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The Role of Genetically Engineered Probiotics for Treatment of Inflammatory Bowel Disease: A Systematic Review.
Zhang, T, Zhang, J, Duan, L
Nutrients. 2023;15(7)
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Inflammatory bowel disease (IBD), largely classified as Crohn’s disease (CD) or ulcerative colitis (UC), is a chronic intestinal inflammatory disorder mediated by genetic, immune, microbial, and environmental factors. The aim of this study was to summarise the efficacy of different genetically modified probiotics compared to wild-type probiotics in the treatment of IBD in animal models and patients and to investigate the specific effects and main mechanisms involved. This study was a systematic review of forty-five preclinical studies and one clinical study. Results showed a protective effect of genetically modified organisms (gm) probiotics in colitis. Several protective mechanisms have been identified: reduction of the pro- to anti-inflammatory cytokine ratio in colonic tissue and plasma, modulation of the activity of oxidative stress in the colon, improvement of intestinal barrier integrity, modulation of the diversity and composition of gut microbiota, and production of favourable metabolites, including short-chain fatty acids, by beneficial bacteria. Authors concluded that gm probiotics are more effective and safer than wild-type probiotics, to facilitate clinical translation.
Expert Review
Conflicts of interest:
None
Take Home Message:
Conclusions of this review were largely based on mouse models and although treatment using probiotics is generally considered safe in humans, with only minor side-effects (flatulence), practitioners need to be aware that in an IBD population the use of GM formulations might not be completely without risk.
Evidence Category:
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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:
Introduction
This paper summarises the efficacy of specific genetically modified (GM) probiotic formulations for Inflammatory Bowel Disease (IBD) when compared to wild type probiotics. The aim was to ascertain what specific effects and mechanisms such probiotics have on IBD symptomatology.
Methods
- A total of 46 published articles were included; 45 mouse experimental models (induced acute or chronic colitis) (n=15-130) and 1 human IBD population clinical trial (n=10)
- The effect of GM probiotics were compared to placebo and wild-type probiotics in trials including preclinical studies, randomised controlled trials and cohort studies
- Animals received probiotics via gastric gavage (105 - 4 x 1012 CFU) for 3-6 weeks
- The human placebo-uncontrolled trial lasted 7 days and patients received 10 GM capsules of L.lactis (1 x 1010 CFU) twice daily.
Results
- GM probiotics that secrete immunoregulatory cytokines such as IL-10 appear to reduce intestinal damage
- The human trial using GM L.lactis resulted in 5 patients who went into complete clinical remission (CDAI, <150) with 3 patients exhibiting a clinical response (decrease in CDAI, >70). with only minor adverse events (flatulence)
- However, human cytokines that promote intestinal barrier function and epithelial restitution were not enhanced with oral administration of probiotics
- Two studies concluded that GM L.lactis and S.boulardii, that secrete atrial natriuretic peptide, might be the most effective options in supporting colitis
- GM L.casei resulted in faster recovery from weight loss in acute colitis models
- Superoxide dismutase (SOD) producing GM L.fermentum increased SOD activity by almost eightfold compared to the wild type
- GM Lact. fermentum furthermore showed a higher survival rate and lower disease activity index (P <0·05) in colitis models
- GM L.lactis improved gut microbial composition and GM S.cerevisiae improved microbial diversity whilst reducing the Firmicutes to Bacteroides ratio
- GM E.coli significantly reduced weight loss, colon shortening plus lower disease activity and histological changes (P < 0.05).
Conclusion
Despite the heterogeneity of the trials, GM probiotics appear to play a notable part in ameliorating IBD symptomatology and disease severity when compared to wild-type probiotics. Human efficacy and potential adverse effects require more in-depth trials to ascertain safety and optimal dosages.
Clinical practice applications:
- Probiotics species used in the trials included S.thermophilus, E.coli, L.lactis, B.ovatus, S.boulardii, L.fermentum, B.longhum, L.casei, L.plantarum, and S.cerevisiae. Wild-types of some of these are already available to use in clinical practice
- Note that oral administration in the human trial showed no significant health outcome, therefore efficacy and safety need to be ascertained on an individual patient level
- Colonisation of beneficial bacteria in the gut of IBD patients might be difficult and any form of supplementation therefore needs to be closely monitored.
Considerations for future research:
- More evidence is needed to demonstrate that GM probiotic formulations result in significantly improved outcomes when compared to wild-types
- Future randomised placebo-controlled trials need to include larger cohorts to determine supplement efficacy
- Longer periods of intervention are needed to confirm efficacy, safety, and tolerance for both Crohn’s Disease and Colitis
- Optimal GM probiotic formulation, doses, and means of application need to be identified.
Abstract
BACKGROUND Many preclinical studies have demonstrated the effectiveness of genetically modified probiotics (gm probiotics) in animal models of inflammatory bowel disease (IBD). OBJECTIVE This systematic review was performed to investigate the role of gm probiotics in treating IBD and to clarify the involved mechanisms. METHODS PubMed, Web of Science, Cochrane Library, and Medline were searched from their inception to 18 September 2022 to identify preclinical and clinical studies exploring the efficacy of gm probiotics in IBD animal models or IBD patients. Two independent researchers extracted data from the included studies, and the data were pooled by the type of study; that is, preclinical or clinical. RESULTS Forty-five preclinical studies were included. In these studies, sodium dextran sulfate and trinitrobenzene sulfonic acid were used to induce colitis. Eleven probiotic species have been genetically modified to produce therapeutic substances, including IL-10, antimicrobial peptides, antioxidant enzymes, and short-chain fatty acids, with potential therapeutic properties against colitis. The results showed generally positive effects of gm probiotics in reducing disease activity and ameliorating intestinal damage in IBD models; however, the efficacy of gm probiotics compared to that of wild-type probiotics in many studies was unclear. The main mechanisms identified include modulation of the diversity and composition of the gut microbiota, production of regulatory metabolites by beneficial bacteria, reduction of the pro- to anti-inflammatory cytokine ratio in colonic tissue and plasma, modulation of oxidative stress activity in the colon, and improvement of intestinal barrier integrity. Moreover, only one clinical trial with 10 patients with Crohn's disease was included, which showed that L. lactis producing IL-10 was safe, and a decrease in disease activity was observed in these patients. CONCLUSIONS Gm probiotics have a certain efficacy in colitis models through several mechanisms. However, given the scarcity of clinical trials, it is important for researchers to pay more attention to gm probiotics that are more effective and safer than wild-type probiotics to facilitate further clinical translation.
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Dietary macronutrients and the gut microbiome: a precision nutrition approach to improve cardiometabolic health.
Jardon, KM, Canfora, EE, Goossens, GH, Blaak, EE
Gut. 2022;71(6):1214-1226
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The global rise in the prevalence of obesity is strongly associated with an increase in the incidence and prevalence of cardiometabolic diseases, including insulin resistance (IR) and type 2 diabetes mellitus. In recent years, advancements have been made in understanding the involvement of the gut microbiome in obesity and related cardiometabolic complications as regulator of host energy and substrate metabolism. This study is a review that discusses the latest research describing interactions between dietary composition, the gut microbiome and host metabolism. Results show that current evidence for developing optimal dietary interventions targeting bodyweight control and IR via the gut microbiota is still in its infancy and does not capture the complexity of the integration of a whole-diet approach, the microbial and the host’s metabolic phenotype. Furthermore, implementation of targeted, precision nutrition intervention strategies or dietary guidelines for individuals or subgroups in public health requires further insight in the mechanisms involved in (non-)response to dietary intervention. Authors conclude that future studies are needed and these should focus on assessing detailed individual phenotyping and gaining insight into the balance between carbohydrate and protein fermentation by the gut microbiota as well as the site of fermentation in the colon.
Abstract
Accumulating evidence indicates that the gut microbiome is an important regulator of body weight, glucose and lipid metabolism, and inflammatory processes, and may thereby play a key role in the aetiology of obesity, insulin resistance and type 2 diabetes. Interindividual responsiveness to specific dietary interventions may be partially determined by differences in baseline gut microbiota composition and functionality between individuals with distinct metabolic phenotypes. However, the relationship between an individual's diet, gut microbiome and host metabolic phenotype is multidirectional and complex, yielding a challenge for practical implementation of targeted dietary guidelines. In this review, we discuss the latest research describing interactions between dietary composition, the gut microbiome and host metabolism. Furthermore, we describe how this knowledge can be integrated to develop precision-based nutritional strategies to improve bodyweight control and metabolic health in humans. Specifically, we will address that (1) insight in the role of the baseline gut microbial and metabolic phenotype in dietary intervention response may provide leads for precision-based nutritional strategies; that (2) the balance between carbohydrate and protein fermentation by the gut microbiota, as well as the site of fermentation in the colon, seems important determinants of host metabolism; and that (3) 'big data', including multiple omics and advanced modelling, are of undeniable importance in predicting (non-)response to dietary interventions. Clearly, detailed metabolic and microbial phenotyping in humans is necessary to better understand the link between diet, the gut microbiome and host metabolism, which is required to develop targeted dietary strategies and guidelines for different subgroups of the population.
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Nutrition in Menopausal Women: A Narrative Review.
Silva, TR, Oppermann, K, Reis, FM, Spritzer, PM
Nutrients. 2021;13(7)
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Menopause is the permanent cessation of menstrual cycles following the loss of ovarian follicular activity. It is associated with increased prevalence of obesity, metabolic syndrome, cardiovascular disease, and osteoporosis. The aim of this narrative review was to discuss the current evidence on the association between dietary patterns and clinical endpoints in postmenopausal women (body composition, bone mass, and risk markers for cardiovascular disease), and thereby providing novel insight into the establishment of optimal dietary guidelines for healthy postmenopausal period. Research shows that: - the changes in weight and fat distribution in women are associated with aging and mainly with the decrease in oestradiol levels during peri- and post-menopause. - calcium, vitamin D, vitamin K, selenium, magnesium, and beta-carotene adequate intake could be linked with better BMD in postmenopausal women. - diet is a major modifiable risk factor for cardiovascular disease and could be a powerful intervention to reduce cardiovascular risks in postmenopausal women. - the Mediterranean diet is composed of healthy foods that have anti-inflammatory and antioxidant properties. Authors indicate that future studies evaluating the effects of low-fat, plant-based diets on fat mass in post-menopausal women are needed.
Abstract
Among the various aspects of health promotion and lifestyle adaptation to the postmenopausal period, nutritional habits are essential because they concern all women, can be modified, and impact both longevity and quality of life. In this narrative review, we discuss the current evidence on the association between dietary patterns and clinical endpoints in postmenopausal women, such as body composition, bone mass, and risk markers for cardiovascular disease. Current evidence suggests that low-fat, plant-based diets are associated with beneficial effects on body composition, but further studies are needed to confirm these results in postmenopausal women. The Mediterranean diet pattern along with other healthy habits may help the primary prevention of bone, metabolic, and cardiovascular diseases in the postmenopausal period. It consists on the use of healthy foods that have anti-inflammatory and antioxidant properties, and is associated with a small but significant decrease in blood pressure, reduction of fat mass, and improvement in cholesterol levels. These effects remain to be evaluated over a longer period of time, with the assessment of hard outcomes such as bone fractures, diabetes, and coronary ischemia.
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Liver injury is associated with severe coronavirus disease 2019 (COVID-19) infection: A systematic review and meta-analysis of retrospective studies.
Parohan, M, Yaghoubi, S, Seraji, A
Hepatology research : the official journal of the Japan Society of Hepatology. 2020;50(8):924-935
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Severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS) and Coronavirus disease 2019 (COVID-19) can cause intestinal, respiratory, neuronal and hepatic diseases, and may lead to respiratory distress syndrome, organ failure, and even death in severe cases. The aim of this study was to assess the association between serum levels of Aspartate aminotransferase [enzyme], Alanine aminotransferase [enzyme], total Bilirubin [yellowish blood pigment] and Albumin [protein] with severity of COVID-19 infection. This study is a systemic review and meta-analysis of 20 retrospective studies conducted in China. The sample size of studies ranged from 21 to 651 patients (mean age, 53.3 years). Results indicate that high serum levels of aspartate aminotransferase, alanine aminotransferase, total bilirubin and lower serum levels of albumin are associated with a significant increase in the severity of COVID-19 infection. Authors conclude that attention should be paid to monitor the occurrence of liver dysfunction in patients with COVID-19 infection.
Abstract
The coronavirus disease 2019 (COVID-19) outbreak is a major threat to human beings. Lung injury has been reported as the major outcome of COVID-19 infection. However, liver damage has also been considered to occur in severe cases. The current meta-analysis of retrospective studies was carried out to summarize available findings on the association between liver injury and severity of COVID-19 infection. Online databases including PubMed, Scopus, Web of Science, and Cochrane Library were searched to detect relevant publications up to 1 April 2020, using relevant keywords. To pool data, a fixed- or random-effects model was used depending on the heterogeneity between studies. Furthermore, publication bias test and sensitivity analysis were also applied. In total, 20 retrospective studies with 3428 COVID-19 infected patients (severe cases, n = 1455; mild cases, n = 1973), were included in this meta-analysis. Higher serum levels of aspartate aminotransferase (weighted mean difference, 8.84 U/L; 95% confidence interval [CI] 5.97 to 11.71; P < 0.001), alanine aminotransferase (weighted mean difference, 7.35 U/L; 95% CI, 4.77 to 9.93; P < 0.001), total bilirubin (weighted mean difference, 2.30 mmol/L; 95% CI, 1.24 to 3.36; P < 0.001), and lower serum levels of albumin (weighted mean difference, -4.24 g/L; 95% CI, -6.20 to -2.28; P < 0.001) were associated with a significant increase in the severity of COVID-19 infection. The incidence of liver injury, as assessed by serum analysis (aspartate aminotransferase, alanine aminotransferase, total bilirubin, and albumin levels), seems to be higher in patients with severe COVID-19 infection.
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The role of diet and probiotics in prevention and treatment of bacterial vaginosis and vulvovaginal candidiasis in adolescent girls and non-pregnant women.
Mizgier, M, Jarzabek-Bielecka, G, Mruczyk, K, Kedzia, W
Ginekologia polska. 2020;91(7):412-416
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In adolescent girls and non-pregnant women, vaginitis, including fungal infections, is a common problem. Vaginitis clinically manifests as abnormal vaginal discharge, irritation, itching, burning and discomfort, and is especially prevalent with a decrease in immunity. The normal bacterial flora of the vagina and cervix protect against the development of pathogenic strains, while abnormal flora tend to be the most common starting point for the development of infections. The aim of this study was to determine the role of proper diet and probiotics and prebiotics use in relation to therapy and prophylaxis of vulvovaginal candidiasis (VVC) and bacterial vaginosis (BV) in non-pregnant women and girls. This review shows that: - An unbalanced diet can be a risk factor for BV. Women tend to be more exposed to BV if they have poor micronutrient status, including vitamins A, E, D, C and beta carotene — indicating a lower fruit and vegetable intake. - Many studies proved that regulated use of probiotics, administered both orally and vaginally, are effective in the prevention and treatment of vaginal infections such as BV and VVC. - To create a positive environment for probiotics, it is important to provide prebiotics that support the development of probiotic strains. Authors conclude that gynaecologists, obstetricians, general practitioners and dieticians should share their findings, and raise awareness among the general population as to the importance of optimal nutrition. Probiotics and prebiotics could be considered to prevent infections of the genital tract, reduce associated disease, and maintain reproductive health.
Abstract
The article raises important issues regarding the use of diet and probiotics in prevention and treatment of vaginitis. Vaginitis is defined as any condition with symptoms of abnormal vaginal discharge. The most common causes of vaginitis are vulvovaginal candidiasis (VVC), trichomoniasis and bacterial vaginosis (BV). Vaginitis has been linked to itching, burning, pain, discharge, irritation and also adverse reproductive and obstetric health outcomes. Moreover, microorganisms that build vaginal flora in the state of bacterial vaginosis are a source of cervicitis and endometritis (often in subclinical forms) and pelvic inflammatory disease (PID) The proper diet and probiotics consumption may influence the composition of the gut microbiota, improve gut integrity, and have an impact on maintaining and recovering the normal vaginal microbiota. Future studies and reviews investigating the role of diet and probiotics in changes to gut and vaginal microbiome need to focus on deciphering the mechanismus of host bacteria interaction in vulvovaginal health.
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Anti-aging Effects of Calorie Restriction (CR) and CR Mimetics based on the Senoinflammation Concept.
Kim, DH, Bang, E, Jung, HJ, Noh, SG, Yu, BP, Choi, YJ, Chung, HY
Nutrients. 2020;12(2)
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Low grade, systemic, chronic inflammation is a feature of ageing and underlies many age-related chronic diseases states. As cells age their capacity to proliferate declines, which is referred to as cell senescence. Such senescent cells release multiple inflammatory markers contributing to a pro-inflammatory state. This is further aggravated by elevated oxidative stress and a reduced capacity to manage it, eventually leading to improper gene regulation and DNA damage. To define this age-related, complex inflammatory phenomena the authors introduced the term senoinflammation. A well-established intervention to reverse or slow down the ageing process and many ageing-associated diseases is calorie restriction (CR), by means of reducing overall caloric intake without malnutrition. CR exhibits potent anti-inflammatory effects, reduces age-associated oxidative stress, improves age-related metabolic dysregulation and enhances favourable gene expression. This review summarises how CR and CR-mimicking substances exert their anti-inflammatory effect and some of the cellular mechanism involved and may be of interest to those who are looking to get a more detailed understanding on ageing, inflammation and the benefits of CR.
Abstract
Chronic inflammation, a pervasive feature of the aging process, is defined by a continuous, multifarious, low-grade inflammatory response. It is a sustained and systemic phenomenon that aggravates aging and can lead to age-related chronic diseases. In recent years, our understanding of age-related chronic inflammation has advanced through a large number of investigations on aging and calorie restriction (CR). A broader view of age-related inflammation is the concept of senoinflammation, which has an outlook beyond the traditional view, as proposed in our previous work. In this review, we discuss the effects of CR on multiple phases of proinflammatory networks and inflammatory signaling pathways to elucidate the basic mechanism underlying aging. Based on studies on senoinflammation and CR, we recognized that senescence-associated secretory phenotype (SASP), which mainly comprises cytokines and chemokines, was significantly increased during aging, whereas it was suppressed during CR. Further, we recognized that cellular metabolic pathways were also dysregulated in aging; however, CR mimetics reversed these effects. These results further support and enhance our understanding of the novel concept of senoinflammation, which is related to the metabolic changes that occur in the aging process. Furthermore, a thorough elucidation of the effect of CR on senoinflammation will reveal key insights and allow possible interventions in aging mechanisms, thus contributing to the development of new therapies focused on improving health and longevity.
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Small Intestinal Bacterial Overgrowth in Children: A State-Of-The-Art Review.
Avelar Rodriguez, D, Ryan, PM, Toro Monjaraz, EM, Ramirez Mayans, JA, Quigley, EM
Frontiers in pediatrics. 2019;7:363
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Small intestinal bacterial overgrowth (SIBO) occurs when microorganisms overpopulate the small intestine and is characterised by gastrointestinal symptoms such as abdominal pain, diarrhoea, and flatulence. This review focuses on paediatric SIBO, known to be increasing, with emphasis on the impact on gut microbiota. The gut microbiota is influenced by several factors including genetics, vaginal delivery, exercise and diet. SIBO in children has been studied in the context of stunting, irritable bowel syndrome (IBS), obesity, and related to use of proton pump inhibitors (PPIs). This review analysed 149 studies published since 2000 through till May 2019 with the aim of presenting the most up-to-date information. Risk factors included gastric acids and medications which suppress this activity, intestinal motility disturbances leading to bacterial overgrowth, anatomical anomalies where there is an absence of one or more intestinal valves, and poor socioeconomic status and diet. The review concluded that the recommended diagnosis is by methane and hydrogen breath testing and that Gold Standard treatment is antibiotic ‘rifaximin’ at 1,200 mg/d, reduced to 600 mg/d for 1 week in children. Alternative treatments discussed include FODMAP diets and probiotic protocols with best results coming from combining antibiotic and probiotic protocols. It concludes that SIBO in children is heterogenous and poorly understood and that a better diagnostic criteria is necessary in paediatrics.
Abstract
Small intestinal bacterial overgrowth (SIBO) is a heterogenous and poorly understood entity characterised by an excessive growth of select microorganisms within the small intestine. This excessive bacterial biomass, in turn, disrupts host physiology in a myriad of ways, leading to gastrointestinal and non-gastrointestinal symptoms and complications. SIBO is a common cause of non-specific gastrointestinal symptoms in children, such as chronic abdominal pain, abdominal distention, diarrhoea, and flatulence, amongst others. In addition, it has recently been implicated in the pathophysiology of stunting, a disease that affects millions of children worldwide. Risk factors such as acid-suppressive therapies, alterations in gastrointestinal motility and anatomy, as well as impoverished conditions, have been shown to predispose children to SIBO. SIBO can be diagnosed via culture-dependant or culture-independent approaches. SIBO's epidemiology is limited due to the lack of uniformity and consensus of its diagnostic criteria, as well as the paucity of literature available. Antibiotics remain the first-line treatment option for SIBO, although emerging modalities such as probiotics and diet manipulation could also have a role. Herein, we present a state-of-the-art-review which aims to comprehensively outline the most current information on SIBO in children, with particular emphasis on the gut microbiota.
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Raw Cow's Milk and Its Protective Effect on Allergies and Asthma.
Sozańska, B
Nutrients. 2019;11(2)
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In the last decades, a significant increase in the prevalence of allergic diseases and asthma has been observed. Living on a farm can reduce the risk of allergen sensitisation and allergic diseases in children. Most proposed explanations have been based on variations in the “hygiene hypothesis” and a possible effects on immune balance of a farm environment. Here, the author reviews epidemiological and experimental evidence for the documented protective effects of unpasteurised milk on allergies and asthma. Epidemiological studies from a number of countries show that children who consume raw milk early in life are less likely to develop allergies, independent of other factors. In one study that looked into possible components for this effect found that certain milk proteins (α-lactalbumin, β-lactoglobulin, and bovine serum albumin whey protein) reduced the risk of developing asthma . Total fat and protein content, amount of bacteria in the milk, and lactose levels were not associated with allergies or asthma. Another study found that higher levels of total fat and of omega-3 polyunsaturated fatty acids in raw milk had protective effects. The author discusses differences between raw and treated milk. Homogenisation changes the physical structure of fats and proteins, resulting in casein proteins being more easily adsorbed. The aim of heating milk, either through pasteurisation or UHT sterilisation, is to reduce bacterial numbers and growth, but it also affects heat-sensitive milk components, including whey proteins, immunoglobulins and lactoferrin, which have been shown to modulate the immune system. The author concludes that components of raw milk can influence immune function, and acknowledges the controversy with regards to raw milk carrying a risk of bacterial pathogens and that a proof based on controlled studies in infants is not possible due to ethical reasons.
Abstract
Living on a farm and having contact with rural exposures have been proposed as one of the most promising ways to be protected against allergy and asthma development. There is a significant body of epidemiological evidence that consumption of raw milk in childhood and adulthood in farm but also nonfarm populations can be one of the most effective protective factors. The observation is even more intriguing when considering the fact that milk is one of the most common food allergens in childhood. The exact mechanisms underlying this association are still not well understood, but the role of raw milk ingredients such as proteins, fat and fatty acids, and bacterial components has been recently studied and its influence on the immune function has been documented. In this review, we present the current understanding of the protective effect of raw milk on allergies and asthma.
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Nutritional labelling for healthier food or non-alcoholic drink purchasing and consumption.
Crockett, RA, King, SE, Marteau, TM, Prevost, AT, Bignardi, G, Roberts, NW, Stubbs, B, Hollands, GJ, Jebb, SA
The Cochrane database of systematic reviews. 2018;2:CD009315
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Poor quality diets are a threat to health internationally and a challenge to health services. Implementing methods to change people's choices is difficult; even those who start making healthier choices often find it hard to maintain long-term. There is recognition that our environment has a powerful influence over our food choices and altering this may stimulate behavioural change. Nutritional labels provide information about the nutritional content of a food or drink. The type of information provided varies e.g. what nutrients they describe (e.g. macronutrients like fat or energy content) and the form also varies e.g. as a single number, as a proportion of a guideline for daily consumption, or with colours indicative of relative healthiness. Nutritional labelling has been rolled-out in many forms, across many countries but there is currently no consensus as to the best way of applying this information to products to stimulate healthier food choices. This review explored whether nutritional labels persuade consumers to buy alternative types of food and included 28 articles. Findings from these 28 articles suggest that nutritional labelling specially indicating energy content may cause people to opt to buy foods with a lower energy content in restaurants. This result (only based on 3 studies) suggests that nutritional labelling could be rolled-out on menus in restaurants, but high-quality research is required. Higher-quality research is also needed to explore the impact of nutritional labelling in shops and vending machines.
Abstract
BACKGROUND Nutritional labelling is advocated as a means to promote healthier food purchasing and consumption, including lower energy intake. Internationally, many different nutritional labelling schemes have been introduced. There is no consensus on whether such labelling is effective in promoting healthier behaviour. OBJECTIVES To assess the impact of nutritional labelling for food and non-alcoholic drinks on purchasing and consumption of healthier items. Our secondary objective was to explore possible effect moderators of nutritional labelling on purchasing and consumption. SEARCH METHODS We searched 13 electronic databases including CENTRAL, MEDLINE and Embase to 26 April 2017. We also handsearched references and citations and sought unpublished studies through websites and trials registries. SELECTION CRITERIA Eligible studies: were randomised or quasi-randomised controlled trials (RCTs/Q-RCTs), controlled before-and-after studies, or interrupted time series (ITS) studies; compared a labelled product (with information on nutrients or energy) with the same product without a nutritional label; assessed objectively measured purchasing or consumption of foods or non-alcoholic drinks in real-world or laboratory settings. DATA COLLECTION AND ANALYSIS Two authors independently selected studies for inclusion and extracted study data. We applied the Cochrane 'Risk of bias' tool and GRADE to assess the quality of evidence. We pooled studies that evaluated similar interventions and outcomes using a random-effects meta-analysis, and we synthesised data from other studies in a narrative summary. MAIN RESULTS We included 28 studies, comprising 17 RCTs, 5 Q-RCTs and 6 ITS studies. Most (21/28) took place in the USA, and 19 took place in university settings, 14 of which mainly involved university students or staff. Most (20/28) studies assessed the impact of labelling on menus or menu boards, or nutritional labelling placed on, or adjacent to, a range of foods or drinks from which participants could choose. Eight studies provided participants with only one labelled food or drink option (in which labelling was present on a container or packaging, adjacent to the food or on a display board) and measured the amount consumed. The most frequently assessed labelling type was energy (i.e. calorie) information (12/28).Eleven studies assessed the impact of nutritional labelling on purchasing food or drink options in real-world settings, including purchases from vending machines (one cluster-RCT), grocery stores (one ITS), or restaurants, cafeterias or coffee shops (three RCTs, one Q-RCT and five ITS). Findings on vending machines and grocery stores were not interpretable, and were rated as very low quality. A meta-analysis of the three RCTs, all of which assessed energy labelling on menus in restaurants, demonstrated a statistically significant reduction of 47 kcal in energy purchased (MD -46.72 kcal, 95% CI -78.35, -15.10, N = 1877). Assuming an average meal of 600 kcal, energy labelling on menus would reduce energy purchased per meal by 7.8% (95% CI 2.5% to 13.1%). The quality of the evidence for these three studies was rated as low, so our confidence in the effect estimate is limited and may change with further studies. Of the remaining six studies, only two (both ITS studies involving energy labels on menus or menus boards in a coffee shop or cafeteria) were at low risk of bias, and their results support the meta-analysis. The results of the other four studies which were conducted in a restaurant, cafeterias (2 studies) or a coffee shop, were not clearly reported and were at high risk of bias.Seventeen studies assessed the impact of nutritional labels on consumption in artificial settings or scenarios (henceforth referred to as laboratory studies or settings). Of these, eight (all RCTs) assessed the effect of labels on menus or placed on a range of food options. A meta-analysis of these studies did not conclusively demonstrate a reduction in energy consumed during a meal (MD -50 kcal, 95% CI -104.41, 3.88, N = 1705). We rated the quality of the evidence as low, so our confidence in the effect estimate is limited and may change with further studies.Six laboratory studies (four RCTs and two Q-RCTs) assessed the impact of labelling a single food or drink option (such as chocolate, pasta or soft drinks) on energy consumed during a snack or meal. A meta-analysis of these studies did not demonstrate a statistically significant difference in energy (kcal) consumed (SMD 0.05, 95% CI -0.17 to 0.27, N = 732). However, the confidence intervals were wide, suggesting uncertainty in the true effect size. We rated the quality of the evidence as low, so our confidence in the effect estimate is limited and may change with further studies.There was no evidence that nutritional labelling had the unintended harm of increasing energy purchased or consumed. Indirect evidence came from five laboratory studies that involved mislabelling single nutrient content (i.e. placing low energy or low fat labels on high-energy foods) during a snack or meal. A meta-analysis of these studies did not demonstrate a statistically significant increase in energy (kcal) consumed (SMD 0.19, 95% CI -0.14to 0.51, N = 718). The effect was small and the confidence intervals wide, suggesting uncertainty in the true effect size. We rated the quality of the evidence from these studies as very low, providing very little confidence in the effect estimate. AUTHORS' CONCLUSIONS Findings from a small body of low-quality evidence suggest that nutritional labelling comprising energy information on menus may reduce energy purchased in restaurants. The evidence assessing the impact on consumption of energy information on menus or on a range of food options in laboratory settings suggests a similar effect to that observed for purchasing, although the evidence is less definite and also of low quality.Accordingly, and in the absence of observed harms, we tentatively suggest that nutritional labelling on menus in restaurants could be used as part of a wider set of measures to tackle obesity. Additional high-quality research in real-world settings is needed to enable more certain conclusions.Further high-quality research is also needed to address the dearth of evidence from grocery stores and vending machines and to assess potential moderators of the intervention effect, including socioeconomic status.
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The Role of Bacteria, Probiotics and Diet in Irritable Bowel Syndrome.
Harper, A, Naghibi, MM, Garcha, D
Foods (Basel, Switzerland). 2018;7(2)
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Irritable bowel syndrome (IBS) affects 10-25% of the population worldwide but to date, no definitive effective treatment protocol has been established. This review explores the role of probiotics, bacteria and diet as potential causes of IBS and what role they may play in its treatment and management. The authors concluded that though there is clear evidence of alteration in the overall diversity and specific abundance of intestinal bacteria in IBS sufferers there, is no clear picture in relation to how this affects symptoms of IBS. Future randomised control trials are required to establish effectiveness of diet and probiotic supplementation as interventions in the management of IBS.
Abstract
Irritable bowel syndrome is a highly prevalent gastrointestinal disorder that threatens the quality of life of millions and poses a substantial financial burden on healthcare systems around the world. Intense research into the human microbiome has led to fascinating discoveries which directly and indirectly implicate the diversity and function of this occult organ in irritable bowel syndrome (IBS) pathophysiology. The benefit of manipulating the gastrointestinal microbiota with diet and probiotics to improve symptoms has been demonstrated in a wealth of both animal and human studies. The positive and negative mechanistic roles bacteria play in IBS will be explored and practical probiotic and dietary choices offered.