The impact of long-term dietary pattern of fecal donor on in vitro fecal fermentation properties of inulin

Although the composition of the gut microbiota is of interest, the functionality, or metabolic activity, of the gut microbiota is of equal importance: the gut microbiota can produce either harmful metabolites associated with human disease or beneficial metabolites that protect against disease. The purposes of this study were to determine the associations between dietary intake variables and fecal short and branched chain fatty acid (S/BCFA) concentrations; to determine the associations between dietary intake variables and inulin degradation, short and branched chain fatty acid (S/BCFA) production, and ammonia production during in vitro fecal fermentation of a highly fermentable substrate (inulin); and finally to compare results from the fermentation of inulin with those obtained in a previous report using a poorly fermentable substrate (whole wheat; Yang and Rose, Nutr. Res., 2014, 34, 749–759). Stool samples from eighteen individuals that had completed one-year dietary records were used in an in vitro fecal fermentation system with long-chain inulin as substrate. Few dietary intake variables were correlated with fecal S/BCFA concentrations; however, intakes of several plant-based foods, especially whole grain, dry beans, and certain vegetables that provided dietary fiber, plant protein, and B vitamins, were associated with acetate, propionate, butyrate, and total SCFA production during inulin fermentation. In contrast, intake of dairy and processed meats that provided cholesterol and little fiber, were associated with ammonia and BCFA production. Comparing results between inulin and whole wheat fermentations, significant correlations were only found for butyrate and BCFA, suggesting that regardless of the type of carbohydrate provided to the microbiota, long-term diet may have a pronounced effect on the propensity of the gut microbiota toward either beneficial metabolism (butyrate production) or detrimental metabolism (BCFA production). These results may help in the development of new dietary strategies to improve gut microbiota functionality to promote human health

US Consumer Identification of the Health Benefits of Dietary Fiber and Consideration of Fiber When Making Food Choices

The purposes of this study were to (1) determine beliefs in the health benefits of dietary fiber, an under-consumed nutrient of public health concern, and (2) determine the relationship between beliefs about dietary fiber and consideration of fiber when making food choices. We conducted a nationally representative within-subject randomized online survey of 42,018 US primary shoppers in May–June 2021. Participants selected health benefits they believed were associated with consumption of fiber from a list of six benefits recognized by the Food and Drug Administration (FDA), one indirect benefit, and one unrelated benefit. Respondents then indicated which nutrients, if any, they considered when making food choices. Respondents selected 1.77 (95% CI = 1.76–1.77) FDA-recognized benefits out of a total six; half (50.6%) of respondents identified zero or one FDA-recognized benefit. The most-cited benefit was “improving bowel movements” (64.4%). Older participants perceived significantly more FDA-recognized fiber benefits. Identification of FDA-recognized benefits increased odds ratios for consideration of fiber during food choice (relative to zero benefits) from 3.0 for one benefit (95% CI = 2.8–3.3) to 14.3 for six benefits (95% CI = 12.4–16.6). Consumers are largely unaware of the many health benefits of dietary fiber, which dramatically decreases the likelihood that they consider this important, under-consumed nutrient during food choice

Changes in enzymatic activities and functionality of whole wheat flour due to steaming of wheat kernels

The effects of steaming wheat kernels on lipolytic degradation of resulting whole flour was studied by quantifying enzyme activities and lipid degradation products during storage. Lipase, lipoxygenase, polyphenol oxidase, and peroxidase activities were decreased by up to 81%, 63%, 22%, and 34%, respectively, as the time of steaming increased up to 90 s. Steaming had no effect on starch and gluten properties. Upon storage free fatty acids decreased with respect to time of steaming. Time of steaming did not affect lipid oxidation in flour; however, total carbonyls produced in dough made from stored flour were decreased with the increase in steaming duration. Thus, steaming wheat kernels prior to milling reduced lipase activity and consequently hydrolytic rancidity during storage without affecting starch and gluten fractions. Steam treatment did not affect oxidative rancidity in flour during storage, but did reduce oxidation once the flour was made into a dough

Repeated cooking and freezing of whole wheat flour increases resistant starch with beneficial impacts on in vitro fecal fermentation properties

Resistant starch (RS) has shown benefits to gastrointestinal health, but it is present in only small amounts in most grain-based foods. The purpose of this study was to increase RS in whole wheat flour to improve its potential health benefits. Zero to 7 cycles of cooking (20 min, boiling water) and freezing (−18 °C, 23 h) of whole wheat flour in water (1:15 %w/v) were performed. Increasing cooking–freezing cycles increased RS from 1.03 to 8.07% during in vitro starch digestion. During in vitro fecal fermentation, increasing cooking–freezing cycles increased short chain fatty acids, mainly propionate. Increases in butyrate were also noted during the first 8 h of fermentation. All flours resulted in significant increases in Bifidobacterium of \u3e0.5 log during fermentation compared to baseline. Thus, even modest increases in the RS content of whole wheat flour modulated the metabolic activity of gut microbiota to increase production of beneficial metabolites

Holobiont nutrition: Considering the role of the gastrointestinal microbiota in the health benefits of whole grains

Intake of whole grains and other food products high in dietary fiber have long been linked to the prevention of chronic diseases associated with inflammation. A contribution of the gastrointestinal microbiota to these effects has been suggested, but little is known on how whole grains interact with gut bacteria. We have recently published the first human trial that made use of next-generation sequencing to determine the effect of whole grains (whole grain barley, brown rice or a mixture of the two) on fecal microbiota structure and tested for associations between the gut microbiota and blood markers of inflammation, glucose and lipid metabolism. Our study revealed that whole grains impacted gut microbial ecology by increasing microbial diversity and inducing compositional alterations, some of which are considered to have beneficial effects on the host. Interestingly, whole grains, and in particular the combination of whole grain barley and brown rice, caused a reduction in plasma interleukin-6 (IL-6), which was linked to compositional features of the gut microbiota. Therefore, the study provided evidence that a short-term increased intake of whole grains led to compositional alterations of the gut microbiota that coincided with improvements in systemic inflammation. In this addendum, we summarize the findings of the study and provide a perspective on the importance of regarding humans as holobionts when considering the health effects of dietary strategies

Predicting Personalized Responses to Dietary Fiber Interventions: Opportunities for Modulation of the Gut Microbiome to Improve Health

Inadequate dietary fiber consumption has become common across industrialized nations, accompanied by changes in gut microbial composition and a dramatic increase in chronic metabolic diseases.The human gut microbiome harbors genes that are required for the digestion of fiber, resulting in the production of end products that mediate gastrointestinal and systemic benefits to the host. Thus, the use of fiber interventions has attracted increasing interest as a strategy to modulate the gut microbiome and improve human health. However, considerable interindividual differences in gut microbial composition have resulted in variable responses toward fiber interventions. This variability has led to observed nonresponder individuals and highlights the need for personalized approaches to effectively redirect the gut ecosystem. In this review, we summarize strategies used to address the responder and nonresponder phenomenon in dietary fiber interventions and propose a targeted approach to identify predictive features based on knowledge of fiber metabolism and machine learning approaches

In Vitro Bioaccessibility of Low-Crystallinity Phytosterol Nanoparticles Generated Using Nanoporous Starch Bioaerogels

Phytosterols are natural health-promoting bioactive compounds; however, phytosterols have very limited bioavailability due to their crystalline lipophilic structure. With the aim of improving bioaccessibility, low-crystallinity phytosterol nanoparticles were generated by supercritical carbon dioxide (SC-CO2) impregnation of phytosterols into nanoporous starch aerogels (NSAs). The in vitro bioaccessibility of the phytosterol nanoparticles (35%) was significantly higher than that of the crude phytosterols (3%) after sequential oral, gastric, and intestinal digestion. The percentages of starch hydrolysis were not different among the various NSA preparations and reached to 64% after sequential digestion. The zeta potential of the phytosterol nanoparticles was higher compared to that of crude phytosterols in the micellar phase; indicating higher stability. The findings of this study support the use of NSA to produce nanoparticles of reduced crystallinity to improve the bioaccessibility of the lipophilic bioactive compounds. Keywords: aerogel, bioaccessibility, nanoparticles, phytosterol, supercritical Practical Applications: This novel process can decrease the size and crystallinity of phytosterols and thus improve phytosterols’ bioavailability. It is a blueprint to apply to other water insoluble food bioactives. This novel approach may (i) improve the health benefits of water-insoluble bioactives; (ii) enable food manufacturers to add water-insoluble bioactives into low- and high-fat foods to produce health-promoting foods; and (iii) enhance the cost-benefit ratio of water insoluble bioactives

Influence of Foliar Fungicide Treatment on Lipolytic Enzyme Activity of Whole Wheat

Lipolytic enzymes play a key role in the deterioration of whole wheat flour upon storage but may also be involved in plant disease and stress tolerance while the crop is in the field. Therefore, the purpose of this study was to determine the effect of foliar fungicide treatment on lipolytic activity in wheat. A significant cultivar × fungicide × year interaction for esterase (p-nitrophenyl butyrate as substrate [EA-B]) and lipoxygenase (LOX) activities was observed; however, a large portion of the variability was owing to year (environment). Fungicide influenced lipase (olive oil as substrate [LA-O]), EA-B, and LOX activities. Lipase (p-nitrophenyl palmitate as substrate [LA-P]) showed variation in terms of cultivar and year rather than the application of fungicide. Partial correlation (year as a partial variable) between LA-P and EA-B activities was observed (r = 0.78, P \u3c 0.001), although neither was correlated with LA-O. The influence of foliar fungicide on lipolytic enzyme activities depends mostly on growing conditions but is also affected by disease stress, disease resistance of the varieties tested, and the substrate being used in the assay

Microstructural changes to proso millet protein bodies upon cooking and digestion

Cooking results in a drastic decline in digestibility of proso millet proteins, panicins. Scanning electron and confocal microscopy were used to observe morphological changes in proso millet protein bodies upon cooking and digestion that could be associated with the loss in digestibility. Spherical protein bodies (1–2.5 mm) were observed in proso millet flour and extracted protein. Cooking did not result in any noticeable change in the size or shape of the protein bodies. However, upon digestion with pepsin the poor digestibility of cooked proso millet protein was clearly evident from the differences in microstructure of the protein bodies: large cavities were observed in the uncooked protein bodies while cooked protein bodies had only tiny holes. When proso millet was cooked in 8M urea and then digested, the protein bodies appeared similar to uncooked digested protein bodies. The morphological changes observed in proso millet protein upon cooking and digestion did not show any visible aggregates, but the inability of pepsin to digest cooked protein bodies was clearly evident under microscopy and is in agreement with the chemical analyses reported previously