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Exploring choices of early nutritional support for patients with sepsis based on changes in intestinal microecology.
Yang, XJ, Wang, XH, Yang, MY, Ren, HY, Chen, H, Zhang, XY, Liu, QF, Yang, G, Yang, Y, Yang, XJ
World journal of gastroenterology. 2023;29(13):2034-2049
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Sepsis is a condition brought about by infection and results in organ dysfunction and gut microbiota imbalance. Nutrition plays a large part in recovery from sepsis, however it is unclear as to the optimal diet for gut microbial balance in individuals with sepsis. This randomised control trial of 30 individuals with sepsis aimed to determine the optimal delivery of nutrition for gut microbial health either through a gastric tube (TEN), through the jugular vein (TPN), or a mixture of the two modes (SPN). The results showed differences in gut microbiota composition between the different modes of nutrition. Enterococcus increased in TEN, Campylobacter decreased in TPN, and Dialister decreased in SPN groups. Fermentation products produced by gut microbiota also changed depending on the mode of nutrition, with the TEN group showing improvements amongst the most fermentation products. Individuals in the TEN group also showed improved immune system function alongside those in the SPN group. It was concluded that based upon improvements to the immune system and gut microbiota, TEN is the most suitable mode for nutrition in individuals with sepsis. This study could be used by healthcare professionals to understand that nutrition methods for individuals with sepsis aren’t equally effective and recovery may be faster if individuals receive nutrition through a gastric tube.
Abstract
BACKGROUND Sepsis exacerbates intestinal microecological disorders leading to poor prognosis. Proper modalities of nutritional support can improve nutrition, immunity, and intestinal microecology. AIM: To identify the optimal modality of early nutritional support for patients with sepsis from the perspective of intestinal microecology. METHODS Thirty patients with sepsis admitted to the intensive care unit of the General Hospital of Ningxia Medical University, China, between 2019 and 2021 with indications for nutritional support, were randomly assigned to one of three different modalities of nutritional support for a total of 5 d: Total enteral nutrition (TEN group), total parenteral nutrition (TPN group), and supplemental parenteral nutrition (SPN group). Blood and stool specimens were collected before and after nutritional support, and changes in gut microbiota, short-chain fatty acids (SCFAs), and immune and nutritional indicators were detected and compared among the three groups. RESULTS In comparison with before nutritional support, the three groups after nutritional support presented: (1) Differences in the gut bacteria (Enterococcus increased in the TEN group, Campylobacter decreased in the TPN group, and Dialister decreased in the SPN group; all P < 0.05); (2) different trends in SCFAs (the TEN group showed improvement except for Caproic acid, the TPN group showed improvement only for acetic and propionic acid, and the SPN group showed a decreasing trend); (3) significant improvement of the nutritional and immunological indicators in the TEN and SPN groups, while only immunoglobulin G improved in the TPN group (all P < 0.05); and (4) a significant correlation was found between the gut bacteria, SCFAs, and nutritional and immunological indicators (all P < 0.05). CONCLUSION TEN is recommended as the preferred mode of early nutritional support in sepsis based on clinical nutritional and immunological indicators, as well as changes in intestinal microecology.
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Consumption of 85% cocoa dark chocolate improves mood in association with gut microbial changes in healthy adults: a randomized controlled trial.
Shin, JH, Kim, CS, Cha, L, Kim, S, Lee, S, Chae, S, Chun, WY, Shin, DM
The Journal of nutritional biochemistry. 2022;99:108854
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Disturbances in a person’s mood interrupts their personal well-being and the ability to participate in social interactions, leading to physical health problems such as chronic diseases. The role of diet as a mood regulator has received a great deal of interest. Certain dietary components have been shown to reduce anxiety and depression and improve quality of life. The aim of this study was to investigate the effects of dark chocolate intake on mood in everyday life, with special emphasis on the gut-brain axis. This study is a randomized controlled trial. Participants who met the criteria for eligibility were randomly assigned to one of three groups: (1) control group (CON, n=14); 2) 85% cocoa chocolate group (DC85, n=18); and 3) 70% cocoa chocolate group (DC70, n=16). Results show that daily intake of dark chocolate significantly reduced negative affect in the DC85, but not in the DC70. Furthermore, gut microbial diversity was significantly higher in DC85 than the CON. Authors conclude that dark chocolate has prebiotic effects by restructuring the diversity and composition of the gut microbiome, which may in turn improve mood via the gut-brain axis.
Expert Review
Conflicts of interest:
None
Take Home Message:
- To highlight the potential benefits of high cocoa content dark chocolate in relation to mental states
- To promote more awareness of how dietary habits may impact emotional wellbeing
- To emphasise the importance of microbiota and the gut-brain axis regarding dietary habits.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Background
The authors highlight that dark chocolate has been continually identified for its effects on mood. However, there is a dearth of evidence concerning the emotional impact of daily consumption of dark chocolate. Hence, the impact of dark chocolate consumption on daily mood, focusing on the gut-brain axis, is being investigated in this study.
Objectives
- To evaluate the correlation between the effect on emotional state after consuming dark chocolate and the gut microbiota in healthy adults
- To identify alterations in the composition and diversity of the microorganisms in the gastrointestinal tract on account of dark chocolate intake.
Study Design
A randomised controlled trial was performed at Seoul National University from July to December 2017, This involved. consumption of two types of dark chocolate (70% and 85% cocoa content). Subjects in the treatment groups were blinded although investigators and the control cohort were unblinded.
Participants
117 individuals were screened. However, 48 healthy males and females aged 20-30 years were eligible at baseline.
Interventions
- Subjects (n=16): Consumed 30g/day of 70% cocoa chocolate for 3 weeks
- Participants (n=18): Consumed 30g/day of 85% cocoa chocolate for 3 weeks
- Participants (n=14): The control group consumed no chocolate for 3 weeks.
Main Health Outcomes Measured
- Mood states were quantified via the Positive and Negative Affect Schedule in tandem with Microbiota analysis pre- and post-experiment
- Body composition analysis and dietary assessment were also conducted pre- and post-intervention
- Faecal 16S rRNA sequencing analysis of bacterial genomic DNA was conducted for the cohort who consumed 85% cocoa chocolate and the control arm to evaluate the association between the mood-altering effects of dark chocolate and the gut microbiota
- Statistical tests were performed based on intention-to-treat analysis. The Chi-squared test, Kruskal-Wallis test, one-way ANOVA, unpaired t-test and Mann-Whitney U test were employed for inter-group analysis. Spearman's correlation analysis was used to assess the association between gut microbiota composition and mood scores and P<.05 was considered statistically significant.
Results
- Daily intake of dark chocolate substantially diminished negative emotional states in the cohort consuming 85% cocoa content, but not in the 70% cocoa treatment arm
- Gut microbial diversity was substantially greater in the 85% cacao cohort than the control group (P<.05)
- Blautia obeum levels were significantly elevated and Faecalibacterium prausnitzii levels were decreased in the 85% cacao cohort than the control arm (P<.05).
- Furthermore, it was observed that changes in negative affect scores were inversely correlated with diversity and relative abundance of Blautia obeum (P<.05).
Conclusions
The observations suggest that consumption of dark chocolate with a higher cocoa content may induce prebiotic effects due to its capacity to restructure the diversity and composition of the gut microbiota. Furthermore, consuming dark chocolate with a higher cocoa might exert a positive effect on negative emotional states through the gut-brain axis.
Clinical practice applications:
- To inform practitioners of the benefits of 30g/day high (85%) cocoa chocolate consumption and its potential positive impact on mood through the gut-brain axis
- To educate clients regarding the potential benefits of daily high cocoa content chocolate consumption and its possible favourable effect on emotional states associated with gut microbiota.
Considerations for future research:
- More extensive research could investigate interventions of a longer period
- Further studies could evaluate if any difference exists between cocoa and cacao consumption and emotional states via the gut-brain axis, and the strength of any associations
- Interventions could investigate which strains of bacteria that high cocoa content dark chocolate may affect.
Abstract
Dark chocolate has long been recognized for its mood-altering properties; however, the evidence regarding the emotional effects of daily dark chocolate intake is limited. Therefore, we aimed to investigate the effects of dark chocolate intake on mood in everyday life, with special emphasis on the gut-brain axis. Two different dark chocolates (85% and 70% cocoa content) were tested in this study. In a randomized controlled trial, healthy adults (20-30 y) consumed either 30 g/d of 85% cocoa chocolate (DC85, n=18); 70% cocoa chocolate (DC70, n=16); or no chocolate (control group, CON; n=14); for 3 weeks. Mood states were measured using the Positive and Negative Affect Schedule (PANAS). Daily consumption of dark chocolate significantly reduced negative affect in DC85, but not in DC70. To assess the association between the mood-altering effects of dark chocolate and the gut microbiota, we performed fecal 16S rRNA sequencing analysis for the DC85 and CON groups. Gut microbial diversity was significantly higher in DC85 than CON (P<.05). Blautia obeum levels were significantly elevated and Faecalibacterium prausnitzii levels were reduced in DC85 compared to CON (P<.05). Furthermore, we found that the observed changes in negative affect scores were negatively correlated with diversity and relative abundance of Blautia obeum (P<.05). These findings indicate that dark chocolate exerts prebiotic effects, as evidenced by its ability to restructure the diversity and abundance of intestinal bacteria; thus, it may improve negative emotional states via the gut-brain axis.
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Effects of Lactobacillus curvatus HY7601 and Lactobacillus plantarum KY1032 on Overweight and the Gut Microbiota in Humans: Randomized, Double-Blinded, Placebo-Controlled Clinical Trial.
Mo, SJ, Lee, K, Hong, HJ, Hong, DK, Jung, SH, Park, SD, Shim, JJ, Lee, JL
Nutrients. 2022;14(12)
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Probiotics are defined by the WHO as live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. Recent studies suggest that probiotics play a role as natural therapeutic supplements with the potential to improve lipid metabolism, and improve weight control through interventions that affect gut microbiome diversity. The aim of this study was to explore how Lactobacillus curvatus HY7601 (HY7601) and Lactobacillus plantarum KY1032 (KY1032) supplementation alleviate obesity by modulating the human gut microbiome. This study was a 12-week randomised, double-blind, placebo-controlled study on overweight and obese Koreans. Subjects (n =72) were randomly assigned to receive either probiotics or placebo. Results showed that probiotic supplementation with HY7601 and KY1032 decreased body weight, visceral fat mass, waist circumference, and increased adiponectin. Furthermore, these probiotics changed the bacterial gut microbiota characteristics associated with each obesity indicator. HY7601 and KY1032 exerted anti-obesity effects by regulating the gut microbiota composition. Authors conclude that HY7601 and KY1032 intake can alter the composition and diversity of the human gut microbiome, and thereby help prevent obesity and its associated metabolic syndrome.
Abstract
Obesity and overweight are closely related to diet, and the gut microbiota play an important role in body weight and human health. The aim of this study was to explore how Lactobacillus curvatus HY7601 and Lactobacillus plantarum KY1032 supplementation alleviate obesity by modulating the human gut microbiome. A randomized, double-blind, placebo-controlled study was conducted on 72 individuals with overweight. Over a 12-week period, probiotic groups consumed 1 × 1010 colony-forming units of HY7601 and KY1032, whereas the placebo group consumed the same product without probiotics. After treatment, the probiotic group displayed a reduction in body weight (p < 0.001), visceral fat mass (p < 0.025), and waist circumference (p < 0.007), and an increase in adiponectin (p < 0.046), compared with the placebo group. Additionally, HY7601 and KY1032 supplementation modulated bacterial gut microbiota characteristics and beta diversity by increasing Bifidobacteriaceae and Akkermansiaceae and decreasing Prevotellaceae and Selenomonadaceae. In summary, HY7601 and KY1032 probiotics exert anti-obesity effects by regulating the gut microbiota; hence, they have therapeutic potential for preventing or alleviating obesity and living with overweight.
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Personalised nutrition advice reduces intake of discretionary foods and beverages: findings from the Food4Me randomised controlled trial.
Livingstone, KM, Celis-Morales, C, Navas-Carretero, S, San-Cristobal, R, Forster, H, Woolhead, C, O'Donovan, CB, Moschonis, G, Manios, Y, Traczyk, I, et al
The international journal of behavioral nutrition and physical activity. 2021;18(1):70
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Food4Me is an internet-based personalised nutrition study that evaluates the effectiveness of personalized dietary advice in avoiding discretionary foods compared to conventional advice. In different countries, discretionary foods are classified differently. Therefore, this study included two measures of discretionary foods identified by the Food4Me Food Frequency Questionnaire, which covered 22 discretionary foods classified by Food Standards Scotland and 59 discretionary foods identified by Australian Dietary Guidelines. For six months, 1607 participants from seven European countries were randomly assigned to receive generalised dietary advice or one of three levels of personalised nutrition advice (based on diet [L1], phenotype [L2] and genotype [L3]). Personalised nutrition advice was found to be effective in reducing discretionary foods when categorisation included foods high in fat, added sugar and salt. There was a greater reduction in energy, sugar, salt, and saturated fat intakes in people who received personalised nutrition advice [L1-3] as compared to generalised dietary advice after six months. Results of this study can be used by healthcare professionals to support personalised nutrition strategies in the general population targeting discretionary foods to increase compliance with personalised nutrition strategies and achieve better health outcomes.
Abstract
BACKGROUND The effect of personalised nutrition advice on discretionary foods intake is unknown. To date, two national classifications for discretionary foods have been derived. This study examined changes in intake of discretionary foods and beverages following a personalised nutrition intervention using these two classifications. METHODS Participants were recruited into a 6-month RCT across seven European countries (Food4Me) and were randomised to receive generalised dietary advice (control) or one of three levels of personalised nutrition advice (based on diet [L1], phenotype [L2] and genotype [L3]). Dietary intake was derived from an FFQ. An analysis of covariance was used to determine intervention effects at month 6 between personalised nutrition (overall and by levels) and control on i) percentage energy from discretionary items and ii) percentage contribution of total fat, SFA, total sugars and salt to discretionary intake, defined by Food Standards Scotland (FSS) and Australian Dietary Guidelines (ADG) classifications. RESULTS Of the 1607 adults at baseline, n = 1270 (57% female) completed the intervention. Percentage sugars from FSS discretionary items was lower in personalised nutrition vs control (19.0 ± 0.37 vs 21.1 ± 0.65; P = 0.005). Percentage energy (31.2 ± 0.59 vs 32.7 ± 0.59; P = 0.031), percentage total fat (31.5 ± 0.37 vs 33.3 ± 0.65; P = 0.021), SFA (36.0 ± 0.43 vs 37.8 ± 0.75; P = 0.034) and sugars (31.7 ± 0.44 vs 34.7 ± 0.78; P < 0.001) from ADG discretionary items were lower in personalised nutrition vs control. There were greater reductions in ADG percentage energy and percentage total fat, SFA and salt for those randomised to L3 vs L2. CONCLUSIONS Compared with generalised dietary advice, personalised nutrition advice achieved greater reductions in discretionary foods intake when the classification included all foods high in fat, added sugars and salt. Future personalised nutrition approaches may be used to target intake of discretionary foods. TRIAL REGISTRATION Clinicaltrials.gov NCT01530139 . Registered 9 February 2012.
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Effects of Synbiotic Supplement on Human Gut Microbiota, Body Composition and Weight Loss in Obesity.
Sergeev, IN, Aljutaily, T, Walton, G, Huarte, E
Nutrients. 2020;12(1)
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The gut microbiota plays a role in the development of obesity and associated diseases. Whilst energy-restricted, low-carbohydrate, high-protein diets can facilitate substantial weight-loss, they also have been linked to ill-effects and unfavourable changes in the gut microbiota from excess protein fermentation. Pro-and prebiotics (synbiotics) have become a promising intervention in the management of obesity. This small placebo-controlled clinical trial involved 20 obese adults following an energy-restricted (approx.950 kcal/day) low-carbohydrate, high-protein diet. The study examined whether a supplementary synbiotic contributed to additional changes in body composition and metabolic biomarkers. The synbiotic contained Lactobacilli spp. and Bifidobacteria spp. and a prebiotic mixture of galactooligosaccharides. Overall, at the end of the 3-month trial, there was no remarkable difference between the groups. Both experienced a significant and decreasing trend in body mass, waist circumference, body mass index, fat mass, fat percentage, and glucose level, affirming the known benefits of the described weight-loss diet. However, the synbiotic supplementation group had a greater decrease in HbA1C and significant alterations in gut microbiota, showing an increased abundance of gut bacteria associated with positive health effects. Due to the complexity of microbial species and host interactions, the authors advocate for more research to identify their significance and shed light on contradictory findings. This study identified that synbiotics may not contribute to additional changes in body composition when combined with an energy-restricted, low-carbohydrate, high-protein diet but they can offer additional health benefits by inducing favourable changes to the gut microbiota.
Abstract
Targeting gut microbiota with synbiotics (probiotic supplements containing prebiotic components) is emerging as a promising intervention in the comprehensive nutritional approach to reducing obesity. Weight loss resulting from low-carbohydrate high-protein diets can be significant but has also been linked to potentially negative health effects due to increased bacterial fermentation of undigested protein within the colon and subsequent changes in gut microbiota composition. Correcting obesity-induced disruption of gut microbiota with synbiotics can be more effective than supplementation with probiotics alone because prebiotic components of synbiotics support the growth and survival of positive bacteria therein. The purpose of this placebo-controlled intervention clinical trial was to evaluate the effects of a synbiotic supplement on the composition, richness and diversity of gut microbiota and associations of microbial species with body composition parameters and biomarkers of obesity in human subjects participating in a weight loss program. The probiotic component of the synbiotic used in the study contained Lactobacillus acidophilus, Bifidobacterium lactis, Bifidobacterium longum, and Bifidobacterium bifidum and the prebiotic component was a galactooligosaccharide mixture. The results showed no statistically significant differences in body composition (body mass, BMI, body fat mass, body fat percentage, body lean mass, and bone mineral content) between the placebo and synbiotic groups at the end of the clinical trial (3-month intervention, 20 human subjects participating in weight loss intervention based on a low-carbohydrate, high-protein, reduced energy diet). Synbiotic supplementation increased the abundance of gut bacteria associated with positive health effects, especially Bifidobacterium and Lactobacillus, and it also appeared to increase the gut microbiota richness. A decreasing trend in the gut microbiota diversity in the placebo and synbiotic groups was observed at the end of trial, which may imply the effect of the high-protein low-carbohydrate diet used in the weight loss program. Regression analysis performed to correlate abundance of species following supplementation with body composition parameters and biomarkers of obesity found an association between a decrease over time in blood glucose and an increase in Lactobacillus abundance, particularly in the synbiotic group. However, the decrease over time in body mass, BMI, waist circumstance, and body fat mass was associated with a decrease in Bifidobacterium abundance. The results obtained support the conclusion that synbiotic supplement used in this clinical trial modulates human gut microbiota by increasing abundance of potentially beneficial microbial species.
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Prolonged Collagen Peptide Supplementation and Resistance Exercise Training Affects Body Composition in Recreationally Active Men.
Kirmse, M, Oertzen-Hagemann, V, de Marées, M, Bloch, W, Platen, P
Nutrients. 2019;11(5)
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Currently little is known concerning collagen protein supplementation combined with a prolonged resistance exercising training (RET) programme. The aim of this study was to determine the effects of long-term collagen peptide supplementation and RET on body composition, strength and muscle fibre cross-sectional surface area (fCSA) in 57 recreationally active men. In this double-blind, placebo-controlled study, participants were randomly allocated to receive either collagen peptides or placebo for 12 weeks. Both groups trained three times a week. Strength testing, bioimedance analysis and muscle biopsies were taken at baseline and post-intervention. Most notably the collagen group experienced a significant increase in fat-free mass while body fat mass remained unchanged, compared to the placebo group. Both groups showed significant increases in strength tests and the fCSA increased significantly without differences. Based on these results, the authors conclude collagen protein supplementation have positive impact on body composition however suggest further study include connective tissue in addition to muscle tissue to better understand the mechanisms underlying these changes.
Abstract
We aimed to determine the effects of long-term collagen peptide (CP) supplementation and resistance exercise training (RET) on body composition, strength, and muscle fiber cross-sectional area (fCSA) in recreationally active men. Fifty-seven young men were randomly and double-blinded divided into a group receiving either collagen peptides (COL, 15 g/day) or a placebo (PLA). Strength testing, bioimpedance analysis, and muscle biopsies were used prior to and after an RET intervention. Food record protocols were performed during the RET intervention. The groups trained three times a week for 12 weeks. Baseline parameters showed no differences between groups, and the external training load and dietary food intake were also similar. COL showed a significant increase in fat-free mass (FFM) compared with the placebo group (p < 0.05). Body fat mass (BFM) was unchanged in COL, whereas a significant increase in BFM was observed in PLA. Both groups showed significant increases in all strength tests, with a trend for a slightly more pronounced effect in COL. The fCSA of type II muscle fibers increased significantly in both groups without differences between the two groups. We firstly demonstrated improved body composition in healthy, recreationally active men subsequent to prolonged CP supplementation in combination with RET. As the observed increase in FFM was not reflected in differences in fCSA hypertrophy between groups, we assume enhanced passive connective tissue adaptations in COL due to CP intake.
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The Effect of Nutrition Intervention with Oral Nutritional Supplements on Pancreatic and Bile Duct Cancer Patients Undergoing Chemotherapy.
Kim, SH, Lee, SM, Jeung, HC, Lee, IJ, Park, JS, Song, M, Lee, DK, Lee, SM
Nutrients. 2019;11(5)
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Despite the advantages of chemotherapy, it can cause cancer-related malnutrition leading to both reduced quality of life and reduced survival rate. Oral nutritional supplements (ONSs) provide balanced nutrients, calories, and protein to complement insufficient oral intake, and ONS provision during treatment may improve nutritional status. The aim of this study was to investigate the impact of ONS on nutritional status in patients undergoing chemotherapy for pancreatic and bile duct cancer. Patients were randomly allocated to the ONS group (15) and non-ONS group (19) and dietary intake and body weight were assessed at weeks 1, 2, 4 and 8. Body composition and quality of life was assessed at baseline and week 8. This study found the supply of ONS helped promote health by increasing body fat mass, improving quality of life and decreasing fatigue symptoms in pancreatic and bile duct cancer patients. These results were more pronounced in patients in the first cycle of chemotherapy. Based on these results, the authors conclude ONS may improve nutritional status by increasing fat mass and/or maintaining the body composition of patients undergoing chemotherapy.
Abstract
Chemotherapy may negatively affect nutritional status and quality of life (QOL) in pancreatic cancer patients. Our aim was to investigate the beneficial effects of oral nutrition supplements (ONS) on pancreatic and bile duct cancer patients undergoing chemotherapy. Among patients with progressive pancreatic and bile duct cancer receiving chemotherapy, the ONS group (n = 15) received two packs of ONS daily for 8 weeks while the non-ONS group (n = 19) did not. Anthropometric measures, dietary intake, nutritional status, and quality of life were assessed. ONS significantly increased daily intakes of energy, carbohydrates, proteins, and lipids at 8 weeks compared to the baseline. After 8 weeks, fat mass significantly increased in the ONS group. For patients in their first cycle of chemotherapy, body weight, fat-free mass, skeletal muscle mass, body cell mass, and fat mass increased in the ONS group but decreased in the non-ONS group. Fat mass increased in second or higher cycle only in the ONS group. Patient-generated subjective global assessments (PG-SGA) and fatigue scores in the Quality of Life Questionnaire Core 30 (QLQ-C30) improved in the ONS group. ONS might improve nutritional status by increasing fat mass and/or maintaining the body composition of pancreatic and bile duct cancer patients with chemotherapy, especially those in the first cycle, and alleviate fatigue symptoms.
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Lifestyle Risk Factors for Serrated Colorectal Polyps: A Systematic Review and Meta-analysis.
Bailie, L, Loughrey, MB, Coleman, HG
Gastroenterology. 2017;152(1):92-104
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Colorectal cancer (CRC) is a heterogeneous disease thought to result from the accumulation of various aberrant mutations in the cells lining the colorectal mucosa. The aim of this systematic review and meta-analysis was to evaluate modifiable and lifestyle factors and the risk of serrated polyps (a type of growth that stick out from the surface of the colon or rectum) of the colorectum. A search of 3 databases yielded a potential 2446 studies for inclusion, from which 43 remained for systematic review. Results indicate that smoking, alcohol consumption, body fatness, dietary fat and meat consumption increased the risk of developing serrated polyps. Whereas, nonsteroidal anti-inflammatory drugs, aspirin and dietary folate decreased this risk. Authors conclude that their findings strengthen public health messages promoting awareness and change in order to reduce the risk of these precancerous lesions and consequently CRC.
Abstract
BACKGROUND & AIMS Certain subsets of colorectal serrated polyps (SP) have malignant potential. We performed a systematic review and meta-analysis to investigate the association between modifiable lifestyle factors and risk for SPs. METHODS We conducted a systematic search of Medline, Embase, and Web of Science for observational or interventional studies that contained the terms risk or risk factor, and serrated or hyperplastic, and polyps or adenomas, and colorectal (or synonymous terms), published by March 2016. Titles and abstracts of identified articles were independently reviewed by at least 2 reviewers. Adjusted relative risk (RR) and 95% confidence interval (CI) were combined using random effects meta-analyses to assess the risk of SP, when possible. RESULTS We identified 43 studies of SP risk associated with 7 different lifestyle factors: smoking, alcohol, body fatness, diet, physical activity, medication, and hormone-replacement therapy. When we compared the highest and lowest categories of exposure, factors we found to significantly increase risk for SP included tobacco smoking (RR, 2.47; 95% CI, 2.12-2.87), alcohol intake (RR, 1.33; 95% CI, 1.17-1.52), body mass index (RR, 1.40; 95% CI, 1.22-1.61), and high intake of fat or meat. Direct associations for smoking and alcohol, but not body fat, tended to be stronger for sessile serrated adenomas/polyps than hyperplastic polyps. In contrast, factors we found to significantly decrease risks for SP included use of nonsteroidal anti-inflammatory drugs (RR, 0.77; 95% CI, 0.65-0.92) or aspirin (RR, 0.81; 95% CI, 0.67-0.99), as well as high intake of folate, calcium, or fiber. No significant associations were detected between SP risk and physical activity or hormone replacement therapy. CONCLUSIONS Several lifestyle factors, most notably smoking and alcohol, are associated with SP risk. These findings enhance our understanding of mechanisms of SP development and indicate that risk of serrated pathway colorectal neoplasms could be reduced with lifestyle changes.