Learning to like vegetables during breastfeeding: a randomized clinical trial of lactating mothers and infants

Influence of maternal diet on flavor transfer to amniotic fluid and breast milk and children's responses: a systematic review

BACKGROUND

Maternal diet during pregnancy and lactation may provide the earliest opportunity to positively influence child food acceptance.

OBJECTIVE

Systematic reviews were completed to examine the relation among maternal diet during pregnancy and lactation, amniotic fluid flavor, breast-milk flavor, and children's food acceptability and overall dietary intake.

DESIGN

A literature search was conducted in 10 databases (e.g., PubMed, Embase, Cochrane, and CINAHL) to identify articles published from January 1980 to June 2017. Data from each included study were extracted, risk of bias assessed, evidence synthesized qualitatively, conclusion statements developed, and strength of the evidence graded.

RESULTS

Eleven and 15 articles met a priori criteria for inclusion to answer questions related to maternal diet during pregnancy and lactation, respectively.

CONCLUSIONS

Limited but consistent evidence indicates that flavors (alcohol, anise, carrot, garlic) originating from the maternal diet during pregnancy can transfer to and flavor amniotic fluid, and fetal flavor exposure increases acceptance of similarly flavored foods when re-exposed during infancy and potentially childhood. Moderate evidence indicates that flavors originating from the maternal diet during lactation (alcohol, anise/caraway, carrot, eucalyptus, garlic, mint) transmit to and flavor breast milk in a time-dependent manner. Moderate evidence indicates that infants can detect diet-transmitted flavors in breast milk within hours of a single maternal ingestion (alcohol, garlic, vanilla, carrot), within days after repeated maternal ingestion (garlic, carrot juice), and within 1-4 mo postpartum after repeated maternal ingestion (variety of vegetables including carrot) during lactation. Findings may not generalize to all foods and beverages. Conclusions cannot be drawn to describe the relationship between mothers' diet during either pregnancy or lactation and children's overall dietary intake.

Repeated exposure and conditioning strategies for increasing vegetable liking and intake: systematic review and meta-analyses of the published literature

Background

Vegetable intakes are typically lower than recommended for health. Although repeated exposure has been advocated to increase vegetable liking and consumption, no combination of the evidence yet provides a measure of benefit from repeated exposure or alternative conditioning strategies.

Objective

This work aimed to identify and synthesize the current evidence for the use of repeated exposure and conditioning strategies for increasing vegetable liking and consumption.

Design

Three academic databases were searched over all years of records using prespecified search terms. Published data from all suitable articles were tabulated in relation to 3 research questions and combined via meta-analyses.

Results

Forty-three articles detailing 117 comparisons investigating the use of repeated exposure and conditioning strategies for increasing liking and intakes of vegetables were found. Our analyses demonstrate: 1) increased liking and intakes of the exposed vegetable after repeated exposure compared with no exposure; 2) increased liking for the exposed vegetable after conditioning compared with repeated exposure, increased intakes after the use of rewards, and some suggestion of decreased intakes after flavor-nutrient conditioning; and 3) increased liking and intakes of a novel vegetable after repeated exposure to a variety of other vegetables compared with no exposure or repeated exposure to one other vegetable. Effect sizes, however, are small, and limited evidence suggests long-term benefits. Our analyses, furthermore, are limited by limitations in study design, compliance, and/or reporting.

Conclusions

Based on our findings, we recommend the use of repeated exposure to one and a variety of vegetables, and the use of rewards, for increasing vegetable liking and consumption. Confirmation from further large, well-conducted studies that use realistic scenarios, however, is also required. This study was registered at PROSPERO as CRD42017056919.

Duration of exclusive breastfeeding may be related to eating behaviour and dietary intake in obesity prone normal weight young children

Infants who are breastfed are introduced to a variety of flavours from the maternal milk, and thus the transition from maternal milk to complementary foods may be easier for these children. The aim of this study was to investigate if duration of exclusive breastfeeding was associated with pickiness or dietary intake of vegetables, fruit, starchy foods or sugar sweetened beverages among obesity prone normal weight children aged 2–6 years. This cohort study was based on data from the Healthy Start primary intervention study, the Danish Medical Birth registry and the Danish Health Visitor’s Child Health Database. Infant feeding was registered by health nurses while home-visiting the mother and child up to four times within the first year. Information on eating behaviour and diet intake at age 2–6 years was obtained by parents. Crude and adjusted logistic and general linear regression models were used to investigate associations. A total of 236 children had complete information on all variables. Data showed lower odds of picky eating behaviour when exclusively breastfed until age 4–5 months compared to exclusively breastfed for 0–1 months (OR = 0.35, 95CI = 0.16;0.76, p = 0.008). In the crude analysis only, exclusively breastfed until age 6–10 months was associated with a higher daily intake of vegetables (p = 0.04). This study suggests that exclusive breastfeeding duration seems to influence pickiness and may contribute to facilitate the consumption of more vegetables in later childhood in obesity prone normal weight children.

Interventions for increasing fruit and vegetable consumption in children aged five years and under

BACKGROUND

Insufficient consumption of fruits and vegetables in childhood increases the risk of future non-communicable diseases, including cardiovascular disease. Interventions to increase consumption of fruit and vegetables, such as those focused on specific child-feeding strategies and parent nutrition education interventions in early childhood may therefore be an effective strategy in reducing this disease burden.

OBJECTIVES

To assess the effectiveness, cost effectiveness and associated adverse events of interventions designed to increase the consumption of fruit, vegetables or both amongst children aged five years and under.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase and two clinical trials registries to identify eligible trials on 25 January 2018. We searched Proquest Dissertations and Theses in November 2017. We reviewed reference lists of included trials and handsearched three international nutrition journals. We contacted authors of included studies to identify further potentially relevant trials.

SELECTION CRITERIA

We included randomised controlled trials, including cluster-randomised controlled trials and cross-over trials, of any intervention primarily targeting consumption of fruit, vegetables or both among children aged five years and under, and incorporating a dietary or biochemical assessment of fruit or vegetable consumption. Two review authors independently screened titles and abstracts of identified papers; a third review author resolved disagreements.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the risks of bias of included studies; a third review author resolved disagreements. Due to unexplained heterogeneity, we used random-effects models in meta-analyses for the primary review outcomes where we identified sufficient trials. We calculated standardised mean differences (SMDs) to account for the heterogeneity of fruit and vegetable consumption measures. We conducted assessments of risks of bias and evaluated the quality of evidence (GRADE approach) using Cochrane procedures.

MAIN RESULTS

We included 63 trials with 178 trial arms and 11,698 participants. Thirty-nine trials examined the impact of child-feeding practices (e.g. repeated food exposure) in increasing child vegetable intake. Fourteen trials examined the impact of parent nutrition education in increasing child fruit and vegetable intake. Nine studies examined the impact of multicomponent interventions (e.g. parent nutrition education and preschool policy changes) in increasing child fruit and vegetable intake. One study examined the effect of a nutrition education intervention delivered to children in increasing child fruit and vegetable intake.We judged 14 of the 63 included trials as free from high risks of bias across all domains; performance, detection and attrition bias were the most common domains judged at high risk of bias for the remaining studies.There is very low quality evidence that child-feeding practices versus no intervention may have a small positive effect on child vegetable consumption equivalent to an increase of 3.50 g as-desired consumption of vegetables (SMD 0.33, 95% CI 0.13 to 0.54; participants = 1741; studies = 13). Multicomponent interventions versus no intervention may have a very small effect on child consumption of fruit and vegetables (SMD 0.35, 95% CI 0.04 to 0.66; participants = 2009; studies = 5; low-quality evidence), equivalent to an increase of 0.37 cups of fruit and vegetables per day. It is uncertain whether there are any short-term differences in child consumption of fruit and vegetables in meta-analyses of trials examining parent nutrition education versus no intervention (SMD 0.12, 95% CI -0.03 to 0.28; participants = 3078; studies = 11; very low-quality evidence).Insufficient data were available to assess long-term effectiveness, cost effectiveness and unintended adverse consequences of interventions. Studies reported receiving governmental or charitable funds, except for four studies reporting industry funding.

AUTHORS' CONCLUSIONS

Despite identifying 63 eligible trials of various intervention approaches, the evidence for how to increase children's fruit and vegetable consumption remains limited. There was very low- and low-quality evidence respectively that child-feeding practice and multicomponent interventions may lead to very small increases in fruit and vegetable consumption in children aged five years and younger. It is uncertain whether parent nutrition education interventions are effective in increasing fruit and vegetable consumption in children aged five years and younger. Given that the quality of the evidence is very low or low, future research will likely change estimates and conclusions. Long-term follow-up is required and future research should adopt more rigorous methods to advance the field.This is a living systematic review. Living systematic reviews offer a new approach to review updating, in which the review is continually updated, incorporating relevant new evidence as it becomes available. Please refer to the Cochrane Database of Systematic Reviews for the current status of this review.

The Development and Public Health Implications of Food Preferences in Children

Food preferences are a primary determinant of dietary intake and behaviors, and they persist from early childhood into later life. As such, establishing preferences for healthy foods from a young age is a promising approach to improving diet quality, a leading contributor to cardiometabolic health. This narrative review first describes the critical period for food preference development starting in utero and continuing through early childhood. Infants’ innate aversion to sour and bitter tastes can lead them to initially reject some healthy foods such as vegetables. Infants can learn to like these foods through exposures to their flavors in utero and through breastmilk. As solid foods are introduced through toddlerhood, children’s food preferences are shaped by parent feeding practices and environmental factors such as food advertising. Next, we discuss two key focus areas to improve diet quality highlighted by the current understanding of food preferences: (1) promoting healthy food preferences through breastfeeding and early exposures to healthy foods and (2) limiting the extent to which innate preferences for sweet and salty tastes lead to poor diet quality. We use an ecological framework to summarize potential points of intervention and provide recommendations for these focus areas, such as worksite benefits that promote breastfeeding, and changes in food retail and service environments. Individuals’ choices around breastfeeding and diet may ultimately be influenced by policy and community-level factors. It is thus crucial to take a multilevel approach to establish healthy food preferences from a young age, which have the potential to translate into lifelong healthy diet.