Quantifying the mediating effect of body mass index on the relation between a Mediterranean diet and development of maternal pregnancy complications: the Australian Longitudinal Study on Women's Health

Maternal Dietary Carbohydrate and Pregnancy Outcomes: Quality over Quantity

Dietary nutrition plays a crucial role in determining pregnancy outcomes, with poor diet being a major contributor to pregnancy metabolic syndrome and metabolic disorders in offspring. While carbohydrates are essential for fetal development, the excessive consumption of low-quality carbohydrates can increase the risk of pregnancy complications and have lasting negative effects on offspring development. Recent studies not only highlighted the link between carbohydrate intake during pregnancy, maternal health, and offspring well-being, but also suggested that the quality of carbohydrate foods consumed is more critical. This article reviews the impacts of low-carbohydrate and high-carbohydrate diets on pregnancy complications and offspring health, introduces the varied physiological effects of different types of carbohydrate consumption during pregnancy, and emphasizes the importance of both the quantity and quality of carbohydrates in nutritional interventions during pregnancy. These findings may offer valuable insights for guiding dietary interventions during pregnancy and shaping the future development of carbohydrate-rich foods.

Systolic blood pressure as a critical mediator in the association between adult height and 25-year risk of stroke

BACKGROUND

Adult height is associated with the risk of stroke. However, the underlying mechanism remains unclear. We explored the mediating role of metabolic factors in the association between adult height and stroke incidence.

METHODS

We used data from 3306 community-dwelling participants with complete information on adult height, metabolic factors, and 25-year cardiovascular outcomes. Participants were classified into three adult height groups based on sex-specific height quartiles: short (Q1), average (Q2-Q3), and tall (Q4). The primary endpoint was the occurrence of cardiovascular disease, including coronary artery disease and stroke.

RESULTS

Taller adult height was associated with a lower risk of stroke. Compared with the short group the risk of stroke reduced with taller height with a hazard ratio (HR) of 0.68 in the average group (95% confidence interval [CI]: 0.50-0.93), and 0.45 in the tall group (95% CI: 0.31-0.65). Low systolic blood pressure was considered as a protective mediator in the effect of adult height on the risk of stroke in the average (HR: 0.86; 95% CI: 0.82-0.93) and the tall group (HR: 0.85; 95% CI: 0.78-0.91). Systolic blood pressure significantly contributed to height-related stroke risk (proportion mediated: 0.41; 95% CI: 0.19-1.56).

CONCLUSIONS

This study found an inverse association between adult height and stroke risk, which is partly driven by lower systolic blood pressure. These findings highlight the importance of systolic blood pressure management as a potential preventive strategy against stroke.

Association between the Maternal Mediterranean Diet and Perinatal Outcomes: A Systematic Review and Meta-Analysis

The Mediterranean diet is a global, well-known healthy dietary pattern. This review aims to synthesize the existing evidence on the relationship between the maternal Mediterranean diet during pregnancy and perinatal outcomes, including randomized controlled trials (RCTs) and cohort studies. PubMed, Web of Science, and the Cochrane Library were searched from inception to 10 March, 2023, supplemented by manual screening. A random-effect model was used to estimate pooled sizes with 95% confidence intervals (CIs) for specific outcomes of interest. Data from 5 RCTs and 18 cohort studies with 107,355 pregnant participants were synthesized. In RCTs, it was observed that the maternal Mediterranean diet significantly reduced the incidence of gestational diabetes mellitus [odds ratio (OR), 0.56; 95% CI: 0.34, 0.93], as well as small for gestational age (0.55; 95% CI: 0.35, 0.88). In cohort studies, the highest adherence score to the maternal Mediterranean diet was inversely associated with a lower risk of various adverse pregnancy outcomes, including gestational diabetes mellitus (OR, 0.82; 95% CI: 0.67, 1.00), pregnancy-induced hypertension (0.73; 95% CI: 0.60, 0.89), pre-eclampsia (0.77; 95% CI: 0.64, 0.93), preterm delivery (0.67; 95% CI: 0.49, 0.91), low birth weight (0.70; 95% CI: 0.64, 0.78), intrauterine growth restriction (0.46; 95% CI: 0.23, 0.91), and increased gestational age at delivery (weighted mean difference, 0.11 wk; 95% CI: 0.03, 0.20). Meta-regression analyses did not identify the adjustment for confounders and geographical location as predictive factors for heterogeneity. The results suggest that adherence to the Mediterranean diet during pregnancy appears to be beneficial for perinatal outcomes. Future, larger, and higher-quality RCTs and cohort studies are warranted to confirm the present findings. PROSPERO registration no.: CRD42023406317.

Dietary supplements, guideline alignment and biochemical nutrient status in pregnancy: Findings from the Queensland Family Cohort pilot study

In high-income nations, multiple micronutrient (MMN) supplementation during pregnancy is a common practice. We aimed to describe maternal characteristics associated with supplement use and daily dose of supplemental nutrients consumed in pregnancy, and whether guideline alignment and nutrient status are related to supplement use. The Queensland Family Cohort is a prospective, Australian observational longitudinal study. Maternal characteristics, nutrient intake from food and supplements, and biochemical nutrient status were assessed in the second trimester (n = 127). Supplement use was reported by 89% of participants, of whom 91% reported taking an MMN supplement. Participants who received private obstetric care, had private health insurance and had greater alignment to meat/vegetarian alternatives recommendations were more likely to report MMN supplement use. Private obstetric care and general practitioner shared care were associated with higher daily dose of supplemental nutrients consumed compared with midwifery group practice. There was high reliance on supplements to meet nutrient reference values for folate, iodine and iron, but only plasma folate concentrations were higher in MMN supplement versus nonsupplement users. Exceeding the upper level of intake for folic acid and iron was more likely among combined MMN and individual supplement/s users, and associated with higher plasma concentrations of the respective nutrients. Given the low alignment with food group recommendations and potential risks associated with high MMN supplement use, whole food diets should be emphasized. This study confirms the need to define effective strategies for optimizing nutrient intake in pregnancy, especially among those most vulnerable where MMN supplement use may be appropriate.

Assessing the Mediterranean diet adherence during pregnancy: Practical considerations based on the associations with cardiometabolic risk

OBJECTIVE

The aim of the present study was to provide practical considerations for assessing MD adherence during pregnancy based on the association with cardiometabolic risk.

STUDY DESIGN

Longitudinal study.

MAIN OUTCOME MEASURES

A food frequency questionnaire was fulfilled by 152 pregnant women at the 16th gestational week (g.w.). We calculated the Mediterranean Food Pattern (MFP), the MD Scale (MDScale), the Short MD questionnaire (SMDQ), the MD Score (MedDietScore), and the MD scale for pregnant women (MDS-P). The cardiometabolic risk score consisted of pre-pregnancy body mass index, blood pressure, glucose, triglycerides, and high-density lipoprotein-cholesterol (at 16th and 34th g.w.).

RESULTS

Multiple linear regression models showed that the MFP, the MedDietScore, and the SMDQ were associated with lower cardiometabolic risk at the 16th and 34th g.w. (β's: -0.193 to -0.415, all p < 0.05); and the MDS-P at the 34th g.w. (β = -0.349, p < 0.01). A comparison of these models with the J test showed that the MFP and the MedDietScore outperformed the SMDQ at the 16th g.w. (p's < 0.05); while the MedDietScore outperformed the SMDQ, MFP, and MDS-P (p's < 0.05) at the 34th g.w. Receiver-Operating-Characteristic-derived thresholds for the MFP, MedDietScore and MDS-P indices were 21, 30, and 6 points, respectively, to identify women with high cardiometabolic risk.

CONCLUSION

The MFP and MedDietScore are recommended to assess MD adherence during pregnancy, as these showed the strongest associations with cardiometabolic risk. Our validated thresholds might assist in the detection of poor dietary patterns during pregnancy.

Dietary fiber intake and non-alcoholic fatty liver disease: The mediating role of obesity

Background and aims

Dietary pattern rich in fiber is negatively associated with the risk of non-alcoholic fatty liver disease (NAFLD). Meanwhile, obesity is a known predisposing factor for NAFLD. Nutrient-focused research can enhance the mechanistic understanding of dietary effects. We thus hypothesized that higher dietary fiber intake was associated with lower risk of NAFLD through the mediating role of obesity.

Methods

In this nationwide cross-sectional study, dietary fiber was surveyed using two 24-h recalls. NAFLD and clinically significant fibrosis (CSF) were determined by vibration-controlled transient elastography. Multivariable logistic and linear regression were applied to investigate the association of dietary fiber with NAFLD, CSF, and liver function parameters. We used counterfactual-based mediation analysis to estimate the direct and indirect effect of dietary fiber on NAFLD.

Results

Of the 3,974 participants, ~36.86% and 7.78% of participants were diagnosed with NAFLD and CSF. Compared with participants among the lowest tertile, the highest tertile of dietary fiber consumption was associated with lower odds of NAFLD (OR = 0.81; 95% CI: 0.66-0.98; P _overall = 0.019). Dietary fiber intake appeared to be linked with lower odds of CSF (OR _{Tertile3vs.Tertile1} = 0.81; 95% CI: 0.58-1.14; P _overall = 0.107). Mediation analysis showed that obesity fully mediated the association of dietary fiber with NAFLD. Dietary fiber was associated with improved hepatic parameters.

Conclusions

The findings indicated that increasing dietary fiber intake could confer a greater benefit to protect against NAFLD. Translating these findings regarding dietary fiber into dietary advice might be an attractive strategy for NAFLD prevention.

Prenatal Nutrition Care in Alberta: The Perspectives of Pregnant Women and Registered Dietitians

Introduction: Optimizing women’s diets in pregnancy improves maternal and child health outcomes; however, the best format for supporting women’s nutrition goals in pregnancy is not clear, and access to dietetic services is not standard in prenatal care in Alberta. This study explored women’s perceptions about access to Registered Dietitians (RDs) throughout pregnancy and RDs experiences providing prenatal nutrition counselling.

Methods: Two studies were conducted. Study A: Pregnant women completed a short survey while attending a prenatal appointment in a large prenatal clinic. The survey assessed women’s perspectives about accessing dietetic services during pregnancy. Survey data were analyzed using descriptive statistics. Study B: RDs participated in either a semi-structured phone interview or a focus group and described their experiences working with pregnant women. Data were analyzed using thematic analysis.

Results: One hundred pregnant women completed the survey. Ninety percent indicated that they had not seen a RD at this time in pregnancy, and 48% reported that they would like to access a RD in pregnancy, if available. Dietitians discussed the diversity of women’s concerns and the challenges to providing prenatal nutrition support.

Conclusions: Women have nutrition-related questions during pregnancy. Dietitians experience challenges providing services in the current care systems.

Geographic Variations in Dietary Patterns and Their Associations with Overweight/Obesity and Hypertension in China: Findings from China Nutrition and Health Surveillance (2015-2017)

Regional dietetic cultures were indicated in China, but how dietary patterns geographically varied across China is unknown. Few studies systematically investigated the association of dietary patterns with overweight/obesity and hypertension and the potential mechanism with a national sample. This study included 34,040 adults aged 45 years and older from China Nutrition and Health Surveillance (2015−2017), who had complete outcome data, reliable intakes of calorie and cooking oils, unchanged diet habits, and without diagnosed cancer or cardiovascular disease. Outcomes were overweight/obesity and hypertension. By using the Gaussian finite mixture models, four dietary patterns were identified—common rice-based dietary pattern (CRB), prudent diversified dietary pattern (PD), northern wheat-based dietary pattern (NWB), and southern rice-based dietary pattern (SRB). Geographic variations in dietary patterns were depicted by age−sex standardized proportions of each pattern across 31 provinces in China. We assessed the association of these dietary patterns with outcomes and calculated the proportion mediated (PM) by overweight/obesity in the association of the dietary patterns with hypertension. Evident geographic disparities in dietary patterns across 31 provinces were observed. With CRB as reference group and covariates adjusted, the NWB had higher odds of being overweight/obese (odds ratio (OR) = 1.44, 95% confidence interval (CI): 1.36−1.52, p < 0.001) and hypertension (OR = 1.07, 95%CI: 1.01−1.14, p < 0.001, PM = 43.2%), while the SRB and the PD had lower odds of being overweight/obese (ORs = 0.84 and 0.92, 95%CIs: 0.79−0.89 and 0.85−0.99, p < 0.001 for both) and hypertension (ORs = 0.93 and 0.87, 95%CIs: 0.87−0.98 and 0.80−0.94, p = 0.038 for SRB and p < 0.001 for PD, PMs = 27.8% and 9.9%). The highest risk of overweight/obesity in the NWB presented in relatively higher carbohydrate intake (about 60% of energy) and relatively low fat intake (about 20% of energy). The different trends in the association of protein intake with overweight/obesity among dietary patterns were related to differences in animal food sources. In conclusion, the geographic distribution disparities of dietary patterns illustrate the existence of external environment factors and underscore the need for geographic-targeted dietary actions. Optimization of the overall dietary pattern is the key to the management of overweight/obesity and hypertension in China, with the emphasis on reducing low-quality carbohydrate intake, particularly for people with the typical northern diet, and selection of animal foods, particularly for people with the typical southern diet.

Equal Weighting of the Healthy Eating Index-2010 Components May Not be Appropriate for Pregnancy

BACKGROUND

Adherence to the Dietary Guidelines for Americans is often assessed using the Healthy Eating Index (HEI). The HEI total score reflects overall diet quality, with all aspects equally important. Using the traditional weighting scheme for the HEI, all components are generally weighted equally in the total score. However, there is limited empirical basis for applying the traditional weighting for pregnancy specifically.

OBJECTIVES

We aimed to assess associations between the 12 HEI-2010 component scores and select pregnancy outcomes.

METHODS

The Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be was a prospective pregnancy cohort (US multicenter, 2010-2013). Participants enrolled in the study between 6 and 13 weeks of gestation. An FFQ assessed usual dietary intake 3 months prior to pregnancy (n = 7880). Scores for the HEI-2010 components were assigned using prespecified standards based on densities (standard units per 1000 kcal) of relevant food groups for most components, a ratio (PUFAs and MUFAs to SFAs) for fatty acids, and the contribution to total energy for empty calories. Using binomial regression, we estimated risk differences between each component score and cases of small-for-gestational age (SGA) birth, preterm birth, preeclampsia, and gestational diabetes, controlling for total energy and scores for the other HEI-2010 components.

RESULTS

Higher scores for greens and beans and total vegetables were associated with fewer cases of SGA birth, preterm birth, and preeclampsia. For instance, every 1-unit increase in the greens and beans score was associated with 1.2 fewer SGA infants (95% CI, 0.7-1.7), 0.7 fewer preterm births (95% CI, 0.3-1.1), and 0.7 fewer preeclampsia cases (95% CI, 0.2-1.1) per 100 deliveries. For gestational diabetes, the associations were null.

CONCLUSIONS

Vegetable-rich diets were associated with fewer cases of SGA birth, preterm birth, and preeclampsia, controlling for overall diet quality. Examination of the equal weighting of the HEI components (and underlying guidance) is needed for pregnancy.

Association between pre-conceptional carbohydrate quality index and the incidence of gestational diabetes: the SUN cohort study

The aim of the study was to investigate the association between pre-gestational carbohydrate quality index (CQI) and the incidence of gestational diabetes mellitus (GDM). Data from the 'Seguimiento Universidad de Navarra' (SUN) cohort were used, which includes 3827 women who notified at least one pregnancy between December 1999 and December 2019. We used a validated semi-quantitative 136-item FFQ to evaluate dietary exposures at baseline and at 10-year follow-up. The CQI was defined by four criteria: glycaemic index, whole-grain/total-grain carbohydrate, dietary fibre intake and solid/total carbohydrate ratio. We fitted generalised estimating equations with repeated measurements of the CQI to assess its relationship with incident GDM. A total of 6869 pregnancies and 202 new cases of incident GDM were identified. The inverse association between the global quality of carbohydrate and the development of GDM was not statistically significant: OR the highest v. the lowest CQI category: 0·67, 95 % CI (0·40, 1·10), Pfor trend = 0·10. Participants at the highest CQI category and with daily carbohydrate amounts ≥50 % of total energy intake had the lowest incidence of GDM (OR = 0·29 (95 % CI (0·09, 0·89)) compared with those with the lowest quality (lowest CQI) and quantity (≤40 %). Further studies are needed to overcome the limitations of our study. Those studies should jointly consider the quality and the quantity of dietary carbohydrates, as the quality might be of importance, especially in women with a higher intake of carbohydrates.

Behaviors, Beliefs, and Recommendations to Optimize Promotion of Safe Fish Consumption Before and During Pregnancy: A Physician Survey

INTRODUCTION

Eating fish before and during pregnancy is important but care must be taken to choose fish which maximize developmental outcomes. Physicians, a trusted health information source, could provide this nuanced communication. This cross-sectional survey of a representative sample of 400 family medicine and obstetrics and gynecology (OB-GYN) physicians in Minnesota was designed to understand physician behaviors and beliefs about safe fish consumption, describe barriers to physician-patient conversations about safe fish consumption generally and as part of prenatal care and to identify resources to help facilitate conversations on this topic.

METHODS

Data was collected January to April 2020. Two hundred nineteen surveys were completed (55% response rate) with 194 reporting seeing patients at least 1 day a week. Descriptive survey results from all were summarized and analyzed overall and by physician specialty. Responses to 3 open-ended questions were thematically coded to enrich the quantitative results.

RESULTS

While 62% of these reported discussing nutrition topics, only about one-third reported discussing with patients the benefits and about one-quarter the risks of eating fish. Despite the relative infrequency of fish discussions, almost all (>90%) respondents agreed that it is important to discuss fish consumption with people who are or may become pregnant. The largest reported barrier to these conversations was time (82%), and the most endorsed resource to overcome identified barriers was talking points (72%).

CONCLUSIONS

Because physicians report limited time, resources that facilitate fish consumption should be succinct while serving to both nudge the message and direct clinicians and their patients to robust information.

Association of maternal pre-pregnancy dietary intake with adverse maternal and neonatal outcomes: A systematic review and meta-analysis of prospective studies

This study aimed to summarize the evidence regarding the effects of dietary intake before conception on pregnancy outcomes by performing a systematic review and meta-analysis of prospective studies. Electronic databases were searched from inception up to August 2021. Overall, 65 studies involving 831 798 participants were included and 38 studies were quantitatively pooled. With regard to maternal outcomes, pre-pregnancy intake of fried food, fast food, red and processed meat, heme iron and a low-carbohydrate dietary pattern was positively associated with the risk of gestational diabetes mellitus (GDM) (all P < 0.05). However, a high dietary fiber intake and folic acid supplementation were negatively associated with GDM risk (both P < 0.05). With regard to neonatal outcomes, maternal caffeine intake before pregnancy significantly increased the risk of spontaneous abortion, while folic acid supplementation had protective effects on total adverse neonatal outcomes, preterm birth, and small-for-gestational age (SGA, all P < 0.05). However, no significant associations were found between adverse pregnancy outcomes (i.e., GDM and SGA) and the pre-pregnancy dietary intake of sugar-sweetened beverages, potato, fish, and carbohydrates and the Healthy Eating Index. Our study suggests that maintaining a healthy diet before conception has significant beneficial effects on pregnancy outcomes.Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2021.1989658.

Dietary patterns and cardiometabolic risks in diverse less-developed ethnic minority regions: results from the China Multi-Ethnic Cohort (CMEC) Study

Background In Western developed countries, food-based dietary patterns have been associated with the risk of cardiometabolic diseases, but little is known about such associations in less developed ethnic minority regions (LEMRs), where the cardiometabolic disease burden is growing rapidly and food patterns differ substantially.

Methods Between May 2018 and September 2019, we recruited 99556 participants aged 30-79 years from the China Multi-Ethnic Cohort (CMEC) Study. We measured habitual dietary intake with validated food frequency questionnaire (FFQ) and then calculated dietary pattern scores for two of the most studied a priori dietary patterns, i.e., Dietary Approaches to Stop Hypertension (DASH) and alternative Mediterranean (aMED) style diets, and three a posteriori dietary patterns. Four cardiometabolic risks, including hypertension, diabetes, dyslipidaemia and metabolic syndrome (MetS), were newly diagnosed by medical examination and blood tests. We estimated adjusted odds ratios (OR) relating various dietary pattern scores to cardiometabolic risks using marginal structural models under the guidance of directed acyclic graphs. For the above associations, we further calculated the proportion mediated by overweight (PM) using regression-based mediation analysis for better public health implications.

Findings The final study sample consisted of 68834 participants. Among them, we newly diagnosed 12803 hypertension, 3527 diabetes, 16342 hyperlipidaemia, and 8198 MetS cases. Overall, all 5 dietary patterns showed considerable associations with risks of hypertension and MetS. Comparing the highest with the lowest quintiles, the DASH score showed the strongest inverse associations with risks of hypertension (OR=0.74, 95% CI:0.70-0.79; PM=10%) and MetS (OR=0.79, 95% CI:0.74-0.85; PM=35%); conversely, scores of the localized a posteriori Yunnan-Guizhou plateau dietary pattern in LEMRs showed the strongest positive associations with risks of hypertension (OR=1.44, 95% CI:1.35-1.52; PM=10%) and MetS (OR=1.35, 95% CI:1.26-1.46; PM=33%), with all P values for trend <0.001. These associations were consistent in various subgroups defined by sex, age, smoking and physical activity, but with magnitudes that differed substantially across different ethnic regions and urbanicity. By investigating the single-component effects of dietary patterns, the dairy intake component contributed a major proportion to the beneficial effects of DASH (41.9% for hypertension and 100.5% for MetS).

Interpretation Substantial socioeconomic status and ethnic disparities in diet quality and related cardiometabolic risks were seen in LEMRs, with hypertension being the top diet-related cardiometabolic risk. Our findings support that DASH provides superior dietary guidance compared to aMED for reducing cardiometabolic risks in LEMRs. In particular, the dairy intake encouraged by DASH may produce considerable beneficial effects.

Funding This study was funded by the National Key R&D Program of China; full funding sources listed in the acknowledgements.

Adherence to Mediterranean diet impacts gastrointestinal microbial diversity throughout pregnancy

Background

Consumption of a diet with high adherence to a Mediterranean diet pattern (MDP) has been associated with a favorable gastrointestinal tract (GIT) microbiome. A healthy GIT microbiome in pregnancy, as defined by increased alpha diversity, is associated with lower chance of adverse perinatal outcomes. This study aimed to evaluate the impact of adherence to an MDP on GIT microbial diversity longitudinally throughout pregnancy.

Methods

Adherence to MDP was scored by the Alternate Mediterranean (aMED) Diet Quality Score, after being applied to a validated Food Frequency Questionnaire. Association of aMED Scores with GIT alpha diversity profiles were compared linearly and across time using a linear mixed model, including covariates of age, body mass index (BMI), ethnicity, and parity.

Results

Forty-one participants of Filipino, Japanese, Native Hawaiian, and Non-Hispanic White descent provided dietary information and microbiome samples during each trimester of pregnancy. Alpha diversity profiles changed over gestation, with decreased microbial diversity in the third trimester. aMED scores positively correlated with Chao1 Index and Observed Species Number (r = 0.244, p = 0.017, and r = 0.233, p = 0.023, respectively). The strongest association was detected in the third trimester (Chao 1: r = 0.43, p = 0.020, Observed Species Number: r = 0.41, p = 0.026). Participants with higher aMED scores had higher relative abundance of Acidaminoacaeae at the family level (p = 0.0169), as well as higher abundance of several species known to increase production of short chain fatty acids within the GIT.

Conclusions

Adherence to MDP pattern is associated with increased maternal GIT microbial diversity, and promotes the abundance of bacteria that produce short chain fatty acids. Increased consumption of fruits, vegetables and legumes with low red meat consumption were key components driving this association. The effect of nutrition however, was less of an effect than pregnancy itself. Further studies are needed to determine if adherence to a Mediterranean diet translates not only into microbial health, but also into reduced risk of adverse pregnancy outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-04033-8.

Mediterranean diet adherence and dietary calcium intake in a group of pregnant women: Results of an Italian survey

Pregnancy is a delicate phase in woman's life that could become a risk factor for osteoporosis in pregnant women who do not meet recommended nutrient standards, especially for calcium and vitamin D. Mediterranean diet (MD) has been demonstrated to be beneficial for adequate nutrient intake. This article aims to evaluate the MD adherence and dietary calcium intake in a group of pregnant Italian women and to investigate how these are linked to each other and to fast glycemia at first trimester of pregnancy. Two hundred and seventy-nine pregnant women were recruited at the gynecology units of two hospitals in Florence. Socio-demographic, clinical information, and results of the first trimester blood sample analysis were collected. Two questionnaires, validated for evaluation of MD adherence and calcium intake, were administered to the pregnant women. Approximately 60% of the women had a high level of MD adherence, with a mean dietary calcium intake of 870.3 ± 335.3. In women with higher MD adherence level, fast glycemia resulted lower. Calcium intake was lower than Population Rate Intake for the Italian population (1,200 mg/daily) and was positively correlated to MD adherence score. The MD proved to be nutritious, as it was related to a higher calcium intake in this group of Italian women.

Prevention of Gestational Diabetes: The Role of Dietary Intake, Physical Activity, and Weight before, during, and between Pregnancies

Gestational diabetes mellitus (GDM) is the most common complication of pregnancy and a significant clinical and public health problem with lifelong and intergenerational adverse health consequences for mothers and their offspring. The preconception, early pregnancy, and interconception periods represent opportune windows to engage women in preventive and health promotion interventions. This review provides an overview of findings from observational and intervention studies on the role of diet, physical activity, and weight (change) during these periods in the primary prevention of GDM. Current evidence suggests that supporting women to increase physical activity and achieve appropriate weight gain during early pregnancy and enabling women to optimize their weight and health behaviors prior to and between pregnancies have the potential to reduce rates of GDM. Translation of current evidence into practice requires further development and evaluation of co-designed interventions across community, health service, and policy levels to determine how women can be reached and supported to optimize their health behaviors before, during, and between pregnancies to reduce GDM risk.

Associations of DASH Diet in Pregnancy With Blood Pressure Patterns, Placental Hemodynamics, and Gestational Hypertensive Disorders

Background The Dietary Approaches to Stop Hypertension (DASH) diet improves blood pressure in nonpregnant populations. We hypothesized that adherence to the DASH diet during pregnancy improves hemodynamic adaptations, leading to a lower risk of gestational hypertensive disorders. Methods and Results We examined whether the DASH diet score was associated with blood pressure, placental hemodynamics, and gestational hypertensive disorders in a population-based cohort study among 3414 Dutch women. We assessed DASH score using food-frequency questionnaires. We measured blood pressure in early-, mid-, and late pregnancy (medians, 95% range: 12.9 [9.8-17.9], 20.4 [16.6-23.2], 30.2 [28.6-32.6] weeks gestation, respectively), and placental hemodynamics in mid- and late pregnancy (medians, 95% range: 20.5 [18.7-23.1], 30.4 [28.5-32.8] weeks gestation, respectively). Information on gestational hypertensive disorders was obtained from medical records. Lower DASH score quartiles were associated with a higher mid pregnancy diastolic blood pressure, compared with the highest quartile (P<0.05). No associations were present for early- and late pregnancy diastolic blood pressure and systolic blood pressure throughout pregnancy. Compared with the highest DASH score quartile, the lower DASH score quartiles were associated with a higher mid- and late pregnancy umbilical artery pulsatility index (P≤0.05) but not with uterine artery resistance index. No associations with gestational hypertensive disorders were present. Conclusions A higher DASH diet score is associated with lower mid pregnancy diastolic blood pressure and mid- and late pregnancy fetoplacental vascular function but not with uteroplacental vascular function or gestational hypertensive disorders within a low-risk population. Further studies need to assess whether the effects of the DASH diet on gestational hemodynamic adaptations are more pronounced among higher-risk populations.

Consumption of fat-free dairy products is not associated with a lower risk of maternofetal adverse events

BACKGROUND

The consumption of dairy products in pregnancy is widely extended. However, whether the consumption of low or high fat dairy produce is more beneficial for maternofetal health has yet to be established.

RESEARCH DESIGN AND METHODS

This prospective cohort study evaluated the effect of consumption of dairy products during pregnancy on the frequency of gestational diabetes mellitus (GDM) and a composite of adverse maternofetal outcomes (CMFO). Pregnant women receiving obstetric care between 2014 and 2017 were eligible. Those who consumed ≥3 servings/day of dairy products at 24-28 gestational weeks (GWs) were included and analyzed (n=2004). The population was stratified into three groups according to intake of fat-free dairy products-skimmed milk and fat-free yoghurt and cheese-(days/week): infrequent (1-2), average (3-6) and regular (7). Logistic regression analysis compared ORs (95% CI) for GDM and CMFO between the three groups (where the group of reference was the 'infrequent' intake group).

RESULTS

After adjusting for confounding factors, no significant associations were found between the degree of consumption of fat-free dairy products and the risk of GDM and a CMFO. Moreover, when categorized by the degree of adherence to the Mediterranean diet (above or below the median score), associations were found between the 'regular' intake group and an increased risk of having a CMFO in women with a high adherence to the Mediterranean diet (OR: 1.50; 95% CI: 1.01 to 2.22; p<0.05). Weight gain during pregnancy did not differ among groups.

CONCLUSIONS

The consumption of fat-free dairy products during pregnancy does not seem to be beneficial for maternofetal health.

Cohort Profile: The Dutch Perined-Lifelines birth cohort

BACKGROUND

Maternal nutrition status (e.g. dietary/nutrient intake) during pregnancy has been associated with pregnancy outcomes including birth weight, infant survival and metabolic health of the offspring during later life. During the past few years, maternal dietary intake, at least three months before conception, has been shown to affect pregnancy outcomes also. However, literature investigating this link is still scarce. The studies that have looked at preconception dietary intake in relation to pregnancy outcome were either animal studies, had small sample sizes or focused on only selected macronutrient intake rather than complete (macro)nutrient composition or dietary intakes (e.g. food groups). Therefore, we aim to investigate the association between preconception diet and pregnancy outcomes in a linked birth cohort. The main objective of this manuscript is to describe the methodology of establishing this birth cohort and to describe both the characteristics of the study population included as well as the representativeness in terms of dietary intake.

METHODS

We created the birth cohort by linking two existing databases; a large population-based cohort study in the Netherlands (The Lifelines Cohort study) and the Dutch national birth registry (Perined), through a 'trusted third party'. The birth cohort contains information on maternal dietary intake during preconception as well as pregnancy outcomes.

RESULTS AND DISCUSSION

In the Lifelines Cohort study, 3,418 pregnancies were available for linking with Perined. In total, 2,368 pregnancies (86.9%) were linked with Perined, resulting in the birth cohort. With this linked cohort we are able to provide insights on the associations between dietary intake before conception and pregnancy outcomes. Such data could potentially improve nutritional care for women of childbearing age. Lifestyle changes in the period preceding pregnancy may be most effective in improving pregnancy outcomes. A focus on this window of opportunity may provide both sufficient time, as well as a period when women are potentially motivated to adopt health optimizing behaviours.

Behavioral Determinants of Objectively Assessed Diet Quality in Obese Pregnancy

Interventions to promote healthy pregnancy in women with obesity by improving diet quality have been widely unsuccessful. We hypothesized that diet quality is determined by eating behaviors, but evidence in women with obesity is lacking. We evaluated diet quality and eating behavior in 56 women with obesity (mean ± SEM, 36.7 ± 0.7 kg/m2, 46% White, 50% nulliparous) early in pregnancy (14.9 ± 0.1 weeks). Diet quality was objectively assessed with food photography over six days and defined by Healthy Eating Index. Eating behaviors were assessed by validated questionnaires. Women reported consuming diets high in fat (38 ± 1% of energy) and the HEI was considered "poor" on average (46.7 ± 1.3), and for 71% of women. Diet quality was independently associated with education level (p = 0.01), food cravings (p < 0.01), and awareness towards eating (p = 0.01). Cravings for sweets and fast foods were positively correlated with respective intakes of these foods (p < 0.01 and p = 0.04, respectively), whereas cravings for fruits and vegetables did not relate to diet intake. We provide evidence of the determinants of poor diet quality in pregnant women with obesity. Based on this observational study, strategies to improve diet quality and pregnancy outcomes are to satisfy cravings for healthy snacks and foods, and to promote awareness towards eating behaviors.

Dietary patterns before and during pregnancy and maternal outcomes: a systematic review

BACKGROUND

Hypertensive disorders of pregnancy (HDP) and gestational diabetes mellitus (GDM) are common maternal complications during pregnancy, with short- and long-term sequelae for both mothers and children.

OBJECTIVE

Two systematic review questions were used to examine the relation between 1) dietary patterns before and during pregnancy, 2) HDP, and 3) GDM.

METHODS

A search was conducted from January 1980 to January 2017 in 9 databases including PubMed, Embase, and Cochrane. Two analysts independently screened articles using a priori inclusion and exclusion criteria; data were extracted from included articles, and risk of bias was assessed. After qualitative synthesis, a conclusion statement was drafted for each question and the evidence supporting the conclusion was graded.

RESULTS

Of the 9103 studies identified, 8 [representing 4 cohorts and 1 randomized controlled trial (RCT)] were included for HDP and 11 (representing 6 cohorts and 1 RCT) for GDM. Limited evidence in healthy Caucasian women with access to health care suggests dietary patterns before and during pregnancy that are higher in vegetables, fruits, whole grains, nuts, legumes, fish, and vegetable oils and lower in meat and refined grains are associated with reduced risk of HDP, including preeclampsia and gestational hypertension. Limited but consistent evidence suggests certain dietary patterns before pregnancy are associated with reduced risk of GDM. These protective dietary patterns are higher in vegetables, fruits, whole grains, nuts, legumes, and fish and lower in red and processed meats. Most of the research was conducted in healthy, Caucasian women with access to health care. Insufficient evidence exists on the associations between dietary patterns before and during pregnancy and risk of HDP in minority women and those of lower socioeconomic status, and dietary patterns during pregnancy and risk of GDM.

CONCLUSIONS

Although some conclusions were drawn from these systematic reviews, more research is needed to address gaps and limitations in the evidence.

Can Nurse-Based Management Screening Ensure Adequate Outcomes in Patients With Gestational Diabetes? A Comparison of 2 Organizational Models

BACKGROUND

Gestational diabetes mellitus (GDM) is an impaired glucose tolerance with onset or first recognition during pregnancy. The purpose of this study is to evaluate the clinical outcomes of a blood glucose monitoring protocol implemented by nurses and dietitians in a diabetes team to the previously established protocol of direct monitoring of GDM patients by a diabetologist.

METHODS

Two groups of patients were formed: The first group was based on a traditional protocol (P1: 230 patients) with patients' blood glucose constantly checked by a diabetologist. In the second structured group (P2: 220 patients) patients were referred to a diabetologist only if they required insulin therapy.

RESULTS

The number of medical visits (P2: 1.28 ± 0.70 vs P1: 3.27 ± 1.44; P < .001) and the percentage of patients with hypoglycemia (P2: 6.8% vs P1: 15.2%; P < .006) were found to be lower in group P2 than in group P1. In both groups, a direct relationship was found between a parental history of diabetes and the risk of GDM (odds ratio [OR]: P1 = 2.2 [1.17-4.12]; P2 = 2.5 [1.26-5.12]). In group P1, it was observed that hyperweight gain in patients who were already overweight before becoming pregnant significantly increased the risk of macrosomia (OR: 3.11 [1.39-25.7]), whereas this was not detected in patients in group P2. In group P2, a correlation was found between macrosomia and insulin therapy (OR: 0.066 vs 0.34). In group P1 and group P2, a correlation was observed between insulin therapy and a family history of diabetes (OR: 2.20 vs 2.27), and a body mass index of greater than 30 kg/m in group P2 (OR: 3.0 vs 1.47).

CONCLUSIONS

The data we collected show that creating a structured protocol for GDM management reduces the number of medical visits required by patients without increasing the risk of hypoglycemia, macrosomia, or hyperweight gain during pregnancy.

Maternal dietary patterns and risk of adverse pregnancy (hypertensive disorders of pregnancy and gestational diabetes mellitus) and birth (preterm birth and low birth weight) outcomes: a systematic review and meta-analysis

OBJECTIVE

Epidemiological studies have indicated that dietary patterns during pregnancy are associated with adverse pregnancy and birth outcomes such as hypertensive disorders of pregnancy (HDP), gestational diabetes mellitus (GDM), preterm birth (PTB) and low birth weight (LBW). However, the results of these studies are varied and inconsistent. The present study aimed to assess the association between dietary patterns and the risk of adverse pregnancy and birth outcomes.

DESIGN

Systematic review and meta-analysis. Seven databases were searched for articles. Two reviewers performed the study selection and data extraction. A random-effects model was used to estimate pooled effect sizes of eligible studies.

SETTING

Studies conducted all over the world were incorporated.

SUBJECTS

The review focused on pregnant women.

RESULTS

A total of twenty-one studies were identified. Adherence to a healthy dietary pattern (intake of vegetables, fruits, legumes, whole grains) was significantly associated with lower odds (OR; 95 % CI) of pre-eclampsia (0·78; 0·70, 0·86; I2=39·0 %, P=0·178), GDM (0·78; 0·56, 0·99; I2=68·6 %, P=0·013) and PTB (0·75; 0·57, 0·93; I2=89·6 %, P=0·0001).

CONCLUSIONS

Our review suggests that dietary patterns with a higher intake of fruits, vegetables, legumes, whole grains and fish are associated with a decreased likelihood of adverse pregnancy and birth outcomes. Further research should be conducted in low-income countries to understand the impact of limited resources on dietary intake and adverse pregnancy and birth outcomes.

Associations of Diet and Physical Activity with Risk for Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis

Rising rates of gestational diabetes mellitus (GDM) and related complications have prompted calls to identify potentially modifiable risk factors that are associated with gestational diabetes mellitus (GDM). We systematically reviewed the scientific literature for observational studies examining specific dietary and/or physical activity (PA) factors and risk of GDM. Our search included PubMed, Medline, CINAHL/EBSCO, Science Direct and EMBASE, and identified 1167 articles, of which 40 met our inclusion criteria (e.g., singleton pregnancy, reported diet or PA data during pre-pregnancy/early pregnancy and GDM as an outcome measure). Studies were assessed for quality using a modified Quality Criteria Checklist from American Dietetic Association. Of the final 40 studies, 72% obtained a positive quality rating and 28% were rated neutral. The final analysis incorporated data on 30,871 pregnant women. Dietary studies were categorised into either caffeine, carbohydrate, fat, protein, calcium, fast food and recognized dietary patterns. Diets such as Mediterranean Diet (MedDiet), Dietary Approaches to Stop Hypertension (DASH) diet and Alternate Healthy Eating Index diet (AHEI) were associated with 15–38% reduced relative risk of GDM. In contrast, frequent consumption of potato, meat/processed meats, and protein (% energy) derived from animal sources was associated with an increased risk of GDM. Compared to no PA, any pre-pregnancy or early pregnancy PA was associated with 30% and 21% reduced odds of GDM, respectively. Engaging in >90 min/week of leisure time PA before pregnancy was associated with 46% decreased odds of GDM. We conclude that diets resembling MedDiet/DASH diet as well as higher PA levels before or in early pregnancy were associated with lower risks or odds of GDM respectively. The systematic review was registered at PROSPERO (www.crd.york.ac.uk/PROSPERO) as CRD42016027795.

Before the beginning: nutrition and lifestyle in the preconception period and its importance for future health

A woman who is healthy at the time of conception is more likely to have a successful pregnancy and a healthy child. We reviewed published evidence and present new data from low-income, middle-income, and high-income countries on the timing and importance of preconception health for subsequent maternal and child health. We describe the extent to which pregnancy is planned, and whether planning is linked to preconception health behaviours. Observational studies show strong links between health before pregnancy and maternal and child health outcomes, with consequences that can extend across generations, but awareness of these links is not widespread. Poor nutrition and obesity are rife among women of reproductive age, and differences between high-income and low-income countries have become less distinct, with typical diets falling far short of nutritional recommendations in both settings and especially among adolescents. Several studies show that micronutrient supplementation starting in pregnancy can correct important maternal nutrient deficiencies, but effects on child health outcomes are disappointing. Other interventions to improve diet during pregnancy have had little effect on maternal and newborn health outcomes. Comparatively few interventions have been made for preconception diet and lifestyle. Improvements in the measurement of pregnancy planning have quantified the degree of pregnancy planning and suggest that it is more common than previously recognised. Planning for pregnancy is associated with a mixed pattern of health behaviours before conception. We propose novel definitions of the preconception period relating to embryo development and actions at individual or population level. A sharper focus on intervention before conception is needed to improve maternal and child health and reduce the growing burden of non-communicable diseases. Alongside continued efforts to reduce smoking, alcohol consumption, and obesity in the population, we call for heightened awareness of preconception health, particularly regarding diet and nutrition. Importantly, health professionals should be alerted to ways of identifying women who are planning a pregnancy.

The Mediterranean diet adherence by pregnant women delivering prematurely: association with size at birth and complications of prematurity

Background: The Mediterranean diet (MD) is associated with decreased risk of metabolic syndrome and gestational diabetes due to the anti-inflammatory and antioxidative properties of its components. The aim was to investigate the potential association of MD adherence (MDA) during pregnancy by mothers delivering prematurely, with intrauterine growth as expressed by neonates' anthropometry at birth and complications of prematurity. Participants and methods: This is a single-center, prospective, observational cohort study of 82 women who delivered preterm singletons at post conceptional age (PCA) ≤ 34 weeks and their live-born neonates. Maternal and neonatal demographic and clinical data were recorded. All mothers filled in a food frequency questionnaire, and the MDA score was calculated. Based on 50th centile of MD score, participants were classified into high-MDA and low-MDA groups. Results: The low-MDA mothers had significantly higher pregestational BMI and rates of overweight/obesity (odd ratios (OR) 3.5) and gestational hypertension/preeclampsia (OR 3.8). Neonates in the low-MDA group had significantly higher incidence of intrauterine growth restriction (IUGR) (OR 3.3) and lower z-scores of birth weight and BMI. Regarding prematurity-related complications, the low MDA-group was more likely to develop necrotizing enterocolitis, bronchopulmonary dysplasia, and retinopathy of prematurity (OR 3.2, 1.3, and 1.6, respectively), while they were less likely to develop respiratory distress syndrome (OR 0.49), although the differences were not statistically significant. However, adjustment for confounders revealed MDA as a significant independent predictor of hypertension/preeclampsia, IUGR, birth weight z-score, necrotizing enterocolitis, and bronchopulmonary dysplasia. Conclusions: High MDA during pregnancy may favorably affect intrauterine growth and certain acute and chronic complications of prematurity as well as maternal hypertension/preeclampsia.

Best (but oft-forgotten) practices: mediation analysis

This contribution in the "Best (but Oft-Forgotten) Practices" series considers mediation analysis. A mediator (sometimes referred to as an intermediate variable, surrogate endpoint, or intermediate endpoint) is a third variable that explains how or why ≥2 other variables relate in a putative causal pathway. The current article discusses mediation analysis with the ultimate intention of helping nutrition researchers to clarify the rationale for examining mediation, avoid common pitfalls when using the model, and conduct well-informed analyses that can contribute to improving causal inference in evaluations of underlying mechanisms of effects on nutrition-related behavioral and health outcomes. We give specific attention to underevaluated limitations inherent in common approaches to mediation. In addition, we discuss how to conduct a power analysis for mediation models and offer an applied example to demonstrate mediation analysis. Finally, we provide an example write-up of mediation analysis results as a model for applied researchers.