健康与营养科学团队出版物

Xie, Z., Mui, T., Sintara, M., Ou, B., . . . Chen, Y. (2017). Rapid quantitation of avenanthramides in oat-containing products by high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (HPLC-TQMS). Food Chemistry, 224, 280-288. doi:10.1016/j.foodchem.2016.12.079

Abstract:

Avenanthramides (AVNs) are a family of nitrogen-containing phenolic compounds produced in oat; AVN 2c, 2p, and 2f are the three major members. An LC-MS/MS method was developed, with the limit of detection (LOD) and the limit of quantitation (LOQ) being, respectively, 0.29 ng/mL and 1.96 ng/mL for AVN 2c, 0.24 ng/mL and 0.60 ng/mL for AVE 2p, and 0.42 ng/mL and 2.2 ng/mL for AVN 2f. The method was validated in oat-containing hot cereal and snack bar samples. The recovery of AVN 2c, 2p, and 2f from these two oat products was 95–113%, and the relative standard deviations ranged from 5% to 9%. This method was used to evaluate oat products and raw oat samples. The effects of location and variety on AVN composition were investigated. The method presented here provides a novel and rapid tool to quantitate the abundance of AVN 2c, 2p, and 2f in oat-containing products.

Harjani, Y., Tee, E. S., & Garcia, J. (2016). Proceedings of the NSM update series: Sugar substitutes-understanding the basics, global regulatory approvals, safety assessment protocols and benefits. Malaysian Journal of Nutrition, 22(1), 91-102.

Abstract:

A seminar titled "Sugar Substitutes: Understanding the Basics, Global Regulatory Approvals, Safety Assessment Protocols and Benefits" organised by the Nutrition Society of Malaysia was held on 15th Apri12015 for nutritionists and other health care professionals, to review and discuss the latest evidence on safety and efficacy of sugar substitutes. Highlights from lectures by local and international speakers about this topical subject are presented in this report. Sugar substitutes have been extensively evaluated for decades and regulatory agencies world-wide continue to review and confirm their safety. Furthermore, the effects of sugar substitutes on human health continue to be the subject of research studies. Many studies have shown that replacement of sugar with sugar substitutes may help in weight management, glucose control for people with diabetes, and in the prevention of tooth decay. It is important for health professionals to discern whether the available evidence is based on good science and adequate protocols in order to guide consumers with the responsible use of sugar substitutes following national and international dietary guidelines. The use of sugar substitutes for certain health outcomes was discussed, specifically in regard to appetite, energy balance, body weight and other cardio-metabolic risk factors. Overall, the seminar provided an understanding of the different types of commercially available sugar substitutes, their use in a range of food and beverages, and calorie contribution to the diet. The seminar also covered the approvals of different sugar substitutes and the protocols for assessing the safety of these sugar substitutes, especially in the case of children and pregnant women.

Rebello, C. J., Johnson, W. D., Martin, C. K., Han, H., . . . Greenway, F. L. (2016). Instant oatmeal increases satiety and reduces energy intake compared to a ready-to-eat oat-based breakfast cereal: A randomized crossover trial. Journal of the American College of Nutrition, 35(1), 41-49. doi:10.1080/07315724.2015.1032442

Abstract:

Background: Foods that enhance satiety can help consumers to resist environmental cues to eat and help adherence to calorie restriction. The objective of this study was to compare the effect of 2 oat-based breakfast cereals on appetite, satiety, and food intake. Methods: Forty-eight healthy individuals, 18 years of age or older, were enrolled in a randomized, crossover trial. Subjects consumed isocaloric servings of either oatmeal or an oat-based ready-to-eat breakfast cereal (RTEC) in random order at least a week apart. Visual analogue scales measuring appetite and satiety were completed before breakfast and throughout the morning. Lunch was served 4 hours after breakfast. The physicochemical properties of oat soluble fiber (β-glucan) were determined. Appetite and satiety responses were analyzed by area under the curve. Food intake and β-glucan properties were analyzed using t tests. Results: Oatmeal increased fullness (p = 0.001) and reduced hunger (p = 0.005), desire to eat (p = 0.001), and prospective intake (p = 0.006) more than the RTEC. Energy intake at lunch was lower after eating oatmeal compared to the RTEC (p = 0.012). Oatmeal had higher viscosity (p = 0.03), β-glucan content, molecular weight (p < 0.001), and radius of gyration (p < 0.001) than the RTEC. Conclusions: Oatmeal suppresses appetite, increases satiety, and reduces energy intake compared to the RTEC. The physicochemical properties of β-glucan and sufficient hydration of oats are important factors affecting satiety and subsequent energy intake.

Korczak, R., Marquart, L., Slavin, J. L., Ringling, K., . . . Unnevehr, L. (2016). Thinking critically about whole-grain definitions: Summary report of an interdisciplinary roundtable discussion at the 2015 Whole Grains Summit. American Journal of Clinical Nutrition, 104(6), 1508-1514. doi:10.3945/ajcn.115.126672

Abstract:

Definitions for whole grain (WG) have been published by governments, the food industry, and grain organizations and generally fall into 2 categories: WG and WG food. WG definitions focus on the principal components of the WGs and their proportions, whereas WG-food definitions describe the quantity of WGs present in food. In the United States, widespread agreement exists on the main parts of a definition for a WG, with a definition for a WG food still in its early stages; a standard definition that has been universally accepted does not exist. Furthermore, nutrition policy advises consumers to eat WGs for at least one-half of their total grain intake (2010 and 2015 Dietary Guidelines for Americans), but confusion exists over which foods are considered WGs and how much is needed to achieve health benefits. In December 2014, a workshop sponsored by the subcommittee on collaborative process of the US Government’s Interagency Committee on Human Nutrition Research convened in Washington, DC, and recognized WG definitions as a key nutrition and public health–related issue that could benefit from further collaboration. As a follow-up to that meeting, an interdisciplinary roundtable meeting was organized at the Whole Grains Summit on 25 June 2015 in Portland, Oregon, to help resolve the issue. This article summarizes the main opportunities and challenges that were identified during the meeting for defining WGs and WG foods internationally. Definitions of WGs and WG foods that are uniformly adopted by research, food industry, consumer, and public health communities are needed to enable comparison of research results across populations.

Wang, X., Storsley J., Thandapilly S. J., Chu, Y. F., & Ames, N. (2016). Effect of processing, cultivar, and environment on the physicochemical properties of oat β-glucan. Cereal Chemistry, 93(4), 402-408. doi:10.1094/CCHEM-12-15-0245-R

Abstract:

Several food regulatory agencies around the world have approved health claims for oat-derived β-glucan for cholesterol lowering and glycemic control. The biological efficacy of β-glucan appears to depend both on daily intake and on physicochemical properties, such as molecular weight and viscosity. The objective of this study was to determine the effects of oat processing, genotype, and growing location on the physicochemical properties of β-glucan. Five oat genotypes (HiFi, Leggett, CDC Dancer, Marion, and CDC Morrison) grown in two locations (Saskatoon and Kernen) were dehulled (untreated) and processed in a pilot facility through kilning (kilned, not flaked) and subsequent steaming and flaking (kilned, flaked). Untreated groats gave a relatively low Rapid Visco Analyzer (RVA) apparent viscosity (164 cP) and a low extractable β-glucan molecular weight (332,440) but exhibited high β-glucan solubility (90.49%). Compared with untreated groats, the kilned (not flaked) samples had significantly increased RVA apparent viscosity (314 cP) and extractable β-glucan molecular weight (604,710). Additional processing into kilned and flaked products further increased RVA apparent viscosity (931 cP) and β-glucan molecular weight (1,221,760), but β-glucan solubility (63.83%) was significantly reduced. Genotype and growing environment also significantly affected β-glucan viscosity and molecular weight, but no significant interaction effects between processing, genotype, and environment were found. Results indicate that there is potential for processors to improve the physicochemical and nutritional properties of oat end products through processing of specific oat genotypes from selected growing locations.

Dong, H., Rendeiro, C., Kristek, A., Sargent, L. J., . . . Lovegrove, J. A. (2016). Addition of orange pomace to orange juice attenuates the increases in peak glucose and insulin concentrations after sequential meal ingestion in men with elevated cardiometabolic risk. The Journal of Nutrition, 146(6), 1197-1203. doi:10.3945/jn.115.226001

Abstract:

Background: Prospective cohort studies show that higher dietary fiber intake is associated with reduced cardiovascular disease risk, yet the impact on postprandial glucose and insulin responses is unclear. Objective: This study aims to evaluate the effects of orange beverages with differing fiber concentrations on postprandial glycemic responses (secondary outcome measure) after a sequential breakfast and lunch challenge in men with increased cardiometabolic risk. Methods: Thirty-six men (aged 30–65 y; body mass index 25–30 kg/m²: fasting triacylglycerol or total cholesterol concentrations: 0.8–2.2 or 6.0–8.0 mmol/L, respectively) were provided with a high-fat mixed breakfast and were randomly assigned to consume 240 mL Tropicana (PepsiCo, Inc.) pure premium orange juice without pulp (OJ), OJ with 5.5 g added orange pomace fiber (OPF), juice made from lightly blended whole orange, or an isocaloric sugar-matched control (Control) on 4 occasions separated by 2 wk. A medium-fat mixed lunch was provided at 330 min. Blood samples were collected before breakfast and on 11 subsequent occasions for 420 min (3 time points postlunch) to determine postprandial glucose, insulin, lipid, and inflammatory biomarker responses. Repeated-measures ANOVA was used for data analysis. Results: OPF significantly (P < 0.05) reduced the maximal change in glucose concentrations (1.9 ± 0.21 mmol/L) reached after breakfast compared with other treatments (2.3–2.4 mmol/L) and after lunch (3.0 ± 0.05 mmol/L) compared with OJ (3.6 ± 0.05 mmol/L). The maximal change in insulin concentration (313 ± 25 pmol/L) was also lower compared with Control (387 ± 30 pmol/L) and OJ (418 ± 39 pmol/L) after breakfast. OPF significantly delayed the time to reach the peak glucose concentration compared with Control and OJ, and of insulin compared with Control after breakfast. Conclusion: OPF consumed with breakfast may lower postprandial glycemic and insulinemic responses to typical meal ingestion in men with increased cardiometabolic risk.

Alharbi, M. H., Lamport, D. J., Dodd, G. F., Saunders, C., . . . Spencer, J. P. E. (2016). Flavonoid-rich orange juice is associated with acute improvements in cognitive function in healthy middle-aged males. European Journal of Nutrition, 55(6), 2021-2029. doi:10.1007/s00394-015-1016-9

Abstract:

Purpose Epidemiological evidence suggests that chronic consumption of fruit-based flavonoids is associated with cognitive benefits; however, the acute effects of flavonoid-rich (FR) drinks on cognitive function in the immediate postprandial period require examination. The objective was to investigate whether consumption of FR orange juice is associated with acute cognitive benefits over 6 h in healthy middle-aged adults. Methods Males aged 30–65 consumed a 240-ml FR orange juice (272 mg) and a calorie-matched placebo in a randomized, double-blind, counterbalanced order on 2 days separated by a 2-week washout. Cognitive function and subjective mood were assessed at baseline (prior to drink consumption) and 2 and 6 h post consumption. The cognitive battery included eight individual cognitive tests. A standardized breakfast was consumed prior to the baseline measures, and a standardized lunch was consumed 3 h post-drink consumption. Results Change from baseline analysis revealed that performance on tests of executive function and psychomotor speed was significantly better following the FR drink compared to the placebo. The effects of objective cognitive function were supported by significant benefits for subjective alertness following the FR drink relative to the placebo. Conclusions These data demonstrate that consumption of FR orange juice can acutely enhance objective and subjective cognition over the course of 6 h in healthy middle-aged adults.

Lamport, D. J., Pal, D., Macready, A. L., Barbosa-Boucas, S., . . . Butler, L. T. (2016). The effects of flavanone-rich citrus juice on cognitive function and cerebral blood flow: An acute, randomised, placebo-controlled cross-over trial in healthy, young adults. British Journal of Nutrition, 116(12), 2160-2168. doi:10.1017/S000711451600430X

Abstract:

A plausible mechanism underlying flavonoid-associated cognitive effects is increased cerebral blood flow (CBF). However, behavioural and CBF effects following flavanone-rich juice consumption have not been explored. The aim of this study was to investigate whether consumption of flavanone-rich juice is associated with acute cognitive benefits and increased regional CBF in healthy, young adults. An acute, single-blind, randomised, cross-over design was applied with two 500-ml drink conditions – high-flavanone (HF; 70·5 mg) drink and an energy-, and vitamin C- matched, zero-flavanone control. A total of twenty-four healthy young adults aged 18–30 years underwent cognitive testing at baseline and 2-h after drink consumption. A further sixteen, healthy, young adults were recruited for functional MRI assessment, whereby CBF was measured with arterial spin labelling during conscious resting state at baseline as well as 2 and 5 h after drink consumption. The HF drink was associated with significantly increased regional perfusion in the inferior and middle right frontal gyrus at 2 h relative to baseline and the control drink. In addition, the HF drink was associated with significantly improved performance on the Digit Symbol Substitution Test at 2 h relative to baseline and the control drink, but no effects were observed on any other behavioural cognitive tests. These results demonstrate that consumption of flavanone-rich citrus juice in quantities commonly consumed can acutely enhance blood flow to the brain in healthy, young adults. However, further studies are required to establish a direct causal link between increased CBF and enhanced behavioural outcomes following citrus juice ingestion.

Rendeiro, C., Dong, H., Saunders, C., Harkness, L., . . . Spencer, J. P. E. (2016). Flavanone-rich citrus beverages counteract the transient decline in postprandial endothelial function in humans: A randomised, controlled, double-masked, cross-over intervention study. British Journal of Nutrition, 116(12), 1999-2010. doi:10.1017/S0007114516004219

Abstract:

Specific flavonoid-rich foods/beverages are reported to exert positive effects on vascular function; however, data relating to effects in the postprandial state are limited. The present study investigated the postprandial, time-dependent (0–7 h) impact of citrus flavanone intake on vascular function. An acute, randomised, controlled, double-masked, cross-over intervention study was conducted by including middle-aged healthy men (30–65 years, n 28) to assess the impact of flavanone intake (orange juice: 128·9 mg; flavanone-rich orange juice: 272·1 mg; homogenised whole orange: 452·8 mg; isoenergetic control: 0 mg flavanones) on postprandial (double meal delivering a total of 81 g of fat) endothelial function. Endothelial function was assessed by flow-mediated dilatation (FMD) of the brachial artery at 0, 2, 5 and 7 h. Plasma levels of naringenin/hesperetin metabolites (sulphates and glucuronides) and nitric oxide species were also measured. All flavanone interventions were effective at attenuating transient impairments in FMD induced by the double meal (7 h post intake; P<0·05), but no dose–response effects were observed. The effects on FMD coincided with the peak of naringenin/hesperetin metabolites in circulation (7 h) and sustained levels of plasma nitrite. In summary, citrus flavanones are effective at counteracting the negative impact of a sequential double meal on human vascular function, potentially through the actions of flavanone metabolites on nitric oxide.

Murphy, M. M., Barraj, L. M., Toth, L. D., Harkness, L. S., & Bolster, D. R. (2016). Daily intake of dairy products in Brazil and contributions to nutrient intakes: A cross-sectional study. Public Health Nutrition, 19(3), 393-400. doi:10.1017/S1368980015001780

Abstract:

Objective Dairy products are sources of protein and micronutrients important in a healthy diet. The purpose of the present analysis was to estimate consumption of dairy products by Brazilians and identify contributions of dairy products to nutrient intakes. Design Dairy consumption data were obtained from 24 h dietary records. Dairy products were defined as milk (including flavoured), cheese and yoghurt. Estimates of dairy product intakes were generated for all individuals, individuals in urban and rural households and for age groups 10–18 years, 19–59 years and ≥60 years. Contributions to nutrient intakes were estimated for the total sample and sub-populations. Setting Nationwide cross-sectional survey, 2008–2009. Subjects Nationally representative sample of individuals aged ≥10 years in the Individual Food Intake survey, a component of the Brazilian Household Budget Survey (n 34 003). Results Among individuals aged ≥10 years, per capita intake of dairy products was 142 (SE 2·1) g/d. Dairy product intake was higher among individuals in urban compared with rural areas and among groups 10–18 years and ≥60 years compared with adults aged 19–59 years. Dairy products accounted for 6·1 % of daily energy intake, 7·3 % of protein, 16·9 % of saturated fat, 11·1 % and 4·3 % of total and added sugars, respectively, and 10·2–37·9 % of daily Ca, vitamin D, P, vitamin A and K. Conclusions Dairy products were substantial contributors to daily intakes of selected nutrients of concern in Brazil, although mean daily dairy product consumption was less than a typical portion. Education efforts in Brazil to raise awareness about the nutritional role of dairy foods may serve to improve overall diet quality.

Musa-Veloso, K., Fallah, S., O’Shea, M., & Chu, Y. F. (2016). Assessment of intakes and patterns of cooked oatmeal consumption in the U.S. using data from the National Health and Nutrition Examination Surveys. Nutrients, 8(8), 503. doi:10.3390/nu8080503

Abstract:

The objective of the present study was to characterize the consumption of cooked oatmeal in the United States (U.S.) and to determine whether oatmeal consumption is associated with body mass index (BMI). To estimate current intakes of cooked oatmeal in the various age and gender population groups, we used dietary intake data from Day 1 of the U.S. 2009–2010 and 2011–2012 National Health and Nutrition Examination Surveys (NHANES). We also used dietary intake data from Day 1 of the U.S. 2003–2012 NHANES to assess associations between intakes of cooked oatmeal (in g/kg body weight) and NHANES cycle (2003–2004, 2005–2006, 2007–2008, 2009–2010, 2011–2012), age category (3–11 years, 12–18 years, 19–44 years, 45 years+), gender, and BMI classification (underweight, normal weight, overweight, or obese), using a multiple linear regression model. A consumer of oatmeal was defined as any individual who reported the consumption of any amount of oatmeal on Day 1 of the survey. Approximately 6% of the total population consumed oatmeal, with an average intake of 238 g/day of cooked oatmeal among consumers. The greatest prevalence of oatmeal consumption was in infants (14.3%) and older female adults (11.1%). Amongst oatmeal consumers, underweight, normal weight, and overweight individuals consumed significantly more oatmeal than obese individuals. Oatmeal was consumed almost exclusively at breakfast and, among consumers, contributed an average of 54.3% of the energy consumed at breakfast across all age groups examined. The association between oatmeal consumption and BMI is interesting and requires confirmation in future clinical studies. 

Dong, H., Sargent, L. J., Chatzidiakou, Y., Saunders, C., . . . Lovegrove, J. A. (2016). Orange pomace fibre increases a composite scoring of subjective ratings of hunger and fullness in healthy adults. Appetite, 107, 478-485. doi:10.1016/j.appet.2016.08.118

Abstract:

Dietary fibre has been shown to increase subjective satiating ratings. However data from human trials has produced mixed results, possibly due to different types of fibre which have diverse physicochemical properties and gastrointestinal transit behaviour. The aim of study 1 was to investigate whether orange juice (OJ) with 5.5 g of added orange pomace fibre (OPF) was as satiating as whole orange (WO, chopped and blended to a puree/liquid) compared with OJ. Study 2 was to evaluate the dose-dependent satiating effect of OPF delivered in an orange-flavoured beverage. Both studies were randomized, controlled, double blind, cross over in design with 4 intervention arms in study 1 including OJ, OPF, WO, and water, and 3 arms in study 2: orange-flavoured beverage with low (2.5 g) and high (5.5 g) dose of OPF (LD-OPF and HD-OPF), and orange-flavoured beverage without fibre (Control). Volunteers were asked to response to 8 questions relating to hunger, fullness, desire to eat, thirst and discomfort by visual analogue scale (VAS) for each question. Differences were detected in least squares mean estimates of composite satiety scores and each individual question with statistical modelling to adjust for differences in baseline scores. Addition of 5.5 g OPF either to OJ or to orange-flavoured beverage significantly increased the composite satiety scores compared with OJ (P < 0.0001) or Control (P < 0.0001), and the effect was comparative to WO. LD-OPF showed some satiating effect (less desire to eat) compared with Control (P = 0.038), though less effective than HD-OPF (P = 0.043). In conclusion, the addition of OPF to OJ was as effective at increasing satiety as WO consumption compared with OJ; and there was a trend of dose-dependent effect of OPF on satiety compared with the control.

Hamer, M., Dye, L., Siobhan Mitchell, E., Layé, S., . . . Sijben, J. (2016). Examining techniques for measuring the effects of nutrients on mental performance and mood state. European Journal of Nutrition, 55(6), 1991-2000. doi:10.1007/s00394-015-1143-3

Abstract:

Purpose Intake of specific nutrients has been linked to mental states and various indices of cognitive performance although the effects are often subtle and difficult to interpret. Measurement of so-called objective variables (e.g. reaction times) is often considered to be the gold standard for assessing outcomes in this field of research. It can, however, be argued that data on subjective experience (e.g. mood) are also important and may enrich existing objective data. The aim of this review is to evaluate methods for measuring mental performance and mood, considering the definition of subjective mood and the validity of measures of subjective experience. Methods A multi-stakeholder expert group was invited by ILSI Europe to come to a consensus around the utility of objective and subjective measurement in this field, which forms the basis of the paper. Therefore, the present review reflects a succinct overview of the science but is not intended to be a systematic review.  Results The proposed approach extends the traditional methodology using standard ‘objective’ measurements to also include the consumers’ subjective experiences in relation to food. Specific recommendations include 1) using contemporary methods to capture transient mood states; 2) using sufficiently sensitive measures to capture effects of nutritional intervention; 3) considering the possibility that subjective and objective responses will occur over different time frames; and 4) recognition of the importance of expectancy and placebo effects for subjective measures. Conclusions The consensus reached was that the most informative approach should involve collection and consideration of both objective and subjective data.

Koenig, R. T., Dickman, J. R., Kang, C. H., Zhang, T., . . . Ji, L. L. (2016). Avenanthramide supplementation attenuates eccentric exercise-inflicted blood inflammatory markers in women. European Journal of Applied Physiology, 116(1), 67-76. doi:10.1007/s00421-015-3244-3

Abstract:

Purpose Rigorous exercise is known to generate reactive oxygen species (ROS) and inflict inflammatory response. The present study investigated whether dietary supplementation of avenanthramides (AVA) in oats would increase antioxidant protection and reduce inflammation in humans after an acute bout of eccentric exercise. Methods Young women (age 18–30 years, N = 16) were randomly divided into two groups in a double-blinded fashion, receiving two cookies made of oat flour providing 9.2 mg AVA (AVA) or 0.4 mg AVA (Control, C) each day for 8 weeks. Before and after the dietary regimen each group of subjects ran downhill (DR) on a treadmill at −9 % grade for 1 h at a speed to elicit 75 % of maximal heart rate. Blood samples were collected at rest, immediately and 24 h post-DR. Results Before dietary supplementation plasma creatine kinase activity and tumor necrosis factor (TNF)-α concentration were increased immediately after DR (P < 0.05), whereas neutrophil respiratory burst (NRB) was elevated 24 h post-DR (P < 0.05). CK and TNF-α response to DR was abolished during post-supplementation tests in both AVA and C groups, whereas NRB was blunted only in AVA but not in C. Plasma interleukin-6 level and mononuclear cell nuclear factor (NF) κB activity were not affected by DR either before or after dietary supplementation, but were lowered 24 h post-DR in AVA versus C (P < 0.05). Both groups increased plasma total antioxidant activity following 8-week dietary regimen (P < 0.05), whereas only AVA group increased resting plasma glutathione (GSH) concentration (P < 0.05), decreased glutathione disulfide response to DR, and lowered erythrocyte GSH peroxidase activity (P < 0.05). Conclusions Our data of pre- and post-supplementation difference reflect an interaction between repeated measure effect of eccentric exercise and AVA in diet. Long-term AVA supplementation can attenuate blood inflammation markers, decrease ROS generation and NFkB activation, and increased antioxidant capacity during an eccentric exercise bout.

Wolever, T. M. S., Van Klinken, B. J., Bordenave, N., Kaczmarczyk, M., . . . Harkness, L. (2016). Reformulating cereal bars: High resistant starch reduces in vitro digestibility but not in vivo glucose or insulin response; whey protein reduces glucose but disproportionately increases insulin. American Journal of Clinical Nutrition, 104(4), 995-1003. doi:10.3945/ajcn.116.132431

Abstract:

Background: Resistant starch (RS) and whey protein are thought to be effective nutrients for reducing glycemic responses. Objective: We aimed to determine the effect of varying the sucrose, RS, and whey protein content of cereal bars on glucose and insulin responses. Design: Twelve healthy subjects [mean ± SD age: 36 ± 12 y; mean ± SD body mass index (in kg/m²): 24.9 ± 2.7] consumed 40 g available-carbohydrate (avCHO) portions of 5 whole-grain cereal bars that contained varying amounts of RS and whey protein concentrate [WPC; 70% protein; RS:WPC, %wt:wt: 15:0 (Bar15/0); 15:0, low in sucrose (Bar15/0LS); 15:5 (Bar15/5); 10:5 (Bar10/5); and 10:10 (Bar10/10)] and 2 portion sizes of a control bar low in whole grains, protein, and RS [control 1 contained 40 g avCHO (Control1); control 2 contained total carbohydrate equal to Bar15/0LS (Control2)] on separate days by using a randomized crossover design. Glucose and insulin responses in vivo and carbohydrate digestibility in vitro were measured over 3 h. Results: Incremental area under the curve (iAUC) over 0–3 h for glucose (min × mmol/L) differed significantly between treatments (P < 0.001) [Bar15/0LS (mean ± SEM), 169 ± 14; Control2, 164 ± 20; Bar15/0, 144 ± 15; Control1, 140 ± 17; Bar10/5, 117 ± 12; Bar15/5, 116 ± 9; and Bar10/10, 100 ± 9; Tukey’s least significant difference = 42, P < 0.05], but insulin iAUC did not differ significantly. Higher protein content was associated with a lower glucose iAUC (P = 0.028) and a higher insulin-to-glucose iAUC ratio (P = 0.002) All 5 RS-containing bars were digested in vitro ∼30% more slowly than the control bars (P < 0.05); however, in vivo responses were not related to digestibility in vitro. Glucose and insulin responses elicited by high-RS, whey protein–free bars were similar to those elicited from control bars. Conclusions: The inclusion of RS in cereal bar formulations did not reduce glycemic responses despite slower starch digestion in vitro. Thus, caution is required when extrapolating in vitro starch digestibility to in vivo glycemic response. The inclusion of whey protein in cereal bar formulations to reduce glycemic response requires caution because this may be associated with a disproportionate increase in insulin as judged by an increased insulin-to-glucose iAUC ratio. 

Wolever, T. M. S., van Klinken, B. J., Spruill, S. E., Jenkins, A. L., . . . Harkness, L. (2016). Effect of serving size and addition of sugar on the glycemic response elicited by oatmeal: A randomized, cross-over study. Clinical Nutrition ESPEN, 16, 48-54. doi:10.1016/j.clnesp.2016.07.003

Abstract:

Background & aims We aimed to determine the impact of serving size and addition of sucrose on the glycemic response elicited by oatmeal. Methods We studied 38 healthy subjects (mean ± SD age 40 ± 12 yr, BMI 26.4 ± 3.6 kg/m²) on 8 separate days using a randomized, cross-over design. Capillary blood-glucose responses over 2hr after consuming 30, 40 and 60 g Classic Quaker Quick Oats (18, 24 and 36 g available-carbohydrate [avCHO], respectively) and 30 g Oats plus 9 g sucrose (27 g avCHO) were compared with those after avCHO-matched servings of Cream of Rice cereal (Control) (22, 29, 44 and 33 g cereal, respectively). Blood-glucose incremental area under the curve (iAUC), peak-rise, rate-of-decline, time-to-peak and time-to-baseline were calculated. Results As serving size increased, iAUC, peak-rise, rate-of-decline and time-to-baseline increased significantly for both cereals, but the rate of increase was significantly greater for Control than for Oats. Time-to-peak increased significantly with serving size only for Oats. Compared to avCHO-matched servings of Control, mean (95%CI) iAUC, peak-rise and rate-of-decline, respectively were 22 (16, 27)%, 22 (19, 26)% and 23 (18, 27)% lower after consuming Oats without sucrose and 26 (18, 34)%, 14 (9, 20)% and 16 (9, 24)% lower after consuming Oats plus sucrose. Conclusions Oatmeal elicited a significantly lower glycemic response than avCHO-matched servings of Cream of Rice, even when sucrose was added to the oatmeal. Measures of glycemic response tended to increase with increased serving size; although the pattern of change varied between cereal types. These results suggest that oatmeal may be a good choice for minimizing postprandial glycemia.

Tosh, S. M., & Chu, Y. (2015). Systematic review of the effect of processing of whole-grain oat cereals on glycaemic response. British Journal of Nutrition, 114(8), 1256-1262. doi:10.1017/S0007114515002895

Abstract:

Whole-grain oats have been identified as a type of food that blunts blood glucose increase after a meal. However, processing of oats changes the physical characteristics of the grain, which may influence human glycaemic response. Therefore, the effect of different processes on acute postprandial glycaemic response, quantified using glycaemic index (GI) measurements, was investigated in a systematic review. A review of the literature identified twenty publications containing fifty-six individual tests. An additional seventeen unpublished tests were found in an online database. Of the seventy-two measurements included in the review, two were for steel-cut oats, eleven for large-flake oats, seven for quick-cooking (small flake) oats, nine for instant oatmeal and twenty-eight for muesli or granola. One granola measurement was identified as an outlier and was removed from the statistical analysis. In all, fifteen clinical tests were reported for rolled oat porridge that did not specify the type of oats used, and thus the effect of processing could not be assessed. Steel-cut oats (GI=55 (SE 2·5)), large-flake oats (GI=53 (SE 2·0)) and muesli and granola (GI=56 (SE 1·7)) elicited low to medium glycaemic response. Quick-cooking oats and instant oatmeal produced significantly higher glycaemic response (GI=71 (SE 2·7) and 75 (SE 2·8), respectively) than did muesli and granola or large-flake oatmeal porridge. The analysis establishes that differences in processing protocols and cooking practices modify the glycaemic response to foods made with whole-grain oats. Smaller particle size and increased starch gelatinisation appear to increase the glycaemic response.

Gao, C., Gao, Z., Greenway, F. L., Burton, J. H., . . . Zheng, J. (2015). Oat consumption reduced intestinal fat deposition and improved health span in Caenorhabditis elegans model. Nutrition Research, 35(9), 834-843. doi:10.1016/j.nutres.2015.06.007

Abstract:

In addition to their fermentable dietary fiber and the soluble β-glucan fiber, oats have unique avenanthramides that have anti-inflammatory and antioxidant properties that reduce coronary heart disease in human clinical trials. We hypothesized that oat consumption will increase insulin sensitivity, reduce body fat, and improve health span in Caenorhabditis elegans through a mechanism involving the daf-2 gene, which codes for the insulin/insulin-like growth factor-1–like receptor, and that hyperglycemia will attenuate these changes. Caenorhabditis elegans wild type (N2) and the null strains sir-2.1, daf-16, and daf-16/daf-2 were fed Escherichia coli (OP50) and oat flakes (0.5%, 1.0%, or 3%) with and without 2% glucose. Oat feeding decreased intestinal fat deposition in N2, daf-16, or daf-16/daf-2 strains (P < .05); and glucose did not affect intestinal fat deposition response. The N2, daf-16, or sir-2.1 mutant increased the pharyngeal pumping rate (P < .05), a surrogate marker of life span, following oat consumption. Oat consumption increased ckr-1, gcy-8, cpt-1, and cpt-2 mRNA expression in both the N2 and the sir-2.1 mutant, with significantly higher expression in sir-2.1 than in N2 (P < .01). Additional glucose further increased expression 1.5-fold of the 4 genes in N2 (P < .01), decreased the expression of all except cpt-1 in the daf-16 mutant, and reduced mRNA expression of the 4 genes in the daf-16/daf-2 mutant (P < .01). These data suggest that oat consumption reduced fat storage and increased ckr-1, gcy-8, cpt-1, or cpt-2 through the sir-2.1 genetic pathway. Oat consumption may be a beneficial dietary intervention for reducing fat accumulation, augmenting health span, and improving hyperglycemia-impaired lipid metabolism.

Fulgoni, V. L., Chu, Y., O'Shea, M., Slavin, J. L., & DiRienzo, M. A. (2015). Oatmeal consumption is associated with better diet quality and lower body mass index in adults: The National Health and Nutrition Examination Survey (NHANES), 2001-2010. Nutrition Research, 35(12), 1052-1059. doi:10.1016/j.nutres.2015.09.015

Abstract:

Data from the 2001-2010 National Health and Nutrition Examination Survey were analyzed to assess the relationship between oatmeal consumption and nutrient intake, diet quality, and physiological measures in adults 19 years and older (n = 22,823). We hypothesized that oatmeal consumption is associated with a more favorable nutrient intake profile, better diet quality, and healthier physiological end points. Oatmeal consumers (n = 1429) were defined as those who had consumed any amount of cooked oatmeal cereal during a 24-hour recall period. Multiple regression analysis, after transforming variables to normality and using appropriate sample weights to ensure national representation, was used to assess differences between oatmeal consumers and nonconsumers in terms of demographics, and covariate-adjusted analysis of variance was used to assess differences between consumers and nonconsumers in nutrient intakes, diet quality (calculated using the Healthy Eating Index-2010), and physiological measures. Our results show that oatmeal consumers were older than nonconsumers and more likely to be female; they also were less likely to smoke and consumed less alcohol. Consumers had higher intakes of protein, dietary fiber, vitamin A, thiamin, calcium, phosphorus, magnesium, iron, copper, selenium, and potassium and lower intakes of total, monounsaturated, and saturated fats; cholesterol; and vitamin B₁₂. Oatmeal consumers had higher Healthy Eating Index-2010 scores and lower body weights, waist circumferences, and body mass indices. To conclude, our results suggest that consuming oatmeal is consistent with better nutrient intakes and a higher diet quality.

Fu, J., Zhu, Y., Yerke, A., Wise, M. L., . . . Sang, S. (2015). Oat avenanthramides induce heme oxygenase-1 expression via Nrf2-mediated signaling in HK-2 cells. Molecular Nutrition and Food Research, 59(12), 2471-2479. doi:10.1002/mnfr.201500250

Abstract:

Scope Numerous studies have shown that avenanthramides (AVAs), unique compounds found in oats, are strong antioxidants, though the mechanism of action remains unclear. Here, we investigated whether AVAs affect heme oxygenase-1 (HO-1) expression through the activation of Nrf2 translocation. Methods and results We investigated the effects AVA 2c, 2f, and 2p on HK-2 cells, and found that AVAs could significantly increase HO-1 expression in both a dose- and time-dependent manner. Furthermore, we found that AVA-induced HO-1 expression is mediated by Nrf2 translocation. The addition of N-acetylcysteine (NAC), but not specific inhibitors of p38 (SB202190), PI3K (LY294002), and MEK1 (PD098059) attenuated AVA-induced HO-1 expression, demonstrating an important role for reactive oxygen species, but not PI3K or MAPK activation, in activating the HO-1 pathway. Moreover, hydrogenation of the double bond of the functional α,β-unsaturated carbonyl group of AVAs eliminated their effects on HO-1 expression, suggesting that this group is crucial for the antioxidant activity of AVAs. Conclusion Our results suggest a novel mechanism whereby AVAs exert an antioxidant function on human health. Further investigation of these markers in human is warranted to explore the beneficial health effects of whole grain oat intake.