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Cardiometabolic risk factors in vegans; A meta-analysis of observational studies.
Benatar, JR, Stewart, RAH
PloS one. 2018;13(12):e0209086
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Healthy, balanced, plant-based diets have been associated with better health outcomes, however the role of dairy and meat products on heart disease and death due to heart disease is not fully understood. Vegan diets are strictly plant-based and could provide an opportunity to investigate the effect of eliminating animal products on heart disease risk. This meta-analysis of 40 observational studies aimed to evaluate the effect of a vegan diet on heart disease risk factors. The results showed that vegans in most countries had improved heart disease risk factors such as a small waist circumference, lower body mass index (BMI) and balanced blood sugars compared to omnivores, however studies from Taiwan failed to show this trend. It was concluded that a vegan diet in most countries is associated with better health outcomes compared to an omnivorous diet. This study could be use by healthcare practitioners to recommend a vegan diet to those at a higher risk of heart disease.
Abstract
BACKGROUND There is increasing evidence that plant based diets are associated with lower cardiovascular risk. OBJECTIVE To evaluate effects of a vegan compared to an omnivorous diet on cardio-metabolic risk factors. METHODS Meta-analysis of observational studies published between 1960 and June 2018 that reported one or more cardio-metabolic risk factors in vegans and controls eating an omnivorous diet were undertaken. Macro-nutrient intake and cardio-metabolic risk factors were compared by dietary pattern. The Newcastle Ottawa Scale (NOS) was used to assess the quality of each study. The inverse-variance method was used to pool mean differences. Statistical analyses were performed using RevMan software version 5•2 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen. RESULTS 40 studies with 12 619 vegans and 179 630 omnivores were included. From food frequency questionnaires in 28 studies, vegans compared to omnivores consumed less energy (-11%, 95% confidence interval -14 to -8) and less saturated fat (- 51%, CI -57 to -45). Compared to controls vegans had a lower body mass index (-1.72 kg/m2, CI -2.30 to -1.16), waist circumference (-2.35 cm, CI -3.93 to -0.76), low density lipoprotein cholesterol (-0.49 mmol/L CI -0.62 to -0.36), triglycerides (-0.14 mmol/L, CI -0.24 to -0.05), fasting blood glucose (-0.23 mmol/, CI -0.35 to -0.10), and systolic (-2.56 mmHg, CI -4.66 to -0.45) and diastolic blood pressure (-1.33 mmHg, CI -2.67 to -0.02), p<0.0001 for all. Results were consistent for studies with < and ≥ 50 vegans, and published before and after 2010. However in several large studies from Taiwan a vegan diet was not associated with favourable cardio-metabolic risk factors compared to the control diets. CONCLUSION In most countries a vegan diet is associated with a more favourable cardio- metabolic profile compared to an omnivorous diet.
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Body mass index, abdominal fatness, weight gain and the risk of psoriasis: a systematic review and dose-response meta-analysis of prospective studies.
Aune, D, Snekvik, I, Schlesinger, S, Norat, T, Riboli, E, Vatten, LJ
European journal of epidemiology. 2018;33(12):1163-1178
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Psoriasis is an immune-mediated inflammatory skin disease characterised by red, itchy, scaly and flaky skin. Research has shown an association between adiposity and inflammation cytokine release triggered by adipose tissue and increased body mass index and psoriasis. In this meta-analysis, seven prospective studies were included, and the association between BMI, abdominal fat, and psoriasis was examined. According to this meta-analysis, the relative risk of psoriasis increases by 19% for every 5-unit increase in BMI, 24% for a 10 cm increase in waist circumference, 37% for a 0.1-unit increase in waist-to-hip ratio, and 11% for a 5 kg weight gain. The risk of psoriasis was lower for people with a BMI below 20, and it was significantly higher for those with a BMI between 22.5-24. Psoriasis risk was positively associated with waist circumference, waist-to-hip ratio, and weight gain. Psoriasis risk escalates by 2-4 times with an increase in each measure of adiposity. Several potential strategies to reduce the risk of psoriasis are identified in this meta-analysis, including weight loss, dietary factors, and physical activity. To evaluate their effectiveness and develop appropriate strategies, further robust studies are needed. Healthcare professionals can use the results of this study to develop potential therapeutic strategies to reduce the risk of psoriasis by understanding the mechanisms and factors associated with the disease.
Abstract
Greater body mass index (BMI) has been associated with increased risk of psoriasis in case-control and cross-sectional studies, however, the evidence from prospective studies has been limited. We conducted a systematic review and dose-response meta-analysis of different adiposity measures and the risk of psoriasis to provide a more robust summary of the evidence based on data from prospective studies. PubMed and Embase databases were searched for relevant studies up to August 8th 2017. Summary relative risks (RRs) and 95% confidence intervals (CIs) were calculated using a random effects model. The summary relative risk (RR) for a 5 unit increment in BMI was 1.19 (95% CI 1.10-1.28, I2 = 83%, n = 7). The association appeared to be stronger at higher compared to lower levels of BMI, pnonlinearity < 0.0001, and the lowest risk was observed at a BMI around 20. The summary RR was 1.24 (95% CI 1.17-1.31, I2 = 0%, pheterogeneity = 0.72, n = 3) per 10 cm increase in waist circumference, 1.37 (95% CI 1.23-1.53, I2 = 0%, pheterogeneity = 0.93, n = 3) per 0.1 unit increase in waist-to-hip ratio, and 1.11 (95% CI 1.07-1.16, I2 = 47%, pheterogeneity = 0.15, n = 3) per 5 kg of weight gain. Adiposity as measured by BMI, waist circumference, waist-to-hip ratio, and weight gain is associated with increased risk of psoriasis.
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Effect of ω-3 polyunsaturated fatty acid-supplemented parenteral nutrition on inflammatory and immune function in postoperative patients with gastrointestinal malignancy: A meta-analysis of randomized control trials in China.
Zhao, Y, Wang, C
Medicine. 2018;97(16):e0472
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Omega-3 polyunsaturated fatty acids (PUFAs) can have a beneficial effect on inflammation and immune function. This meta-analysis looked at the effectiveness of omega-3 PUFAs on inflammatory and immune function in patients with stomach or colorectal cancers, following surgery. 16 Chinese randomised controlled trials with over 1000 patients carried out between 2000 and 2017 were included in the analysis. The researchers found that the numbers of immune cells in the omega-3 group were significantly higher than those in the control group. The levels of antibodies in people given omega-3 were significantly higher than those in the control group. Inflammatory markers in the omega-3 group were significantly lower. Those given omega-3 were 64% less likely to experience post-surgical infections. The result of this meta-analysis confirmed that supplementing gastrointestinal cancer patients with omega-3 improves post-surgery indicators of immune function, reduces inflammation, and reduces infections related to surgery. The authors recommend that omega-3 should be added to the nutrition formula given to gastrointestinal cancer patients following surgery.
Abstract
BACKGROUND There are no consensus regarding the efficacy of omega-3polyunsaturated fatty acids (PUFAs) on inflammatory and immune function in postoperative patients with gastrointestinal malignancy. METHODS The literatures published randomized control trials (RCT) were searched in PubMed, Embase, Scopus, Cochrane Library, CNKI, Weipu, and Wanfang Databases. The immune efficacy outcomes of ω-3 polyunsaturated fatty acid-supplemented parenteral nutrition in patients with gastrointestinal malignancy were compared. RESULTS Sixteen RCTs involving 1008 patients (506 in the omega-3 group, 502 in the control group) were enrolled into the analysis. The results of meta-analysis: the cell immunity: The proportions of CD3, CD4, CD4/CD8 in the omega-3 group were significantly higher than those in the control group (CD3: WMD = 4.48; 95% CI, 3.34-5.62; P < .00001; I = 0%; CD4: WMD = 5.55; 95% CI, 4.75-6.34; P < .00001; I = 0%; CD4/CD8: WMD = .28; 95% CI, 0.13-0.44; P = .0004; I = 81%). In the humoral immunity: The levels of IgA, IgM and IgG in the omega-3 group were significantly higher than those in the control group (IgA: WMD = 0.31; 95% CI, 0.25-0.37; P < .00001; I = 0%; IgM: WMD = 0.12; 95% CI, 0.06-1.81; P < .00001; I = 0%; IgG: WMD = 1.19; 95% CI, 0.80-1.58; P < .00001; I = 0%). The count of lymphocyte in the omega-3 group was significantly higher than that in the control group (WMD = 0.22; 95% CI, 0.12-0.33; P < .0001; I = 40%). In the postoperative inflammatory cytokine: The levels of interleukin-6, tumor necrosis factor (TNF)-α and C-reactive protein in the omega-3 group were significantly lower than those in the control group (IL-6: WMD = -3.09; 95% CI, -3.91 to 2.27; P < .00001; I = 45%; TNF-α: WMD = -1.65; 95% CI, -2.05 to 1.25; P < .00001; I = 28%; CRP: WMD = -4.28; 95% CI, -5.26 to 3.30; P < .00001; I = 37%). The rate of postoperative infective complications in the omega-3 group was significantly lower than that in the control group (OR = 0.36; 95% CI, 0.20-0.66; P = .0008; I = 0%). CONCLUSION This meta-kanalysis confirmed that early intervention with Omega -3 fatty acid emulsion in gastrointestinal cancer can not only improve the postoperative indicators of immune function, reduce inflammatory reaction, and improve the postoperative curative effect but also improve the immune suppression induced by conventional PN or tumor. Therefore, postoperative patients with gastrointestinal cancer should add omega-3 unsaturated fatty acids in their PN formula. Further high-quality RCTs are needed to verify its efficacy.
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Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease.
Abdelhamid, AS, Brown, TJ, Brainard, JS, Biswas, P, Thorpe, GC, Moore, HJ, Deane, KH, AlAbdulghafoor, FK, Summerbell, CD, Worthington, HV, et al
The Cochrane database of systematic reviews. 2018;7:CD003177
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Dietary intake or supplementation with omega-3 fats from fish and some plant foods such as flaxseed, are commonly believed to reduce the risk of cardiovascular disease. This systematic review of 79 trials, including 112,000 individuals, aimed to assess the impacts of greater omega-3 intake versus lower or no omega-3 intake for heart and circulatory disease. The results of this systematic review showed that increasing EPA and DHA (omega-3 oils from fish) had little or no effect on all cause death or cardiovascular events and probably little or no effect on cardiovascular deaths (evidence mainly from supplement trials). EPA and DHA were found to reduce blood fat levels (triglycerides) and raise HDL (good cholesterol). Eating more ALA (omega-3 fats from walnuts for example) probably makes little or no difference to all-cause or cardiovascular death but probably slightly reduce cardiovascular events.
Abstract
BACKGROUND Researchers have suggested that omega-3 polyunsaturated fatty acids from oily fish (long-chain omega-3 (LCn3), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)), as well as from plants (alpha-linolenic acid (ALA)) benefit cardiovascular health. Guidelines recommend increasing omega-3-rich foods, and sometimes supplementation, but recent trials have not confirmed this. OBJECTIVES To assess effects of increased intake of fish- and plant-based omega-3 for all-cause mortality, cardiovascular (CVD) events, adiposity and lipids. SEARCH METHODS We searched CENTRAL, MEDLINE and Embase to April 2017, plus ClinicalTrials.gov and World Health Organization International Clinical Trials Registry to September 2016, with no language restrictions. We handsearched systematic review references and bibliographies and contacted authors. SELECTION CRITERIA We included randomised controlled trials (RCTs) that lasted at least 12 months and compared supplementation and/or advice to increase LCn3 or ALA intake versus usual or lower intake. DATA COLLECTION AND ANALYSIS Two review authors independently assessed studies for inclusion, extracted data and assessed validity. We performed separate random-effects meta-analysis for ALA and LCn3 interventions, and assessed dose-response relationships through meta-regression. MAIN RESULTS We included 79 RCTs (112,059 participants) in this review update and found that 25 were at low summary risk of bias. Trials were of 12 to 72 months' duration and included adults at varying cardiovascular risk, mainly in high-income countries. Most studies assessed LCn3 supplementation with capsules, but some used LCn3- or ALA-rich or enriched foods or dietary advice compared to placebo or usual diet.Meta-analysis and sensitivity analyses suggested little or no effect of increasing LCn3 on all-cause mortality (RR 0.98, 95% CI 0.90 to 1.03, 92,653 participants; 8189 deaths in 39 trials, high-quality evidence), cardiovascular mortality (RR 0.95, 95% CI 0.87 to 1.03, 67,772 participants; 4544 CVD deaths in 25 RCTs), cardiovascular events (RR 0.99, 95% CI 0.94 to 1.04, 90,378 participants; 14,737 people experienced events in 38 trials, high-quality evidence), coronary heart disease (CHD) mortality (RR 0.93, 95% CI 0.79 to 1.09, 73,491 participants; 1596 CHD deaths in 21 RCTs), stroke (RR 1.06, 95% CI 0.96 to 1.16, 89,358 participants; 1822 strokes in 28 trials) or arrhythmia (RR 0.97, 95% CI 0.90 to 1.05, 53,796 participants; 3788 people experienced arrhythmia in 28 RCTs). There was a suggestion that LCn3 reduced CHD events (RR 0.93, 95% CI 0.88 to 0.97, 84,301 participants; 5469 people experienced CHD events in 28 RCTs); however, this was not maintained in sensitivity analyses - LCn3 probably makes little or no difference to CHD event risk. All evidence was of moderate GRADE quality, except as noted.Increasing ALA intake probably makes little or no difference to all-cause mortality (RR 1.01, 95% CI 0.84 to 1.20, 19,327 participants; 459 deaths, 5 RCTs),cardiovascular mortality (RR 0.96, 95% CI 0.74 to 1.25, 18,619 participants; 219 cardiovascular deaths, 4 RCTs), and it may make little or no difference to CHD events (RR 1.00, 95% CI 0.80 to 1.22, 19,061 participants, 397 CHD events, 4 RCTs, low-quality evidence). However, increased ALA may slightly reduce risk of cardiovascular events (from 4.8% to 4.7%, RR 0.95, 95% CI 0.83 to 1.07, 19,327 participants; 884 CVD events, 5 RCTs, low-quality evidence), and probably reduces risk of CHD mortality (1.1% to 1.0%, RR 0.95, 95% CI 0.72 to 1.26, 18,353 participants; 193 CHD deaths, 3 RCTs), and arrhythmia (3.3% to 2.6%, RR 0.79, 95% CI 0.57 to 1.10, 4,837 participants; 141 events, 1 RCT). Effects on stroke are unclear.Sensitivity analysis retaining only trials at low summary risk of bias moved effect sizes towards the null (RR 1.0) for all LCn3 primary outcomes except arrhythmias, but for most ALA outcomes, effect sizes moved to suggest protection. LCn3 funnel plots suggested that adding in missing studies/results would move effect sizes towards null for most primary outcomes. There were no dose or duration effects in subgrouping or meta-regression.There was no evidence that increasing LCn3 or ALA altered serious adverse events, adiposity or lipids, although LCn3 slightly reduced triglycerides and increased HDL. ALA probably reduces HDL (high- or moderate-quality evidence). AUTHORS' CONCLUSIONS This is the most extensive systematic assessment of effects of omega-3 fats on cardiovascular health to date. Moderate- and high-quality evidence suggests that increasing EPA and DHA has little or no effect on mortality or cardiovascular health (evidence mainly from supplement trials). Previous suggestions of benefits from EPA and DHA supplements appear to spring from trials with higher risk of bias. Low-quality evidence suggests ALA may slightly reduce CVD event risk, CHD mortality and arrhythmia.
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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.
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The effects of probiotics on total cholesterol: A meta-analysis of randomized controlled trials.
Wang, L, Guo, MJ, Gao, Q, Yang, JF, Yang, L, Pang, XL, Jiang, XJ
Medicine. 2018;97(5):e9679
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Total cholesterol levels are commonly used as a marker of cardiovascular disease risk. The impact of probiotics on total cholesterol has been controversial. This meta-analysis of 32 randomised controlled trials including 1971 patients aimed to explore the effects of different probiotic strains on serum total cholesterol. The results of the meta-analysis showed that total cholesterol levels were significantly reduced in the probiotic group when compared with controls. Lactobacillus acidophilus, Bifidobacterium lactis, VSL#3 and Lactobacillus plantarum were found to have the most significant effects. In addition, a higher total cholesterol at the start of probiotic supplementation, a supplementation duration of longer than 8 weeks and taking the probiotics in capsule form as opposed to yoghurt, were found to have a greater impact. Nutrition practitioners wishing to support clients in the reduction of total cholesterol levels may want to consider the use of targeted probiotic therapy in their nutrition protocols.
Abstract
BACKGROUND Probiotics supplements provide a new nonpharmacological alternative to reduce cardiovascular risk factors. The impact of probiotics on the reduction of total cholesterol (TC) remains controversial. We conducted a meta-analysis to showcase the most updated and comprehensive evaluation of the studies. METHODS Randomized controlled trials (RCTs) were searched from electronic databases, including PubMed, Embase, Cochrane Central Register of Controlled Trials, Chinese Biomedical Literature Database, China National Knowledge Infrastructure, Wanfang database dating from January 2007 to January 2017. The curative effects of probiotics on the reduction of TC were assessed using mean difference (MD), as well as their 95% confidence interval (CI). RevMan software (version 5.3) was used to carry out this meta-analysis. RESULTS Thirty-two RCTs including 1971 patients met the inclusion criteria. Results of this analysis showed that compared with the control group serum TC was significantly reduced in probiotics group [MD = -13.27, 95% CI (-16.74 to 9.80), P < .05]. In addition, specific strains also significantly reduced serum TC, L acidophilus and B lactis [MD = -8.30, 95% CI (-10.44, -6.15), P < .05]; VSL#3 [MD = -11.04, 95% CI (-19.61, -2.48), P < .05]; L plantarum t ≤ 6 weeks: [MD = -1.56, 95% CI (-6.97, -3.86), P < .05] or t > 6 weeks: [MD = -22.18, 95% CI (-28.73, -15.63), P < .05]. Subgroup analysis indicated that the difference of baseline TC, probiotics forms and intervention duration might have a significant impact on the results. However, strains and doses of probiotics had no significant influence on curative effects. CONCLUSION Available evidence indicates that probiotics supplements can significantly reduce serum TC. Furthermore, higher baseline TC, longer intervention time, and probiotics in capsules form might contribute to a better curative effect.
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The influence of prebiotic or probiotic supplementation on antibody titers after influenza vaccination: a systematic review and meta-analysis of randomized controlled trials.
Yeh, TL, Shih, PC, Liu, SJ, Lin, CH, Liu, JM, Lei, WT, Lin, CY
Drug design, development and therapy. 2018;12:217-230
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Influenza vaccination is widely used although concerns regarding its efficacy exist. Both prebiotics and probiotics have been shown to produce protective effects against influenza infection and may enhance the immune response to the vaccination, especially in the elderly. The aim of this systematic review and meta-analysis was to determine the effect of pre- and probiotics on immune response to the influenza vaccination. According to the existing literature, participants who took prebiotics or probiotics were found to have higher hemagglutination inhibition (HI) antibodies, meaning a reduced likelihood of the virus attaching to the host’s red blood cells. Based on these results, the authors conclude both pre- or probiotic supplementation may enhance immune response in three influenza strains. While these results are promising, larger controlled trials are warranted to confirm the effectiveness and establish best clinical practice for supplementation.
Abstract
BACKGROUND Influenza infection is a common disease with a huge disease burden. Influenza vaccination has been widely used, but concerns regarding vaccine efficacy exist, especially in the elderly. Probiotics are live microorganisms with immunomodulatory effects and may enhance the immune responses to influenza vaccination. METHODS We conducted a systematic review and meta-analysis to determine the influence of prebiotics/probiotics/synbiotics supplementation on vaccine responses to influenza vaccination. Studies were systematically identified from electronic databases up to July 2017. Information regarding study population, influenza vaccination, components of supplements, and immune responses were extracted and analyzed. Twelve studies, investigating a total of 688 participants, were included in this review. RESULTS Patients with prebiotics/probiotics supplements were found to have higher influenza hemagglutination inhibition antibody titers after vaccination (for A/H1N1, 42.89 vs 35.76, mean difference =7.14, 95% CI =2.73, 11.55, P=0.002; for A/H3N2, 105.4 vs 88.25, mean difference =17.19, 95% CI =3.39, 30.99, P=0.01; for B strain, 34.87 vs 30.73, mean difference =4.17, 95% CI =0.37, 7.96, P=0.03). CONCLUSION Supplementation with prebiotics or probiotics may enhance the influenza hemagglutination inhibition antibody titers in all A/H1N1, A/H3N2, and B strains (20%, 19.5%, and 13.6% increases, respectively). Concomitant prebiotics or probiotics supplementation with influenza vaccination may hold great promise for improving vaccine efficacy. However, high heterogeneity was observed and further studies are warranted.
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Consumption of red and processed meat and breast cancer incidence: A systematic review and meta-analysis of prospective studies.
Farvid, MS, Stern, MC, Norat, T, Sasazuki, S, Vineis, P, Weijenberg, MP, Wolk, A, Wu, K, Stewart, BW, Cho, E
International journal of cancer. 2018;143(11):2787-2799
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Red meat and processed meat are hypothesised to be a dietary risk factor for several types of cancer. The aim of this meta-analysis was to summarise the current evidence regarding the association between red meat and processed meat consumption with breast cancer incidence. According to the existing literature, there is evidence that higher consumption of processed meat, but not red meat, is associated with higher risk of breast cancer. Based on these results, the authors conclude further research is required to better understand the effects of dietary risk factors in various molecular subtypes of breast cancer.
Abstract
Prior studies on red and processed meat consumption with breast cancer risk have generated inconsistent results. We performed a systematic review and meta-analysis of prospective studies to summarize the evidence regarding the relation of red meat and processed meat consumption with breast cancer incidence. We searched in MEDLINE and EMBASE databases through January 2018 for prospective studies that reported the association between red meat and processed meat consumption with incident breast cancer. The multivariable-adjusted relative risk (RR) was combined comparing the highest with the lowest category of red meat (unprocessed) and processed meat consumption using a random-effect meta-analysis. We identified 13 cohort, 3 nested case-control and two clinical trial studies. Comparing the highest to the lowest category, red meat (unprocessed) consumption was associated with a 6% higher breast cancer risk (pooled RR,1.06; 95% confidence intervals (95%CI):0.99-1.14; I2 = 56.3%), and processed meat consumption was associated with a 9% higher breast cancer risk (pooled RR, 1.09; 95%CI, 1.03-1.16; I2 = 44.4%). In addition, we identified two nested case-control studies evaluating the association between red meat and breast cancer stratified by N-acetyltransferase 2 acetylator genotype. We did not observe any association among those with either fast (per 25 g/day pooled odds ratio (OR), 1.18; 95%CI, 0.93-1.50) or slow N-acetyltransferase 2 acetylators (per 25 g/day pooled OR, 0.99; 95%CI, 0.91-1.08). In the prospective observational studies, high processed meat consumption was associated with increased breast cancer risk.
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Resistance Training Prevents Muscle Loss Induced by Caloric Restriction in Obese Elderly Individuals: A Systematic Review and Meta-Analysis.
Sardeli, AV, Komatsu, TR, Mori, MA, Gáspari, AF, Chacon-Mikahil, MPT
Nutrients. 2018;10(4)
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Caloric restriction (55% carbohydrate, 15% protein, 30% fat) is associated with increased lifespans and the attenuation of the harmful effects of aging. Furthermore, it has been shown that resistance training increases lean body mass, promotes strength, and attenuates muscle loss and function in elderly people. The aim of the study is to determine the level of lean body mass that can be preserved when resistance training is associated with caloric restriction interventions in elderly obese humans. The study is a meta-analysis, based on data from randomised-controlled trials. The participants were older adults or elderly people with a mean age > 57 year. Results indicate that caloric restriction associated with resistance training prevents 93% lean body mass loss induced by caloric restriction. Authors conclude that caloric restriction with resistance training almost stopped caloric restriction induced lean body mass loss completely.
Abstract
It remains unclear as to what extent resistance training (RT) can attenuate muscle loss during caloric restriction (CR) interventions in humans. The objective here is to address if RT could attenuate muscle loss induced by CR in obese elderly individuals, through summarized effects of previous studies. Databases MEDLINE, Embase and Web of Science were used to perform a systematic search between July and August 2017. Were included in the review randomized clinical trials (RCT) comparing the effects of CR with (CRRT) or without RT on lean body mass (LBM), fat body mass (FBM), and total body mass (BM), measured by dual-energy X-ray absorptiometry, on obese elderly individuals. The six RCTs included in the review applied RT three times per week, for 12 to 24 weeks, and most CR interventions followed diets of 55% carbohydrate, 15% protein, and 30% fat. RT reduced 93.5% of CR-induced LBM loss (0.819 kg [0.364 to 1.273]), with similar reduction in FBM and BM, compared with CR. Furthermore, to address muscle quality, the change in strength/LBM ratio tended to be different (p = 0.07) following CRRT (20.9 ± 23.1%) and CR interventions (−7.5 ± 9.9%). Our conclusion is that CRRT is able to prevent almost 100% of CR-induced muscle loss, while resulting in FBM and BM reductions that do not significantly differ from CR.
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Association of l-Arginine Supplementation with Markers of Endothelial Function in Patients with Cardiovascular or Metabolic Disorders: A Systematic Review and Meta-Analysis.
Rodrigues-Krause, J, Krause, M, Rocha, IMGD, Umpierre, D, Fayh, APT
Nutrients. 2018;11(1)
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L-arginine is an amino acid supplement that has shown potential for treating cardiovascular and metabolic diseases, however the current evidence has not produced clear results. The aim of this systematic review and meta-analysis was to verify the effects of L-arginine supplementation in individuals with cardiovascular disease, obesity or diabetes. Of the existing research, 13 studies were included for data extraction. The major outcome analysed was blood flow with a focus on specific biochemical markers that regulate vascular dilation. Based on the current literature, no difference was found between oral L-arginine supplementation and improvements in vascular function compared with placebo. The authors conclude this review may provide insight into potential mechanisms for improving endothelial function in individuals experiencing cardiovascular risk, but also note there were significant differences among the participants and intervention strategies in the studies reviewed.
Abstract
l-Arginine supplementation is a potential therapy for treating cardiovascular and metabolic diseases. However, the use of distinct l-arginine sources, intervened populations, and treatment regimens may have yielded confusion about their efficacy. This research constitutes a systematic review and meta-analysis summarizing the effects of l-arginine supplementation compared to placebo in individuals with cardiovascular disease (CVD), obesity, or diabetes. Eligibility criteria included randomized clinical trials and interventions based on oral supplementation of l-arginine with a minimum duration of three days; comparison groups consisted of individuals with the same disease condition receiving an oral placebo substance. The primary outcome was flow-mediated dilation, and secondary outcomes were nitrite/nitrate (NOx) rate and asymmetric dimethylarginine (ADMA). Statistical heterogeneity among studies included in the meta-analyses was assessed using the inconsistency index (I2). Fifty-four full-text articles from 3761 retrieved references were assessed for eligibility. After exclusions, 13 studies were included for data extraction. There was no difference in blood flow after post-ischemic hyperemia between the supplementation of l-arginine and placebo groups before and after the intervention period (standardized mean difference (SMD) = 0.30; 95% confidence intervals (CIs) = -0.85 to 1.46; I2 = 96%). Sensitivity analysis showed decreased heterogeneity when the studies that most favor arginine and placebo were removed, and positive results in favor of arginine supplementation were found (SMD = 0.59; 95% CIs = 0.10 to 1.08; I2 = 75%). No difference was found in meta-analytical estimates of NOx and ADMA responses between arginine or placebo treatments. Overall, the results indicated that oral l-arginine supplementation was not associated with improvements on selected variables in these patients (PROSPERO Registration: CRD42017077289).