Systematic review and meta-analysis of energy and macronutrient intakes during pregnancy in developed countries

Early fatty acid exposure and later obesity risk

PURPOSE OF REVIEW

The impact of fatty acids in early nutrition on later body composition and obesity risk remains elusive. Aim of this review was to summarize and discuss recent studies on the role of early supply with long-chain polyunsaturated fatty acids (LCPUFAs) through maternal nutrition during pregnancy and lactation for later offspring obesity.

RECENT FINDINGS

Recent human studies, either interventional or observational, investigating the role of dietary fatty acids, in particular of LCPUFAs, on body composition and later obesity risk provide inconsistent results concerning BMI as well as fat mass development in the offspring. A recent meta-analysis of randomized controlled trials found no significant effect of maternal supplementation with n-3 LCPUFA on BMI in both preschool and school-aged children.

SUMMARY

There is currently no conclusive evidence that dietary intervention to modify fat intake during pregnancy and lactation is a reasonable strategy to prevent childhood obesity in humans, but more research is clearly needed to address this issue.

A review of the impact of dietary intakes in human pregnancy on infant birthweight

Studies assessing maternal dietary intakes and the relationship with birthweight are inconsistent, thus attempting to draw inferences on the role of maternal nutrition in determining the fetal growth trajectory is difficult. The aim of this review is to provide updated evidence from epidemiological and randomized controlled trials on the impact of dietary and supplemental intakes of omega-3 long-chain polyunsaturated fatty acids, zinc, folate, iron, calcium, and vitamin D, as well as dietary patterns, on infant birthweight. A comprehensive review of the literature was undertaken via the electronic databases Pubmed, Cochrane Library, and Medline. Included articles were those published in English, in scholarly journals, and which provided information about diet and nutrition during pregnancy and infant birthweight. There is insufficient evidence for omega-3 fatty acid supplements’ ability to reduce risk of low birthweight (LBW), and more robust evidence from studies supplementing with zinc, calcium, and/or vitamin D needs to be established. Iron supplementation appears to increase birthweight, particularly when there are increases in maternal hemoglobin concentrations in the third trimester. There is limited evidence supporting the use of folic acid supplements to reduce the risk for LBW; however, supplementation may increase birthweight by ~130 g. Consumption of whole foods such as fruit, vegetables, low-fat dairy, and lean meats throughout pregnancy appears beneficial for appropriate birthweight. Intervention studies with an understanding of optimal dietary patterns may provide promising results for both maternal and perinatal health. Outcomes from these studies will help determine what sort of dietary advice could be promoted to women during pregnancy in order to promote the best health for themselves and their baby.

Impact of singlehood during pregnancy on dietary intake and birth outcomes- a study in the Norwegian Mother and Child Cohort Study

Background

Little attention has been given to the impact of singlehood during pregnancy. The aim of this study was to examine the impact of marital status on diet during pregnancy and pregnancy outcome.

Methods

The study population comprised 62,773 women participating in the Norwegian Mother and Child Cohort Study. Marital status was categorised into singles living alone, singles living with parents and married/cohabiting (reference group). Participants answered a general health questionnaire in gestational week 15–17 and a food frequency questionnaire in gestational week 22. We used nonparametric tests to compare dietary intakes by marital status, and multiple logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) for infants being small for gestational age (SGA), large for gestational age (LGA), and preterm delivery (defined as delivery before gestational week 37).

Results

Single women living with parents had lower intakes of fruits and vegetables, higher intake of total energy, higher proportion of energy from added sugar, and lower intake of fibre than the reference group. Singles living alone also had a higher intake of added sugar. In both of the single groups, daily smoking was more prevalent than in women living with a partner. In analyses adjusted for maternal age, pre-pregnancy BMI, energy intake, energy contributed by protein, education, income, parity and nausea, single women living alone had increased risk of SGA with OR = 1.27 (95% CI: 1.05, 1.55). When smoking was included among the confounding variables, the association was no longer significant. Likewise, singles living alone had increased risk of preterm delivery, with OR = 1.32 (95% CI: 1.01, 1.72) in a partly adjusted model, but the association did not remain significant in a model fully adjusted for confounding variables.

Conclusions

Single mothers had lower dietary quality and included more smokers than women who lived with a partner. Single mothers living alone had higher prevalence of SGA and preterm delivery, but the associations with adverse pregnancy outcomes were confounded by other variables. This study shows that single mothers should be given special attention during antenatal care and counselling.

Dietary and health profiles of Spanish women in preconception, pregnancy and lactation

The nutritional status and lifestyle of women in preconception, pregnancy and lactation determine maternal, fetal and child health. The aim of this cross-sectional study was to evaluate dietary patterns and lifestyles according the perinatal physiological status in a large sample of Spanish women. Community pharmacists that were previously trained to collect the data recruited 13,845 women. General information, anthropometric measurements, physical activity, unhealthy habits and dietary data were assessed using a validated questionnaire. Mean values and percentages were used as descriptive statistics. The t-test, ANOVA or chi-squared test were used to compare groups. A score that included dietary and behavioral characteristics was generated to compare lifestyles in the three physiological situations. The analysis revealed that diet quality should be improved in the three stages, but in a different manner. While women seeking a pregnancy only met dairy recommendations, those who were pregnant only fulfilled fresh fruits servings and lactating women only covered protein group requirements. In all cases, the consumption allowances of sausages, buns and pastries were exceeded. Food patterns and unhealthy behaviors of Spanish women in preconception, pregnancy and lactation should be improved, particularly in preconception. This information might be useful in order to implement educational programs for each population group.

First trimester vitamin D status and placental epigenomics in preeclampsia among Northern Plains primiparas

AIMS

As maternal vitamin D status has been associated with preeclampsia, the purpose of this study was to determine variations in DNA methylation patterns and associated protein expression in placental genes regulating vitamin D metabolism.

MAIN METHODS

A convenience sample of 48 pregnant nulliparous women, including 11 later diagnosed with preeclampsia, were recruited in this prospective study. Using a case-control design in two groups of women, we administered a food frequency questionnaire to determine vitamin D dietary intake. Laboratory measures included serum vitamin D levels (25[OH]D), DNA methylation patterns and protein expression in placental genes regulating vitamin D metabolism (1α-hydroxylase, CYP27B1; vitamin D receptor, VDR; retinoid X receptor, RXR) from placental tissue collected at delivery among those diagnosed with preeclampsia and those who remained normotensive throughout pregnancy.

KEY FINDINGS

There were no significant differences in vitamin D dietary intake or mean serum 25[OH]D levels, although the proportion of women with deficient 25[OH]D levels was higher in the preeclampsia group (46%) than the normotensive group (20%). Placenta samples from women with preeclampsia also had increased DNA methylation of CYP27B1, VDR and RXR genes with lower protein expression levels limited to RXR.

SIGNIFICANCE

Hypermethylation of key placental genes involved in vitamin D metabolism suggests uncoupling of processes that may interfere with placentation and availability of vitamin D at the maternal-fetal interface.

Preconception dietary patterns in human pregnancies are associated with preterm delivery

Maternal nutrition can have a profound effect on fetal growth, development, and subsequent infant birth weight. Preconception dietary patterns have not been assessed in relation to perinatal outcomes. The objectives of this study were to identify associations between maternal dietary patterns in the 12 mo before conception on fetal growth and preterm delivery. Preconception food frequency data were collected retrospectively in 309 women. Dietary patterns were derived using factor analysis. Perinatal outcomes were collected at delivery with birth weight data calculated into percentiles to assess small and large for gestational age and preterm delivery at <37 wk. Three dietary patterns were identified: 1) high-protein/fruit (characterized by fish, meat, chicken, fruit, and some whole grains); 2) high-fat/sugar/takeaway (takeaway foods, potato chips, refined grains); and 3) vegetarian-type (vegetables, legumes, whole grains). A 1-SD increase in the scores on the high-protein/fruit pattern was associated with decreased likelihood of preterm birth (adjusted OR: 0.31; 95% CI: 0.13, 0.72; P = 0.007), whereas the reverse direction was apparent for the high-fat/sugar/takeaway pattern (adjusted OR: 1.54; 95% CI: 1.10, 2.15; P = 0.011). A 1-SD increase in the scores on the high fat/sugar/takeaway pattern was also associated with shorter gestation (adjusted regression coefficient: -2.7; 95% CI: -4.3, -1.1; P = 0.001) and birth length (adjusted regression coefficient: -0.5; 95% CI: -0.8, -0.1; P = 0.004). Nutrition before pregnancy is associated with perinatal outcomes. A dietary pattern containing several protein-rich food sources, fruit, and some whole grains is associated with reduced likelihood for preterm delivery, whereas a dietary pattern mainly consisting of discretionary items is associated with preterm delivery, shorter birth length, and earlier gestation. Poor dietary behaviors in the periconceptional period could be altered to promote behavior change in dietary intake to improve perinatal outcomes and the long-term health of the child.

The Maternal Obesity Management (MOM) Trial Protocol: a lifestyle intervention during pregnancy to minimize downstream obesity

BACKGROUND

Maternal obesity and/or high gestational weight gain (GWG) are associated with downstream child obesity. Pregnancy represents a critical period for prevention as women are highly motivated and more receptive to behavior change.

OBJECTIVE

This pilot study was developed to test the feasibility of intervening with the mother, specifically keeping her GWG within the Institute of Medicine (IOM) limits, with the intended target of preventing obesity in her child downstream. We are testing the practicality of delivering a structured physical activity and nutrition intervention to pregnant women during gestation and then following mom and baby to 24 months of age.

STUDY DESIGN

This study is a two-arm, parallel group, randomized controlled trial being conducted in Ottawa. Pregnant women, with pregravid BMI >18.5, between 12 and 20 weeks gestation are randomized to one of two groups: intervention (n=30) who receive the MOM trial Handbook (guide to healthy gestation) plus a structured physical activity and nutrition program, or a standard clinical care control group (n=30). The intervention lasts 25-28 weeks (6 months) depending on anticipated delivery date, with follow-up assessment on mother and child at 3, 6, 12 and 24 months post-delivery.

SIGNIFICANCE

Pregnancy, a critical time of growth, development and physiological change, provides an opportunity for early lifestyle intervention. The goal of identifying an effective lifestyle program for the gestational period that leads to healthy fetal development and subsequently normal weight offspring, less likely to develop obesity and its co-morbidities, is unique and could possibly attenuate the inter-generational cycle of obesity.

Early life nutritional programming of obesity: mother-child cohort studies

BACKGROUND

The obesity epidemic has resulted in more overweight/obese women before and during pregnancy. Their offspring tend to have higher birth weights and more body fat, and carry an increased risk of obesity later in life. These effects may partly be related to the heightened risk of gestational diabetes, occurring in at least 16% of all pregnancies irrespective of current body weight.

METHODS

An ILSI Europe workshop reviewed the key contributors leading to adverse outcomes in pregnancy and childhood, including gestational weight gain and nutrition. New research opportunities from prospective mother-child cohort studies were explored.

RESULTS

Simple measures of gestational weight gain provide insufficient detail of the underlying physiological and metabolic adaptations occurring in pregnancy, and should be complemented by measures of body composition, metabolic and endocrine responses. Recordings of maternal dietary intake and nutrient status are often limited and potential correlations with gestational weight gain have been poorly studied. Many pregnancies in overweight/obese women are uncomplicated and result in offspring of normal weight, leaving the main determinants of later adverse outcomes to be clarified.

CONCLUSIONS

The workshop provided insights of primary measurements for the characterization of sustainable nutritional intervention strategies in the mother, infant and child for preventing obesity in later life.

A systematic review and meta-analysis of micronutrient intakes during pregnancy in developed countries

Micronutrient status during pregnancy influences maternal and fetal health, birth outcomes, and the risk of chronic disease in offspring. Research reporting dietary intake during pregnancy in nationally representative population samples, however, is limited. This review summarizes the micronutrient intakes of pregnant women from developed countries and compares them with relevant national recommendations. A systematic search without date limits was conducted. All studies reporting the micronutrient intakes of pregnant women were considered, irrespective of design. Two authors independently identified studies for inclusion and assessed methodological quality. Nutritional adequacy was summarized, with confounding factors considered. Meta-analysis data are reported for developed countries collectively, by geographical region, and by dietary methodology. Pregnant women in developed countries are at risk of suboptimal micronutrient intakes. Folate, iron, and vitamin D intakes were consistently below nutrient recommendations in each geographical region, and calcium intakes in Japan were below the Japanese recommendations and the average intake levels in other developed countries. Research examining the implications of potential nutrient insufficiency on maternal and offspring health outcomes is needed along with improvements in the quality of dietary intake reporting.

Comparison of national gestational weight gain guidelines and energy intake recommendations

Although data showing adverse effects with high and low gestational weight gain (GWG) come from a large number of countries, a variety of guidelines about the GWG exist. Our objectives were to compare existing GWG and energy recommendations across various countries, as well as the rationale or evidence on which they were based. We used the United Nations' Human Developmental Index to determine the ranking of the country to ensure broad sampling and then searched for guidelines. We first searched the national government websites, and if necessary searched Medline and EMBASE, Global Health databases, and bibliographies of published articles for both guidelines and the studies on which they were based. We found guidelines for 31% of the countries, and 59% of these had a GWG recommendation, 68% had an energy intake recommendation (EIR), and 36% had both. About half of the GWG guidelines are similar to the 2009 American Institutes of Medicine (IOM) and 73% of the EIRs are similar to the 2006 IOM. Despite the documented relationship between both high GWG and adverse outcomes for women and infants and low GWG and adverse outcomes in infants, there are a wide variety of guidelines for GWG and energy recommendations by different countries around the world.

The association between the macronutrient content of maternal diet and the adequacy of micronutrients during pregnancy in the Women and Their Children’s Health (WATCH) study

Nutrition during pregnancy can induce alterations in offspring phenotype. Maternal ratio of protein to non-protein (P:NP) energy has been linked to variations in offspring body composition and adult risk of metabolic disease. This study describes the dietary patterns of pregnant women by tertiles of the P:NP ratio and compares diet to Australian recommendations. Data are from 179 Australian women enrolled in the Women and Their Children's Health Study. Diet was assessed using a validated 74-item food frequency questionnaire. Food group servings and nutrient intakes were compared to the Australian Guide to Healthy Eating and Australian Nutrient Reference Values. Higher maternal P:NP tertile was positively associated with calcium (P = 0.003), zinc (P = 0.001) and servings of dairy (P = 0.001) and meat (P = 0.001) food groups, and inversely associated with the energy dense, nutrient poor non-core (P = 0.003) food group. Micronutrient intakes were optimized with intermediate protein (18%E-20%E), intermediate fat (28%E-30%E) and intermediate carbohydrate (50%E-54%E) intakes, as indicated in tertile two. Results suggest a moderate protein intake may support pregnant women to consume the largest variety of nutrients across all food groups.