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Cruciferous Vegetables, Isothiocyanates, and Bladder Cancer Prevention.
Abbaoui, B, Lucas, CR, Riedl, KM, Clinton, SK, Mortazavi, A
Molecular nutrition & food research. 2018;62(18):e1800079
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Worldwide, almost 400,000 cases of bladder cancer are diagnosed each year, with 150,000 deaths, a high rate of recurrence and a high treatment cost. This review article evaluates the literature regarding the potential role of cruciferous vegetables (broccoli, cauliflower, cabbages, pak choi, watercress, wasabi are all examples of cruciferous vegetables) in bladder cancer prevention and as an adjunct to current treatment protocols. In vitro studies have shown inhibition of bladder cancer cell reproduction, stalled cancer cell cycles, and cancer cell death by compounds in cruciferous vegetables, in particular sulphoraphane (known to be high in broccoli and broccoli sprouts) and erucin (available in rocket for example). Studies show an inverse relationship between cruciferous vegetable intake and risk of bladder cancer, with those consuming 2 or more portions per week having a 39% lower risk of bladder cancer than those who consume less than 1 portion per week. The review also looks at cooking method, with steaming, stir-frying and sauteeing protecting the important nutrients when compared to boiling. The authors call for pre-clinical studies to be performed, examining multiple formulations of cruciferous vegetables in a variety of bladder cancer models, looking at prevention in high risk groups and adjuvant to standard treatment protocols. Nutrition Practitioners may want to consider including regular intake of cruciferous vegetables in their client protocols.
Abstract
Bladder cancer is a significant health burden due to its high prevalence, risk of mortality, morbidity, and high cost of medical care. Epidemiologic evidence suggests that diets rich in cruciferous vegetables, particularly broccoli, are associated with lower bladder cancer risk. Phytochemicals in cruciferous vegetables, such as glucosinolates, which are enzymatically hydrolyzed to bioactive isothiocyanates, are possible mediators of an anticancer effect. In vitro studies have shown inhibition of bladder cancer cell lines, cell cycle arrest, and induction of apoptosis by these isothiocyanates, in particular sulforaphane and erucin. Although not yet completely understood, many mechanisms of anticancer activity at the steps of cancer initiation, promotion, and progression have been attributed to these isothiocyanates. They target multiple pathways including the adaptive stress response, phase I/II enzyme modulation, pro-growth, pro-survival, pro-inflammatory signaling, angiogenesis, and even epigenetic modulation. Multiple in vivo studies have shown the bioavailability of isothiocyanates and their antitumoral effects. Although human studies are limited, they support oral bioavailability with reasonable plasma and urine concentrations achieved. Overall, both cell and animal studies support a potential role for isothiocyanates in bladder cancer prevention and treatment. Future studies are necessary to examine clinically relevant outcomes and define guidelines on ameliorating the bladder cancer burden.
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The effect of a short-term low-carbohydrate, high-fat diet with or without postmeal walks on glycemic control and inflammation in type 2 diabetes: a randomized trial.
Myette-Côté, É, Durrer, C, Neudorf, H, Bammert, TD, Botezelli, JD, Johnson, JD, DeSouza, CA, Little, JP
American journal of physiology. Regulatory, integrative and comparative physiology. 2018;315(6):R1210-R1219
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Inflammation is associated with the pathogenesis of insulin resistance, type 2 diabetes (T2D), and related complications. Lifestyle therapy is a frontline treatment for improving glucose control in people with T2D. The main aim of this study was to determine whether reducing hyperglycaemia with a low-carbohydrate high-fat (LC) diet could lower markers of innate immune cell activation and systemic inflammation in people with T2D. A secondary aim was to examine if the combination of an LCHF diet with strategically timed postmeal walking was superior to an LCHF diet alone. The study is a randomised cross over study which enrolled Individuals with physician-diagnosed T2D to complete three short-term controlled-intervention periods. Sixteen participants were enrolled (men = 8 and women = 8) who were aged between 48 and 72 years. Results indicate that while LC and LC together with exercise (LC+Ex) led to superior improvements in glucose control and fasting proinsulin (the pro-hormone precursor to insulin) levels as compared with low-fat low glycaemic index diet (GL), all three diets (GL, LC and LC+Ex), appeared to lower a particular marker of cellular inflammation over the short-term. Authors conclude that an LCHF diet with or without daily postmeal walks improved four-day glycaemic control and fasting proinsulin levels compared with a GL diet.
Abstract
Lowering carbohydrate consumption effectively lowers glucose, but impacts on inflammation are unclear. The objectives of this study were to: 1) determine whether reducing hyperglycemia by following a low-carbohydrate, high-fat (LC) diet could lower markers of innate immune cell activation in type 2 diabetes (T2D) and 2) examine if the combination of an LC diet with strategically timed postmeal walking was superior to an LC diet alone. Participants with T2D ( n = 11) completed a randomized crossover study involving three 4-day diet interventions: 1) low-fat low-glycemic index (GL), 2) and 3) LC with 15-min postmeal walks (LC+Ex). Four-day mean glucose was significantly lower in the LC+Ex group as compared with LC (-5%, P < 0.05), whereas both LC+Ex (-16%, P < 0.001) and LC (-12%, P < 0.001) conditions were lower than GL. A significant main effect of time was observed for peripheral blood mononuclear cells phosphorylated c-Jun N-terminal kinase ( P < 0.001), with decreases in all three conditions (GL: -32%, LC: -45%, and LC+Ex: -44%). A significant condition by time interaction was observed for monocyte microparticles ( P = 0.040) with a significant decrease in GL (-76%, P = 0.035) and a tendency for a reduction in LC (-70%, P = 0.064), whereas there was no significant change in LC+Ex (0.5%, P = 0.990). Both LC (-27%, P = 0.001) and LC+Ex (-35%, P = 0.005) also led to significant reductions in circulating proinsulin. An LC diet improved 4-day glycemic control and fasting proinsulin levels when compared with GL, with added glucose-lowering benefits when LC was combined with postmeal walking.
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Circulating bile acids in healthy adults respond differently to a dietary pattern characterized by whole grains, legumes and fruits and vegetables compared to a diet high in refined grains and added sugars: A randomized, controlled, crossover feeding study.
Ginos, BNR, Navarro, SL, Schwarz, Y, Gu, H, Wang, D, Randolph, TW, Shojaie, A, Hullar, MAJ, Lampe, PD, Kratz, M, et al
Metabolism: clinical and experimental. 2018;83:197-204
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Bile acids are produced in the liver and are important for the absorption of fat and fat-soluble vitamins. About 95% of bile acids are reabsorbed. Circulating plasma bile acids can affect glucose metabolism and inflammation, and are thought to play a role in the development of metabolic syndrome. The aim of this study was to evaluate how plasma bile acid levels are influenced by a diet rich in whole grains, legumes, fruit and vegetables (low glycaemic load, GL) compared to a diet high in refined grains and sugar (high GL). The study evaluated data from a previous double-blind randomised, cross over feeding trial. 80 healthy adults had the low or high GL diet for four weeks, and after a four-week washout period, received the other diet for four weeks. Three specific plasma bile acids, which are thought to have a positive impact on glucose metabolism, were higher in the low GL group compared to the high GL group. Some individual plasma bile acids were positively associated with HOMA-IR (a measure of glucose metabolism/insulin resistance). There was no significant association between bile acid concentrations and C-reactive protein (a marker of inflammation). The authors conclude that the increase in certain bile acids on the low GL diet may be beneficial and that this effect may be to some extent mediated by the impact of the higher fibre content of the low GL diet on the gut microbial metabolism, which affects plasma bile acid levels.
Abstract
OBJECTIVE The effects of diets high in refined grains on biliary and colonic bile acids have been investigated extensively. However, the effects of diets high in whole versus refined grains on circulating bile acids, which can influence glucose homeostasis and inflammation through activation of farnesoid X receptor (FXR) and G protein-coupled bile acid receptor 1 (TGR5), have not been studied. MATERIALS AND METHODS We conducted a secondary analysis from a randomized controlled crossover feeding trial (NCT00622661) in 80 healthy adults (40 women/40 men, age 18-45 years) from the greater Seattle Area, half of which were normal weight (BMI 18.5-25.0 kg/m2) and half overweight to obese (BMI 28.0-39.9 kg/m2). Participants consumed two four-week controlled diets in randomized order: 1) a whole grain diet (WG diet), designed to be low in glycemic load (GL), high in whole grains, legumes, and fruits and vegetables, and 2) a refined grain diet (RG diet), designed to be high GL, high in refined grains and added sugars, separated by a four-week washout period. Quantitative targeted analysis of 55 bile acid species in fasting plasma was performed using liquid chromatography tandem mass spectrometry. Concentrations of glucose, insulin, and CRP were measured in fasting serum. Linear mixed models were used to test the effects of diet on bile acid concentrations, and determine the association between plasma bile acid concentrations and HOMA-IR and CRP. Benjamini-Hochberg false discovery rate (FDR) < 0.05 was used to control for multiple testing. RESULTS A total of 29 plasma bile acids were reliably detected and retained for analysis. Taurolithocholic acid (TLCA), taurocholic acid (TCA) and glycocholic acid (GCA) were statistically significantly higher after the WG compared to the RG diet (FDR < 0.05). There were no significant differences by BMI or sex. When evaluating the association of bile acids and HOMA-IR, GCA, taurochenodeoxycholic acid, ursodeoxycholic acid (UDCA), 5β‑cholanic acid‑3β,12α‑diol, 5‑cholanic acid‑3β‑ol, and glycodeoxycholic acid (GDCA) were statistically significantly positively associated with HOMA-IR individually, and as a group, total, 12α‑hydroxylated, primary and secondary bile acids were also significant (FDR < 0.05). When stratifying by BMI, chenodeoxycholic acid (CDCA), cholic acid (CA), UDCA, 5β-cholanic acid-3β, deoxycholic acid, and total, 12α-hydroxylated, primary and secondary bile acid groups were significantly positively associated with HOMA-IR among overweight to obese individuals (FDR < 0.05). When stratifying by sex, GCA, CDCA, TCA, CA, UDCA, GDCA, glycolithocholic acid (GLCA), total, primary, 12α‑hydroxylated, and glycine-conjugated bile acids were significantly associated with HOMA-IR among women, and CDCA, GDCA, and GLCA were significantly associated among men (FDR < 0.05). There were no significant associations between bile acids and CRP. CONCLUSIONS Diets with comparable macronutrient and energy composition, but differing in carbohydrate source, affected fasting plasma bile acids differently. Specifically, a diet characterized by whole grains, legumes, and fruits and vegetables compared to a diet high in refined grains and added sugars led to modest increases in concentrations of TLCA, TCA and GCA, ligands for FXR and TGR5, which may have beneficial effects on glucose homeostasis.
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Inflammation and glucose homeostasis are associated with specific structural features among adults without knee osteoarthritis: a cross-sectional study from the osteoarthritis initiative.
Stout, AC, Barbe, MF, Eaton, CB, Amin, M, Al-Eid, F, Price, LL, Lu, B, Lo, GH, Zhang, M, Pang, J, et al
BMC musculoskeletal disorders. 2018;19(1):1
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Individuals with osteoarthritis (OA) typically present with greater systemic inflammation and impaired glucose homeostasis. Currently it is unclear whether these factors are associated with early-stage OA, namely bone marrow lesions and swelling. The purpose of this cross-sectional study was to investigate the role of inflammation and glucose homeostasis in early-stage OA. Using baseline data from the Osteoarthritis Initiative, 343 participants were enrolled and tested for markers of inflammation and impaired glucose homeostasis. Bone marrow lesions and swelling were also assessed through imaging results. Results indicate that among individuals without OA, those with greater systemic inflammation were more likely to have bone marrow lesions and knee swelling. According to these results, the authors conclude that systemic inflammation and glucose homeostasis are related to structural features of osteoarthritis. Future studies should explore whether these factors are predictive of OA in order to identify therapeutic targets to prevent or delay the onset of knee OA.
Abstract
BACKGROUND Greater age and body mass index are strong risk factors for osteoarthritis (OA). Older and overweight individuals may be more susceptible to OA because these factors alter tissue turnover in menisci, articular cartilage, and bone via altered glucose homeostasis and inflammation. Understanding the role of inflammation and glucose homeostasis on structural features of early-stage OA may help identify therapeutic targets to delay or prevent the onset of OA among subsets of adults with these features. We examined if serum concentrations of glucose homeostasis (glucose, glycated serum protein [GSP]) or inflammation (C-reactive protein [CRP]) were associated with prevalent knee bone marrow lesions (BMLs) or effusion among adults without knee OA. METHODS We conducted a cross-sectional study using baseline data from the Osteoarthritis Initiative. We selected participants who had no radiographic knee OA but were at high risk for knee OA. Blinded staff conducted assays for CRP, GSP, and glucose. Readers segmented BML volume and effusion using semi-automated programs. Our outcomes were prevalent BML (knee with a BML volume > 1 cm3) and effusion (knee with an effusion volume > 7.5 cm3). We used logistic regression models with CRP, GSP, or glucose concentrations as the predictors. We adjusted for age, sex, body mass index (BMI), and Physical Activity Scale for the Elderly (PASE) scores. RESULTS We included 343 participants: mean age = 59 ± 9 years, BMI = 27.9 ± 4.5 kg/m2, PASE score = 171 ± 82, and 64% female. Only CRP was associated with BML prevalence (odds ratio [OR] = 1.43, 95% confidence interval [CI] = 1.09 to 1.87). For effusion, we found an interaction between BMI and CRP: only among adults with a BMI <25 kg/m2 was there a significant trend towards a positive association between CRP and effusion (OR = 1.40, 95% CI = 1.00 to 1.97). We detected a U-shaped relationship between GSP and effusion prevalence. Fasting glucose levels were not significantly associated with the presence of baseline effusion or BML. CONCLUSIONS Among individuals without knee OA, CRP may be related to the presence of BMLs and effusion among normal weight individuals. Abnormal GSP may be associated with effusion. Future studies should explore whether inflammation and glucose homeostasis are predictive of symptomatic knee OA.
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High-Dose Vitamin D3 Administration Is Associated With Increases in Hemoglobin Concentrations in Mechanically Ventilated Critically Ill Adults: A Pilot Double-Blind, Randomized, Placebo-Controlled Trial.
Smith, EM, Jones, JL, Han, JE, Alvarez, JA, Sloan, JH, Konrad, RJ, Zughaier, SM, Martin, GS, Ziegler, TR, Tangpricha, V
JPEN. Journal of parenteral and enteral nutrition. 2018;42(1):87-94
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Anaemia is common in critically ill patients and is associated with increased mortality and potentially an extended need for a ventilator. Treatment for anaemia can be invasive and carries a level of risk; therefore further studies on complementary therapies are warranted. Vitamin D has the potential to decrease anaemia through decreasing the production of the iron-regulatory hormone hepcidin. The study aimed to test whether high dose vitamin D would affect haemoglobin concentrations in critically ill patients. In this pilot double-blind randomised control trial, 30 critically ill patients were assigned 250,000 IU vitamin D, 500,000 IU vitamin D or placebo split over 5 doses in 5 days. Blood was taken weekly for up to four weeks and analysed for vitamin D and hepcidin concentrations. Vitamin D concentrations increased significantly in both groups that received vitamin D, compared to no change in the placebo group. Compared to placebo, haemaglobin concentrations significantly increased by 8% in the group receiving 500,000 IU vitamin D but not in the lower dose group. After one week, hepcidin concentrations were significantly decreased in the 500,000 IU vitamin D group, however this was not sustained and no differences between either group and placebo were observed at the end of the study. This did not translate into a reduction in anaemia in either group at any point throughout the study. Extremely high dose vitamin D supplementation was shown to significantly increase circulating vitamin D concentrations and acutely reduce hepcidin. Although anaemia was not affected, clinicians could use this study as an example of safe usage of high dose vitamin D in critically ill patients to improve haemaglobin concentrations, which could reduce the need for invasive treatments, reduce hospital stay duration and treatment costs.
Abstract
BACKGROUND Anemia and vitamin D deficiency are highly prevalent in critical illness, and vitamin D status has been associated with hemoglobin concentrations in epidemiologic studies. We examined the effect of high-dose vitamin D therapy on hemoglobin and hepcidin concentrations in critically ill adults. MATERIALS AND METHODS Mechanically ventilated critically ill adults (N = 30) enrolled in a pilot double-blind, randomized, placebo-controlled trial of high-dose vitamin D3 (D3 ) were included in this analysis. Participants were randomized to receive placebo, 50,000 IU D3 , or 100,000 IU D3 daily for 5 days (totaling 250,000 IU D3 and 500,000 IU D3 , respectively). Blood was drawn weekly throughout hospitalization for up to 4 weeks. Linear mixed-effects models were used to assess change in hemoglobin and hepcidin concentrations by treatment group over time. RESULTS At enrollment, >75% of participants in all groups had plasma 25-hydroxyvitamin D (25(OH)D) concentrations <30 ng/mL, and >85% of participants across groups were anemic. In the 500,000-IU D3 group, hemoglobin concentrations increased significantly over time (Pgroup × time = .01) compared with placebo but did not change in the 250,000-IU D3 group (Pgroup × time = 0.59). Hepcidin concentrations decreased acutely in the 500,000-IU D3 group relative to placebo after 1 week (P = .007). Hepcidin did not change significantly in the 250,000-IU D3 group. CONCLUSION In these critically ill adults, treatment with 500,000 IU D3 was associated with increased hemoglobin concentrations over time and acutely reduced serum hepcidin concentrations. These findings suggest that high-dose vitamin D may improve iron metabolism in critical illness and should be confirmed in larger studies.
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A spatial gradient of bacterial diversity in the human oral cavity shaped by salivary flow.
Proctor, DM, Fukuyama, JA, Loomer, PM, Armitage, GC, Lee, SA, Davis, NM, Ryder, MI, Holmes, SP, Relman, DA
Nature communications. 2018;9(1):681
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Identifying spatial patterns in the human microbiota is necessary to provide insight into mechanisms that either maintain or disrupt its healthy state. The aim of this study was to identify the type and extent of oral spatial patterns formed by bacterial communities, as well as observe the impact of low salivary flow on the spatial patterns. Dental exams were performed on 31 participants to evaluate the oral health status and follow-up was dependent on group allocation. This study found bacterial communities were distinguishable depending on types of teeth and tissue. Further, bacteria on soft and hard tissues varied across the front and back of the oral cavity in a gradient-manner, implying that salivary flow plays a role in establishing the bacterial community gradient in the oral cavity. Based on these results, the authors recommend spatial patterns and processes be explored in other body parts to better understand health and disease.
Abstract
Spatial and temporal patterns in microbial communities provide insights into the forces that shape them, their functions and roles in health and disease. Here, we used spatial and ecological statistics to analyze the role that saliva plays in structuring bacterial communities of the human mouth using >9000 dental and mucosal samples. We show that regardless of tissue type (teeth, alveolar mucosa, keratinized gingiva, or buccal mucosa), surface-associated bacterial communities vary along an ecological gradient from the front to the back of the mouth, and that on exposed tooth surfaces, the gradient is pronounced on lingual compared to buccal surfaces. Furthermore, our data suggest that this gradient is attenuated in individuals with low salivary flow due to Sjögren's syndrome. Taken together, our findings imply that salivary flow influences the spatial organization of microbial communities and that biogeographical patterns may be useful for understanding host physiological processes and for predicting disease.
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Breast cancer risk markedly lower with serum 25-hydroxyvitamin D concentrations ≥60 vs <20 ng/ml (150 vs 50 nmol/L): Pooled analysis of two randomized trials and a prospective cohort.
McDonnell, SL, Baggerly, CA, French, CB, Baggerly, LL, Garland, CF, Gorham, ED, Hollis, BW, Trump, DL, Lappe, JM
PloS one. 2018;13(6):e0199265
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Numerous studies have shown an association between Vitamin D status and risk of breast cancer. However to date, there are few studies that look at concentrations of Vitamin D in excess of 100 nmol/l and breast cancer risk. This study pooled the results of 2 randomised controlled trials and one prospective cohort study to investigate the relationship between Vitamin D levels and breast cancer incidence. The pooled results included 5,038 women. The analysis revealed that women with Vitamin D status of >150 nmol/l had an 80% lower risk of breast cancer than women with Vitamin D concentrations of <50 nmol/l, adjusting for age, BMI, smoking status and calcium supplementation. The findings also show that the risk of breast cancer is dose responsive, with the lowest risk of breast cancer at Vitamin D levels of >150 nmol/l. Testing for Vitamin D status and optimising levels to >150 nmol/l could be considered as part of a strategy for breast cancer prevention.
Abstract
BACKGROUND While numerous epidemiologic studies have found an association between higher serum 25-hydroxyvitamin D [25(OH)D] concentrations and lower breast cancer risk, few have assessed this association for concentrations >40 ng/ml. OBJECTIVE To investigate the relationship between 25(OH)D concentration and breast cancer risk across a broad range of 25(OH)D concentrations among women aged 55 years and older. METHODS Analyses used pooled data from two randomized clinical trials (N = 1129, N = 2196) and a prospective cohort (N = 1713) to examine a broad range of 25(OH)D concentrations. The outcome was diagnosis of breast cancer during the observation periods (median: 4.0 years). Three analyses were conducted: 1) Incidence rates were compared according to 25(OH)D concentration from <20 to ≥60 ng/ml (<50 to ≥150 nmol/L), 2) Kaplan-Meier plots were developed and 3) multivariate Cox regression was used to examine the association between 25(OH)D and breast cancer risk using multiple 25(OH)D measurements. RESULTS Within the pooled cohort (N = 5038), 77 women were diagnosed with breast cancer (age-adjusted incidence: 512 cases per 100,000 person-years). Results were similar for the three analyses. First, comparing incidence rates, there was an 82% lower incidence rate of breast cancer for women with 25(OH)D concentrations ≥60 vs <20 ng/ml (Rate Ratio = 0.18, P = 0.006). Second, Kaplan-Meier curves for concentrations of <20, 20-39, 40-59 and ≥60 ng/ml were significantly different (P = 0.02), with the highest proportion breast cancer-free in the ≥60 ng/ml group (99.3%) and the lowest proportion breast cancer-free in the <20 ng/ml group (96.8%). The proportion with breast cancer was 78% lower for ≥60 vs <20 ng/ml (P = 0.02). Third, multivariate Cox regression revealed that women with 25(OH)D concentrations ≥60 ng/ml had an 80% lower risk of breast cancer than women with concentrations <20 ng/ml (HR = 0.20, P = 0.03), adjusting for age, BMI, smoking status, calcium supplement intake, and study of origin. CONCLUSIONS Higher 25(OH)D concentrations were associated with a dose-response decrease in breast cancer risk with concentrations ≥60 ng/ml being most protective.
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Emollient use alters skin barrier and microbes in infants at risk for developing atopic dermatitis.
Glatz, M, Jo, JH, Kennedy, EA, Polley, EC, Segre, JA, Simpson, EL, Kong, HH
PloS one. 2018;13(2):e0192443
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Atopic dermatitis (AD) is a type of eczema common in babies and young children. Poor function of the skin barrier is thought to lead to changes in the composition of bacteria found on the skin. This small study investigated the effects of daily use of an emollient, Cetaphil Moisturising Cream, on the barrier function and bacterial communities on the skin of infants at risk of developing AD. After 6 months, the emollient group had a lower skin pH than the control group. The group using the emollient had more diverse skin bacterial communities than the control group. The proportion of Streptococcus salivarius was higher in the emollient versus control groups. The authors concluded that lower skin pH and increased skin bacterial diversity after long-term emollient use may reduce inflammation and lower the risk of infants developing AD.
Abstract
BACKGROUND Emollients are a mainstay of treatment in atopic dermatitis (AD), a disease distinguished by skin bacterial dysbiosis. However, changes in skin microbiota when emollients are used as a potential AD preventative measure in infants remain incompletely characterized. RESULTS We compared skin barrier parameters, AD development, and bacterial 16S ribosomal RNA gene sequences of cheek, dorsal and volar forearm samples from 6-month-old infants with a family history of atopy randomized to receive emollients (n = 11) or no emollients (controls, n = 12). The emollient group had a lower skin pH than the control group. The number of bacterial taxa in the emollient group was higher than in the control group at all sites. The Streptococcus salivarius proportion was higher in the emollient versus control groups at all sites. S. salivarius proportion appeared higher in infants without AD compared to infants with AD. A decrease in S. salivarius abundance was further identified in a separate larger population of older children demonstrating an inverse correlation between AD severity at sampling sites and S. salivarius proportions. CONCLUSIONS The decreased skin pH and the increased proportion of S. salivarius after long-term emollient use in infants at risk for developing AD may contribute to the preventative effects of emollients in high-risk infants.
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Maternal diet during pregnancy is related with the infant stool microbiome in a delivery mode-dependent manner.
Lundgren, SN, Madan, JC, Emond, JA, Morrison, HG, Christensen, BC, Karagas, MR, Hoen, AG
Microbiome. 2018;6(1):109
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The mechanism by which the maternal diet may influence the gut microbiota of an infant remains unknown. This study aimed to examine the association of maternal diet during pregnancy and mode of delivery on the gut microbiome 6 weeks post-delivery. 976 subjects were enrolled aged of 18 and 45 years old, between 24 and 28 weeks of gestation and their maternal diet during pregnancy was assessed with a validated food frequency questionnaire. Effects of maternal dairy intake on infant gut microbiota showed decreased colonization of milk-digesting bacteria in infants delivered by caesarean section, when compared to those who were born vaginally. The authors concluded that future studies examining the relationship between maternal diet and components of breast milk including microbial and nutritional profiles, may help to offer insight into the mechanism by which maternal diet influences the gut microbiome of an infant.
Abstract
BACKGROUND The gut microbiome has an important role in infant health and immune development and may be affected by early-life exposures. Maternal diet may influence the infant gut microbiome through vertical transfer of maternal microbes to infants during vaginal delivery and breastfeeding. We aimed to examine the association of maternal diet during pregnancy with the infant gut microbiome 6 weeks post-delivery in mother-infant dyads enrolled in the New Hampshire Birth Cohort Study. Infant stool samples were collected from 145 infants, and maternal prenatal diet was assessed using a food frequency questionnaire. We used targeted sequencing of the 16S rRNA V4-V5 hypervariable region to characterize infant gut microbiota. To account for differences in baseline and trajectories of infant gut microbial profiles, we stratified analyses by delivery mode. RESULTS We identified three infant gut microbiome clusters, characterized by increased abundance of Bifidobacterium, Streptococcus and Clostridium, and Bacteroides, respectively, overall and in the vaginally delivered infant stratum. In the analyses stratified to infants born vaginally and adjusted for other potential confounders, maternal fruit intake was associated with infant gut microbial community structure (PERMANOVA, p < 0.05). In multinomial logistic regression analyses, increased fruit intake was associated with an increased odds of belonging to the high Streptococcus/Clostridium group among infants born vaginally (OR (95% CI) = 2.73 (1.36, 5.46)). In infants delivered by Cesarean section, we identified three clusters that differed slightly from vaginally delivered infants, which were characterized by a high abundance of Bifidobacterium, high Clostridium and low Streptococcus and Ruminococcus genera, and high abundance of the family Enterobacteriaceae. Maternal dairy intake was associated with an increased odds of infants belonging to the high Clostridium cluster in infants born by Cesarean section (OR (95% CI) = 2.36 (1.05, 5.30)). Linear models suggested additional associations between maternal diet and infant intestinal microbes in both delivery mode strata. CONCLUSIONS Our data indicate that maternal diet influences the infant gut microbiome and that these effects differ by delivery mode.
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Dietary carbohydrate intake and mortality: a prospective cohort study and meta-analysis.
Seidelmann, SB, Claggett, B, Cheng, S, Henglin, M, Shah, A, Steffen, LM, Folsom, AR, Rimm, EB, Willett, WC, Solomon, SD
The Lancet. Public health. 2018;3(9):e419-e428
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Previous trials have shown that low carbohydrate diets are beneficial for short-term weight loss. However, the long-term impact of carbohydrate restriction on mortality is less clear, with research producing conflicting results. Additionally, previous studies have not addressed the source or quality of proteins and fats consumed in low-carbohydrate diets. This study aimed to find out whether there is an association between carbohydrate consumption and mortality. It also looked at whether animal-based or plant-based foods had any impact on the association. The researchers began by studying over 15,000 adults in the US, enrolled between 1987 and 1989. At the start of the study and again six years later, participants completed food frequency questionnaires. These were used to estimate the percentage of calories they derived from carbohydrate, fat and protein. The results showed a U-shape association between overall carbohydrate intake and life expectancy, with low (less than 40% of calories from carbohydrates) and high (more than 70%) intake of carbohydrates associated with a higher risk of mortality compared with moderate intake (50-55% of calories). The researchers estimated that the average life expectancy was 4 years shorter for those with low carbohydrate consumption, and 1 year shorter for those with high carbohydrate consumption, compared to those with a moderate carbohydrate intake. However, the authors point out that since diets were only recorded at the start of the trial and six years later, participants’ diets could have changed during the 25-year follow-up period. Next, the authors performed a meta-analysis of data from eight previous studies. This revealed similar trends, with participants whose overall diets were high and low in carbohydrates having a shorter life expectancy than those with moderate consumption. In further analyses examining the source of proteins and fats, animal-derived protein and fat sources, such as lamb, beef, pork and chicken, were associated with higher mortality, whereas plant-derived protein and fat intake, from sources such as vegetables, nuts, peanut butter and whole-grains, were associated with lower mortality. The authors suggest that, when restricting carbohydrate intake, replacement of carbohydrates with predominantly plant-based fats and proteins could be considered as a long-term approach to promote healthy ageing.
Abstract
BACKGROUND Low carbohydrate diets, which restrict carbohydrate in favour of increased protein or fat intake, or both, are a popular weight-loss strategy. However, the long-term effect of carbohydrate restriction on mortality is controversial and could depend on whether dietary carbohydrate is replaced by plant-based or animal-based fat and protein. We aimed to investigate the association between carbohydrate intake and mortality. METHODS We studied 15 428 adults aged 45-64 years, in four US communities, who completed a dietary questionnaire at enrolment in the Atherosclerosis Risk in Communities (ARIC) study (between 1987 and 1989), and who did not report extreme caloric intake (<600 kcal or >4200 kcal per day for men and <500 kcal or >3600 kcal per day for women). The primary outcome was all-cause mortality. We investigated the association between the percentage of energy from carbohydrate intake and all-cause mortality, accounting for possible non-linear relationships in this cohort. We further examined this association, combining ARIC data with data for carbohydrate intake reported from seven multinational prospective studies in a meta-analysis. Finally, we assessed whether the substitution of animal or plant sources of fat and protein for carbohydrate affected mortality. FINDINGS During a median follow-up of 25 years there were 6283 deaths in the ARIC cohort, and there were 40 181 deaths across all cohort studies. In the ARIC cohort, after multivariable adjustment, there was a U-shaped association between the percentage of energy consumed from carbohydrate (mean 48·9%, SD 9·4) and mortality: a percentage of 50-55% energy from carbohydrate was associated with the lowest risk of mortality. In the meta-analysis of all cohorts (432 179 participants), both low carbohydrate consumption (<40%) and high carbohydrate consumption (>70%) conferred greater mortality risk than did moderate intake, which was consistent with a U-shaped association (pooled hazard ratio 1·20, 95% CI 1·09-1·32 for low carbohydrate consumption; 1·23, 1·11-1·36 for high carbohydrate consumption). However, results varied by the source of macronutrients: mortality increased when carbohydrates were exchanged for animal-derived fat or protein (1·18, 1·08-1·29) and mortality decreased when the substitutions were plant-based (0·82, 0·78-0·87). INTERPRETATION Both high and low percentages of carbohydrate diets were associated with increased mortality, with minimal risk observed at 50-55% carbohydrate intake. Low carbohydrate dietary patterns favouring animal-derived protein and fat sources, from sources such as lamb, beef, pork, and chicken, were associated with higher mortality, whereas those that favoured plant-derived protein and fat intake, from sources such as vegetables, nuts, peanut butter, and whole-grain breads, were associated with lower mortality, suggesting that the source of food notably modifies the association between carbohydrate intake and mortality. FUNDING National Institutes of Health.