Targeting the perinatal diet to modulate the gut microbiota increases dietary variety and prebiotic and probiotic food intakes: results from a randomised controlled trial

Effective dietary interventions during pregnancy: a systematic review and meta-analysis of behavior change techniques to promote healthy eating

Improving dietary intake during pregnancy can mitigate adverse consequences for women and their children. The effective techniques and features for supporting and sustaining dietary change during pregnancy and postpartum are minimally reported. The primary aims of this systematic review and meta-analysis were to summarise the effectiveness of dietary interventions for pregnant woman, identify which behaviour change techniques (BCTs) and intervention features were most frequently used and determine which were most effective at improving dietary intake. Six databases were searched to identify randomised control trials (RCTs) reporting on dietary intake in pregnant women over the age of sixteen, with an active intervention group compared to a control group receiving usual care or less intensive interventions. The Cochrane Risk of Bias Tool 1 was used to assess study validity. BCTs were coded by two authors using Michie et al.'s BCT taxonomy V1. A random effect model assessed intervention effects on indices of dietary quality and food groups (fruit, vegetables, grains and cereals, meat, and dairy) in relation to the use of BCTs and intervention features. Thirty- seven RCTs met the inclusion criteria. High heterogeneity was observed across intervention characteristics and measures of fidelity. Only half of the available BCTs were used, with eleven used once. The BCT category Reward and threat was successful in improving dietary quality and vegetable intake, whilst 'Action planning' (1.4) from the category Goals and planning significantly improved dietary quality. Interventions delivered by a nutrition professional and those that included group sessions improved dietary quality more than those delivered by other health professionals, research staff, or application-delivered interventions and delivered via other modalities. Future dietary interventions during pregnancy should incorporate and report on BCTs used in the intervention. Successful design elements for improving antenatal dietary intake may include multimodal interventions delivered by nutrition professionals and the use of Rewards and Goal setting.

Designing a behaviour change intervention using COM-B and the Behaviour Change Wheel: Co-designing the Healthy Gut Diet for preventing gestational diabetes

BACKGROUND

Evidence suggests that modulating the gut microbiota during pregnancy may help prevent gestational diabetes mellitus (GDM). The Healthy Gut Diet study is a complex behaviour change intervention co-designed with women who have a lived experience of GDM. The aim of the study was to describe the development of the behaviour change dietary intervention, the Healthy Gut Diet.

METHODS

This study followed the process for designing behaviour change interventions using the Behaviour Change Wheel. Six researchers and 12 women with lived experience participated in online workshops to co-design the Healthy Gut Diet intervention. This included "diagnosing" the barriers and enablers to two target behaviours: eating more plant foods and eating less ultra processed/saturated fat containing foods. Content analysis of the workshop transcripts and activities was undertaken, underpinned by the Capability, Opportunity, Motivation and Behaviour (COM-B) model and the Theoretical Domains Framework (TDF).

RESULTS

Barriers and enablers to the target behaviours were described across all six COM-B components and 10 TDF domains. The intervention functions for the Healthy Gut Diet were education, enablement, environmental restructuring, persuasion and incentivisation. Forty behaviour change techniques were integrated into five modes of delivery for the Healthy Gut Diet intervention. The feasibility, acceptability and effectiveness of the Healthy Gut Diet is being tested within a randomised controlled trial.

CONCLUSIONS

Using the Behaviour Change Wheel process in partnership with consumers resulted in a clearly described complex intervention targeting barriers and enablers of dietary behaviour change to improve the gut microbiota diversity in pregnant women.

Early- and life-long intake of dietary advanced glycation end-products (dAGEs) leads to transient tissue accumulation, increased gut sensitivity to inflammation, and slight changes in gut microbial diversity, without causing overt disease

Dietary advanced glycation end-products (dAGEs) accumulate in organs and are thought to initiate chronic low-grade inflammation (CLGI), induce glycoxidative stress, drive immunosenescence, and influence gut microbiota. Part of the toxicological interest in glycation products such as dietary carboxymethyl-lysine (dCML) relies on their interaction with receptor for advanced glycation end-products (RAGE). It remains uncertain whether early or lifelong exposure to dAGEs contributes physiological changes and whether such effects are reversible or permanent. Our objective was to examine the physiological changes in Wild-Type (WT) and RAGE KO mice that were fed either a standard diet (STD - 20.8 ± 5.1 µg dCML/g) or a diet enriched with dCML (255.2 ± 44.5 µg dCML/g) from the perinatal period for up to 70 weeks. Additionally, an early age (6 weeks) diet switch (dCML→STD) was explored to determine whether potential harmful effects of dCML could be reversed. Previous dCML accumulation patterns described by our group were confirmed here, with significant RAGE-independent accumulation of dCML in kidneys, ileum and colon over the 70-week dietary intervention (respectively 3-fold, 17-fold and 20-fold increases compared with controls). Diet switching returned tissue dCML concentrations to their baseline levels. The dCML-enriched diet had no significative effect on endogenous glycation, inflammation, oxidative stress or senescence parameters. The relative expression of TNFα, VCAM1, IL6, and P16 genes were all upregulated (∼2-fold) in an age-dependent manner, most notably in the kidneys of WT animals. RAGE knockout seemed protective in this regard, diminishing age-related renal expression of TNFα. Significant increases in TNFα expression were detectable in the intestinal tract of the Switch group (∼2-fold), suggesting a higher sensitivity to inflammation perhaps related to the timing of the diet change. Minor fluctuations were observed at family level within the caecal microbiota, including Eggerthellaceae, Anaerovoracaceae and Marinifilaceae communities, indicating slight changes in composition. Despite chronic dCML consumption resulting in higher free CML levels in tissues, there were no substantial increases in parameters related to inflammageing. Age was a more important factor in inflammation status, notably in the kidneys, while the early-life dietary switch may have influenced intestinal susceptibility to inflammation. This study affirms the therapeutic potential of RAGE modulation and corroborates evidence for the disruptive effect of dietary changes occurring too early in life. Future research should prioritize the potential influence of dAGEs on disease aetiology and development, notably any exacerbating effects they may have upon existing health conditions.

A gut-focused perinatal dietary intervention is associated with lower alpha diversity of the infant gut microbiota: results from a randomised controlled trial

OBJECTIVES

In experimental models, the prenatal diet influences gut microbiota composition in mothers and offspring; however, it is unclear whether this occurs in humans. We investigated the effects of a gut-focused perinatal dietary intervention on maternal and infant gut microbiota composition four weeks after birth.

METHODS

This randomised controlled trial randomised pregnant women to receive dietary advice as part of standard care, or additionally receive a dietary intervention focused on the Australian Dietary Guidelines and increasing prebiotic and probiotic/fermented food intakes (ACTRN12616000936426). Study assessments occurred from gestation week 26 (baseline) to four weeks postpartum (follow-up). Faecal samples, collected at baseline for mothers, and follow-up for mothers and infants, underwent 16SrRNA sequencing. The primary outcome was a between-group mean difference in infant faecal Shannon index. Secondary outcomes included between-group differences in other microbiota measures, including maternal change from baseline CLR-transformed Prevotella abundance.

RESULTS

Forty-four women and 45 infants completed the study. The mean Shannon index of infants in the intervention group was -0.35 (95% CI: -0.64, -0.06, SD: 0.52) units lower than control group infants, corresponding to a medium effect size (Cohen's D: -0.74, 95% CI: -1.34, -0.13). The findings were similar using other metrics of α-diversity. There were no between-group differences in β-diversity, nor any differentially abundant taxa in infants. The intervention increased abundances of the genus Prevotella in mothers compared to controls.

DISCUSSION

This gut-focused perinatal dietary intervention was associated with differences in the maternal and infant gut microbiota composition. Larger studies are required to replicate and extend these findings.

Co-designing The Healthy Gut Diet for Preventing Gestational Diabetes: Co-design methods and process outcomes

BACKGROUND

Gestational diabetes mellitus (GDM) is a common and costly condition of pregnancy. The Healthy Gut Diet for Preventing Gestational Diabetes study is a novel randomised controlled trial that aims to prevent GDM through a diet that modulates the gut microbiota for pregnant women with GDM risk factors. Despite increasing interest in co-designing interventions with consumers (lived experience experts), co-design methods and outcomes are often poorly reported. The present study aims to report on the co-design process used to develop The Healthy Gut Diet intervention.

METHODS

Co-design occurred across three online workshops with consumer participants (women with a lived experience of GDM, n = 11), researchers (n = 6) and workshop co-facilitators (including a consumer co-facilitator, n = 2). The workshops explored women's preferences for the mode and length of education sessions, as well as the types of information and supportive resources women wanted to receive, and undertook a "behaviour diagnosis" to understand barriers and enablers to the target behaviours (eating for gut health). The final intervention is reported according to the Template for Intervention Description and Replication.

RESULTS

A co-designed dietary intervention (The Healthy Gut Diet), delivered via telehealth, with a suite of educational and supportive resources that integrates published behaviour change techniques, was developed. Generally, the co-design process was reported as a positive experience based on participant feedback and evidenced by no participant dropouts over the 3-month study period.

CONCLUSIONS

Co-design is recognised as a process that creates a partnership between lived experience experts and researchers who can engage and empower research recipients and improve health behaviours.

Depressive Symptoms and Gut Microbiota after Bowel Preparation and Colonoscopy: A Pre-Post Intervention Study

Mechanical bowel preparation (MBP) is essential for visualisation of the colon during colonoscopy. Previous studies have identified changes in gut microbiota composition after MBP and colonoscopy. Considering the gut microbiota is increasingly implicated in psychiatry, we explored the potential impact of this intervention on mood and the microbiota-gut-brain axis. We conducted a pre-post intervention study in adults, with timepoints of one week before and one month after MBP and colonoscopy. Our primary outcome was change in average Hospital Anxiety and Depression Scale depression sub-scores. We examined changes in average anxiety, stress, and quality of life scores and gut microbiota composition using 16S rRNA sequencing. We further explored associations between changes in depressive symptoms and gut microbiota and conducted post hoc analyses to explore potential effect modifiers. Average depressive symptom scores decreased one month post-procedure compared to baseline (n = 59; adjusted β = -0.64; 95%CI: -1.18, -0.11). Irritable bowel syndrome (IBS) appeared to moderate this relationship (β = 1.78; 95%CI: 0.292, 3.26); depressive symptoms increased in those with, and decreased in those without, IBS. Reduced alpha diversity, modest effects on beta-diversity, and increases in health-associated genera were observed one month post-procedure. Increases in the CLR-transformed abundances of Ruminococcaceae UCG-009 were associated with improvements in depressive symptoms. There is preliminary evidence of a potential mental health effect of MBP and colonoscopy, particularly for those with IBS, which may be associated with changes to the gut microbiota. Further research is required to confirm these findings and their clinical relevance.

Prior Appendicectomy and Gut Microbiota Re-Establishment in Adults after Bowel Preparation and Colonoscopy

Emerging evidence suggests that the human vermiform appendix is not a vestigial organ but rather an immunological organ of biological relevance. It is hypothesised that the appendix acts as a bacterial 'safe house' for commensal gut bacteria and facilitates re-inoculation of the colon after disruption through the release of biofilms. To date, no studies have attempted to explore this potential mechanistic function of the appendix. We conducted a pre-post intervention study in adults (n = 59) exploring re-establishment of the gut microbiota in those with and without an appendix after colonic disruption via bowel preparation and colonoscopy. Gut microbiota composition was measured one week before and one month after bowel preparation and colonoscopy using 16S rRNA sequencing. We observed between group differences in gut microbiota composition between those with (n = 45) and without (n = 13) an appendix at baseline. These differences were no longer evident one-month post-procedure, suggesting that this procedure may have 'reset' any potential appendix-related differences between groups. Both groups experienced reductions in gut microbiota richness and shifts in beta diversity post-procedure, with greater changes in those without an appendix, and there were five bacterial genera whose re-establishment post-procedure appeared to be moderated by appendicectomy status. This small experimental study provides preliminary evidence of a potential differential re-establishment of the gut microbiota after disruption in those with and without an appendix, warranting further investigation into the potential role of the appendix as a microbial safe house.

Food Insecurity Is Associated with Diet Quality in Pregnancy: A Cross-Sectional Study

Household food insecurity (HFI) and poorer prenatal diet quality are both associated with adverse perinatal outcomes. However, research assessing the relationship between HFI and diet quality in pregnancy is limited. A cross-sectional online survey was conducted to examine the relationship between HFI and diet quality among 1540 pregnant women in Australia. Multiple linear regression models were used to examine the associations between HFI severity (marginal, low, and very low food security compared to high food security) and diet quality and variety, adjusting for age, education, equivalised household income, and relationship status. Logistic regression models were used to assess the associations between HFI and the odds of meeting fruit and vegetable recommendations, adjusting for education. Marginal, low, and very low food security were associated with poorer prenatal diet quality (adj β = -1.9, -3.6, and -5.3, respectively; p < 0.05), and very low food security was associated with a lower dietary variety (adj β = -0.5, p < 0.001). An association was also observed between HFI and lower odds of meeting fruit (adjusted odds ratio [AOR]: 0.61, 95% CI: 0.49-0.76, p < 0.001) and vegetable (AOR: 0.40, 95% CI: 0.19-0.84, p = 0.016) recommendations. Future research should seek to understand what policy and service system changes are required to reduce diet-related disparities in pregnancy.

Preventing Gestational Diabetes with a Healthy Gut Diet: Protocol for a Pilot, Feasibility Randomized Controlled Trial

Around 14% of pregnancies globally are affected by gestational diabetes mellitus (GDM), making it one of the most common disorders experienced by women in pregnancy. While dietary, physical activity and supplement interventions have been implemented to prevent GDM, with varying levels of success, altering the gut microbiota through diet is a promising strategy for prevention. Several studies have demonstrated that women with GDM likely have a different gut microbiota to pregnant women without GDM, demonstrating that the gut microbiota may play a part in glycemic control and the development of GDM. To date, there have been no randomized controlled trials using diet to alter the gut microbiota in pregnancy with the aim of preventing GDM. Here, we present the study protocol for a single-blind randomized controlled trial which aims to determine the effectiveness of the Healthy Gut Diet on reducing the diagnosis of GDM in pregnant women with one or more risk factors. Consenting women will be randomized into either the Healthy Gut Diet intervention group or the usual care (control) group after 11 weeks gestation. The women in the intervention group will receive three telehealth counseling appointments with an Accredited Practicing Dietitian with the aim of educating and empowering these women to build a healthy gut microbiota through their diet. The intervention was co-designed with women who have lived experience of GDM and incorporates published behavior change techniques. The control group will receive the usual care and will also be shown a brief (3 min) video on general healthy eating in pregnancy. The primary outcome is the diagnosis of GDM at any stage of the pregnancy. Secondary outcomes include changes to gut microbiota composition and diversity; gestational weight gain; maternal and infant outcomes; management of GDM (where relevant); dietary quality and intake; physical activity; and depression scoring. We aim to recruit 120 women over 16 months. Recruitment commenced in January 2023. The trial has been registered with the Australian New Zealand Clinical Trials Registry (ACTRN12622001285741).

Lifestyle and the hypertensive disorders of pregnancy in nulliparous women in the United States: a secondary data analysis of the nuMom2b

BACKGROUND

Hypertensive disorders of pregnancy are a leading cause of maternal and fetal morbidity and mortality and a significant risk factor for future cardiovascular disease development in women. This study aimed to explore lifestyle wellness-related variables and how they impact the risk of hypertension in pregnancy.

METHODS

This is a secondary analysis of data from the prospective cohort study Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-To-Be (nuMoM2b). Data was collected through questionnaires, clinical evaluations, and medical records review at 8 academic medical centers in the United States. Four study visits were scheduled throughout the participant's pregnancy (visits one-four): 6⁰-13⁶, 16⁰-21⁶, and 22⁰-29⁶ weeks gestation and birth. A series of statistical modeling and logistical regression were performed using 15 lifestyle variables related to sleep, nutrition, resilience, illness avoidance, and physical activity were selected as predictor variables with an outcome variable of hypertension.

RESULTS

Of 9289 nulliparous participants considered for inclusion in our analyses, 1464 had any HDP during study participation, and 554 participants had complete data available for the study and were included in our final sample. Results were statistically significant at a level of p < 0.05. Of the sleep variables, snoring at visit 1 increased the risk of hypertension in pregnancy. Greater vegetable consumption reported at visit one decreased risks of hypertension in pregnancy. Physical activity reported at visit two and visit three were associated with decreased risk of hypertension. Physical activity reported at visit three combined with more hours of sleep each night, or through napping habit reported at visit one decreased hypertension risk. Increased fish oil consumption combined with more hours of sleep at visit one increased odds of hypertension in pregnancy.

CONCLUSIONS

Our results support that lifestyle wellness-related variables relating to sleep, physical activity and nutrition affect hypertension in pregnancy. The studied variables and others should be considered in future research and intervention development to reduce hypertension in pregnancy and improve maternal wellness.

Parents' Perspective on Probiotics in Preschool Children: A Cross-sectional Survey

Introduction

The composition of the human gut microbiota, which can also be regulated by the consumption of probiotics, has a significant impact on host health. The main source of probiotics can be foods such as fermented foods, yogurts, fermented drinks and/or probiotic supplements. While parents play a critical role in ensuring the well-being of their children, this cross-sectional study is focused on parents' perspectives regarding the use of probiotics in the preschool period.

Methods

The self-administered online survey consisted of 24 questions arranged across two thematic sections. The final data analysis included 102 parents (96% F; 4% M), aged between 22 and 47. Their children were aged up to 6 years.

Results

The majority (52%) of the parents were familiar with the term 'probiotics' and 86.3% were including probiotics in their children's diet at the time of the survey. The main source was probiotic food (36.3%), of which yoghurt was the most commonly consumed (87.2%). The inclusion of probiotic supplements in a child's diet was positively correlated with parents' consumption and level of knowledge about the term 'probiotics'. Digestive tract-related disorders were the most frequently reported motive for the initial introduction of probiotics into children's diet.

Conclusions

Based on our study results, parents are familiar with probiotics and include them in their children's diet. However, an attempt should be made to close the gaps in parents' knowledge that our research identified. Further studies are needed to determine the recommended amount of probiotic foods, as well as strategies to educate parents about the benefits of including probiotic foods in their children's diet.