The associations between dairy product consumption and biomarkers of inflammation, adipocytokines, and oxidative stress in children: a cross-sectional study

The association between dairy product consumption and biomarkers of inflammation, adipocytokines, and oxidative stress is poorly studied in children. Therefore, these associations were examined in a representative subsample of 1338 schoolchildren with a mean age of 11.5 (±0.7) years in the Healthy Growth Study. Information on dairy product consumption was collected by dietary recalls. Total dairy consumption was calculated by summing the intake of milk, yogurt, and cheese. Inflammatory markers, i.e., high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and adipocytokines, i.e., leptin, adiponectin, and the antioxidant enzyme glutathione peroxidase (GPx) were analysed. Due to the skewed distribution hs-CRP, IL-6, and leptin were log transformed. Multivariable regression analyses adjusted for age, sex, energy intake, physical activity, parental education, Tanner stage, and fat mass were used to assess the associations between consumption of total dairy, milk, yogurt, cheese, and markers of inflammation, adipocytokines, oxidative stress, and adiponectin−leptin ratio. Our results showed that milk consumption was inversely associated with leptin (β: −0.101; 95% CI: −0.177, −0.025, p = 0.009) and positively associated with the adiponectin−leptin ratio (β: 0.116; 95% CI: 0.020, 0.211; p = 0.018), while total dairy, cheese, and yogurt consumption were not associated with inflammatory, adipocytokine, or antioxidant markers. Further prospective studies are needed to confirm these results

Association between dairy intake and fracture in an Australian-based cohort of women: a prospective study

Objective Given the inconsistent evidence on dairy consumption and risk of fracture, we assessed the association between milk/total dairy consumption and major osteoporotic fracture (MOF) in women from the Geelong Osteoporosis Study (GOS). Methods Women aged ≥50 years (n=833) were followed from baseline (1993-1997) to date of first fracture, death or 31 December 2017, whichever occurred first. Dairy consumption was assessed by self-report at baseline and the follow-up phases. MOFs (hip, forearm, clinical spine and proximal humerus) were confirmed radiologically. Multivariable-adjusted Cox proportional hazard models were used to determine associations between milk/total dairy (milk, cheese, yoghurt, ice cream) consumption and MOFs. Cross-sectional associations between milk/total dairy consumption and serum high-sensitivity C reactive protein (hsCRP), C-terminal telopeptide (CTx) and procollagen type 1 N-terminal propeptide (P1NP) at baseline were investigated using multivariable linear regression. Results During follow-up (11 507 person-years), 206 women had an MOF. Consuming >500 mL/d of milk was not significantly associated with increased HR for MOF. Non-milk (1.56; 95% CI 0.99 to 2.46) drinkers and consumption of ≥800 g/d total dairy (1.70; 95% CI 0.99 to 2.93) had marginally higher HR for MOF compared with consuming <250 mL/d of milk and 200-399 g/d of total dairy, respectively. Milk consumption was inversely associated with serum hsCRP and CTx, but total dairy consumption was not associated with these serum markers. Conclusion Higher milk consumption did not increase the risk for MOF in older women. However, a trend for increased MOF was detected in zero milk and higher total dairy consuming women

Possible use of fermented foods in rehabilitation of anorexia nervosa: the gut microbiota as a modulator

Anorexia nervosa is a serious psychiatric disorder with high morbidity and mortality rate. Evidence for the optimal psychopharmacological approach to managing the disorder remains limited, with nutritional treatment, focused on weight restoration through the consumption of high energy diet, regarded as one of the fundamental steps in treatment. The human gut microbiome is increasingly recognised for its proposed role in gastrointestinal, metabolic, immune and mental health, all of which may be compromised in individuals with anorexia nervosa. Dietary intake plays an important role in shaping gut microbiota composition, whilst the use of fermented foods, foods with potential psychobiotic properties that deliver live bacteria, bacterial metabolites, prebiotics and energy, have been discussed to a lesser extent. However, fermented foods are of increasing interest due to their potential capacity to affect gut microbiota composition, provide beneficial bacterial metabolites, and confer beneficial outcomes to host health. This review provides an overview of the role of the gut microbiota in relation to the disease pathology in anorexia nervosa and especially focuses on the therapeutic potential of fermented foods, proposed here as a recommended addition to the current nutritional treatment protocols warranting further investigation

Gut microbiome diversity and composition are associated with habitual dairy intakes: a cross-sectional study in men

Background: At a population level, the relation between dairy consumption and gut microbiome composition is poorly understood. Objectives: We sought to study the cross-sectional associations between individual dairy foods (i.e., milk, yogurt, and cheese), as well as total dairy intake, and the gut microbiome composition in a large, representative sample of men living in south-eastern Australia. Methods: Data on 474 men (mean ± SD: 64.5 ± 13.5 y old) from the Geelong Osteoporosis Study were used to assess the cross-sectional association between dairy consumption and gut microbiome. Information on dairy intake was self-reported. Men were categorized as consumers and nonconsumers of milk, yogurt, cheese, and high- and low-fat milk. Milk, yogurt, and cheese intakes were summed to calculate the total dairy consumed per day and categorized into either low (<2.5 servings/d) or high (≥2.5 servings/d) total dairy groups. Fecal samples were analyzed using bacterial 16S ribosomal RNA (rRNA) gene sequencing. After assessment of α and β diversity, differential abundance analysis was performed to identify bacterial taxa associated with each of milk, yogurt, and cheese consumption compared with nonconsumption, low compared with high total dairy, and low- compared with high-fat milk consumption. All analyses were adjusted for potential confounders. Results: α Diversity was not associated with consumption of any of the dairy groups. Differences in β diversity were observed between milk and yogurt consumption compared with nonconsumption. Taxa belonging to the genera Ruminococcaceae UCG-010 and Bifidobacterium showed negative and weak positive associations with milk consumption, respectively. A taxon from the genus Streptococcus was positively associated with yogurt consumption, whereas a taxon from the genus Eisenbergiella was negatively associated with cheese consumption. No specific taxa were associated with low- compared with high-fat milk nor low compared with high total dairy consumption. Conclusions: In men, community-level microbiome differences were observed between consumers and nonconsumers of milk and yogurt. Bacterial taxon-level associations were detected with milk, yogurt, and cheese consumption. Total dairy consumption was not associated with any microbiome measures, suggesting that individual dairy foods may have differential roles in shaping the gut microbiome in men

Associations between dairy consumption and constipation in adults: A cross-sectional study

Objective: The current study aimed to assess the association between dairy consumption and constipation in the general adult population. Design: Data from the Geelong Osteoporosis Study were used to assess the association between dairy consumption and constipation in women ( n=632) and men ( n=609). Information on milk, yogurt and cheese, and constipation were self-reported. Total dairy was calculated by summing the intake of milk, yogurt and cheese and expressed as servings per day. Multivariable logistic regression models adjusted for irritable bowel syndrome, major depressive disorders, mobility, body mass index, age and fibre intake were used to examine the odds ratio (OR) and 95% confidence interval (CI) between the consumption of categories of total dairy, milk, yogurt, cheese, and constipation. Results: In women, consumption of 1–2 servings/d of total dairy was associated with reduced odds for constipation (OR: 0.49; 95% CI: 0.26-0.90; P=0.021) compared to consuming &lt;1 serving/d of total dairy after adjusting for covariates. Also, consumption of 1–4 servings/d of milk was associated with marginally reduced odds for constipation (OR: 0.63; 95% CI: 0.39-1.02; P=0.058) compared to women who consumed &lt;1 serving/d of milk after adjusting for covariates. There were no significant associations detected between other types of dairy consumption and constipation in women, and none in men. Conclusion: In women, consumption of moderate amounts of dairy is associated with reduced odds for constipation whereas in men no associations were detected between dairy consumption and constipation. Further studies are warranted to confirm results. </jats:sec

The effects of dairy and dairy derivatives on the gut microbiota: a systematic literature review

The effects of dairy and dairy-derived products on the human gut microbiota remains understudied. A systematic literature search was conducted using Medline, CINAHL, Embase, Scopus, and PubMed databases with the aim of collating evidence on the intakes of all types of dairy and their effects on the gut microbiota in adults. Risk of bias was assessed using the Cochrane risk-of-bias tool.The search resulted in 6,592 studies, of which eight randomized controlled trials (RCTs) met pre-determined eligibility criteria for inclusion, consisting of a total of 468 participants. Seven studies assessed the effect of type of dairy (milk, yogurt, and kefir) and dairy derivatives (whey and casein) on the gut microbiota, and one study assessed the effect of the quantity of dairy (high dairy vs low dairy). Three studies showed that dairy types consumed (milk, yogurt, and kefir) increased the abundance of beneficial genera Lactobacillus and Bifidobacterium. One study showed that yogurt reduced the abundance of Bacteroides fragilis, a pathogenic strain. Whey and casein isolates and the quantity of dairy consumed did not prompt changes to the gut microbiota composition. All but one study reported no changes to bacterial diversity in response to dairy interventions and one study reported reduction in bacterial diversity in response to milk intake.In conclusion, the results of this review suggest that dairy products such as milk, yogurt, and kefir may modulate the gut microbiota composition in favor to the host. However, the broader health implications of these findings remain unclear and warrant further studies

Reply to V Gianfredi et al

Dear Editor: We thank Gianfredi et al. for their generous comments regarding the methodology used in our recent umbrella review and welcome their clear discussion of common queries regarding the scope and methods of umbrella reviews..

Peri-Operative Risk Factors Associated with Post-Operative Cognitive Dysfunction (POCD): An Umbrella Review of Meta-Analyses of Observational Studies

This umbrella review aimed to systematically identify the peri-operative risk factors associated with post-operative cognitive dysfunction (POCD) using meta-analyses of observational studies. To date, no review has synthesised nor assessed the strength of the available evidence examining risk factors for POCD. Database searches from journal inception to December 2022 consisted of systematic reviews with meta-analyses that included observational studies examining pre-, intra- and post-operative risk factors for POCD. A total of 330 papers were initially screened. Eleven meta-analyses were included in this umbrella review, which consisted of 73 risk factors in a total population of 67,622 participants. Most pertained to pre-operative risk factors (74%) that were predominantly examined using prospective designs and in cardiac-related surgeries (71%). Overall, 31 of the 73 factors (42%) were associated with a higher risk of POCD. However, there was no convincing (class I) or highly suggestive (class II) evidence for associations between risk factors and POCD, and suggestive evidence (class III) was limited to two risk factors (pre-operative age and pre-operative diabetes). Given that the overall strength of the evidence is limited, further large-scale studies that examine risk factors across various surgery types are recommended