Dietary Guidelines Advisory Committee emphasized dietary patterns and health rather than a focus on specific nutrients or foods. The committee took this approach to shift the national emphasis onto the context of total rather than individual nutrient consumption. A broader research paradigm is needed to elucidate the actual exposure to LCS and how they are consumed within dietary patterns in the US population. National-level databases exist that can be used to broaden scientific understanding of the effects of LCS and health outcomes. These databases are underutilized, and they provide potential tools for grasping a fuller picture of LCS in the US diet.

Musa-Veloso, K., Poon, T., Harkness, L. S., O'Shea, M., & Chu, Y. (2018). The effects of whole-grain compared with refined wheat, rice, and rye on the postprandial blood glucose response: A systematic review and meta-analysis of randomized controlled trials. American Journal of Clinical Nutrition, 108(4), 759-774. doi:10.1093/ajcn/nqy112

Abstract:

Background: Whole grains are often referred to collectively, despite differences in their composition, physical structure, processing, and potential health benefits. Objective: The aim of this study was to compare the postprandial blood glucose response of whole-grain with refined wheat, rice, or rye, while controlling for the food delivery matrix and the processing of the grain (e.g., grinding, germination). Design: Eleven electronic databases were systematically searched to identify studies published up to and including November 2017. Randomized controlled trials comparing the effects of whole-grain wheat, rice, or rye with those of each grain's refined counterpart on postprandial blood glucose area under the curve (AUC) were included. Pooled effect sizes were computed by using the difference in the blood glucose AUC after the consumption of the whole compared with the refined grain. Results: Twenty publications were included, with 10, 14, and 5 strata (or active-control comparisons) on whole-grain wheat, rice, and rye, respectively. The consumption of ground (wholemeal) wheat, compared with white wheat, was not associated with a significant reduction in blood glucose AUC (−6.7 mmol/L ⋅ min; 95% CI: −25.1, 11.7 mmol/L ⋅ min; P = 0.477). The consumption of wholemeal rye, compared with endosperm rye, was not associated with a significant reduction in blood glucose AUC (−5.5 mmol/L ⋅ min; 95% CI: −24.8, 13.8 mmol/L ⋅ min; P = 0.576). The consumption of intact (whole-grain) rice, compared with white rice, was associated with a significant reduction in blood glucose AUC (−40.5 mmol/L ⋅ min; 95% CI: −59.6, −21.3 mmol/L ⋅ min; P < 0.001). Conclusions: Compared with white rice, whole-grain rice significantly attenuates the postprandial blood glucose response. In most of the studies on wheat and rye, the postprandial blood glucose responses to foods formulated with wholemeal compared with refined flours were compared. Whether reductions in the blood glucose AUC can be achieved with whole-grain (as opposed to wholemeal) wheat and rye requires further investigation.

AlHasawi, F. M., Fondaco, D., Corradini, M. G., Ludescher, R. D., . . . Rogers, M. A. (2018). Gastric viscosity and sugar bioaccessibility of instant and steel cut oat/milk protein blends. Food Hydrocolloids, 82, 424-433. doi:10.1016/j.foodhyd.2018.04.014

Abstract

Milk protein concentrate (MPC; 0 g, 5 g, and 10 g) was added to two commercially available oat products (instant oats and steel cut oats) to examine how MPC addition, and consequent changes in meal formulation, manipulates both gastric lumen viscosity and intestinal carbohydrate-digestion kinetics, in vitro. We used the TNO Intestinal Model-1 (TIM-1) to simulate gastrointestinal digestion of the oats-based meals. Meals containing 5 g or 10 g MPC yielded significantly less total bioaccessible sugar compared with those containing 0 g MPC, while the rate of starch digestion was significantly higher in meals containing 5 g or 10 g MPC. The TIM-1 was coupled with fluorescence spectroscopy and a luminescent molecular rotor to report changes in gastric viscosity in situ, showing that the gastric viscosity was higher in the meals containing MPC. Those findings suggest that MPC in oats-based meals significantly modifies the kinetics of carbohydrate digestion and increases gastric viscosity.

Wolever, T. M. S., Jenkins, A. L., Prudence, K., Johnson, J., . . . Steinert, R. E. (2018). Effect of adding oat bran to instant oatmeal on glycaemic response in humans - A study to establish the minimum effective dose of oat β-glucan. Food and Function, 9(3), 1692-1700. doi:10.1039/c7fo01768e

Abstract:

Reducing the glycaemic response to carbohydrate-containing foods may have desirable physiological effects for many people. Here, we aimed to determine the minimum amount of oat β-glucan from oat-bran which, when added to instant-oatmeal, would reduce the glycaemic response by 20% compared to a β-glucan-free cereal. Therefore, the glycaemic responses elicited by one serving (27 g) instant-oatmeal plus 247 g 2% milk (IO, 28 g available-carbohydrate, 1.2 g β-glucan) or IO plus 0.2, 0.4, 0.8 or 1.6 g oat β-glucan (OBG) from oat-bran, or an available-carbohydrate matched portion of cream of rice (CR) plus milk were measured over 2 h in n = 40 subjects using a randomized, cross-over design. The primary endpoint was incremental area under the curve (iAUC). The secondary endpoint was glucose peak-rise. The results showed that grams OBG consumed were significantly correlated with mean iAUC (p = 0.009) and with mean glucose peak-rise (p = 0.002). Each gram of OBG reduced iAUC by 7% and peak-rise by 15%. Thus, to achieve a ≥20% reduction in iAUC relative to CR, 1.6 g OBG had to be added to IO (74 ± 7 vs. 93 ± 6 mmol min L−1, p < 0.05), but, to achieve a 20% reduction in peak-rise, only 0.4 g OBG was required (2.00 ± 0.1 vs. 2.40 ± 0.1 mmol, p < 0.05). We conclude that adding OBG to IO flattened postprandial glycaemic responses in a dose-dependent fashion; 1.6 g OBG was required to reduce iAUC by ≥20% versus CR, but a 20% reduction in peak-rise required only 0.4 g. The greater effect of OGB on peak-rise than iAUC presumably reflects the way viscous dietary fibres modulate glucose absorption kinetics.

Pasman, W. J., Hendriks, H. F. J., Minekus, M. M., de Ligt, R. A. F., . . . Bellmann, S. (2018). Subjective feelings of appetite of wholegrain breakfasts evaluated under controlled, laboratory and ‘at home’ conditions. Physiology and Behavior, 194, 285-291. doi:10.1016/j.physbeh.2018.06.024

Abstract

Background: Appetite regulating properties of foods are usually investigated under laboratory conditions, whereas in real life, foods are consumed under at home conditions. The objective of this study was to compare the acute effects of breakfasts when tested in a laboratory condition and in an at home condition. Appetite regulating properties of two bread breakfasts and two cereal breakfasts were also compared. Subjects and methods: In this randomized cross-over trial balanced for laboratory and at home test conditions, thirty-two women consumed five breakfasts, i.e. two bread breakfasts, two cereal breakfasts and one fried-egg breakfast. Visual analogue scales for measuring appetite were captured via an on-line scoring system and were analyzed as incremental area under the curve, as satiation phase and as satiety phase. Results: Location effects were limited to two small effects only. An overall location effect in hunger feelings was observed (p = 0.040), which occurred specifically during the short satiation period (p = 0.0002) where hunger feelings scored higher under laboratory conditions. Similarly, a location effect was observed for desire to eat (p = 0.001); this was again higher under laboratory conditions. No other location effects were observed. Bread breakfasts did not differ in their appetite regulating properties. The Steel Cut oatmeal breakfast was reported to be more satiating (p = 0.001) as compared to the ready-to-eat cereal. Conclusions: Whereas the five breakfasts varied somewhat in their appetite regulating properties, evaluation under laboratory conditions overall did not result in different appetite scores compared to the at home conditions. This suggests that at home testing may be a useful alternative to laboratory test conditions for nutrition research.