Long-term flavor recognition in humans with prenatal garlic experience

Does Maternal Diet Influence Future Infant Taste and Odor Preferences? A Critical Analysis

The dietary choices a mother makes during pregnancy offer her developing fetus its earliest exposure to the family's culinary preferences. This comprehensive literature review synthesizes five decades of research, which has provided valuable insights into fetal flavor learning. Converging evidence across various species supports the functionality of fetal chemoreceptive systems by the end of gestation, enabling the detection of an extensive array of chemosensory cues derived from the maternal diet and transmitted to the amniotic fluid. The fetus effectively encodes these flavors, resulting in their enhanced acceptance after birth. While existing studies predominantly concentrate on fetal learning about odor volatiles, limited evidence suggests a capacity for learning about gustatory (i.e., taste) properties. Examining whether these prenatal odor, taste, and flavor experiences translate into enduring shifts in dietary behaviors beyond weaning remains a crucial avenue for further investigation.

Impact of diet on sensory processing in early childhood: summary of an interactive webconference / expert roundtable discussion

Pediatric feeding disorders can be seen in up to 45% of normally developing children aged under 5 years old, mainly during the first three years of life when the child has inadequate food intake and/or difficulty maintaining adequate growth, and/or lack of age-appropriate eating habit. This article describes the opinion of a group of experts on children eating patterns and how to manage pediatric feeding disorders, with the aim to improve the quality of life of children and their caregivers.

Supplementing volatile-flavour herbal-extract mixture to the diet of sows and their weaned offspring improves the growth performance of weaned piglets

A volatile herbal extract (VHE), consisting of 150 g/kg anethole, 15 g/kg bebaudioside A, 2.1 g/kg thymol, 2.0 g/kg eugenol and 2.3 g/kg cinnamic aldehyde, was fed to sows and their weaned offspring to evaluate its effect on the reproductive performance of sows and the growth performance of weaned piglets. A total of 18 sows (Landrace × Yorkshire) were randomly assigned to dietary treatments based on average parity (1.78) with nine replicates per treatment. The feeding period was 35 days, from d 7 before farrowing to d 7 after weaning. The lactation period was 21 d. A total of 96 piglets were randomly selected from each sow treatment group and allocated to 24 replicate pens with four pigs (mixed sex) per pen. The feeding period of weaned piglets was 35 days (phase 1, days 1-7; phase 2, days 8-21; phase 3, days 22-35). Dietary treatments in sows and weaned piglets consisted of a basal control diet with or without 500 mg/kg VHE. The data showed that VHE supplementation had no effect on the reproductive performance of sows, but improved the growth performance of weaned piglets, in which the increase of average daily gain during days 1-7 (P=0.006) and 1-35 (P=0.032) and feed efficiency during days 22-35 (P=0.026) and 1-35 (P=0.020) in weaned piglets were observed. Therefore, supplementing VHE to the diet of sows and their weaned offspring was beneficial to the growth performance of weaned piglets.

Maternal Diet During Pregnancy and Lactation and Child Food Preferences, Dietary Patterns, and Weight Outcomes: a Review of Recent Research

PURPOSE OF REVIEW

Efforts to promote children's preferences for healthy foods hold much potential for improving diet quality and preventing obesity. The purpose of this review was to summarize recent evidence for associations between maternal diet during pregnancy and lactation and child food preferences, dietary patterns, and weight outcomes.

RECENT FINDINGS

Recent research illustrates greater maternal vegetable intakes during pregnancy and lactation predict greater child preferences for and intakes of vegetables. Recent randomized clinical trials to improve maternal weight outcomes during the perinatal period via behavioral lifestyle interventions that included dietary components have yielded mixed findings for effects on child weight outcomes. There is strong evidence that maternal diet during pregnancy and lactation shapes flavor preferences during infancy; more research is needed to understand factors that facilitate versus hinder the translation of these preferences to later dietary patterns and weight outcomes.

First Bites-Why, When, and What Solid Foods to Feed Infants

Humans are the only mammals who feed our young special complementary foods before weaning and we are the only primates that wean our young before they can forage independently. There appears to be a sensitive period in the first several months of life when infants readily accept a wide variety of tastes and this period overlaps with a critical window for oral tolerance. As a result, infants should be exposed to a wide variety of flavors while mother is pregnant, while mother is nursing and beginning at an early age. There also appears to be a sensitive period between 4 and 9 months when infants are most receptive to different food textures. There remains debate about when it is best to begin introducing solid foods into an infant's diet however, the available evidence suggests that provided the water and food supply are free of contamination, and the infant is provided adequate nutrition, there are no clear contraindications to feeding infants complementary foods at any age. There is emerging evidence that introduction of solid foods into an infant's diet by 4 months may increase their willingness to eat a variety of fruits and vegetables later in life, decrease their risk of having feeding problems later in life, and decrease their risk of developing food allergies, and the early introduction of solid foods into an infant's diet does not appear to increase their risk of obesity later in childhood.

Feeding frozen complementary foods promotes food acceptance in infants: The randomized intervention trial Baby Gourmet

Infancy may represent a sensitive window for establishing food preferences that could affect the individual's long-term potential to establish healthy eating patterns. Our study was based on the hypothesis that preserving the natural flavor of the ingredients of commercially prepared complementary foods would increase the acceptance of new foods, especially vegetables. Frozen vegetable-based meals for infants were developed to preserve the natural taste of the ingredients better than sterilization of meals in jars. In a 3-month randomized, controlled intervention study, 51 infants were fed either frozen menus (intervention group) or commercial sterilized meals in jars (control group) on at least 5 days per week. Then the acceptability of a known vegetable-based puree was tested in comparison to an unknown puree, measuring the quantities consumed and also the mother's assessment of the infants' liking. In conclusion, the results of this study clearly indicated that infants fed vegetable-based frozen meals for 3 months accepted a new vegetable better than infants fed sterilized commercial meals in jars.

Effect of Added Sugar on the Consumption of A Lipid-Based Nutrient Supplement Among 7-24-Month-Old Children

Small-quantity lipid-based nutrient supplements (SQ-LNS) could help prevent malnutrition. Our primary objective was to examine the acceptability and consumption of sweetened and unsweetened versions of SQ-LNS before and after 14-days of repeated exposure. A total of 78 mother-infant dyads recruited from health centers in Morelos, Mexico, were randomized to two groups of SQ-LNS (sweetened, LNS-S; unsweetened, LNS-U). During the study, infants were fed SQ-LNS (20 g) mixed with 30 g of complementary food of the caregiver’s choice. The amount of supplement-food mixture consumed was measured before, during and after a 14-day home exposure period. We defined acceptability as consumption of at least 50% of the offered food mixture. At initial exposure, LNS-U consumption was on average 44.0% (95% CI: 31.4, 58.5) and LNS-S 34.8% (25.3, 44.0); at final exposure, LNS-U and LNS-S consumption were 38.5% (27.8, 54.0) and 31.5% (21.6, 43.0). The average change in consumption did not differ between the groups (2.2 p.p. (−17.2, 24.4)). We conclude that the acceptability of sweetened and unsweetened SQ-LNS was low in this study population. Since consumption did not differ between supplement versions, we encourage the use of the unsweetened version given the potential effects that added sugar may have on weight gain especially in regions facing the double burden of malnutrition.

C. elegans aversive olfactory learning generates diverse intergenerational effects

Parental experience can modulate the behavior of their progeny. While the molecular mechanisms underlying parental effects or inheritance of behavioral traits have been studied under several environmental conditions, it remains largely unexplored how the nature of parental experience affects the information transferred to the next generation. To address this question, we used C. elegans, a nematode that feeds on bacteria in its habitat. Some of these bacteria are pathogenic and the worm learns to avoid them after a brief exposure. We found, unexpectedly, that a short parental experience increased the preference for the pathogen in the progeny. Furthermore, increasing the duration of parental exposure switched the response of the progeny from attraction to avoidance. To characterize the underlying molecular mechanisms, we found that the RNA-dependent RNA Polymerase (RdRP) RRF-3, required for the biogenesis of 26 G endo-siRNAs, regulated both types of intergenerational effects. Together, we show that different parental experiences with the same environmental stimulus generate different effects on the behavior of the progeny through small RNA-mediated regulation of gene expression.

From Preconception Care to the First Day of School: Transforming the Health of New Families With Lifestyle Medicine

Lifestyle medicine holds great promise to transform health during the period from preconception to early childhood. Genetic, epigenetic, nutritional, and environmental factors have lifetime impact on the newborn and family. Little is known about the full potential of lifestyle medicine to improve maternal, child, and family health. Additionally, health care providers face limits in time and may have gaps in knowledge, that preclude discussion of the impact lifestyle medicine can the mother, newborn, and family. Greater understanding of the potential impact of lifestyle medicine provides opportunities to identify current deficiencies in care and areas for improvement and highlights the need for further research. This article reviews current evidence supporting the 6 pillars of lifestyle medicine: nutrition, physical activity, sleep, avoiding risky substance use, stress management and social connectedness as applied to maternal child care from preconception to early childhood, examines the current state of practice, and identifies opportunities for both practice change and further research. Rather than view each component of care in isolation, viewing care as a continuum from preconception to childhood can best establish healthy habits and optimize outcomes for the entire family.

Olfaction scaffolds the developing human from neonate to adolescent and beyond

The impact of the olfactory sense is regularly apparent across development. The fetus is bathed in amniotic fluid (AF) that conveys the mother's chemical ecology. Transnatal olfactory continuity between the odours of AF and milk assists in the transition to nursing. At the same time, odours emanating from the mammary areas provoke appetitive responses in newborns. Odours experienced from the mother's diet during breastfeeding, and from practices such as pre-mastication, may assist in the dietary transition at weaning. In parallel, infants are attracted to and recognize their mother's odours; later, children are able to recognize other kin and peers based on their odours. Familiar odours, such as those of the mother, regulate the child's emotions, and scaffold perception and learning through non-olfactory senses. During juvenility and adolescence, individuals become more sensitive to some bodily odours, while the timing of adolescence itself has been speculated to draw from the chemical ecology of the family unit. Odours learnt early in life and within the family niche continue to influence preferences as mate choice becomes relevant. Olfaction thus appears significant in turning on, sustaining and, in cases when mother odour is altered, disturbing adaptive reciprocity between offspring and carer during the multiple transitions of development between birth and adolescence. This article is part of the Theo Murphy meeting issue 'Olfactory communication in humans'.

Effect of environmental exposure to a maternally-learned odorant on anxiety-like behaviors at weaning in mice

Early sensory experience, such as exposure to maternal or other environmental factors, is considered to influence neurocognitive development and behaviors. In many species, exposure to odorants during pregnancy or lactation impacts the morpho-functional development of the olfactory circuitry with changes in olfactory sensitivity, feeding behavior and food preferences at birth or later. However, few studies have investigated the impact of a perinatal exposure to odorants on the anxiety-like behavior of animals to stressfull stimuli. Here, we exposed mice to heptaldehyde (HEP) during pregnancy and lactation and measured the anxiety-like behavior of their offspring to stress-inducing novel stimuli at weaning in presence or absence of odorants. We applied a combined social and maternal separation as a stressor and measured the anxiety-like behavior in an open field (OF) in presence of two odorants, HEP or α-pinene (AP) as a control odorant. Although the presence of the odorant during the social separation did not influence anxiety-like behavior, we found that, if mice born to non-odorized mothers exhibited a decreased exploratory behavior in the presence of both odorants, the effect was restricted to AP for the mice perinatally exposed to HEP. These results show that anxiety-like behaviors during a stress-inducing event could be reduced by the presence of a familiar odorant. We propose that the recall of an early olfactory experience could contribute to the improvement of animal welfare in various situations associated with husbandry practices.

A new look at early exposure to the flavors of the available vegetables as foundational mechanism of vegetable consumption habits and recipes of vegetables-based dishes

The flavor of the maternal diet is transferred to women's amniotic fluid and breast milk, so that the amniotic fluid and breast milk become natural transmitters of flavor-related information developing babies are exposed to at early stages of development. We aimed to review the available evidence regarding the impact of early exposure to flavor on child vegetable intake, and to discuss for the first time possible effects of availability or unavailability of particular vegetables because of geographic reasons on these exposures, a variable that has been forgotten in the literature. We have focused on studies that have examined the association of prenatal and early postnatal -at breastfeeding- exposures to vegetable-related flavors with vegetable consumption in children. We have identified that this particular kind of exposures may lead to increases in children's acceptance, liking of and preference for the vegetables. Especially novel has been to identify that these effects might be modulated not only by the particular flavor of the vegetable -bitter vs. sweet- and the time of exposure -prenatal vs. breastfeeding- but also by vegetable availability because of geographic reasons of the place of residence of the mother, a variable that should be taken into account in future research. This would give rise to a new research line aimed at solving the mentioned gap. Finally, a theoretical model of cyclical processes that might explain the origin and perpetuation of transmission of particular patterns of vegetable consumption and vegetables-composed dishes over time in a given population is also included here as another new contribution.

Weanling Infants Prefer the Odors of Green Vegetables, Cheese, and Fish When Their Mothers Consumed These Foods During Pregnancy and/or Lactation

Infants' olfactory experience begins before birth and extends after birth through milk and complementary foods. Until now, studies on the effects of chemosensory experience in utero and/or through human milk focused on experimentally controlled exposure to only 1 target food bearing a specific odor quality and administered in sizeable amounts. This study aimed to assess whether early olfactory experience effect was measurable in "everyday conditions" of maternal food intake during pregnancy and lactation, and of infant intake at weaning, leading to expose the infant to corresponding odors as fetus, neonate, and infant up to 8 and 12 months of age. Infants' early food exposures were assessed by asking mothers to fill out diaries about their food consumption during pregnancy and breastfeeding, and about their infant's consumption during complementary feeding. To test odor liking, odorants representing a priori pleasant and unpleasant food odors, as well as odorless stimuli, were presented. The infant's exploratory behavior toward odorized bottles and nonodorized control bottles was measured in terms of mouthing duration, which is thought to reflect attraction and/or appetence. At age 8 months only, positive correlations were found between liking of some unpleasant odors and early exposure to these odors through mother's diet. No correlations were found between infants' liking of the pleasant odors and early exposures to the foods bearing these odors. This study highlights that early exposure to unpleasant food odors may increase subsequent liking (or reduce subsequent dislike) of these food odors at least until the age of 8 months.

[Breastfeeding and potential sensory imprinting]

Breastmilk provides well-known nutritional and functional advantages and in addition a greater sensory variety as compared to infant formula. Volatile and soluble sensory components from the mother's diet are transmitted prenatally into the amniotic fluid and postnatally into breastmilk and can be detected by the fetus and infant. Breastfeeding is suggested to serve as a bridge from prenatal flavor experiences to the varied sensory world of complementary feeding and family diet afterwards. Nevertheless definite data to prove this plausible assumption are still missing. Randomized intervention trials with a necessary long-term follow-up are difficult to implement and rarely achieved. Lasting effects of early sensory experiences have so far been demonstrated mostly in the first year of life and by applying intensive sensory interventions, which are hardly possible in a habitual maternal diet. The practical relevance of a potential sensory imprinting by breastfeeding still remains open. Nevertheless a varied diet in pregnancy and lactation can be recommended not only for nutritional reasons but also from a hedonic sensory perspective.

Correlation between human nervous system development and acquisition of fetal skills: An overview

Understanding the association between fetal nervous system structure and functioning should be an important goal in neurodevelopmental sciences, especially when considering the emerging knowledge regarding the importance of prenatal onset. Intrauterine development of the human central nervous system consists of specific processes: neurogenesis, neuronal migration, synaptogenesis, and myelination. However, as extensively shown by the neurobehavioral studies in the last century, the development of the central nervous system involves both structure and functioning. It is now recognised that the developing motor and sensory systems are able to function long before they have completed their neural maturation and that the intrauterine experience contributes to neurobehavioral development. This review analyzes the recent literature, looking at the association between the human nervous system maturation and fetal behavior. This article will follow the development and skill acquisition of the anatomical nervous system across the three trimesters of the gestation period.

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.

Chemical Identification of "Maternal Signature Odors" in Rat

Newborn altricial mammals need just after birth to locate their mother's nipples for suckling. In this precocious behavior, including for the human baby, maternal odor via the olfactory process plays a major role. Maternal odor emitted by lactating females or by amniotic fluid (AF) attracts pups, but the chemical identity of this attractant has not yet been elucidated. Here, using behavioral tests and gas chromatography coupled with mass spectrometry (GC-MS) techniques, we show that AF extracts from rat pregnant female, nipples, ventral skin, milk, and nest extracts of mother contained 3-6 active substances. AF extracts contained 3 active compounds: ethylbenzene, benzaldehyde, and benzyl alcohol, and their mixture in similar proportions to those found in AF extracts, in a ratio, respectively, of 1:1:12 (700 ng), attracts pups as putative maternal attractant substances (MAS). These 3 AF substances have already been identified in milk, nipples, ventral wash, and nest extracts of mother, but not in feces. Moreover, anethole flavor incorporated in pregnant rat and mother's diet is also detected in AF, nipples, milk, and nest extracts and the pups are attracted to anethole odor, but not in the case of the no-anethole pups. MAS, combined with diet flavors present in the AF bath, represent olfactory signals as "maternal signature odors" (MSO) that are learned by fetus and pups. These findings open the way to improved understanding of the neurobiology of early olfactory learning and of the importance of evolutionarily conserved survival behavior in many mammal species.

Pre-birth sense of smell in the wild boar: the ontogeny of the olfactory mucosa

Animals recognize their surrounding environments through the sense of smell by detecting thousands of chemical odorants. Wild boars (Sus scrofa) completely depend on their ability to recognize chemical odorants: to detect food, during scavenging and searching partners, during breeding periods and to avoid potential predators. Wild piglets must be prepared for the chemical universe that they will enter after birth, and they show intense neuronal activity in the olfactory mucosa. With this in mind, we investigated the morpho-functional embryonic development of the olfactory mucosa in the wild boar (in five stages before birth). Using mRNA expression analysis of olfactory marker protein and neuropeptide Y, involved in the function of olfactory sensory neurons, we show early activation of the appropriate genes in the wild boar. We hypothesize olfactory pre-birth development in wild boar is highly adaptive.

The Lasting Influences of Early Food-Related Variety Experience: A Longitudinal Study of Vegetable Acceptance from 5 Months to 6 Years in Two Populations

Children's vegetable consumption falls below current recommendations, highlighting the need to identify strategies that can successfully promote better acceptance of vegetables. Recently, experimental studies have reported promising interventions that increase acceptance of vegetables. The first, offering infants a high variety of vegetables at weaning, increased acceptance of new foods, including vegetables. The second, offering an initially disliked vegetable at 8 subsequent meals markedly increased acceptance for that vegetable. So far, these effects have been shown to persist for at least several weeks. We now present follow-up data at 15 months, 3 and 6 years obtained through questionnaire (15 mo, 3y) and experimental (6y) approaches. At 15 months, participants who had been breast-fed were reported as eating and liking more vegetables than those who had been formula-fed. The initially disliked vegetable that became accepted after repeated exposure was still liked and eaten by 79% of the children. At 3 years, the initially disliked vegetable was still liked and eaten by 73% of the children. At 6 years, observations in an experimental setting showed that children who had been breast-fed and children who had experienced high vegetable variety at the start of weaning ate more of new vegetables and liked them more. They were also more willing to taste vegetables than formula-fed children or the no or low variety groups. The initially disliked vegetable was still liked by 57% of children. This follow-up study suggests that experience with chemosensory variety in the context of breastfeeding or at the onset of complementary feeding can influence chemosensory preferences for vegetables into childhood.

Early Eating Behaviours and Food Acceptance Revisited: Breastfeeding and Introduction of Complementary Foods as Predictive of Food Acceptance

Current dietary advice for children is that they should eat at least five portions of fruit and vegetables a day (Department of Health. National Diet and Nutrition Survey, 2014). However, many parents report that children are reluctant to eat vegetables and often fail to comply with the five-a-day rule. In fact, in surveys carried out in areas in the UK, the number of children eating according to the five-a-day rule has been found to be as low as 16 % (Cockroft et al. Public Health Nutr 8(7):861-69, 2005). This narrative review looks at those factors which contribute to food acceptance, especially fruit and vegetables, and how acceptance might be enhanced to contribute to a wider dietary range in infancy and later childhood. The questions we address are whether the range of foods accepted is determined by the following: innate predispositions interacting with early experience with taste and textures, sensitive periods in infancy for introduction, breastfeeding and the pattern of introduction of complementary foods. Our conclusions are that all of these factors affect dietary range, and that both breastfeeding and the timely introduction of complementary foods predict subsequent food acceptance.

Impacts of in utero and early infant taste experiences on later taste acceptance: a systematic review

BACKGROUND

Dietary behavior exerts a critical influence on health and is the outcome of a broad range of interacting factors, including food and taste acceptance. These may be programmed in utero and during early infancy.

OBJECTIVE

We examined the hypothesis that fetuses and infants exposed to sweet, salty, sour, bitter, umami, or specific tastes show greater acceptance of that same taste later in life.

METHODS

We conducted a systematic review of the literature, using comprehensive searches and following established procedures for screening, data extraction, and quality appraisal. We used harvest plots to synthesize the evidence graphically.

RESULTS

Twenty studies comprising 38 subgroups that differed by taste, age, medium, and duration of exposure were included. Exposure to bitter and specific tastes increased the acceptance of these tastes. Studies on sweet and salty tastes showed equivocal results. Studies on sour tastes were sparse.

CONCLUSION

Our systematic review clearly shows programming of the acceptance of bitter and specific tastes. For other tastes the results were either equivocal or confined to a few number of studies that precluded us from drawing conclusions. Further research should examine the association of salty and sour taste exposures on later preferences of these tastes. Long-term studies and randomized clinical trials on each type of taste are needed.

Eye-catching odors: olfaction elicits sustained gazing to faces and eyes in 4-month-old infants

This study investigated whether an odor can affect infants' attention to visually presented objects and whether it can selectively direct visual gaze at visual targets as a function of their meaning. Four-month-old infants (n = 48) were exposed to their mother's body odors while their visual exploration was recorded with an eye-movement tracking system. Two groups of infants, who were assigned to either an odor condition or a control condition, looked at a scene composed of still pictures of faces and cars. As expected, infants looked longer at the faces than at the cars but this spontaneous preference for faces was significantly enhanced in presence of the odor. As expected also, when looking at the face, the infants looked longer at the eyes than at any other facial regions, but, again, they looked at the eyes significantly longer in the presence of the odor. Thus, 4-month-old infants are sensitive to the contextual effects of odors while looking at faces. This suggests that early social attention to faces is mediated by visual as well as non-visual cues.