Faecal lipid profile as a new marker of fat maldigestion, malabsorption and microbiota.

BACKGROUND: Fat malabsorption in children with cystic fibrosis (CF) leads to poor nutritional status and altered colonic microbiota. This study aimed at establishing the faecal lipid profile in children with CF, and exploring associations between the faecal lipidome and microbiota. METHODS: Cross-sectional observational study with children with CF and an age-matched control group. Faecal lipidome was analysed by UHLC-HRMS and microbiota profiling by 16S rRNA amplicon sequencing. RESULTS: Among 234 identified lipid species, five lipidome clusters (LC) were obtained with significant differences in triacylglycerols (TG), diacylglycerols (DG), monoacylglycerols (MG) and fatty-acids (FA): LC1 subjects with good digestion and absorption: low TG and low MG and FA; LC2 good digestion and poor absorption: low TG and high MG and FA; LC3 Mild digestion and poor absorption: intermediate TG and high MG and FA; LC4 poor digestion and absorption: high TG and high MG and FA; LC5 outliers. Bacteroidota and Verrucomicrobiota decreased over LC1-LC4, while Proteobacteria increased. Nutritional status indicators were significantly higher in LC1 and decreased over LC2-LC4. CONCLUSION: Assessing faecal lipidome may be relevant to determine how dietary lipids are digested and absorbed. This new evidence might be a method to support targeted nutritional interventions towards reverting fat maldigestion or malabsorption. IMPACT: Lipidomic analysis enabled the identification of the lipid species related to maldigestion (triglycerides) or malabsorption (monoglycerides and fatty acids). Children with cystic fibrosis can be grouped depending on the faecal lipidome profile related to dietary fat maldigestion or malabsorption. The lipidome profile in faeces is related to the composition of microbiota and nutritional status indicators.

Effect of beta-glucan supplementation on cystic fibrosis colonic microbiota: an in vitro study.

BACKGROUND: Children with cystic fibrosis (CF) present with gut dysbiosis, and current evidence impedes robust recommendations on the use of prebiotics. This study aimed at establishing the prebiotic potential of a commercial beta-glucan on the in vitro colonic microbiota of a child with CF compared to a healthy counterpart (H). METHODS: A dynamic simulator of colonic fermentation (twin-SHIME® model) was set up including the simulation of the proximal (PC) and distal colon (DC) of the CF and the H subjects by colonizing the bioreactors with faecal microbiota. During two weeks the system was supplied with the beta-glucan. At baseline, during treatment and post-treatment, microbiota composition was profiled by 16 S rRNA and short-chain fatty acids (SCFA) production was determined by GS-MS. RESULTS: At baseline, Faecalibacterium, was higher in CF' DC than in the H, along higher Acidaminococcus and less Megasphaera and Sutterella. Beta-glucan supplementation induced increased microbiota richness and diversity in both subjects during the treatment. At genus level, Pseudomonas and Veillonella decreased, while Akkermansia and Faecalibacterium increased significantly in CF. CONCLUSION: The supplementation with beta-glucan suggests positive results on CF colonic microbiota in the in vitro context, encouraging further research in the in vivo setting. IMPACT: Current evidence supports assessing the effect of prebiotics on modifying cystic fibrosis microbiota. The effect of beta-glucan supplementation was evaluated in a controlled dynamic in vitro colonic ecosystem. Beta-glucan supplement improved diversity in cystic fibrosis colonic microbiota. The treatment showed increased abundance of Faecalibacterium and Akkermansia in cystic fibrosis. New evidence supports the use of prebiotics in future clinical studies.

Association between faecal pH and fat absorption in children with cystic fibrosis on a controlled diet and enzyme supplements dose.

BACKGROUND: Despite treatment with pancreatic enzyme replacement therapy (PERT), patients with cystic fibrosis (CF) can still suffer from fat malabsorption. A cause could be low intestinal pH disabling PERT. The aim of this study was to assess the association between faecal pH (as intestinal pH surrogate) and coefficient of fat absorption (CFA). Additionally, faecal free fatty acids (FFAs) were quantified to determine the amount of digested, but unabsorbed fat. METHODS: In a 24-h pilot study, CF patients followed a standardised diet with fixed PERT doses, corresponding to theoretical optimal doses determined by an in vitro digestion model. Study variables were faecal pH, fat and FFA excretion, CFA and transit time. Linear mixed regression models were applied to explore associations. RESULTS: In 43 patients, median (1st, 3rd quartile) faecal pH and CFA were 6.1% (5.8, 6.4) and 90% (84, 94), and they were positively associated (p < 0.001). An inverse relationship was found between faecal pH and total fat excretion (p < 0.01), as well as total FFA (p = 0.048). Higher faecal pH was associated with longer intestinal transit time (p = 0.049) and the use of proton pump inhibitors (p = 0.009). CONCLUSIONS: Although the clinical significance of faecal pH is not fully defined, its usefulness as a surrogate biomarker for intestinal pH should be further explored. IMPACT: Faecal pH is a physiological parameter that may be related to intestinal pH and may provide important physiopathological information on CF-related pancreatic insufficiency. Faecal pH is correlated with fat absorption, and this may explain why pancreatic enzyme replacement therapy is not effective in all patients with malabsorption related to CF. Use of proton pump inhibitors is associated to higher values of faecal pH. Faecal pH could be used as a surrogate biomarker to routinely monitor the efficacy of pancreatic enzyme replacement therapy in clinical practice. Strategies to increase intestinal pH in children with cystic fibrosis should be targeted.

Fat digestibility in meat products: influence of food structure and gastrointestinal conditions.

Digestibility of macronutrients depends on the food matrix structure as well as on gastrointestinal conditions, especially in patients with exocrine pancreatic insufficiency. In this situation, an oral enzyme supplementation that promotes nutrient hydrolysis is needed. In this context, in the present study, a static in vitro digestion model was used to assess the lipid digestibility of different meat products (processed and fresh), different intestinal conditions of pH (6 or 7), bile concentration (1 or 10 mM) and doses of the enzyme supplement (1000-4000 lipase units/g fat). Results showed that processed (unstructured) meats had better matrix degradation during digestion and reached higher values of lipolysis extents (total free fatty acids/g fat) than the natural meat matrices with a statistically significant association (p < .001). Regarding the intestinal medium, pH of 7 and bile concentration of 10 mM contribute to higher matrix degradation and thus, to a higher lipolysis (p < .001).

In vitro screening of the impact of dietary prebiotic components, probiotic strains, and their symbiotic combinations on colonic microbiota in children with cystic fibrosis.

Children with Cystic Fibrosis (CF) are more likely to have intestinal dysbiosis due to recurrent antibiotic therapy and the conventional hypercaloric diet administered to them. This study aimed at evaluating the effect of isolated prebiotic components and probiotic strains, and their combinations as potential synbiotics, on the intestinal microbiota of CF children. A static in vitro colonic fermentation model was used by colonizing vials with faecal inoculum, a culture medium, and the substrates to be tested. Post treatment, aliquots were taken to determine ammonium, lactate, and short-chain fatty acids production and to profile the microbiota composition by 16s rRNA sequencing. At genus level, Escherichia-Shigella decreased (15.8%) with the treatment pectin + L. rhamnosus, followed by the beta-glucan + L. salivarius (15.5%). Inversely, the most increase in Bacteroides (44%) was obtained by the treatment with Pectin + L. reuteri. Lactate and acetic acid production was significantly increased with prebiotics and their combinations with L. rhamnosus and L. salivarius. In conclusion, the use of beta-glucan and pectin in combination with probiotic strains from the Lactobacillaceae family suggest potential to modulate dysbiosis and metabolic activity on CF colonic microbiota, encouraging further studies in animal studies or clinical settings to confirm the findings in vivo.

Effect of Lactobacillaceae Probiotics on Colonic Microbiota and Metabolite Production in Cystic Fibrosis: A Comparative In Vitro Study.

Cystic Fibrosis-related gut dysbiosis (CFRGD) has become a recognised complication in children with this condition, and current evidence remains insufficient to guide the selection of probiotic strains for supplementation treatments. The aim of this study was to characterise the effect of three probiotic strains on CFRGD by means of a dynamic in vitro simulation of the colonic fermentation (SHIME®). The configuration of the system included three bioreactors colonised with the faecal inoculum of a child with cystic fibrosis. For 20 days, each bioreactor was supplied daily with either Lacticaseibacillus rhamnosus GG (ATCC 53103 TM), Limosilactobacillus reuteri (DSM 17938) or Lactiplantibacillus plantarum (DSM 22266). The baseline microbiota was characterised by a high abundance of Prevotella, Faecalibacterium and Acidaminococcus genera. After 20 days of supplementation, L. rhamnosus and L. plantarum reduced Prevotella significantly, and the three strains led to increased Faecalibacterium and Bifidobacterium and decreased Acidaminococcus, with some of these changes being maintained 10 days after ceasing supplementation. The metabolic activity remained unaltered in terms of short-chain fatty acids, but branched-chain fatty acids showed a significant decrease, especially with L. plantarum. Additionally, ammonia decreased at 20 days of supplementation, and lactate continuously increased with the three strains. The effects on colonic microbiota of L. rhamnosus, L. reuteri or L. plantarum were established, including increased beneficial bacteria, such as Faecalibacterium, and beneficial metabolites such as lactate; and on the other hand, a reduction in pathogenic genera, including Prevotella or Acidaminococcus and branched-chain fatty acids, overall supported their use as probiotics in the context of CFRGD.

Association between Dietary Intake and Faecal Microbiota in Children with Cystic Fibrosis.

A "high-fat, high-energy diet" is commonly recommended for children with cystic fibrosis (CF), leading to negative consequences on dietary patterns that could contribute to altered colonic microbiota. The aim of this study was to assess dietary intake and to identify possible associations with the composition of faecal microbiota in a cohort of children with CF. A cross-sectional observational study was conducted, including a 3-day food record simultaneously with the collection of faecal samples. The results showed a high fat intake (43.9% of total energy intake) and a mean dietary fibre intake of 10.6 g/day. The faecal microbiota was characterised at the phylum level as 54.5% Firmicutes and revealed an altered proportion between Proteobacteria (32%) and Bacteroidota (2.2%). Significant associations were found, including a negative association between protein, meat, and fish intake and Bifidobacterium, a positive association between lipids and Escherichia/Shigella and Streptococcus, a negative association between carbohydrates and Veillonella and Klebsiella, and a positive association between total dietary fibre and Bacteroides and Roseburia. The results reveal that a "high-fat, high-energy" diet does not satisfy dietary fibre intake from healthy food sources in children with CF. Further interventional studies are encouraged to explore the potential of shifting to a high-fibre or standard healthy diet to improve colonic microbiota.

Exploring the Impact of Solid-State Fermentation on Macronutrient Profile and Digestibility in Chia (Salvia hispanica) and Sesame (Sesamum Indicum) Seeds.

Fermentation of plant-based substrates with edible fungi enhances the nutrient profile and digestibility, but it has been scarcely applied to edible seeds, which are rich in healthy lipids. In this study, chia and sesame seeds were solid-state fermented with Pleurotus ostreatus, followed by drying and milling. Fermentation led to increased content of lipid and protein in both seeds' products, and a change in fatty acid profile in favor of increased polyunsaturated fatty acids. Then, the samples were subjected to in vitro digestion. Lipolysis, determined by nuclear magnetic resonance, was higher in sesame than in chia products, and the fermented counterparts had increased values compared to the controls. In terms of physical properties, fermentation showed reduced particle size and increased matrix degradation and decreased viscosity of the digestion medium, which were related to increased lipolysis. In conclusion, applying solid-state fermentation on chia and sesame seeds could be a recommendable approach.

In vitro digestion of salmon: Influence of processing and intestinal conditions on macronutrients digestibility.

Salmon is the main dietary source of omega-3 lipids and contains high-biological value protein. However, processing techniques could affect macronutrient digestibility. Also, altered intestinal conditions, particularly given in pancreatic insufficiency, could threaten digestibility. This study tested both hypotheses by subjecting raw, marinated and microwave-cooked salmon to static in vitro digestion under healthy (pH 7, bile concentration 10 mM) and altered (pH 6, bile 1 or 10 mM) intestinal conditions with different pancreatin concentrations. In the standard conditions, proteolysis was not affected by processing, but lipolysis decreased in marinated (46%) and raw salmon (57%) compared to the cooked matrix (67%). In altered conditions, proteolysis and lipolysis decreased to different extents depending on the treatment. Overall, processing affected proteolysis the most (f-ratio = 5.86), while intestinal conditions were the major determinants of lipolysis (f-ratio = 58.01). This study could set the ground to establish dietary recommendations of salmon for specific population groups.

Clinical evaluation of an evidence-based method based on food characteristics to adjust pancreatic enzyme supplements dose in cystic fibrosis.

BACKGROUND: Patients with cystic fibrosis (CF) and pancreatic insufficiency need pancreatic enzyme replacement therapy (PERT) for dietary lipids digestion. There is limited evidence for recommending the adequate PERT dose for every meal, and controlling steatorrhea remains a challenge. This study aimed to evaluate a new PERT dosing method supported by a self-management mobile-app. METHODS: Children with CF recruited from 6 European centres were instructed to use the app, including an algorithm for optimal PERT dosing based on in vitro digestion studies for every type of food. At baseline, a 24h self-selected diet was registered in the app, and usual PERT doses were taken by the patient. After 1 month, the same diet was followed, but PERT doses were indicated by the app. Change in faecal fat and coefficient of fat absorption (CFA) were determined. RESULTS: 58 patients (median age 8.1 years) participated. Baseline fat absorption was high: median CFA 96.9%, median 2.4g faecal fat). After intervention CFA did not significantly change, but range of PERT doses was reduced: interquartile ranges narrowing from 1447-3070 at baseline to 1783-2495 LU/g fat when using the app. Patients with a low baseline fat absorption (CFA<90%, n=12) experienced significant improvement in CFA after adhering to the recommended PERT dose (from 86.3 to 94.0%, p=0.031). CONCLUSION: the use of a novel evidence-based PERT dosing method, based on in vitro fat digestion studies incorporating food characteristics, was effective in increasing CFA in patients with poor baseline fat absorption and could safely be implemented in clinical practice.

Enhancing the nutritional profile and digestibility of lentil flour by solid state fermentation with Pleurotus ostreatus.

Lentils (Lens culinaris) present an excellent nutrient profile. However, the increasing displacement of legumes from the diet and the possible negative effects of the food matrix and antinutrient factors encourage the application of new strategies to improve nutrient digestibility and to produce food concepts that contribute to the increase of legume consumption. This study approached the solid-state fermentation of lentils with an edible fungus (Pleurotus ostreatus) in order to produce improved lentil flour. Fermentation contributed to the increase of protein (23%), resistant starch (9.8%), and polyphenols (from 2.1 to 3.2 mg gallic acid equivalent per g dry matter). After simulating in vitro digestion, fermented flours presented a higher fraction of digested protein (17%) along with lower starch hydrolysis (34 vs. 24%), while the polyphenol content increased from 3.1 to 7.73 mg gallic acid equivalent per g dry matter. Thus, this study supports the application of solid-state fermentation with this edible fungus to obtain lentil flours with an enhanced digestibility profile as compared to non-fermented counterparts. Lentil flours could be used as a novel raw material in the formulation of new food concepts with an enhanced nutritional profile.

Lessons learnt from MyCyFAPP Project: Effect of cystic fibrosis factors and inherent-to-food properties on lipid digestion in foods.

Unveiling mechanisms underpinning nutrient digestion has raised interest in the field of medical sciences for their potential application in clinical treatments. In the case of Cystic Fibrosis (CF), there exists an urgent need for understanding food lipid digestion to establish a criterion to adjust the dose of pancreatic enzyme supplements; patients have to take the supplements to allow digestion, given the associated exocrine pancreatic insufficiency (EPI). The aim of MyCyFAPP Project was to establish an evidence-based method to adjust pancreatic enzyme replacement therapy. To solve this challenge, the still unexplored field of real foods digestion had to be addressed. This review paper provides a description of the static in vitro digestion model that simulated different EPI intestinal conditions to conduct an extensive experimental work with 52 foods. Then, a summary of the data modelling that allowed for establishing a dosing criterion for enzyme supplements is provided. Following, by means of examples, an overview of the main findings related to the new knowledge generated in the field of lipid digestion in real foods is discussed, including the role of the inherent-to-food and the host factors affecting lipolysis. Finally, a discussion about the translation of the generated results in the lab to the clinical treatment of CF concludes with the lessons learnt from conducting this study.

Impact of Processing and Intestinal Conditions on in Vitro Digestion of Chia (Salvia hispanica) Seeds and Derivatives.

Chia seeds present with an excellent nutrient profile, including polyunsaturated fat, protein, fibre and bioactive compounds, which make them a potential food or ingredient to bring beneficial health effects. However, their tough structure could mean that these seeds remain hardly disrupted during digestion, thus preventing the release and digestibility of nutrients. In the present study, different chia products (seeds, whole flour, partially defatted flour and sprouts) were assessed in terms of proteolysis, lipolysis, calcium and polyphenols bioaccessibility and antioxidant activity. In vitro digestions were performed supporting standard intestinal (pH 7, bile salts concentration 10 mM) and altered (pH 6, bile salts concentration 1 mM) conditions. The altered conditions significantly reduced lipolysis, but not proteolysis. Regarding the food matrix, compared to the chia seeds, whole and partially defatted flour increased the hydrolysis of lipids and protein, relating to reduced particle size. Sprouting had an enhancing effect on proteolysis but prevented lipolysis. Calcium bioaccessibility dropped in all the samples in the two intestinal conditions. The digestion process led to increased polyphenols bioaccessibility in all the structures, but reduced antioxidant activity except in the milled structures. In conclusion, milling should be applied to chia seeds prior to consumption in cases where enhancing the potential uptake of macro and micronutrients is targeted, and sprouting is suitable to enhance protein digestibility and reduce lipolysis.