Camille Schwartz

Development of healthy eating habits early in life. Review of recent evidence and selected guidelines.

Encouraging healthy eating habit development early in life is a way to prevent the onset of diet-related diseases. This review focuses on the period ranging from the beginning of complementary feeding until the age of 3 years. Its first objective was to review relevant themes in the most recent literature on the development of healthy eating habits in this period. Its second objective was to evaluate to what extent international and national feeding guidelines cover these themes. Analysed guidelines included WHO, European Network for Public Health Nutrition, US and two European national guidelines (UK and France). They were evaluated using a 4-pt scale and compared. Well-covered themes in current literature include the influence of exposure on later acceptance, the role of variety and parental styles. Themes that occur more rarely include the role of texture, the development of autonomy, the optimization of variety, acceptable consumption levels of sweet and salty foods, and the way to cope with food refusal. Guidelines in general cover most of the themes, but some of the national guidelines are incomplete. Finally, guidelines should give more practical tips to parents, especially to help them establish a responsive feeding behaviour.

Variability of human saliva composition: Possible relationships with fat perception and liking

Saliva is the medium that bathes the taste receptors in the oral cavity and in which aroma and taste compounds are released when food is eaten. Moreover saliva contains enzymes and molecules that can interact with food. To date, little research has been devoted to the intra- and inter-individual variabilities of these components and their inter-relationships. The first aim of this work was to study intra- and inter-individual variabilities over time in the composition of molecules likely to interact with food in the mouth, with particular focus on molecules that might interact with fat. The second aim was to try to relate this composition to a liking for fat and its perception. Stimulated and unstimulated saliva from 13 subjects was collected in the morning and afternoon on three occasions at 4-month intervals. Saliva characteristics such as flow, protein concentration, lipolysis, proteolysis, amylolysis, lipocalin concentration, lysozyme activity, total antioxidant status and uric acid concentrations were measured, as well as the liking for and perceived fattiness of a fat solution. The results showed that for most of the measured characteristics, intra-subject variability in saliva composition was smaller than inter-subject variability, with remarkable stability over time (8 months) in terms of flow, lypolysis, proteolysis and total antioxidant status. Relationships were found between some of these characteristics (lipolysis, lipocalin and flow) and fat-liking or perception, showing that the composition of saliva may play an important role in fat perception and liking.

Developmental changes in the acceptance of the five basic tastes in the first year of life.

Taste is a major determinant of childrens food preferences, but its development is incompletely known. Thus, exploring infants acceptance of basic tastes is necessary. The first objective was to evaluate the acceptance of tastes and their developmental changes over the first year. The second objective was to compare acceptance across tastes. The third objective was to evaluate global taste reactivity (within-subject variability of acceptance across tastes). Acceptance of sweet, salty, bitter, sour and umami tastes was assessed in three groups of forty-five 3-, 6- and 12-month-old infants using observations based on ingestion and liking scored by the experimenter. For each taste, four bottles were presented (water, tastant, tastant, water). Acceptance of each taste relative to water was defined using proportional variables based on ingestion or liking. Acceptance over the first year only evolved for sweet taste (marginal decrease) and salty taste (clear increase). At each age, sweet and salty tastes were the most preferred tastes. Reactions to umami were neutral. Sour and bitter tastes were the least accepted ones but rejected only when considering liking data. Ingestion and liking were complementary to assess taste acceptance. However, congruency between these measures rose during the first year. Moreover, with increasing age, reactions were more and more contrasted across tastes. Finally, during the first year, inter-individual variability increased for all tastes except salty taste. By enhancing knowledge of the development of taste acceptance the present study contributes to understand better food behaviour in infancy, the foundation of food behaviour in adulthood.

The role of taste in food acceptance at the beginning of complementary feeding.

Introduction of solid foods is a major step in the establishment of eating behavior and is likely to affect childrens health. However, the role of taste in acceptance of new foods, in particular in the first months of complementary feeding, is not fully understood and was the aim of the present study. Infants had to be in good health to participate (N=74). First, the infants reactions to new foods were recorded by their parents between the ages of 5 and 7 months using a 4-point-scale ranging from very negative to very positive. Taste intensities of infant foods were scored by a trained panel and foods were clustered into groups showing similar taste profiles. Infants reactions were used to calculate new food acceptance (NFA) defined as the average reaction towards a group of foods showing a similar taste profile. Second, preferences for the five basic tastes over water were measured using a 4-bottle test at 6 months old comparing intake of tastant solutions to water. Taste acceptance was evaluated through ingestion ratio (IR=intake of tastant solutions/intake of tastant solutions and water). NFAs were compared across food groups. Kendall correlations were calculated between NFA and IR. Most reactions (88%) to new foods were positive. However, NFA varied according to the taste profile of the foods: vegetables in which salt or a salty ingredient was added were more accepted than plain vegetables (P<0.01). On average no rejection of basic tastes was observed. For sweet, sour and umami tastes, significant positive correlations were observed between NFA and IR. Healthy foods like vegetables could be easily introduced in the diet of most, but not all infants. The role of taste preferences in new food acceptance was highlighted: a higher acceptance for a taste was associated to an enhanced acceptance of foods bearing this taste.

A step-by-step introduction to vegetables at the beginning of complementary feeding. The effects of early and repeated exposure ☆

Breastfeeding (BF) is associated with willingness to accept vegetables. This may be due to the variety of flavours delivered via breast milk. Some mothers add vegetables to milk during complementary feeding (CF) to enhance acceptance. The present study tested a step-by-step exposure to vegetables in milk then rice during CF, on intake and liking of vegetables. Just before CF, enrolled mothers were randomised to an intervention (IG, nu2009=u200918; 6 BF) or control group (CG, nu2009=u200918; 6 BF). IG infants received 12 daily exposures to vegetable puree added to milk (days 1-12), then 12u2009×u20092 daily exposures to vegetable puree added to rice at home (days 13-24). Plain milk and rice were given to CG. Then both received 11 daily exposures to vegetable puree. Intake was weighed and liking rated on days 25-26 and 33-35 after the start of CF in the laboratory, supplemented by the same data recorded at home. Vegetables were rotated daily (carrots, green beans, spinach, broccoli). Intake, liking and pace of eating were greater for IG than CG infants. Intake and liking of carrots were greater than green beans. However, at 6m then 18m follow up, vegetable (carrotu2009>u2009green beans) but not group differences were observed. Mothers reported appreciation of the structure and guidance of this systematic approach. Early exposure to vegetables in a step-by-step method could be included in CF guidelines and longer term benefits assessed by extending the exposure period.

Feeding infants and young children. From guidelines to practice

Following a workshop on infant feeding held at the Rowett Institute of Nutrition and Health, University of Aberdeen on March 17, 2010 experts were invited to exchange ideas and to review evidence on both pre and post natal dietary environments in shaping childrens eating habits. A central theme during the workshop was the idea of sensitive periods during infancy for learning about foods and a particular focus was developed around acceptance and intake of fruits and vegetables. Presentations covered the guidelines provided by various governments on how to feed infants during weaning; the importance of the in utero experience; the impact of varying the sensory experience at weaning; the effect of parenting styles and practices on childrens eating habits; the use of visual experience in promoting intake of vegetables; and reports from mothers regarding their decisions about weaning and the introduction of vegetables. This collection of papers seeks to review guidance from governments on feeding infants and to consider current evidence on parental feeding practices with the aim of enhancing insight into best practice in establishing healthy eating in children.

Salivary protein profiles are linked to bitter taste acceptance in infants

Based on recent studies in adult subjects, saliva composition is increasingly considered as a physiological factor contributing to taste sensitivity or acceptance. In order to evaluate a possible link between salivary protein composition and taste acceptance in infants, 73 infants participated longitudinally in taste acceptance tests and donated saliva at the age at 3 and 6xa0months. Intake ratios, reflecting acceptance of a taste solution relative to water were calculated for the five basic tastes. Salivary proteins were separated by one-dimensional electrophoresis and bands were semi-quantified by image analysis. Partial least square (PLS) regression analyses were performed for each taste at both ages to explain intake ratios by band intensities. Bitterness acceptance in the younger infants was unique in the sense that salivary protein profiles could partly predict bitter taste acceptance. At that age, infants were on average indifferent to the 0.18-M urea solution, but great variability in acceptance was observed. The six bands considered as the best predictors for bitterness acceptance were identified by MALDI-TOF mass spectrometry. Higher abundance of bands containing secretory component, zinc-α-2-glycoprotein and carbonic anhydrase 6 was associated to a lower bitterness acceptance, while higher abundance of bands containing lactoperoxidase, prolactin-inducible protein and S-type cystatins was associated to a higher bitterness acceptance. In a second stage, S-type cystatin abundance was measured by Western blotting in order to tentatively confirm this particular finding in an independent group of 22 infants. Although not reaching statistical significance, probably due to a relatively small sample size, it was again observed that cystatin abundance was higher in infants accepting more readily the bitter solution over water. Conclusion: saliva protein composition may contribute to bitter taste acceptance in the younger infants.

Breast-feeding duration: influence on taste acceptance over the first year of life

Early feeding experiences, e.g. related to milk feeding, can affect later food and taste preferences. However, consequences of breast-feeding on taste acceptance are under-investigated. The objective of the present study was to examine the impact of exclusive breast-feeding duration (DEB) on taste acceptance at 6 and 12 months in the same infants (n 122). Mothers recorded the DEB. Acceptance of solutions of each of the five basic tastes relative to water was evaluated in the laboratory at 6 and 12 months by the ingestion ratio (IR). Kendall correlations were calculated between the DEB and the IR. Only 16 % completed at least 6 months of exclusive breast-feeding; 79 % had begun complementary feeding by 6 months. At 6 months, infants preferred sweet, salty and umami solutions over water and were indifferent to sour and bitter solutions. The longer an infant was breast-fed, the more s/he accepted the umami solution at 6 months. At 12 months, infants preferred sweet and salty solutions over water and were indifferent to sour, bitter and umami solutions. The relationship between the DEB and acceptance of the umami solution was not observed at 12 months. No relationship was observed between the DEB and sweet, salty, sour and bitter taste acceptance at 6 or 12 months. The association between the DEB and umami taste acceptance at 6 months may relate to the higher glutamate content of human milk compared with formula milk. Beyond the acknowledged metabolic benefits of breast-feeding, this suggests that prolonged breast-feeding could also be associated with an impact on sensory preference at the beginning of complementary feeding.

Complementary feeding and “donner les bases du goût” (providing the foundation of taste). A qualitative approach to understand weaning practices, attitudes and experiences by French mothers☆

Complementary feeding (CF) practices vary within and across cultures but have been investigated only to a very limited extent. It is however important to understand CF practices and how they differ, as CF sets the foundation for childrens later food choices. The present study was set out to examine practices, attitudes and experiences of CF including the introduction of vegetables amongst French mothers (n=18, 25-39 years). Thematic analysis of transcribed focus groups and interviews revealed the perceived importance of the weaning period, as a critical milestone for infants development but with a sense of now or never for introducing new tastes including vegetables. Flavour exposure and taste discovery during weaning were identified as the beginning of a taste journey, in which educating the palate with a variety of different foods was considered important for childrens later eating habits. Weaning was described as emotional and complex, a transition period in which the baby makes progress away from milk towards the family diet and which goes beyond mere nutrition. Advice was sought from official sources, but adapted to the needs of infants. In agreement with earlier observations of French adults, pleasure and taste development were considered of primary importance. In particular, French mothers believed complementary feeding lay the foundations of taste early in life.

Smell differential reactivity, but not taste differential reactivity, is related to food neophobia in toddlers.

Previous research has identified relationships between chemosensory reactivity and food neophobia in children. However, most studies have investigated this relationship using declarative data and without separately analysing smell and taste reactivity. Our first objective was to assess the relationships between smell and taste differential reactivity in toddlers (i.e. reactivity towards several stimuli), using experimental behavioural measurements. The second objective was to determine the relationships between smell (or taste) differential reactivity and food neophobia in toddlers, with the hypothesis that the more responsive a toddler was across food odours or tastes, the more neophobic s/he would be. An additional objective was to determine whether the potential relationships between smell (or taste) differential reactivity and food neophobia differ according to gender. One hundred and twenty-three toddlers aged from 20 to 22 months from the Opaline birth cohort (Observatory of Food Preferences in Infants and Children) were involved. A questionnaire was used to assess childs food neophobia. Toddlers differential reactivity for smell (and for taste) was defined as the variability of behavioural responses over 8 odorants, and over the five basic tastes. Smell and taste differential reactivities were not correlated. Food neophobia scores were modestly but significantly positively correlated with smell differential reactivity but not with taste differential reactivity. When gender was considered, smell reactivity and neophobia were correlated only among boys. This indicates the need to study smell and taste reactivity separately to determine their associations with eating behaviours. This suggests that the rejection of novel foods in neophobic boys could be partly due to food odour. This finding is new and clearly requires further investigation.