Effects of Walnut Consumption on Colon Carcinogenesis and Microbial Community Structure

Adherence to the Mediterranean diet and its protective effects against colorectal cancer: a meta-analysis of 26 studies with 2,217,404 participants

Colorectal cancer (CRC) is a major global health concern and represents a significant public health challenge in Hungary, where it exhibits some of the highest morbidity and mortality rates in the European Union. The Mediterranean diet has been suggested to reduce the incidence of CRC, but comprehensive evidence from diverse study designs is needed to substantiate this effect. A systematic literature search was conducted in PubMed, ClinicalTrials.gov, CENTRAL, and the Web of Science to identify randomized controlled trials and human clinical trials from 2008 to 2024 to identify relevant studies. Statistical analysis was performed using the https://metaanalysisonline.com web application using a random effects model to estimate the pooled hazard rates (HRs). Forest plots, funnel plots, and Z-score plots were utilized to visualize results. We identified 15 clinical trials and 9 case-control studies, encompassing a total of 2,217,404 subjects. The pooled analysis indicated that adherence to the Mediterranean diet significantly reduced the prevalence of CRC (HR = 0.84, 95% CI = 0.78-0.91, p < 0.01). This protective effect was consistent across sexes, with HRs of 0.85 (95% CI = 0.75-0.97, p = 0.01) for males and 0.88 (95% CI = 0.79-0.99, p = 0.03) for females. Case-control studies specifically showed a substantial effect (HR = 0.51, 95% CI = 0.38-0.68, p < 0.01). Notable heterogeneity was observed across studies, yet the a priori information size was substantially below the cumulative sample size, ensuring sufficient data for reliable conclusions. The findings from this meta-analysis reinforce the protective role of the Mediterranean diet against CRC. The results of this meta-analysis will inform dietary interventions designed to mitigate CRC risk, which are conducted within the framework of the Semmelweis Study, an ongoing comprehensive cohort study at Semmelweis University, designed to explore the multifaceted causes of unhealthy aging in Hungary. These interventions aim to explore the practical application of Mediterranean dietary patterns in reducing CRC incidence among the Hungarian population.

Nut consumption and urogenital and genital, gastrointestinal and women-related cancers: Assessment and review

The prevalence of cancer, especially in industrial countries, is a major problem for health and treatment systems. Cancer can affect the quality of life of all family members and has many negative effects on the community. Despite many advances in cancer treatment, this disease is still a major worldwide problem. There is strong evidence that dietary habits are effective in protecting against cancer and even helping in the disease treatment progress. Nuts with various biologically-active compounds, such as vitamins, phytosterols, isoflavones, flavonoids, and polyphenols have been reported to possess anticarcinogenic properties. Accordingly, this review provides an insight into the association between nut consumption and the prevention of some cancers. We considered the cancers related to the urogenital and genital tract, gastrointestinal tract, as well as women-related cancers. Both cell culture examinations and experimental animal studies alongside observational epidemiological studies demonstrated that regular consumption of a nut-enriched diet is able to reduce the risk of these cancers.

Effect of red wheat, aleurone, and testa layers on colon cancer biomarkers, nitrosative stress, and gut microbiome composition in rats

We previously found greater reduction of colon cancer (CC) biomarkers for red wheat compared to white wheat regardless of refinement state. In the present study we examined whether the phenolic-rich aleurone and testa layers are drivers of chemoprevention by red wheat and their influence on gut microbiota composition using a 1,2-dimethylhydrazine-induced CC rat model. Rats were fed a low-fat diet (16% of energy as fat), high-fat diet (50% of energy as fat), or high-fat diet containing whole red wheat, refined red wheat, refined white wheat, or aleurone- or testa-enriched fractions for 12 weeks. Morphological markers (aberrant crypt foci, ACF) were assessed after methylene blue staining and biochemical markers (3-nitrotyrosine [3-NT], Dclk1) by immunohistochemical determination of staining positivity within aberrant crypts. Gut microbiota composition was evaluated from 16S rRNA gene sequencing of DNA extracted from cecal contents. Relative to the high-fat diet, the whole and refined red wheat, refined white wheat, and testa-enriched fraction decreased ACF, while only the refined red wheat and aleurone-enriched fraction decreased 3-NT. No significant differences were observed for Dclk1. An increase in microbial diversity was observed for the aleurone-enriched fraction (ACE index) and whole red wheat (Inverse Simpson Index). The diet groups significantly modified overall microbiome composition, including altered abundances of Lactobacillus, Mucispirillum, Phascolarctobacterium, and Blautia coccoides. These results suggest that red wheat may reduce CC risk through modifications to the gut microbiota and nitrosative stress, which may be due, in part, to the influence of dietary fiber and the phenolic-rich aleurone layer.

Antioxidant and Anti-Inflammatory Properties of Walnut Constituents: Focus on Personalized Cancer Prevention and the Microbiome

Walnuts have been lauded as a 'superfood', containing a remarkable array of natural constituents that may have additive and/or synergistic properties that contribute to reduced cancer risk. Walnuts are a rich source of polyunsaturated fatty acids (PUFAs: alpha-linolenic acid, ALA), tocopherols, antioxidant polyphenols (including ellagitannins), and prebiotics, including fiber (2 g/oz). There is a growing body of evidence that walnuts may contribute in a positive way to the gut microbiome, having a prebiotic potential that promotes the growth of beneficial bacteria. Studies supporting this microbiome-modifying potential include both preclinical cancer models as well as several promising human clinical trials. Mediated both directly and indirectly via its actions on the microbiome, many of the beneficial properties of walnuts are related to a range of anti-inflammatory properties, including powerful effects on the immune system. Among the most potent constituents of walnuts are the ellagitannins, primarily pedunculagin. After ingestion, the ellagitannins are hydrolyzed at low pH to release ellagic acid (EA), a non-flavonoid polyphenolic that is subsequently metabolized by the microbiota to the bioactive urolithins (hydroxydibenzo[b,d]pyran-6-ones). Several urolithins, including urolithin A, reportedly have potent anti-inflammatory properties. These properties of walnuts provide the rationale for including this tree nut as part of a healthy diet for reducing overall disease risk, including colorectal cancer. This review considers the latest information regarding the potential anti-cancer and antioxidant properties of walnuts and how they may be incorporated into the diet to provide additional health benefits.

Dried Fruits, Nuts, and Cancer Risk and Survival: A Review of the Evidence and Future Research Directions

Dried fruits and nuts contain high amounts of nutrients and phytochemicals-all of which may have anticarcinogenic, anti-inflammatory, and antioxidant properties. This narrative review summarizes the evidence for dried fruits and nuts and cancer incidence, mortality, and survival and their potential anticancer properties. The evidence for dried fruits in cancer outcomes is limited, but existing studies have suggested an inverse relationship between total dried fruit consumption and cancer risk. A higher consumption of nuts has been associated with a reduced risk of several site-specific cancers in prospective cohort studies, including cancers of the colon, lung, and pancreas, with relative risks per 5 g/day increment equal to 0.75 (95% CI 0.60, 0.94), 0.97 (95% CI 0.95, 0.98), and 0.94 (95% CI 0.89, 0.99), respectively. A daily intake of total nuts of 28 g/day has also been associated with a 21% reduction in the rate of cancer mortality. There is also some evidence that frequent nut consumption is associated with improved survival outcomes among patients with colorectal, breast, and prostate cancer; however, further studies are needed. Future research directions include the investigation of additional cancer types, including rare types of cancer. For cancer prognosis, additional studies with pre- and postdiagnosis dietary assessment are warranted.

Dietary Walnuts Preserve Aspects of Health Span and Alter the Hippocampal Lipidome in Aged High-Fat Diet-Fed Mice

Evidence continues to accrue that aging and its diseases can be delayed by pharmacologic and dietary strategies that target the underlying hallmarks of the aging process. However, identifying simple, safe, and effective dietary strategies involving the incorporation of whole foods that may confer some protection against the aging process is also needed. Recent observational studies have suggested that nut consumption can reduce mortality risk in humans. Among these, walnuts are particularly intriguing, given their high content of n-3 fatty acids, fiber, and antioxidant and anti-inflammatory compounds. To this end, 12-month-old male CB6F1 mice were provided either a defined control low-fat diet (LFD), a control high-fat diet (HFD), or an isocaloric HFD containing 7.67% walnuts by weight (HFD + W), and measures of healthspan and related biochemical markers (n = 10-19 per group) as well as survival (n = 20 per group) were monitored. Mice provided the HFD or HFD + W demonstrated marked weight gain, but walnuts lowered baseline glucose (p < 0.05) and tended to temper the effects of HFD on liver weight gain (p < 0.05) and insulin tolerance (p = 0.1). Additional assays suggested a beneficial effect on some indicators of health with walnut supplementation, including preservation of exercise capacity and improved short-term working memory, as determined by Y maze (p = 0.02). However, no effect was observed via any diet on inflammatory markers, antioxidant capacity, or survival (p = 0.2). Ingenuity Pathway Analysis of the hippocampal transcriptome identified two processes predicted to be affected by walnuts and potentially linked to cognitive function, including estrogen signaling and lipid metabolism, with changes in the latter confirmed by lipidomic analysis. In summary, while walnuts did not significantly improve survival on a HFD, they tended to preserve features of healthspan in the context of a metabolic stressor with aging.

Resistant Potato Starch Alters the Cecal Microbiome and Gene Expression in Mice Fed a Western Diet Based on NHANES Data

Several studies indicate that the four major types of resistant starch (RS1-4) are fermented in the cecum and colon to produce short-chain fatty acids (SCFAs) and can alter the microbiome and host physiology. However, nearly all these studies were conducted in rodents fed with a diet that does not approximate what is typically consumed by humans. To address this, mice were fed a Total Western Diet (TWD) based on National Health and Nutrition Examination Survey (NHANES) data that mimics the macro and micronutrient composition of a typical American diet for 6 weeks and then supplemented with 0, 2, 5, or 10% of the RS2, resistant potato starch (RPS), for an additional 3 weeks. The cecal microbiome was analyzed by 16S sequencing. The alpha-diversity of the microbiome decreased with increasing consumption of RPS while a beta-diversity plot showed four discreet groupings based on the RPS level in the diet. The relative abundance of various genera was altered by feeding increasing levels of RPS. In particular, the genus Lachnospiraceae NK4A136 group was markedly increased. Cecal, proximal, and distal colon tissue mRNA abundance was analyzed by RNASeq. The cecal mRNA abundance principal component analysis showed clear segregation of the four dietary groups whose separation decreased in the proximal and distal colon. Differential expression of the genes was highest in the cecum, but substantially decreased in the proximal colon (PC) and distal colon (DC). Most differentially expressed genes were unique to each tissue with little overlap in between. The pattern of the observed gene expression suggests that RPS, likely through metabolic changes secondary to differences in microbial composition, appears to prime the host to respond to a range of pathogens, including viruses, bacteria, and parasites. In summary, consumption of dietary RPS led to significant changes to the microbiome and gene expression in the cecum and to a lesser extent in the proximal and distal colon.

The Emerging Biotherapeutic Agent: Akkermansia

The human gastrointestinal tract (GIT) is a well-recognized hub of microbial activities. The microbiota harboring the mucus layer of the GIT act as a defense against noxious substances, and pathogens including Clostridium difficile, Enterococcus faecium, Escherichia coli, Salmonella Typhimurium. Toxins, pathogens, and antibiotics perturb the commensal floral composition within the GIT. Imbalanced gut microbiota leads to dysbiosis, manifested as diseases ranging from obesity, diabetes, and cancer to reduced lifespan. Among the bacteria present in the gut microbiome, the most beneficial are those representing Firmicutes and Bacteroidetes. Recent studies have revealed the emergence of a novel biotherapeutic agent, Akkermansia, which is instrumental in regaining eubiosis and conferring various health benefits.

Determination of volatile organic compounds by HS-GC-IMS to detect different stages of Aspergillus flavus infection in Xiang Ling walnut

The aim of this study was to evaluate the performance of volatile organic compounds (VOCs) for evolution monitoring and early detection of Aspergillus flavus (A. flavus) contamination in walnuts. We successfully applied headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) to evaluate walnut VOC changes caused by A. flavus contamination. A total of 48 VOCs were identified in walnuts contaminated with A. flavus. After identification of VOCs, a heat map and principal component analysis (PCA) highlighted ethyl acetate-D, 3-methyl-2-butanol, and cyclohexanone as potential biomarkers specific to A. flavus contamination in walnuts. These results provided valid targets for the development of sensors to evaluate the early mold contamination in stored walnuts.

Anti-NAFLD effect of defatted walnut powder extract in high fat diet-induced C57BL/6 mice by modulating the gut microbiota

ETHNOPHARMACOLOGICAL RELEVANCE

Walnut kernel has the actions of removing meteorism, dissipating stagnation and removing blood stasis and is used after being defatted in TCM. Defatted walnut powder extract (DWPE) has the abilities of anti-oxidation and lowering lipid levels in vivo. However, the effects and the potential mechanisms of DWPE on NAFLD have not been explored.

AIM OF THE STUDY

The study were to investigate the anti-NAFLD effect of DWPE in high fat diet-induced C57BL/6 mice and demonstrate that whether DWPE developed the effect on anti-NAFLD by remodeling the compositions and abundances of gut microbiota.

MATERIALS AND METHODS

The inhibitory effect of DWPE on the development of NAFLD was conducted on C57BL/6 mice with a high fat diet and the regulation effect of DWPE on gut microbiota was verified on pseudo-sterile mice with treatment of broad spectrum antibiotics.

RESULTS

The results showed that the oral administration of DWPE remarkably alleviated hepatic lipid accumulation by decreasing the levels of TG, TC, LDL, MDA and increasing HDL. Meanwhile, the expressions of NF-κB and MAPKs family proteins were reduced by DWPE compared with HFD group. Otherwise, the efficacy of anti-NAFLD of DWPE was significantly decreased after treatment of antibiotics, which indicated the key role of gut microbiota in the therapeutic process. Furthermore, sequencing of 16S rRNA gene revealed that DWPE could revert the decreased relative abundance of gut microbiota caused by the long term of a high fat diet. And the disordered microflora was remodeled by DWPE including the reduction of Erysipelotrichia, Firmicutes and Actinobacteria as well as the increment of Bacteroidetes, Clostridiales, Bacteroidales S24-7, Prevotellaceae and Bacteroides.

CONCLUSION

Taken together, DWPE had a preventing effect on NAFLD, which might be associated with the regulation of gut microbiota.

Exploration of walnut components and their association with health effects

Traditionally, walnuts have occupied an imperative position in the functional food market with consistently recognized nutritious and functional properties. In the past years, the lipid profile of walnuts has brought much scientific attention via linking a cascade of biological attributes and health-promoting effects. Over time, researchers have focused on diversified composition (polyphenols and vitamins) of different parts of walnut (flower, pellicle, and kernel) and emphasized their physiological significance. Consequently, a plethora of reports has emerged on the potential role of walnut consumption against a series of diseases including cancer, gut dysbiosis, cardiovascular, and neurodegenerative diseases. Therefore, we accumulated the updated data on composition and classification, extraction methods, and utilization of different parts of walnuts as well as associated beneficial effects under in vivo and clinical studies. Altogether, this review summarized the ameliorative effects of a walnut-enriched diet in chronic diseases which can be designated to the synergistic or individual effects of walnut components mainly through anti-oxidative and anti-inflammatory role.

Ellagic Acid as a Tool to Limit the Diabetes Burden: Updated Evidence

Oxidative stress contributes not only to the pathogenesis of type 2 diabetes (T2D) but also to diabetic vascular complications. It follows that antioxidants might contribute to limiting the diabetes burden. In this review we focus on ellagic acid (EA), a compound that can be obtained upon intestinal hydrolysis of dietary ellagitannins, a family of polyphenols naturally found in several fruits and seeds. There is increasing research on cardiometabolic effects of ellagitannins, EA, and urolithins (EA metabolites). We updated research conducted on these compounds and (I) glucose metabolism; (II) inflammation, oxidation, and glycation; and (III) diabetic complications. We included studies testing EA in isolation, extracts or preparations enriched in EA, or EA-rich foods (mostly pomegranate juice). Animal research on the topic, entirely conducted in murine models, mostly reported glucose-lowering, antioxidant, anti-inflammatory, and anti-glycation effects, along with prevention of micro- and macrovascular diabetic complications. Clinical research is incipient and mostly involved non-randomized and low-powered studies, which confirmed the antioxidant and anti-inflammatory properties of EA-rich foods, but without conclusive results on glucose control. Overall, EA-related compounds might be potential agents to limit the diabetes burden, but well-designed human randomized controlled trials are needed to fill the existing gap between experimental and clinical research.

Effect of walnut (Juglans sigillata) oil on intestinal antioxidant, anti-inflammatory, immunity, and gut microbiota modulation in mice

The study investigated the anti-oxidant, anti-inflammatory, immunity, and gut microbiota modulation in mice (n = 60; 15 mice/group) after intragastric administration of walnut oil (WO; three groups (low (LD), medium (MD), and high doses (HD): 2.5, 5, and 10 ml/kg, respectively) and normal control (NC, saline). WO significantly increased the median villous height/crypt depth (VH/CD) ratio, the activities of superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) in intestinal mucosa. WO exerted the anti-inflammatory effects by decreasing the expression of tumor necrosis factor-α (TNF-α) in the duodenal mucosa. All groups shared 157 operational taxonomic units (OTUs; 97% similarity) representing nine phyla. The relative abundance in gut microbiota shifted from more pathogenic bacteria-Helicobacter (NC: 22% versus MD: 3%) toward probiotic-Lactobacillus (NC: 19% versus MD: 40%). The immune organ index (spleen) and contents of secretory immunoglobulin A (S-IgA) were increased from small intestine. In conclusion, WO decreased the oxidative stress, inflammation, and improved the immunity and beneficial gut microbiota in the mice. PRACTICAL APPLICATIONS: Walnut oil (WO) is widely used in traditional medicine around the world and is prescribed as beneficial food oil in agro-industry. However, the intestinal benefits of WO have not been explored extensively, and even its therapeutic mechanism still remains unknown in modern medicine. In this study, WO from Juglans sigillata was investigated for its preventive and protective effects on the intestinal mucosa in mice including anti-oxidant, anti-inflammatory, immunity, and gut microbiota modulation. WO decreased the oxidative stress, inflammation, and improved immunity and beneficial gut microbiota in the mice. WO has shown strong probiotic effect on the gut, and thus, can be considered as a potential candidate in food. The study outcome would enhance utilization of WO for the prevention of gastrointestinal diseases (e.g., Helicobacter, etc.) both in animals and human (inflammatory bowel diseases, IBD) and the formulation of functional foods.

High oleic peanuts improve parameters leading to fatty liver development and change the microbiota in mice intestine

Background

Oleic-acid consumption can possibly prevent or delay metabolic diseases. In Israel, a Virginia-type peanut cultivar with a high content of oleic acid has been developed.

Objective

This study examined the effect of consuming high oleic peanuts (D7) on the development of fatty liver compared to the standard HN strain.

Design

The two peanut cultivars were added to normal diet (ND) and high-fat (HF) mouse diet. Male C57BL/6 mice were fed for 8 and 10 weeks on a 4% D7, 4% HN, or control diet. At the end of the experiments, blood and tissues were collected. Triglyceride, lipid levels, histology, and protein expression were examined. The diets’ effects on intestinal microbiota were also evaluated.

Results

Both D7 and HFD7 led to a reduction in plasma triglycerides. Lipids, triglycerides, and free fatty acids in the liver were low in diets containing D7. Additionally, CD36 expression decreased in the D7 group. Consumption of D7 led to higher Prevotella levels, and consumption of ND that contained HN or D7 led to a lower Firmicutes/Bacteroidetes ratio.

Conclusion

These findings suggest that consumption of peanuts high in oleic acid (D7) may have the potential to delay primary fatty liver symptoms.

Distinct DNA Metabolism and Anti-proliferative Effects of Goat Urine Metabolites: An Explanation for Xeno-tumor Heterogeneity

Background:

The tumor microenvironment, including microbiome populations in the local niche of several types of solid tumors like mammary and colorectal cancer are distinct. The occurrence of one type of cancer over another varies from animals to human individuals. Further, clinical data suggest that specific cancer types such as mammary and colorectal cancer are rare in ruminants like goat.

Methods:

Fresh urine samples were collected from healthy ruminants (cow, goat, buffalo, ox), non-ruminant animals (horse, jenny) and human. Further, these urine samples were subjected to fractionation by drying, vortexing, centrifugation and sterile filtration in DMSO extraction solvent. Collected urine DMSO fraction (UDF) samples from all sources were subjected to DNA metabolizing assay with plasmid DNA pBR322 and genomic DNA of MCF-7 cells. Next, based on the discernible DNA metabolizing effects of goat UDF among other sources, goat UDF was tested for anti-proliferative effects upon HCT-116 and MCF-7 cells using Trypan blue dye exclusion assay.

Results:

This paper reports that goat UDF possesses very clear DNA metabolizing effects (up to 95%) upon plasmid and genomic DNA compared to other ruminants, non-ruminants and human UDF samples. Interestingly, autoclaving of goat UDF and other sample results in the significant loss of DNA metabolizing effects. In this way, data potentially indicate that the goat UDF sample contains metabolite or similar organic compounds. Further, in vitro treatment of the goat, UDF sample shows clear anti-proliferative effects upon HCT-116 (up to 75%) and MCF-7 (up to 40%).

Conclusion:

This study signifies the clear differences in DNA metabolizing effects of goat UDF over other selected animal sources. Furthermore, the observed DNA metabolizing effects of goat UDF well correlate with anti-proliferative effects upon HCT-116 and MCF-7 cells. This study is a first report to show the comparison of urine metabolites among various animals. Interestingly, findings propose an indirect link that may support the possible reasons behind xeno-tumor heterogeneity in the form of rare occurrences of colorectal and mammary cancer in goat over other ruminants, non-ruminants and human.

The interplay between dietary factors, gut microbiome and colorectal cancer: a new era of colorectal cancer prevention

Colorectal cancer is the third most common cancer in the world and its incidence is on the rise. Dietary intervention has emerged as an attractive strategy to curtail its occurrence and progression. Diet is known to influence the gut microbiome, as dietary factors and gut bacteria can act in concert to cause or protect from colorectal cancer. Several studies have presented evidence for such interactions and have pointed out the different ways by which the diet and gut microbiome can be altered to produce beneficial effects. This review article aims to summarize the interrelationship between diet, gut flora and colorectal cancer so that a better preventive approach can be applied.

Colon Cancer Prevention with Walnuts: A Longitudinal Study in Mice from the Perspective of a Gut Enterotype-like Cluster

There is limited understanding of how walnut consumption inhibits the development of colorectal cancer. A possible mechanism may involve alterations to the gut microbiota. In this study, the effects of walnut on gut microbiota were tested in a mouse tumor bioassay using the colonotropic carcinogen, azoxymethane (AOM) added to the total Western diet (TWD). 16S rRNA pyrosequencing identified three enterotype-like clusters (E1, E2, and E3) in this murine model. E1, E2, and E3 are associated with AOM exposure, walnut consumption, and TWD diet, respectively. E2 and E3 showed distinct taxonomic and functional characteristics, while E1 represented an intermediate state. At the family level, E1 and E3 were both enriched with Bacteroidaceae, but driven by two different operational taxonomic units (OTU; OTU-2 for E1, OTU-4 for E3). E2 was overrepresented with Porphyromonadaceae and Lachnospiraceae, with OTU-3 (family Porphyromonadaceae) as the "driver" OTU for this cluster. Functionally, E3 is overrepresented with genes of glycan biosynthesis and metabolism, xenobiotic metabolism, and lipid metabolism. E2 is enriched with genes associated with cell motility, replication and repair, and amino acid metabolism. Longitudinally, E2 represents the gut microbial status of early life in these mice. In comparison with E1 and E3, E2 is associated with a moderate lower tumor burden (P = 0.12). Our results suggest that walnuts may reduce the risk of colorectal cancer within a Western diet by altering the gut microbiota. Our findings provide further evidence that colorectal cancer risk is potentially modifiable by diet via alterations to the microbiota.

Plant-Based Fat, Dietary Patterns Rich in Vegetable Fat and Gut Microbiota Modulation

Diet is advocated as a key factor influencing gut microbiota. Several studies have focused on the effect of different carbohydrates, mainly fiber, on gut microbiota. However, what remains to be elucidated is the impact of a key component of diet that is widely debated upon: dietary fats. This review highlights the importance of understanding the source, quality, and type of fats that could differentially modify the intestinal microbiome. Fats from plant-based sources such as nuts, or vegetable oils have shown positive alterations in gut microbiota biodiversity both in in vivo and in vitro studies. Nuts and other plant-based fat sources, dietary patterns (e.g., Mediterranean diet) rich in polyunsaturated and monounsaturated fats and, in some cases, polyphenols, and other phytochemicals, have been associated with increased bacterial diversity, as well beneficial butyrate-producing bacteria imparting a positive metabolic influence. It is with this interest, this narrative review brings together evidences on different plant-based fat sources, dietary patterns rich in vegetable fats, and associated changes in gut microbiota.

Neuroprotective and Memory-Enhancing Effects of Antioxidant Peptide From Walnut (Juglans regia L.) Protein Hydrolysates

Peptides have been reported to possess interesting biological properties. The present study was designed to evaluate neuroprotective and memory-enhancing effects of antioxidant peptide from walnut ( Juglans regia L.) protein hydrolysates. The neuroprotective effect of walnut peptide (WP) against oxidative stress on PC12 cells was evaluated. And zebrafish was used as the model to corroborate the effect. Its effect on learning and memory of mice using the Morris water maze and the step-down passive avoidance tests were performed. Moreover, the acute toxicity of WP was carried out to assess its safety profile. It was found that WP was able to suppress H2O2-induced cell death in PC12 cells. In the zebrafish model, WP had an obvious neuroprotective effect, and the ratio reached 42% at 222 µg/mL. The mechanism study revealed that WP could inhibit the activity of caspases 3/7 and 8, reduce the mRNA expression levels of Bax and glial cell line-derived neurotrophic factor, and improve the mRNA expression level of brain-derived neurotrophic factor significantly. Besides, the treatment of mice with WP shortened the escape latency and exhibited much longer target time and more crossing times significantly, compared with untreated control groups in the Morris water maze test. Similarly, the step-down passive avoidance test showed that WP could ameliorate memory impairments. The administrated dose (20.1 g/kg body weight [BW]) did not produce mortality or treatment-related adverse effects with regard to BW, general behavior, or relative organ weights of the tested male and female mice. The current results indicated that WP could exert neuroprotective effect, and attenuated learning and memory impairments. These ameliorating effects of WP may be useful for treatment of memory impairment in Alzheimer’s and its related diseases.

Dietary Walnut Supplementation Alters Mucosal Metabolite Profiles During DSS-Induced Colonic Ulceration

Walnuts contain a complex array of natural compounds and phytochemicals that exhibit a wide range of health benefits, including protection against inflammation and colon cancer. In this study, we assess the effects of dietary supplementation with walnuts on colonic mucosal injury induced in mice by the ulcerogenic agent, dextran sodium sulfate (DSS). C57Bl/6J mice were started on the Total Western Diet supplemented with freshly-ground whole walnuts (0, 3.5, 7 and 14% g/kg) 2 weeks prior to a 5-day DSS treatment and walnut diets were continued throughout the entire experimental period. Mice were examined at 2 days or 10 days after withdrawal of DSS. In a separate study, a discovery-based metabolite profiling analysis using liquid chromatography tandem mass spectrometry (LC-MS/MS) was performed on fecal samples and colonic mucosa following two weeks of walnut supplementation. Dietary walnut supplementation showed significant effects in the 10-day post-DSS recovery-phase study, in which the extent of ulceration was significantly reduced (7.5% vs. 0.3%, p < 0.05) with 14% walnuts. In the metabolite-profiling analysis, walnuts caused a significant increase in several polyunsaturated fatty acids (PUFAs), including docosahexaenoic acid (DHA) and 9-oxo-10(E),12(E)-octadecadienoic acid (9-oxoODA), as well as kynurenic acid. In colon tissue samples, walnuts caused a significant increase in the levels of S-adenosylhomocysteine (SAH) and betaine, important components of fatty acid β-oxidation. These metabolite changes may contribute in part to the observed protection against DSS-induced inflammatory tissue injury.

Heavy Metal Levels and Mineral Nutrient Status of Natural Walnut (Juglans regia L.) Populations in Kyrgyzstan: Nutritional Values of Kernels

In this study, mineral nutrient and heavy metal (Al, Ca, Cd, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, and Zn) contents of the walnut kernels and their co-located soil samples collected from the four different zones of natural walnut forests (Sary-Chelek, Arslanbap, and Kara-Alma in Jalal-Abad Region and Kara-Shoro in Osh Region) in Kyrgyzstan were investigated. The highest concentrations for all elements determined in the soil samples were observed in the Sary-Chelek zone whereas the Arslanbap zone was found to be having the lowest concentrations except Fe and Zn. The highest concentrations in the kernels of walnut samples were found to be in the Sary-Chelek zone for Ca, Fe, K, Mg, and Zn; in the Kara-Shoro zone for Cu; in the Arslanbap zone for Mn; and in the Kara-Alma zone for Na whereas the lowest concentrations were found to be in the Arslanbap zone for Ca, Fe, K, Mg, Na, and Zn and in the Sary-Chelek zone for Cu and Mn, respectively. Also, the levels of Al, Cd, Ni, and Pb in kernel samples could not be detected by ICP-OES because their levels were lower than the threshold detection point (10 μg.kg^-1). Additionally, our data indicated that the walnut kernels from Kyrgyzstan have higher values for RDA (recommended daily allowances) in comparison with the walnut kernels from other countries.

A Mediterranean Diet Mix Has Chemopreventive Effects in a Murine Model of Colorectal Cancer Modulating Apoptosis and the Gut Microbiota

Objectives: Unhealthy dietary patterns have been associated with colorectal cancer (CRC) onset while Mediterranean Diet (MD) has been proposed for CRC prevention. This study evaluated the effect of a Mediterranean Diet Mix (MD-MIX) on colonic tumors development in A/J mice fed a low-fat (LFD) or a high-fat western diet (HFWD), and injected with the procarcinogen azoxymethane (AOM).

Materials and Methods: Forty A/J male mice were randomly assigned into four feeding arms (10 mice/arm; LFD, LFD-MD-MIX, HFWD, HFWD-MD-MIX) to be treated with AOM. Ten mice were exposed to the diets alone (Healthy LFD and Healthy HFWD) to be used as control. Tumor incidence and multiplicity were evaluated at sacrifice. Mucosal fatty acid content and urinary phenolic compounds were assayed by mass spectrometry. Apoptosis was evaluated by TUNEL assay and gene expression markers. Cell proliferation was evaluated by Ki67 immunohistochemistry. Microbiota composition was assessed at different time points by 16S RNA sequencing.

Results: A tumor incidence of 100% was obtained in AOM-treated mice. The MD-MIX supplementation was able to reduce the number of colonic lesions in both LFD and HFWD-fed mice and to induce apoptosis, in particular in the LFD-MD-MIX arm. Moreover, a preventive effect on low-grade dysplasia and macroscopical lesions (>1 mm) development was found in HFWD-fed mice together with a regulation of the AOM-driven intestinal dysbiosis.

Conclusions: MD-MIX was able to counteract CRC development in mice under different dietary backgrounds through the regulation of apoptosis and gut microbiota.

Beneficial effects of walnut consumption on human health: role of micronutrients

PURPOSE OF REVIEW

Nuts in general and walnuts in particular are in the limelight for the association of their consumption with improved health outcomes. Walnuts have an optimal composition in bioactive nutrients and recent clinical and experimental studies have uncovered a number of beneficial effects of walnut micronutrients, working in isolation or in concert, on metabolic pathways and clinical outcomes that make this review timely and relevant.

RECENT FINDINGS

Alpha-linolenic acid, a critical walnut component, is metabolized into bioactive oxylipins, has been shown to protect microglial cells from inflammation, and is associated with lower fatal myocardial infarction rates through a putative antiarrhythmic effect. Phytosterols relate to the cholesterol-lowering effect of nut consumption. Nonsodium minerals are associated with better cardiometabolic health. Walnut phytomelatonin has anticancer effects that are shared by the main walnut polyphenols and their metabolites, ellagitannins and urolithins, respectively.

SUMMARY

This review highlights new evidence on the health-promoting properties of walnuts and their main micronutrient components. The conclusion is that walnuts are optimal healthful foods.

Nut intake and 5-year changes in body weight and obesity risk in adults: results from the EPIC-PANACEA study

PURPOSE

There is inconsistent evidence regarding the relationship between higher intake of nuts, being an energy-dense food, and weight gain. We investigated the relationship between nut intake and changes in weight over 5 years.

METHODS

This study includes 373,293 men and women, 25-70 years old, recruited between 1992 and 2000 from 10 European countries in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Habitual intake of nuts including peanuts, together defined as nut intake, was estimated from country-specific validated dietary questionnaires. Body weight was measured at recruitment and self-reported 5 years later. The association between nut intake and body weight change was estimated using multilevel mixed linear regression models with center/country as random effect and nut intake and relevant confounders as fixed effects. The relative risk (RR) of becoming overweight or obese after 5 years was investigated using multivariate Poisson regressions stratified according to baseline body mass index (BMI).

RESULTS

On average, study participants gained 2.1 kg (SD 5.0 kg) over 5 years. Compared to non-consumers, subjects in the highest quartile of nut intake had less weight gain over 5 years (-0.07 kg; 95% CI -0.12 to -0.02) (P trend = 0.025) and had 5% lower risk of becoming overweight (RR 0.95; 95% CI 0.92-0.98) or obese (RR 0.95; 95% CI 0.90-0.99) (both P trend <0.008).

CONCLUSIONS

Higher intake of nuts is associated with reduced weight gain and a lower risk of becoming overweight or obese.

Walnut Consumption Alters the Gastrointestinal Microbiota, Microbially Derived Secondary Bile Acids, and Health Markers in Healthy Adults: A Randomized Controlled Trial

Background

Epidemiologic data suggest that diets rich in nuts have beneficial health effects, including reducing total and cause-specific mortality from cancer and heart disease. Although there is accumulating preclinical evidence that walnuts beneficially affect the gastrointestinal microbiota and gut and metabolic health, these relations have not been investigated in humans.

Objective

We aimed to assess the impact of walnut consumption on the human gastrointestinal microbiota and metabolic markers of health.

Methods

A controlled-feeding, randomized crossover study was undertaken in healthy men and women [n = 18; mean age = 53.1 y; body mass index (kg/m2): 28.8]. Study participants received isocaloric diets containing 0 or 42 g walnuts/d for two 3-wk periods, with a 1-wk washout between diet periods. Fecal and blood samples were collected at baseline and at the end of each period to assess secondary outcomes of the study, including effects of walnut consumption on fecal microbiota and bile acids and metabolic markers of health.

Results

Compared with after the control period, walnut consumption resulted in a 49-160% higher relative abundance of Faecalibacterium, Clostridium, Dialister, and Roseburia and 16-38% lower relative abundances of Ruminococcus, Dorea, Oscillospira, and Bifidobacterium (P < 0.05). Fecal secondary bile acids, deoxycholic acid and lithocholic acid, were 25% and 45% lower, respectively, after the walnut treatment compared with the control treatment (P < 0.05). Serum LDL cholesterol and the noncholesterol sterol campesterol concentrations were 7% and 6% lower, respectively, after walnut consumption compared with after the control treatment (P < 0.01).

Conclusion

Walnut consumption affected the composition and function of the human gastrointestinal microbiota, increasing the relative abundances of Firmicutes species in butyrate-producing Clostridium clusters XIVa and IV, including Faecalibacterium and Roseburia, and reducing microbially derived, proinflammatory secondary bile acids and LDL cholesterol. These results suggest that the gastrointestinal microbiota may contribute to the underlying mechanisms of the beneficial health effects of walnut consumption. This trial was registered at www.clinicaltrials.gov as NCT01832909.

Dietary Walnuts Protect Against Obesity-Driven Intestinal Stem Cell Decline and Tumorigenesis

Obesity can negatively impact intestinal homeostasis, and increase colon cancer risk and related mortality. Thus, given the alarmingly high rates of obesity in the US and globally, it is critical to identify practical strategies that can break the obesity-cancer link. Walnuts have been increasingly recognized to mitigate cancer risk, and contain many bioactive constituents with antioxidant and anti-inflammatory properties that could potentially counteract pathways thought to be initiators of obesity-related cancer. Therefore, the purpose of this study was to determine if walnuts could preserve intestinal homeostasis, and attenuate tumorigenesis and growth in the context of obesity and a high calorie diet. To this end, we studied effects of walnuts on these parameters under different dietary conditions in wildtype mice, two independent Apc models (Apc^1638N/+ and Apc^Δ14), and in MC38 colon cancer cells in vivo, respectively. Walnuts did not alter the metabolic phenotype or intestinal morphology in normal mice fed either a low-fat diet (LFD), LFD with 6% walnuts (LFD+W), high-fat diet (HFD), or HFD with 7.6% walnuts (HFD+W). However, walnuts did lead to a significant reduction in circulating CCL5 and preserved intestinal stem cell (ISC) function under HFD-fed conditions. Furthermore, walnuts reduced tumor multiplicity in Apc^1638N/+ male HFD+W animals, as compared to HFD controls (3.7 ± 0.5 vs. 2.5 ± 0.3; P = 0.015), tended to reduce the number of adenocarcinomas (0.67 ± 0.16 vs. 0.29 ± 0.12; P = 0.07), and preferentially limited tumor growth in Apc^Δ14 male mice (P = 0.019) fed a high-calorie western-style diet. In summary, these data demonstrate that walnuts confer significant protection against intestinal tumorigenesis and growth and preserve ISC function in the context of a high-calorie diet and obesity. Thus, these data add to the accumulating evidence connecting walnuts as a potentially effective dietary strategy to break the obesity-colon cancer link.

Modeling the Western Diet for Preclinical Investigations

Rodent models have been invaluable for biomedical research. Preclinical investigations with rodents allow researchers to investigate diseases by using study designs that are not suitable for human subjects. The primary criticism of preclinical animal models is that results are not always translatable to humans. Some of this lack of translation is due to inherent differences between species. However, rodent models have been refined over time, and translatability to humans has improved. Transgenic animals have greatly aided our understanding of interactions between genes and disease and have narrowed the translation gap between humans and model animals. Despite the technological innovations of animal models through advances in genetics, relatively little attention has been given to animal diets. Namely, developing diets that replicate what humans eat will help make animal models more relevant to human populations. This review focuses on commonly used rodent diets that are used to emulate the Western dietary pattern in preclinical studies of obesity and type 2 diabetes, nonalcoholic liver disease, maternal nutrition, and colorectal cancer.

A Walnut-Enriched Diet Affects Gut Microbiome in Healthy Caucasian Subjects: A Randomized, Controlled Trial

Regular walnut consumption is associated with better health. We have previously shown that eight weeks of walnut consumption (43 g/day) significantly improves lipids in healthy subjects. In the same study, gut microbiome was evaluated. We included 194 healthy subjects (134 females, 63 ± 7 years, BMI 25.1 ± 4.0 kg/m²) in a randomized, controlled, prospective, cross-over study. Following a nut-free run-in period, subjects were randomized to two diet phases (eight weeks each); 96 subjects first followed a walnut-enriched diet (43 g/day) and then switched to a nut-free diet, while 98 subjects followed the diets in reverse order. While consuming the walnut-enriched diet, subjects were advised to either reduce fat or carbohydrates or both to account for the additional calories. Fecal samples were collected from 135 subjects at the end of the walnut-diet and the control-diet period for microbiome analyses. The 16S rRNA gene sequencing data was clustered with a 97% similarity into Operational Taxonomic Units (OTUs). UniFrac distances were used to determine diversity between groups. Differential abundance was evaluated using the Kruskal–Wallis rank sum test. All analyses were performed using Rhea. Generalized UniFrac distance shows that walnut consumption significantly affects microbiome composition and diversity. Multidimensional scaling (metric and non-metric) indicates dissimilarities of approximately 5% between walnut and control (p = 0.02). The abundance of Ruminococcaceae and Bifidobacteria increased significantly (p < 0.02) while Clostridium sp. cluster XIVa species (Blautia; Anaerostipes) decreased significantly (p < 0.05) during walnut consumption. The effect of walnut consumption on the microbiome only marginally depended on whether subjects replaced fat, carbohydrates or both while on walnuts. Daily intake of 43 g walnuts over eight weeks significantly affects the gut microbiome by enhancing probiotic- and butyric acid-producing species in healthy individuals. Further evaluation is required to establish whether these changes are preserved during longer walnut consumption and how these are linked to the observed changes in lipid metabolism.

Does Modification of the Large Intestinal Microbiome Contribute to the Anti-Inflammatory Activity of Fermentable Fiber?

Fiber is an inadequately understood and insufficiently consumed nutrient. This review examines the possible causal relation between fiber-induced microbiome changes and the anti-inflammatory activity of fiber. To demonstrate the dominant role of fermentable plant fiber in shaping the intestinal microbiome, animal and human fiber-feeding studies are reviewed. Using culture-, PCR-, and sequencing-based microbial analyses, a higher prevalence of Bifidobacterium and Lactobacillus genera was observed from the feeding of different types of fermentable fiber. This finding was reported in studies performed on several host species including human. Health conditions and medications that are linked to intestinal microbial alterations likely also change the nutrient environment of the large intestine. The unique gene clusters of Bifidobacterium and Lactobacillus that enable the catabolism of plant glycans and the ability of Bifidobacterium and Lactobacillus to reduce the colonization of proteobacteria probably contribute to their prevalence in a fiber-rich intestinal environment. The fiber-induced microbiome changes could contribute to the anti-inflammatory activity of fiber. Although most studies did not measure fecal microbial density or total daily fecal microbial output (colon microbial load), limited evidence suggests that the increase in intestinal commensal microbial load plays an important role in the anti-inflammatory activity of fiber. Various probiotic supplements, including Bifidobacterium and Lactobacillus, showed anti-inflammatory activity only in the presence of fiber, which promoted microbial growth as indicated by increasing plasma short-chain fatty acids. Probiotics alone or pure fiber administered under sterile conditions showed no anti-inflammatory activity. The potential mechanisms that could mediate the anti-inflammatory effect of common microbial metabolites are reviewed, but more in vivo trials are needed. Future studies including simultaneous microbial composition and load measurements are also important.

Almond Consumption and Processing Affects the Composition of the Gastrointestinal Microbiota of Healthy Adult Men and Women: A Randomized Controlled Trial

BACKGROUND

Almond processing has been shown to differentially impact metabolizable energy; however, the effect of food form on the gastrointestinal microbiota is under-investigated.

OBJECTIVE

We aimed to assess the interrelationship of almond consumption and processing on the gastrointestinal microbiota.

DESIGN

A controlled-feeding, randomized, five-period, crossover study with washouts between diet periods was conducted in healthy adults (n = 18). Treatments included: (1) zero servings/day of almonds (control); (2) 1.5 servings (42 g)/day of whole almonds; (3) 1.5 servings/day of whole, roasted almonds; (4) 1.5 servings/day of roasted, chopped almonds; and (5) 1.5 servings/day of almond butter. Fecal samples were collected at the end of each three-week diet period.

RESULTS

Almond consumption increased the relative abundances of Lachnospira, Roseburia, and Dialister (p ≤ 0.05). Comparisons between control and the four almond treatments revealed that chopped almonds increased Lachnospira, Roseburia, and Oscillospira compared to control (p < 0.05), while whole almonds increased Dialister compared to control (p = 0.007). There were no differences between almond butter and control.

CONCLUSIONS

These results reveal that almond consumption induced changes in the microbial community composition of the human gastrointestinal microbiota. Furthermore, the degree of almond processing (e.g., roasting, chopping, and grinding into butter) differentially impacted the relative abundances of bacterial genera.

Walnut Supplementation in the Diet Reduces Oxidative Damage and Improves Antioxidant Status in Transgenic Mouse Model of Alzheimer's Disease

Our previous study has shown beneficial effects of walnuts on memory and learning skills in transgenic mouse model of Alzheimer's disease (AD-tg). To understand underlying mechanism, we studied here whether walnuts can reduce oxidative stress in AD. From 4 months of age, experimental AD-tg mice were fed diets containing 6% (T6) or 9% walnuts (T9) (equivalent to 1 or 1.5 oz, of walnuts per day in humans) for 5, 10, or 15 months. The control groups, i.e., AD-tg (T0) and wild-type (Wt) mice, were fed diets without walnuts. Free radicals, i.e., reactive oxygen species (ROS), lipid peroxidation, protein oxidation, and antioxidant enzymes were assessed in these mice at different ages. AD-tg mice on control diet (T0) showed significant age-dependent increase in ROS levels, lipid peroxidation, and protein oxidation coupled with impaired activities of antioxidant enzymes [superoxide dismutase, catalase, and glutathione peroxidase] compared to Wt mice. Oxidative stress was significantly reduced in AD-tg mice on diets with walnuts (T6, T9), as evidenced by decreased levels of ROS, lipid peroxidation, and protein oxidation, as well as by enhanced activities of antioxidant enzymes compared to T0 mice. Long-term supplementation with walnuts for 10 or 15 months was more effective in reducing oxidative stress in AD-tg mice. Our findings indicate that walnuts can reduce oxidative stress, not only by scavenging free radicals, but also by protecting antioxidant status, thus leading to reduced oxidative damage to lipids and proteins in AD. Therefore, by reducing oxidative stress, a walnut-enriched diet may help reduce the risk or delay the onset and progression of AD.

Highlights from the Inaugural International Cancer Microbiome Consortium Meeting (ICMC), 5-6 September 2017, London, UK

The International Cancer Microbiome Consortium (ICMC) is a recently launched collaborative between academics and academic-clinicians that aims to promote microbiome research within the field of oncology, establish expert consensus and deliver education for academics and clinicians. The inaugural two-day meeting was held at the Royal Society of Medicine (RSM), London, UK, 5–6 September 2017. Microbiome and cancer experts from around the world first delivered a series of talks during an educational day and then sat for a day of roundtable discussion to debate key topics in microbiome-cancer research.

Talks delivered during the educational day covered a broad range of microbiome-related topics. The potential role of the microbiome in the pathogenesis of colorectal cancer was discussed and debated in detail with experts highlighting the latest data in animal models and humans and addressing the question of causation versus association. The impact of the microbiota on other cancers—such as lung and urogenital tract—was also discussed. The microbiome represents a novel target for therapeutic manipulation in cancer and a number of talks explored how this might be realised through diet, faecal microbiota transplant and chemotherapeutics.

On the second day, experts debated pre-agreed topics with the aim of producing a consensus statement with a focus on the current state of our knowledge and key gaps for further development. The panel debated the notion of a ‘healthy’ microbiome and, in turn, the concept of dysbiosis in cancer. The mechanisms of microbiota-induced carcinogenesis were discussed in detail and our current conceptual models were assessed. Experts also considered co-factors in microbiome-induced carcinogenesis to conclude that the tripartite ‘interactome’ between genetically vulnerable host, environment and the microbiome is central to our current understanding. To conclude, the roundtable discussed how the microbiome may be exploited for therapeutic benefit in cancer and the safety implications of performing such research in oncology patients.

Chemopreventive effects of Ku-jin tea against AOM-induced precancerous colorectal lesions in rats and metabolomic analysis

Ku-jin tea (KJT) is a health beverage prepared from the leaves of the plant Acer tataricum subsp. ginnala that has been consumed in some regions of China for thousands of years. KJT contains high levels of anti-inflammatory and antioxidative compounds such as ginnalins, but little is known about the chemopreventive effect of KJT on colon cancer. In this study, we investigated the preventive effects of KJT on colon carcinogenesis using the azoxymethane (AOM)-induced precancerous colorectal lesion model in rats. The results showed that the number of aberrant crypts, aberrant crypt foci (ACF) and crypts/focus in rats of the KJT + AOM group were significantly decreased compared with rats of the AOM group (p < 0.01). Further exploration of the prevention mechanism of KJT by UPLC-QTOF/MS-based urinary metabolomics showed that 5 metabolic pathways were modulated, including purine metabolism and amino acid metabolism, in the group with KJT. In addition, the levels of the immunomodulatory cytokines IL-1α and IL-10 were significantly decreased, and the levels of IL-2 in the serum of AOM rats increased after KJT treatment. Our present data suggest that KJT can inhibit AOM-induced colonic ACF formation and might be a useful chemopreventive agent against colorectal carcinogenesis.

Emerging role of chemoprotective agents in the dynamic shaping of plasma membrane organization

In the context of an organism, epithelial cells by nature are designed to be the defining barrier between self and the outside world. This is especially true for the epithelial cells that form the lining of the digestive tract, which absorb nutrients and serve as a barrier against harmful substances. These cells are constantly bathed by a complex mixture of endogenous (bile acids, mucus, microbial metabolites) and exogenous (food, nutrients, drugs) bioactive compounds. From a cell biology perspective, this type of exposure would directly impact the plasma membrane, which consists of a myriad of complex lipids and proteins. The plasma membrane not only functions as a barrier but also as the medium in which cellular signaling complexes form and function. This property is mediated by the organization of the plasma membrane, which is exquisitely temporally (nanoseconds to minutes) and spatially (nanometers to micrometers) regulated. Since numerous bioactive compounds found in the intestinal lumen can directly interact with lipid membranes, we hypothesize that the dynamic reshaping of plasma membrane organization underlies the chemoprotective effect of select membrane targeted dietary bioactives (MTDBs). This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo V. Escribá.

Bacterial community diversity on in-shell walnut surfaces from six representative provinces in China

Walnuts (Juglans regia) have been associated with foodborne illness outbreaks in recent years. Thus, the purpose of this study was to investigate the distribution of bacteria on in-shell walnut surfaces from six representative provinces in China. The bacterial populations on walnut surfaces were investigated by high-throughput sequencing based on the bacterial 16 S rRNA hypervariable region V4. Twenty-eight samples were collected from fourteen regions in six provinces and harvested in different periods (the fresh in 2016 and the old in 2015). Proteobacteria was the most dominant phylum in all samples except for XJ1. In XJ1, and the most abundant phylum was Cyanobacteria, which also accounted for a large proportion of the abundance in YN1, YN11, XJ2 and SC11. In addition, Firmicutes and Actinobacteria were also the abundant phyla in the given samples. Some genera belonging to the opportunistic pathogens were detected, such as Pseudomonas, Acinetobacter, Burkholderia and Bacillus. The results revealed that the composition and abundance of bacterial consortiums on walnut surfaces varied among the geographical sites where they were harvested. Moreover, the storage time of samples also had impact on the abundance of bacteria. This study may provide a better understanding of the bacterial communities' diversity on in-shell walnut surfaces.

Changes in the gut microbial communities following addition of walnuts to the diet

Walnuts are rich in omega-3 fatty acids, phytochemicals and antioxidants making them unique compared to other foods. Consuming walnuts has been associated with health benefits including a reduced risk of heart disease and cancer. Dysbiosis of the gut microbiome has been linked to several chronic diseases. One potential mechanism by which walnuts may exert their health benefit is through modifying the gut microbiome. This study identified the changes in the gut microbial communities that occur following the inclusion of walnuts in the diet. Male Fischer 344 rats (n=20) were randomly assigned to one of two diets for as long as 10 weeks: (1) walnut (W), and (2) replacement (R) in which the fat, fiber, and protein in walnuts were matched with corn oil, protein casein, and a cellulose fiber source. Intestinal samples were collected from the descending colon, the DNA isolated, and the V3-V4 hypervariable region of 16S rRNA gene deep sequenced on an Illumina MiSeq for characterization of the gut microbiota. Body weight and food intake did not differ significantly between the two diet groups. The diet groups had distinct microbial communities with animals consuming walnuts displaying significantly greater species diversity. Walnuts increased the abundance of Firmicutes and reduced the abundance of Bacteriodetes. Walnuts enriched the microbiota for probiotic-type bacteria including Lactobacillus, Ruminococcaceae, and Roseburia while significantly reducing Bacteroides and Anaerotruncus. The class Alphaproteobacteria was also reduced. Walnut consumption altered the gut microbial community suggesting a new mechanism by which walnuts may confer their beneficial health effects.

Protective Effect of Juglans regia L. Walnut Extract Against Oxidative DNA Damage

Walnuts (Juglans regia L.) are relevant components of the Mediterranean diet providing important macronutrients, micronutrients and other bioactive constituents including unsaturated fatty acids, proteins, fiber, vitamins, minerals, phytosterols and polyphenols. Although the walnut beneficial effects in human health are widely recognized by a lot of epidemiologic studies very little is known regarding its effect on damaged DNA. The aim of the present study was to investigate the effect of Juglans regia L. ethanolic extract from kernel on the induction of DNA strand breaks by thiol/Fe³⁺/O₂ mixed function oxidase, tert-butyl hydroperoxide or UVC radiations in acellular and cellular models. Plasmid DNA cleavage and fast Halo assay were used to monitor oxidative damage to DNA. Both approaches showed protection of oxidatively injured DNA. These results agree with a lot of scientific proofs which recommend walnut as dietary adjunct in health promotion and prevention as well as in treatment of lifestyle-related oxidative diseases.

Consumption of the total Western diet differentially affects the response to green tea in rodent models of chronic disease compared to the AIN93G diet

SCOPE

In pre-clinical studies investigating bioactive components, the efficacy of the bioactive is likely influenced by the basal diet provided to rodents. In this study, we hypothesized that a model bioactive, green tea extract (GTE), would have different effects on colon carcinogenesis, body composition, and lipid metabolism in mice fed a basal diet formulated to promote animal health and growth (AIN93G) as compared to a Western diet that emulates typical American intakes of micro- and macronutrients, the total Western diet (TWD).

METHODS AND RESULTS

Mice were fed either AIN93G or TWD, with or without GTE added to drinking water for 18 weeks. Aberrant crypt foci (ACF) in azoxymethane-initiated mice was nearly three times greater in mice fed TWD compared to AIN93G. Consumption of GTE suppressed ACF development only in mice fed the TWD. Similarly, supplementation with GTE suppressed weight gain and fasted glucose only in mice fed TWD, while GTE suppressed fat mass in mice fed either diet. Irrespective of diet, GTE supplementation increased cecum weight and decreased cecal SCFA concentration.

CONCLUSION

Collectively, these observations indicate that the TWD influences the bioactivity of GTE in rodent models of obesity, metabolism, and carcinogenesis.