The effect of extracted and isolated fibers on appetite and energy intake: A comprehensive review of human intervention studies.

In light of the increasing prevalence of obesity and cardiometabolic diseases, the underconsumption of fiber is concerning due to its various associated health benefits such as weight management. Adding extracted or isolated dietary fibers into various consumer products is a practical strategy for addressing the fiber gap. This comprehensive review identified evidence on the efficacy of different types of extracted and isolated fibers in reducing appetite and energy intake. Published reports of randomized controlled trials assessing appetite or energy intake in healthy adults were systematically searched, and those investigating extracted and isolated fibers following acute or chronic intake were selected. A total of 136 studies, consisting of 107 acute studies and 29 chronic studies, were included in the review. Overall, most fiber types did not show significant effects on appetite ratings and energy intakes. Acute intakes of two viscous fibers, alginate or guar gum, as well as oat fiber, were observed to most frequently result in reductions in appetite ratings. Additionally, chronic, but not acute, intakes of resistant maltodextrin/dextrin were also beneficial for appetite ratings. Viscous fibers were more likely to improve appetite ratings compared to non-viscous fibers, and fermentability did not appear to affect appetite ratings. Unfortunately, the current evidence base is highly varied due to the many differences in methodology and limited research on many of the fibers. While the possible benefits of extracted and isolated fibers on appetite sensations, food intake, and ultimately body weight regulation should not be completely dismissed, our review highlights the complexity of this research area and the gaps that need to be addressed to improve the robustness of the evidence.

Bowel habits, faecal microbiota and faecal bile acid composition of healthy adults consuming fruit pomace fibres: two-arm, randomised, double-blinded, placebo-controlled trials.

Dietary fibre modulates gastrointestinal (GI) health and function, providing laxation, shifting microbiota, and altering bile acid (BA) metabolism. Fruit juice production removes the polyphenol- and fibre-rich pomace fraction. The effects of orange and apple pomaces on GI outcomes were investigated in healthy, free-living adults. Healthy adults were enrolled in two double-blinded, crossover trials, being randomised by baseline bowel movement (BM) frequency. In the first trial, subjects (n 91) received orange juice (OJ, 0 g fibre/d) or OJ + orange pomace (OJ + P, 10 g fibre/d) for 4 weeks, separated by a 3-week washout. Similarly, in the second trial, subjects (n 90) received apple juice (AJ, 0 g fibre/d) or AJ + apple pomace (AJ + P, 10 g fibre/d). Bowel habit diaries, GI tolerance surveys and 3-d diet records were collected throughout. Fresh faecal samples were collected from a participant subset for microbiota and BA analyses in each study. Neither pomace interventions influenced BM frequency. At Week 4, OJ + P tended to increase (P = 0·066) GI symptom occurrence compared with OJ, while AJ + P tended (P = 0·089) to increase flatulence compared with AJ. Faecalibacterium (P = 0·038) and Negativibacillus (P = 0·043) were differentially abundant between pre- and post-interventions in the apple trial but were no longer significant after false discovery rate (FDR) correction. Baseline fibre intake was independently associated with several microbial genera in both trials. Orange or apple pomace supplementation was insufficient to elicit changes in bowel habits, microbiota diversity or BA of free-living adults with healthy baseline BM. Future studies should consider baseline BM frequency and habitual fibre intake.

Narrative Review on the Effects of Oat and Sprouted Oat Components on Blood Pressure.

Hypertension (HTN) is a major risk factor for cardiovascular disease (CVD) and cognitive decline. Elevations in blood pressure (BP) leading to HTN can be found in young adults with increased prevalence as people age. Oats are known to decrease CVD risk via an established effect of ß-glucan on the attenuation of blood cholesterol. Many past studies on CVD and oats have also reported a decrease in BP; however, a thorough assessment of oats and BP has not been conducted. Moreover, oats deliver several beneficial dietary components with putative beneficial effects on BP or endothelial function, such as ß-glucan, γ-amino butyric acid (GABA), and phytochemicals such as avenanthramides. We conducted a comprehensive search for systematic reviews, meta-analyses, and clinical intervention studies on oats and BP and identified 18 randomized controlled trials (RCTs) and three meta-analyses that supported the role of oats in decreasing BP. Emerging data also suggest oat consumption may reduce the use of anti-hypertensive medications. The majority of these studies utilized whole oats or oat bran, which include a vast array of oat bioactives. Therefore, we also extensively reviewed the literature on these bioactives and their putative effect on BP-relevant mechanisms. The data suggest several oat components, such as GABA, as well as the delivery of high-quality plant protein and fermentable prebiotic fiber, may contribute to the anti-HTN effect of oats. In particular, GABA is enhanced in oat sprouts, which suggests this food may be particularly beneficial for healthy BP management.

Perspective: Assessing Tolerance to Nondigestible Carbohydrate Consumption.

Human intestinal enzymes do not hydrolyze nondigestible carbohydrates (NDCs), and thus, they are not digested and absorbed in the small intestine. Instead, NDCs are partially to completely fermented by the intestinal microbiota. Select NDCs are associated with health benefits such as laxation and lowering of blood cholesterol and glucose. NDCs provide functional attributes to processed foods, including sugar or fat replacers, thickening agents, and bulking agents. Additionally, NDCs are incorporated into processed foods to increase their fiber content. Although consumption of NDCs can benefit health and contribute functional characteristics to foods, they can cause gastrointestinal symptoms, such as flatulence and bloating. As gastrointestinal symptoms negatively affect consumer well-being and their acceptance of foods containing NDC ingredients, it is crucial to consider tolerance when designing food products and testing their physiological health benefits in clinical trials. This perspective provides recommendations for the approach to assess gastrointestinal tolerance to NDCs, with a focus on study design, population criteria, intervention, comparator, and outcome. Special issues related to studies in children and implications for stakeholders are also discussed. It is recommended that the evaluation of gastrointestinal tolerance to NDCs be conducted in randomized, blinded, controlled crossover studies using standard gastrointestinal questionnaires, with attention to study participant background diets, health status, lifestyle, and medications.

Valuing the Diversity of Research Methods to Advance Nutrition Science.

The ASN Board of Directors appointed the Nutrition Research Task Force to develop a report on scientific methods used in nutrition science to advance discovery, interpretation, and application of knowledge in the field. The genesis of this report was growing concern about the tone of discourse among nutrition professionals and the implications of acrimony on the productive study and translation of nutrition science. Too often, honest differences of opinion are cast as conflicts instead of areas of needed collaboration. Recognition of the value (and limitations) of contributions from well-executed nutrition science derived from the various approaches used in the discipline, as well as appreciation of how their layering will yield the strongest evidence base, will provide a basis for greater productivity and impact. Greater collaborative efforts within the field of nutrition science will require an understanding that each method or approach has a place and function that should be valued and used together to create the nutrition evidence base. Precision nutrition was identified as an important emerging nutrition topic by the preponderance of task force members, and this theme was adopted for the report because it lent itself to integration of many approaches in nutrition science. Although the primary audience for this report is nutrition researchers and other nutrition professionals, a secondary aim is to develop a document useful for the various audiences that translate nutrition research, including journalists, clinicians, and policymakers. The intent is to promote accurate, transparent, verifiable evidence-based communication about nutrition science. This will facilitate reasoned interpretation and application of emerging findings and, thereby, improve understanding and trust in nutrition science and appropriate characterization, development, and adoption of recommendations.

Dietary Supplements for Weight Management: A Narrative Review of Safety and Metabolic Health Benefits.

Dietary supplements for weight management include myriad ingredients with thermogenic, lipotropic, satiety, and other metabolic effects. Recently, the safety of this product category has been questioned. In this review, we summarize the safety evidence as well as relevant clinical findings on weight management and metabolic effects of six representative dietary supplement ingredients: caffeine, green tea extract (GTE), green coffee bean extract (GCBE), choline, glucomannan, and capsaicinoids and capsinoids. Of these, caffeine, GTE (specifically epigallocatechin gallate [EGCG]), and choline have recommended intake limits, which appear not to be exceeded when used according to manufacturers' instructions. Serious adverse events from supplements with these ingredients are rare and typically involve unusually high intakes. As with any dietary component, the potential for gastrointestinal intolerance, as well as possible interactions with concomitant medications/supplements exist, and the health status of the consumer should be considered when consuming these components. Most of the ingredients reviewed also improved markers of metabolic health, such as glucose, lipids, and blood pressure, although the data are limited for some. In summary, weight management supplements containing caffeine, GTE, GCBE, choline, glucomannan, and capsaicinoids and capsinoids are generally safe when taken as directed and demonstrate metabolic health benefits for overweight and obese people.

Dual RN-RDN program: Training for the future of health and nutrition.

PURPOSE: Explore the benefits and feasibility of a dual training program for dietetics and nursing to increase nutrition in clinical practice. METHODS: A professional interest survey on the perceived value of a dual program with 222 registered nurses (RN) and registered dietitian nutritionists (RDN) and an in-depth literature review were completed. RESULTS: A majority of RNs indicated the addition of the RDN would be beneficial for supporting patients with diet-related chronic diseases and performing nutritional assessments and interventions. The RDN respondents indicated a dual program approach would also improve the ability to serve a small community or place of employment that is limited in having both a full-time RDN and RN, and rated benefits for performing more medical and laboratory procedures. The RDNs also indicated the dual program could help increase their income potential. Both dual Master's and dual Bachelor's programs were rated as valuable. Of the 18 (8%) of respondents who had both RDN and RN credentials, half indicated personal growth and interest was the incentive for pursuing the dual training; whereas half indicated professional incentives (e.g., no RDN in the area, improving specialty care, job security, lack of opportunities), The literature review indicated no studies on the efficacy of a dual RDN-RN program on health outcomes; however, studies have shown that individualized counseling from RDNs is more beneficial than general nutritional counselling from other health care providers not specifically trained in dietary assessments. Noted barriers to pursuing dual training included time and cost, and some respondents in both specialties were not interested in a dual program. DISCUSSION: These results support providing students with dual program options, although further exploration of the specific approach is warranted, particularly decreasing time-to-degree while not affecting efficacy.

Beverage Containing Dispersible Yeast ß-Glucan Decreases Cold/Flu Symptomatic Days After Intense Exercise: A Randomized Controlled Trial.

In this double-blind, randomized, placebo-controlled parallel study, we examined the effect of dairy-based beverages (250 mL/day) containing 250 mg of dispersible baker's yeast ß-glucan (Wellmune) compared to a macronutrient- and calorie-matched control on upper respiratory tract infection (URTI) in marathon runners. Healthy adults running in the 2017 Austin Marathon consumed either ß-glucan (N = 132) or control (N = 225) for the 45 days prior to, day of, and 45 days after the marathon (91 days total). Participants completed a daily online survey assessing compliance, training status, and URTI symptoms. URTI occurrence and severity were evaluated using the Jackson Index and confirmed by the study physician. No significant differences in average duration and number of URTI episodes were found between ß-glucan and control. However, those who completed the study per protocol on the ß-glucan beverage reported significantly fewer URTI symptomatic days (3.43 ± 6.44 days, max 27 days) compared to those on control beverage (3.84 ± 6.84 days, max 49 days). Total URTI severity was significantly lower for ß-glucan (4.52 ± 1.61) compared to control (5.60 ± 2.23). Specifically, lower (p < .05) severity ratings for nasal discharge and sore throat were reported for ß-glucan compared to control. Average missed postmarathon workout days due to URTI were significantly less for ß-glucan (0.09 ± 0.38 days, max 2 days) compared to control (0.36 ± 1.40 days, max 10 days). Overall, consumption of dairy-based beverages containing dispersible yeast ß-glucan decreased URTI symptomatic days, severity of specific URTI symptoms, and missed postmarathon workout days due to URTI, without affecting duration and number of URTI episodes.

The effect of egg consumption on cardiometabolic health outcomes: an umbrella review.

OBJECTIVE: This umbrella review provides an overview of the consistency and gaps in the evidence base on eggs and cardiometabolic health. DESIGN: PubMed, Web of Science, Cochrane Library, the Nutrition Evidence Systematic Review and Agency for Healthcare Research and Quality databases were screened for evidence-based reviews in English that assessed human studies on egg consumption and cardiometabolic outcomes. RESULTS: Seven systematic reviews and fifteen meta-analyses were identified, with eighteen of these published since 2015. Overall, the systematic reviews were of low quality, while meta-analyses were of moderate- to high-quality. No association of increased egg intake and risks of heart disease or stroke in the general population were found in the meta-analyses. Increased risk of heart failure was noted in two meta-analyses that analysed the same three cohort studies. Five recent meta-analyses reported no increased risk of type 2 diabetes mellitus (T2DM) in the general population, although increased risk in US-based populations only has been reported. Older (<2013) meta-analyses reported increased risks of cardiovascular disease (CVD) or heart disease in T2DM populations, and no recent evidence-based reviews were identified. Finally, only one meta-analysis reported intervention studies specifically on eggs and biomarkers (i.e. lipids), and the results contradicted those from observation studies. CONCLUSIONS: Recent evidence-based reviews conclude that increased egg consumption is not associated with CVD risk in the general population. More research is needed on the positive associations between egg consumption and heart failure and T2DM risk, as well as CVD risk in diabetics, before firm conclusions can be made.

Soluble and Insoluble Yeast ß-Glucan Differentially Affect Upper Respiratory Tract Infection in Marathon Runners: A Double-Blind, Randomized Placebo-Controlled Trial.

In a previous study, consumption of a dairy beverage incorporating insoluble ß-glucan decreased upper respiratory tract infection (URTI) symptomatic days and severity in marathon runners. In this report, we extended our previous findings by presenting data on a dairy beverage containing soluble ß-glucan and URTI in marathon runners. Healthy adults running in the 2017 Austin Marathon consumed dairy beverages (250 mL/day) containing 250 mg of insoluble (n = 69) or soluble (n = 76) baker's yeast ß-glucan (Wellmune®) or placebo (n = 133) for the 45 days before, day of, and 45 days after the marathon (91 days total). Participants completed a daily online survey assessing compliance and URTI symptoms, which were evaluated using the Jackson Index and confirmed by the study physician. Total severity of URTI was significantly lower in the insoluble yeast ß-glucan group compared to the placebo group, but was not different between the soluble yeast ß-glucan group and placebo group. Severity ratings for nasal discharge were significantly lower in both the insoluble and soluble yeast ß-glucan groups compared to the placebo group. Additionally, severity rating for sore throat was lower in the insoluble, but not the soluble yeast ß-glucan group compared to the placebo group. The insoluble yeast ß-glucan group, but not the soluble yeast ß-glucan group also reported fewer URTI symptomatic days compared to the placebo group. The results suggest that soluble and insoluble yeast ß-glucan, incorporated into a food matrix, differentially affected exercise-induced URTI in marathon runners.

Cashew consumption reduces total and LDL cholesterol: a randomized, crossover, controlled-feeding trial.

Background: Cashews are the third most-consumed tree nut in the United States and are abundant with monounsaturated fatty acids and polyunsaturated fatty acids, which are associated with reduced cardiovascular disease risk. Although a qualified Food and Drug Administration health claim exists for nuts and heart health, cashews have been exempt from its use because cashews exceed the disqualifying amount of saturated fatty acids. Approximately one-third of the saturated fat in cashews is stearic acid, which is relatively neutral on blood lipids, thereby suggesting that cashews could have effects that are similar to those of other nuts. However, clinical data on cashews and blood lipids have been limited.Objective: We investigated the effect of reasonable intakes of cashews on serum lipids in adults with or at risk of high LDL cholesterol.Design: In a randomized, crossover, isocaloric, controlled-feeding study, 51 men and women (aged 21-73 y) with a median LDL-cholesterol concentration of 159 mg/dL (95% CI: 146, 165 mg/dL) at screening consumed typical American diets with cashews (28-64 g/d; 50% of kilocalories from carbohydrate, 18% of kilocalories from protein, and 32% of kilocalories from total fat) or potato chips (control; 54% of kilocalories from carbohydrate, 18% of kilocalories from protein, and 29% of kilocalories from total fat) for 28 d with a ≥2-wk washout period.Results: Consumption of the cashew diet resulted in a significantly greater median change from baseline (compared with the control, all P < 0.05) in total cholesterol [-3.9% (95% CI: -9.3%, 1.7%) compared with 0.8% (95% CI: -1.5%, 4.5%), respectively], LDL cholesterol [-4.8% (95% CI: -12.6%, 3.1%) compared with 1.2% (95% CI: -2.3%, 7.8%), respectively], non-HDL cholesterol [-5.3% (95% CI: -8.6%, 2.1%) compared with 1.7% (95% CI: -0.9%, 5.6%), respectively], and the total-cholesterol:HDL-cholesterol ratio [-0.0% (95% CI: -4.3%, 4.8%) compared with 3.4% (95% CI: 0.6%, 5.2%), respectively]. There were no significant differences between diets for HDL cholesterol and triglyceride.Conclusions: In comparison with a control diet, the incorporation of cashews into typical American diets decreases total cholesterol and LDL cholesterol. Results from this study provide support that the daily consumption of cashews, when substituted for a high-carbohydrate snack, may be a simple dietary strategy to help manage total cholesterol and LDL cholesterol. This study was registered at clinicaltrials.gov as NCT02769741.

Trans fatty acids and cholesterol levels: An evidence map of the available science.

High intakes of industrial trans fatty acids (iTFA) increase circulating low density lipoprotein cholesterol (LDL-C) levels, which has implicated iTFA in coronary heart disease (CHD) risk. Published data on iTFA and LDL-C, however, represent higher intake levels than the U.S. population currently consume. This study used state-of-the-art evidence mapping approaches to characterize the full body of literature on LDL-C and iTFA at low intake levels. A total of 32 independent clinical trials that included at least one intervention or control group with iTFA at ≤3%en were found. Findings indicated that a wide range of oils and interventions were used, limiting the ability to determine an isolated effect of iTFA intake. Few data points were found for iTFA at <3%en, with the majority of low-level exposures actually representing control group interventions containing non-partially hydrogenated (PHO) oils. Further, it appears that few dose-response data points are available to assess the relationship of low levels of iTFA, particularly from PHO exposure, and LDL-C. Therefore, limited evidence is available to determine the effect of iTFA at current consumption levels on CHD risk.

Creating the Future of Evidence-Based Nutrition Recommendations: Case Studies from Lipid Research.

Strategic translational research is designed to address research gaps that answer specific guidance questions. It provides translational value with respect to nutrition guidance and regulatory and public policy. The relevance and the quality of evidence both matter in translational research. For example, design decisions regarding population, intervention, comparator, and outcome criteria affect whether or not high-quality studies are considered relevant to specific guidance questions and are therefore included as evidence within the context of systematic review frameworks used by authoritative food and health organizations. The process used in systematic reviews, developed by the USDA for its Nutrition Evidence Library, is described. An eating pattern and cardiovascular disease (CVD) evidence review is provided as an example, and factors that differentiated the studies considered relevant and included in that evidence base from those that were excluded are noted. Case studies on ω-3 (n-3) fatty acids (FAs) and industrial trans-FAs illustrate key factors vital to relevance and translational impact, including choice of a relevant population (e.g., healthy, at risk, or diseased subjects; general population or high-performance soldiers); dose and form of the intervention (e.g., food or supplement); use of relevant comparators (e.g., technically feasible and realistic); and measures for both exposure and outcomes (e.g., inflammatory markers or CVD endpoints). Specific recommendations are provided to help increase the impact of nutrition research on future dietary guidance, policy, and regulatory issues, particularly in the area of lipids.

Cranberries and Urinary Tract Infections: How Can the Same Evidence Lead to Conflicting Advice?

Cranberry has been used traditionally to prevent urinary tract infections (UTIs), primarily among generally healthy women prone to recurrent UTIs. Results from a number of published clinical studies have supported this benefit; however, meta-analyses on cranberry and UTI prevention have reported conflicting conclusions. This article explores the methodological differences that contributed to these disparate findings. Despite similar research questions, the meta-analyses varied in the studies that were included, as well as the data that were extracted. In the 2 most comprehensive systematic reviews, heterogeneity was handled differently, leading to an I(2) of 65% in one and 43% in the other. Most notably, the populations influencing the conclusions varied. In one analysis, populations with pathological/physiological conditions contributed 75.6% of the total weight to the summary risk estimate (RR: 0.86; 95% CI: 0.71, 1.04); another weighted the evidence relatively equally across UTI populations (RR: 0.62; 95% CI: 0.49, 0.80); and a third included only women with recurrent UTIs (RR: 0.53; 95% CI: 0.33, 0.83). Because women with recurrent UTIs are the group to whom most recommendations regarding cranberry consumption is directed, inclusion of other groups in the efficacy assessment could influence clinical practice quality. Therefore, conclusions on cranberry and UTIs should consider differences in results across various populations studied when interpreting results from meta-analyses.

Maillard reaction products and potatoes: have the benefits been clearly assessed?

Cooking foods affords numerous food safety benefits. During heating, Maillard reaction products (MRPs) are formed. MRPs contribute sensory aspects to food, including color, taste, and texture. One MRP, acrylamide, has been implicated in negative health outcomes; however, emerging data suggests MRPs may also deliver certain health benefits. The food industry has taken steps to decrease acrylamide formation, but the perception that high levels of acrylamide compromise the nutritional benefit of certain foods has continued. Potatoes are susceptible to MRP formation during cooking but also are considered an affordable, high nutrient content food. In particular, potatoes contribute significantly to fiber and potassium intakes in the U.S. population, two nutrients of need. How, then, should potatoes be judged for effects on health? A structured evidence assessment was conducted to identify literature, specifically clinical trials, on MRPs from potatoes and health, as well as nutritional contribution of potatoes. The results indicate limited human clinical data are available on negative health outcomes of potato-based MRPs, whereas potatoes are important contributors of key nutrients, such as fiber and potassium. Therefore, a balanced benefit-risk approach is warranted in order to assure that decreasing consumption of certain foods, like potatoes, does not lead to unintended consequences of nutrition inadequacies.

Effect of a low glycemic index diet with soy protein and phytosterols on CVD risk factors in postmenopausal women.

OBJECTIVES: Cardiovascular disease (CVD) is the leading cause of death in women. Hyperlipidemia is a major risk factor for CVD, but research suggests that metabolic syndrome and type 2 diabetes are also key factors in CVD in postmenopausal women. Most dietary programs, however, focus only on hyperlipidemia and not on insulin resistance associated with diabetes and metabolic syndrome. This 12-wk trial compared the effects of a dietary program combining a low glycemic index diet with a functional food delivering 30 g of soy protein and 4 g of phytosterols per day (LGID) with a standard dietary program (American Heart Association Step 1 diet; AHAD) in postmenopausal women. METHODS: Fifty-nine postmenopausal women (average age 54.6 y, range 44-65 y) with a body mass index of 27 to 39 kg/m2 were randomly assigned to the LGID or the AHAD program for 12 wk. Total caloric intake and exercise were matched in each arm. RESULTS: Twenty-seven women completed the LGID program, and 26 completed the AHAD program. The participants on the LGID program showed statistically significant decreases in total cholesterol (15.8%, P = 0.0036 between-group comparison), low-density lipoprotein cholesterol (14.8%, P = 0.004 between-group comparison), and triacylglycerol (44.8%, P = 0.006 between-group comparison). In addition, significant improvements were observed in ratios of total to high-density lipoprotein cholesterol and of triacylglycerol to high-density lipoprotein cholesterol, blood pressure, and Framingham risk assessment for coronary heart disease compared with the AHAD program. CONCLUSIONS: A significantly greater improvement was observed in CVD risk factors in postmenopausal women on the LGID program (incorporating 30 g of soy protein and 4 g of phytosterols per day) than with a standard therapy.