Toxicological effects of ingested nanocellulose in in vitro intestinal epithelium and in vivo rat models

Influence of cellulose nanocrystals (CNC) on permeation through intestinal monolayer and mucus model in vitro

Cellulose nanocrystals (CNC) as a novel ingredient in foods and pharmaceuticals still lacks the safety and functionality information. We aimed to assess the absorption of CNC in small intestine and the effect on cell viability. In the second part, the impact of CNC on substance permeation through mucus layer, including the potential functionality in improving high blood cholesterol, was tested. No noticeable amount of CNC was found to penetrate through differentiated Caco-2 monolayer and in vitro mucus layer, and CNC had low toxicity on Caco-2 cell viability up to 10 mg/mL. CNC at 2 % (w/w) may affect the permeability of the mucus layer and larger molecules are more easily influenced. CNC may also alleviate hypercholesteremia by increasing viscosity of digesta, adsorbing cholesterol, and decreasing bile acids permeation. The results suggest CNC may not penetrate the small intestinal lining and may be used as a functional supplement.

High-Throughput Screening Platform for Nanoparticle-Mediated Alterations of DNA Repair Capacity

The potential genotoxic effects of engineered nanomaterials (ENMs) may occur through the induction of DNA damage or the disruption of DNA repair processes. Inefficient DNA repair may lead to the accumulation of DNA lesions and has been linked to various diseases, including cancer. Most studies so far have focused on understanding the nanogenotoxicity of ENM-induced damages to DNA, whereas the effects on DNA repair have been widely overlooked. The recently developed fluorescence multiplex-host-cell reactivation (FM-HCR) assay allows for the direct quantification of multiple DNA repair pathways in living cells and offers a great opportunity to address this methodological gap. Herein an FM-HCR-based method is developed to screen the impact of ENMs on six major DNA repair pathways using suspended or adherent cells. The sensitivity and efficiency of this DNA repair screening method were demonstrated in case studies using primary human small airway epithelial cells and TK6 cells exposed to various model ENMs (CuO, ZnO, and Ga2O3) at subcytotoxic doses. It was shown that ENMs may inhibit nucleotide-excision repair, base-excision repair, and the repair of oxidative damage by DNA glycosylases in TK6 cells, even in the absence of significant genomic DNA damage. It is of note that the DNA repair capacity was increased by some ENMs, whereas it was suppressed by others. Overall, this method can be part of a multitier, in vitro hazard assessment of ENMs as a functional, high-throughput platform that provides insights into the interplay of the properties of ENMs, the DNA repair efficiency, and the genomic stability.

Role of Surface Chemistry in the In Vitro Lung Response to Nanofibrillated Cellulose

Wood-derived nanofibrillated cellulose (NFC) has emerged as a sustainable material with a wide range of applications and increasing presence in the market. Surface charges are introduced during the preparation of NFC to facilitate the defibrillation process, which may also alter the toxicological properties of NFC. In the present study, we examined the in vitro toxicity of NFCs with five surface chemistries: nonfunctionalized, carboxymethylated, phosphorylated, sulfoethylated, and hydroxypropyltrimethylammonium-substituted. The NFC samples were characterized for surface functional group density, surface charge, and fiber morphology. Fibril aggregates predominated in the nonfunctionalized NFC, while individual nanofibrils were observed in the functionalized NFCs. Differences in surface group density among the functionalized NFCs were reflected in the fiber thickness of these samples. In human bronchial epithelial (BEAS-2B) cells, all NFCs showed low cytotoxicity (CellTiter-GloVR luminescent cell viability assay) which never exceeded 10% at any exposure time. None of the NFCs induced genotoxic effects, as evaluated by the alkaline comet assay and the cytokinesis-block micronucleus assay. The nonfunctionalized and carboxymethylated NFCs were able to increase intracellular reactive oxygen species (ROS) formation (chloromethyl derivative of 2',7'-dichlorodihydrofluorescein diacetate assay). However, ROS induction did not result in increased DNA or chromosome damage.

Physical, chemical, and toxicological characterization of sulfated cellulose nanocrystals for food-related applications using in vivo and in vitro strategies

Cellulose nanocrystals (CNCs) are a next-generation cellulose product with many unique properties including applications in the food industry as a food additive, food coating, and in food-contact packaging material. While CNC is anticipated to be safe due to its similarity to the many forms of cellulose currently used as food additives, special consideration is given to it as it is the first manufactured form of cellulose that is nanoscale in both length and width. A proactive approach to safety has been adopted by manufacturers to demonstrate CNC safety toward responsible commercialization. As part of the safety demonstration, in vivo and in vitro testing strategies were commissioned side-by-side with conventional cellulose, which has been safely used in food for decades. Testing included a 90-day rodent feeding study as well as additional physical, chemical, and biological studies in vitro that follow European Food Safety Authority (EFSA) guidance to demonstrate the safe use of novel food ingredients. The strategy includes assessment of neat materials side-by-side with simulated digestion, mimicking conditions that occur along the gastrointestinal tract as well as intracellularly. An intestinal co-culture model examined any potential toxicological effects from exposure to either pristine or digested forms of CNC including cytotoxicity, metabolic activity, membrane permeability, oxidative stress, and proinflammatory responses. None of the studies demonstrated any toxicity via oral or simulated oral exposure. These studies demonstrate that CNC produced by InnoTech Alberta is similarly safe by ingestion as conventional cellulose with a no-observed-adverse-effect level of 2085.3 (males) and 2682.8 (females) mg/kg/day.

Effects of Ingested Nanomaterials on Tissue Distribution of Co-ingested Zinc and Iron in Normal and Zinc-Deficient Mice

Cellulose nanofibers (CNF) reduced serum triglyceride levels in rats when co-administered with heavy cream by gavage. Do CNF and other nanomaterials (NMs) alter the tissue distribution and retention of co-administered metal ions? We evaluated whether 5 different NMs affected tissue distribution of co-ingested 65Zn++ and 59Fe+++ in zinc-replete versus zinc-deficient mice. Male C57BL/6J mice were fed either zinc-replete or zinc-deficient diets for 3 weeks, followed by gavage with NM suspensions in water containing both 65ZnCl2 and 59FeCl3. Urine and feces were measured for 48 h post-gavage. Mice were euthanized and samples of 22 tissues were collected and analyzed for 65Zn and 59Fe in a gamma counter. Our data show that zinc deficiency alters the tissue distribution of 65Zn but not of 59Fe, indicating that zinc and iron homeostasis are regulated by distinct mechanisms. Among the tested NMs, soluble starch-coated chitosan nanoparticles, cellulose nanocrystals, and TiO2 reduced Zn and Fe tissue retention in zinc-deficient but not in zinc-replete animals.

Recent Advances in Food Emulsions and Engineering Foodstuffs Using Plant-Based Nanocelluloses

In this article, the application of nanocelluloses, especially cellulose nanofibrils and cellulose nanocrystals, as functional ingredients in foods is reviewed. These ingredients offer a sustainable and economic source of natural plant-based nanoparticles. Nanocelluloses are particularly suitable for altering the physicochemical, sensory, and nutritional properties of foods because of their ability to create novel structures. For instance, they can adsorb to air-water or oil-water interfaces and stabilize foams or emulsions, self-assemble in aqueous solutions to form gel networks, and act as fillers or fat replacers. The functionality of nanocelluloses can be extended by chemical functionalization of their surfaces or by using them in combination with other natural food ingredients, such as biosurfactants or biopolymers. As a result, it is possible to create stimuli-responsive, tailorable, and/or active functional biomaterials suitable for a range of foodapplications. In this article, we describe the chemistry, structure, and physicochemical properties of cellulose as well as their relevance for the application of nanocelluloses as functional ingredients in foods. Special emphasis is given to their use as particle stabilizers in Pickering emulsions, but we also discuss their potential application for creating innovative biomaterials with novel functional attributes, such as edible films and packaging. Finally, some of the challenges associated with using nanocelluloses in foods are critically evaluated, including their potential safety and consumer acceptance.

Nanocellulose Bio-Based Composites for Food Packaging

The food industry is increasingly demanding advanced and eco-friendly sustainable packaging materials with improved physical, mechanical and barrier properties. The currently used materials are synthetic and non-degradable, therefore raising environmental concerns. Consequently, research efforts have been made in recent years towards the development of bio-based sustainable packaging materials. In this review, the potential of nanocelluloses as nanofillers or as coatings for the development of bio-based nanocomposites is discussed, namely: (i) the physico-chemical interaction of nanocellulose with the adjacent polymeric phase, (ii) the effect of nanocellulose modification/functionalization on the final properties of the composites, (iii) the production methods for such composites, and (iv) the effect of nanocellulose on the overall migration, toxicity, and the potential risk to human health. Lastly, the technology readiness level of nanocellulose and nanocellulose based composites for the market of food packaging is discussed.

Biodegradable Antimicrobial Food Packaging: Trends and Perspectives

This review presents a perspective on the research trends and solutions from recent years in the domain of antimicrobial packaging materials. The antibacterial, antifungal, and antioxidant activities can be induced by the main polymer used for packaging or by addition of various components from natural agents (bacteriocins, essential oils, natural extracts, etc.) to synthetic agents, both organic and inorganic (Ag, ZnO, TiO2 nanoparticles, synthetic antibiotics etc.). The general trend for the packaging evolution is from the inert and polluting plastic waste to the antimicrobial active, biodegradable or edible, biopolymer film packaging. Like in many domains this transition is an evolution rather than a revolution, and changes are coming in small steps. Changing the public perception and industry focus on the antimicrobial packaging solutions will enhance the shelf life and provide healthier food, thus diminishing the waste of agricultural resources, but will also reduce the plastic pollution generated by humankind as most new polymers used for packaging are from renewable sources and are biodegradable. Polysaccharides (like chitosan, cellulose and derivatives, starch etc.), lipids and proteins (from vegetal or animal origin), and some other specific biopolymers (like polylactic acid or polyvinyl alcohol) have been used as single component or in blends to obtain antimicrobial packaging materials. Where the package's antimicrobial and antioxidant activities need a larger spectrum or a boost, certain active substances are embedded, encapsulated, coated, grafted into or onto the polymeric film. This review tries to cover the latest updates on the antimicrobial packaging, edible or not, using as support traditional and new polymers, with emphasis on natural compounds.

Lipid and protein corona of food-grade TiO2 nanoparticles in simulated gastrointestinal digestion

In the presence of biological matrices, engineered nanomaterials, such as TiO₂, develop a biomolecular corona composed of lipids, proteins, etc. In this study, we analyzed the biocorona formed on the food grade TiO₂ (E171) going through an in vitro simulated gastrointestinal digestion system in either a fasting food model (FFM), a standardized food model (SFM), or a high fat food model (HFFM). Lipids and proteins were extracted from the biocorona and underwent untargeted lipidomic and label-free shotgun proteomic analyses. Our results showed that the biocorona composition was different before and after food digestion. After digestion, more diverse lipids were adsorbed compared to proteins, most of which were the enzymes added to the simulated digestion system. The corona lipid profile was distinct from the digested food model they presented in, although similarity in the lipid profiles between the corona and the food matrix increased with the fat content in the food model. The corona formed in the two low-fat environments of FFM and SFM shared a higher degree of similarity while very different from their corresponding matrix, with some lipid species adsorbed with high enrichment factors, indicating specific interaction with the TiO₂ surface outperforming lipid matrix concentration in determination of corona formation. Formation of the biocorona may have contributed to the reduced oxidative stress as well as toxicological impacts observed in cellular studies. The present work is the first to confirm persistent adsorption of biomolecules could occur on ingested nanomaterials in food digestae. More future studies are needed to study the in vivo impacts of the biocorona, and shed lights on how the biocorona affects the biotransformations and fate of the ingested nanomaterials, which may impose impacts on human health.

A high-throughput method to characterize the gut bacteria growth upon engineered nanomaterial treatment

Human are increasingly exposed to various types of engineered nanomaterials (ENMs) via dietary ingestion of nano-enabled food products, but these ENMs' impact on the gut bacteria health is still poorly understood. Current efforts in understanding the impact of these ENMs are hampered by their optical interferences in conventional quantification and viability assays, such as optical density and whole cell fluorescence staining assays. Therefore, there is a need to develop a more reliable bacteria quantification method in the presence of ENMs to effectively screen the potential adverse effects arising from the exposure of increasing ENMs on human gut microbiome. In this study, we developed a DNA-based quantification (DBQ) method in a 96-well plate format. Post-spiking method was used to correct the interference from ENMs on the reading. We showed the applicability of this method for several types of ENMs, i.e., cellulose nanofiber (CNF), graphene oxide (GO), silicon dioxide (SiO2), and chitosan, both in pure bacterial culture and in vitro human gut microbiome community. The detection limit for the highest dosing of CNF, GO, SiO2, and chitosan ENMs was approximately 0.18, 0.19, 0.05, and 0.24 as OD600, respectively. The method was also validated by a dose response experiment of E. coli with chitosan in the course of 8 hr. We believe that this method has great potential to be used in screening the effect of ENMs on the growth of gut bacteria or any other in vitro models and normalization for metabolites or proteins analysis.

Manufacturing of Food Packaging Based on Nanocellulose: Current Advances and Challenges

Nowadays, environmental pollution due to synthetic polymers represents one of the biggest worldwide challenges. As demonstrated in numerous scientific articles, plant-based nanocellulose (NC) is a biodegradable and nontoxic material whose mechanical, rheological, and gas barrier properties are competitive compared to those of oil-based plastics. However, the sensitivity of NC in humid ambient and lack of thermosealability have proven to be a major obstacle that hinders its breakthrough in various sectors including food packaging. In recent years, attempts have been made in order to provide a hydrophobic character to NC through chemical modifications. In addition, extensive works on nanocellulose applications in food packaging such as coating, layer-by-layer, casting, and electrospinning have been reported. Despite these enormous advances, it can easily be observed that packaging manufacturers have not yet shown a particular interest in terms of applicability and processability of the nanocellulose due to the lack of guidelines and guarantee on the success of their implementation. This review is useful for researchers and packaging manufacturers because it puts emphasis on recent works that have dealt with the nanocellulose applications and focuses on the best strategies to be adopted for swift and sustainable industrial manufacturing scale-up of high-performance bio-based/compostable packaging in replacement of the oil-based counterparts used today.

In Vitro Biological Impact of Nanocellulose Fibers on Human Gut Bacteria and Gastrointestinal Cells

Wood-derived nanofibrillated cellulose (NFC) has long been recognized as a valuable nanomaterial for food-related applications. However, the safety of NFC cannot be predicted just from the chemical nature of cellulose, and there is a need to establish the effect of the nanofibers on the gastrointestinal tract, to reassure the safe use of NFC in food-related products. The present work selected the intestinal cells Caco-2 and the gut bacteria Escherichia coli and Lactobacillus reuteri to evaluate the in vitro biological response to NFC. NFC materials with different surface modifications (carboxymethylation, hydroxypropyltrimethylammonium substitution, phosphorylation and sulfoethylation) and unmodified NFC were investigated. The materials were characterized in terms of surface functional group content, fiber morphology, zeta potential and degree of crystallinity. The Caco-2 cell response to the materials was evaluated by assessing metabolic activity and cell membrane integrity. The effects of the NFC materials on the model bacteria were evaluated by measuring bacterial growth (optical density at 600 nm) and by determining colony forming units counts after NFC exposure. Results showed no sign of cytotoxicity in Caco-2 cells exposed to the NFC materials, and NFC surface functionalization did not impact the cell response. Interestingly, a bacteriostatic effect on E. coli was observed while the materials did not affect the growth of L. reuteri. The present findings are foreseen to contribute to increase the knowledge about the potential oral toxicity of NFC and, in turn, add to the development of safe NFC-based food products.

Synthesis and Physicochemical Transformations of Size-Sorted Graphene Oxide during Simulated Digestion and Its Toxicological Assessment against an In Vitro Model of the Human Intestinal Epithelium

In the last decade, along with the increasing use of graphene oxide (GO) in various applications, there is also considerable interest in understanding its effects on human health. Only a few experimental approaches can simulate common routes of exposure, such as ingestion, due to the inherent complexity of the digestive tract. This study presents the synthesis of size-sorted GO of sub-micrometer- or micrometer-sized lateral dimensions, its physicochemical transformations across mouth, gastric, and small intestinal simulated digestions, and its toxicological assessment against a physiologically relevant, in vitro cellular model of the human intestinal epithelium. Results from real-time characterization of the simulated digestas of the gastrointestinal tract using multi-angle laser diffraction and field-emission scanning electron microscopy show that GO agglomerates in the gastric and small intestinal phase. Extensive morphological changes, such as folding, are also observed on GO following simulated digestion. Furthermore, X-ray photoelectron spectroscopy reveals that GO presents covalently bound N-containing groups on its surface. It is shown that the GO employed in this study undergoes reduction. Toxicological assessment of the GO small intestinal digesta over 24 h does not point to acute cytotoxicity, and examination of the intestinal epithelium under electron microscopy does not reveal histological alterations. Both sub-micrometer- and micrometer-sized GO variants elicit a 20% statistically significant increase in reactive oxygen species generation compared to the untreated control after a 6 h exposure.

Nanocellulose-Based Inks for 3D Bioprinting: Key Aspects in Research Development and Challenging Perspectives in Applications-A Mini Review

Nanocelluloses have emerged as a catalogue of renewable nanomaterials for bioink formulation in service of 3D bioprinting, thanks to their structural similarity to extracellular matrices and excellent biocompatibility of supporting crucial cellular activities. From a material scientist's viewpoint, this mini-review presents the key research aspects of the development of the nanocellulose-based bioinks in 3D (bio)printing. The nanomaterial properties of various types of nanocelluloses, including bacterial nanocellulose, cellulose nanofibers, and cellulose nanocrystals, are reviewed with respect to their origins and preparation methods. Different cross-linking strategies to integrate into multicomponent nanocellulose-based bioinks are discussed in terms of regulating ink fidelity in direct ink writing as well as tuning the mechanical stiffness as a bioactive cue in the printed hydrogel construct. Furthermore, the impact of surface charge and functional groups on nanocellulose surface on the crucial cellular activities (e.g., cell survival, attachment, and proliferation) is discussed with the cell-matrix interactions in focus. Aiming at a sustainable and cost-effective alternative for end-users in biomedical and pharmaceutical fields, challenging aspects such as biodegradability and potential nanotoxicity of nanocelluloses call for more fundamental comprehension of the cell-matrix interactions and further validation in in vivo models.

Immunological aspects of nanocellulose

Cellulose is the most abundant natural polymer in the world. Nanoscale forms of cellulose, including cellulose nanofibers (CNF), cellulose nanocrystals (CNC) and bacterial nanocellulose (BC), are very attractive in industry, medicine and pharmacy. Biomedical applications of nanocellulose in tissue engineering, regenerative medicine, and controlled drug delivery are the most promising. Nanocellulose is considered a biocompatible nanomaterial and relatively safe for biomedical applications. However, more studies are needed to prove this hypothesis, especially those related to chronic exposure to nanocellulose. Besides toxicity, the response of the immune system is of particular importance in this sense. This paper provides a comprehensive and critical review of the current-state knowledge of the impact of nanocellulose on the immune system, especially on macrophages and dendritic cells (DC), as the central immunoregulatory cells, which has not been addressed in the literature sufficiently. Nanocellulose, especially CNC, can induce the inflammatory response upon the internalization by macrophages, but this reaction may be significantly modulated by introducing different functional groups on their surface. Our original results showed that nanocellulose has a potent immunotolerogenic potential. Native CNF potentiated the capacity of DC to induce conventional Tregs. When carboxyl groups were introduced on the CNF surface, the tolerogenic potential of DC was shifted towards the induction of regulatory CD8⁺ T cells, whereas the introduction of phosphonates on CNF surface potentiated DCs' capacity to induce both regulatory CD8⁺ T cells and Type 1 regulatory (Tr-1) cells. These results are extremely important when considering the application of nanocellulose in vivo, especially for tissue regeneration and wound healing.

Engineering Two-dimensional Nanomaterials to Enable Structure-Activity Relationship Studies in Nanosafety Research

Emerging, two-dimensional engineered nanomaterials (2DNMs) possess unique and diverse physical and chemical properties, such as extreme aspect ratios, adjustable electronic properties as well as functional lattice defects and surface chemistry which underpin their interactions with biological systems. This perspective highlights the need for structure activity relationship (SAR) studies for key properties of emerging grapheme-related and inorganic 2DNMs upon prioritization based on their potential impact and trajectory for large-scale production and applications. Further, it is discussed how a synthesis platform of microbiologically sterile, size-sorted, "model" 2DNMs with precise structure would enable SAR toxicological studies and allow for the sustainable and safe translation of 2D nanotechnology to real-world applications.

Effects of ingested nanocellulose on intestinal microbiota and homeostasis in Wistar Han rats

Micron scale cellulose materials are "generally regarded as safe" (GRAS) as binders and thickeners in food products. However, nanocellulose materials, which have unique properties that can improve food quality and safety, have not received US-Food and Drug Administration (FDA) approval as food ingredients. In vitro and in vivo toxicological studies of ingested nanocellulose revealed minimal cytotoxicity, and no subacute in vivo toxicity. However, ingested materials may modulate gut microbial populations, or alter aspects of intestinal function not elucidated by toxicity testing, which could have important health implications. Here, we report the results of studies conducted in a rat gavage model to assess the effects of ingested cellulose nanofibrils (CNF) on the fecal microbiome and metabolome, intestinal epithelial expression of cell junction genes, and ileal cytokine production. Feces, plasma, and ilea were collected from Wistar Han rats before and after five weeks of biweekly gavages with water or cream, with or without 1% CNF. CNF altered microbial diversity, and diminished specific species that produce short chain fatty acids, and that are associated with increased serum insulin and IgA production. CNF had few effects on the fecal metabolome, with significant changes in only ten metabolites of 366 measured. Exposure to CNF also altered expression of epithelial cell junction genes, and increased production of cytokines that modulate proliferation of CD8 T cells. These perturbations likely represent initiation of an adaptive immune response, however, no associated pathology was seen within the duration of the study. Additional studies are needed to better understand the health implications of these changes in long term.

A 90-day dietary study with fibrillated cellulose in Sprague-Dawley rats

Novel forms of fibrillated cellulose offer improved attributes for use in foods. Conventional cellulose and many of its derivatives are already widely used as food additives and are authorized as safe for use in foods in many countries. However, novel forms have not yet been thoroughly investigated using standardized testing methods. This study assesses the 90-day dietary toxicity of fibrillated cellulose, as compared to a conventional cellulose, Solka Floc. Sprague Dawley rats were fed 2 %, 3 %, or 4 % fibrillated cellulose for 90 consecutive days, and parallel Solka Floc groups were used as controls. Survival, clinical observations, body weight, food consumption, ophthalmologic evaluations, hematology, serum chemistry, urinalysis, post-mortem anatomic pathology, and histopathology were monitored and performed. No adverse observations were noted in relation to the administration of fibrillated cellulose. Under the conditions of this study and based on the toxicological endpoints evaluated, the no-observed-adverse-effect level (NOAEL) for fibrillated cellulose was 2194.2 mg/kg/day (males) and 2666.6 mg/kg/day (females), corresponding to the highest dose tested (4 %) for male and female Sprague Dawley rats. These results demonstrate that fibrillated cellulose behaves similarly to conventional cellulose and raises no safety concerns when used as a food ingredient at these concentrations.

Physicochemical and Morphological Transformations of Chitosan Nanoparticles across the Gastrointestinal Tract and Cellular Toxicity in an In Vitro Model of the Small Intestinal Epithelium

Nanoscale chitosan materials exhibit size-specific properties that make them useful in agri-food and biomedical applications. Chitosan nanoparticles (Chnps) are being explored as nanocarrier platforms to increase oral bioavailability of drugs and nutraceuticals, but little is known of their fate and transformations in the gastrointestinal tract (GIT) or of their potential toxicity. Here, the GIT fate and cytotoxicity of Chnps, soluble starch-coated Chnps (SS-Chnps), and bulk chitosan powder (Chp), were assessed using a 3-phase simulated digestion and an in vitro cellular small intestinal epithelium model. Physico-chemical characterization revealed dissolution of Chp, but not of Chnps or SS-Chnps, during the gastric phase of digestion, stability of the starch coating of SS-Chnps in the oral and gastric phases, and agglomeration of all materials during the small intestinal phase. A slight but significant (10%, p < 0.01) increase in cytotoxicity (LDH release) was observed with exposure to digested Chnps but not Chp or SS-Chnps.

Subchronic exposure to cellulose nanofibrils induces nutritional risk by non-specifically reducing the intestinal absorption

Previous studies of cellulose nanofibrils (CNF) in decreasing fat absorption and glucose release suggested their potential application as food additives or supplements in diets containing high contents of fat and sugars. However, the long-term effects of CNF uptake remained unknown. The purpose of this study was to determine the effects of subchronic oral CNF consumption on various health aspects of Western diets (WD)-fed mice. The results demonstrated that CNF decreased fat absorption in the jejunum and attenuated WD-induced fatty liver, but slightly decreased lean body mass and affected glucose homeostasis. Additional in vivo studies showed that CNF decreased the intestinal absorption. The in vitro studies suggested that CNF did not decrease the viability of any cells used; however, they prevented epithelial and T cells, but not macrophages, from accessing the viability dye. Taken together, CNF decreased the intestinal absorption non-specifically, which might lead to nutritional risks after long-term exposure.