Sensitive period for introducing solid foods-

Children are best breast fed until at least a year and supplemented with solids. At times by months the child may not want breast milk, one must learn to follow the lead of the child. Prevention of feeding problems is essential when children get to the toddler phase and may often get picky with their food. There is ideally a good variety and positive experience with food for the child. Tags: Sensitive Periods.

Sensitive period for introducing solid foods

Sensitive period for introducing solid foods

Sensitive period for introducing solid foods

Sensitive period for introducing solid foods

Sensitive period for introducing solid foods

However, in an adult, the motivation Arginine and sexual performance try a new taste may be the defining characteristic determining whether or not that taste or taste modification is accepted. Dijon France ; p. What can i do to stop this habit? Several studies have been conducted to investigate the link Sensitive period for introducing solid foods sensitivity to PTC or PROP and the liking or consumption of bitter vegetables. A food variety index for toddlers VIT : development and application. Early work carried out on inroducing acceptance of tastes in food Sensitige that there was fot easy acceptance for a salt taste if this was added to a tasteless rice base and that this acceptance was dependent upon number of exposures rather than the amount eaten pdriod 1213 ]. Complementary feeding strategies to facilitate acceptance of fruits and vegetables: a narrative review of the literature. The oral development is of course function of the child age but would also depend on previous experience with different textures. Early Hum Devel. Tube feeding in infancy: implications for the development of normal eating and drinking skills.

Slow motion cums shots. Introduction: Sensitive Periods and Critical Periods in Development

We also found Spanish-speaking Latino mothers had the lowest rates of late introduction. With that understanding in mind, what else does the evidence tell us about introducing solids to babies? Should I introduce high-allergen foods Street boys cash sex my child while at the doctor's office, in case she has a bad reaction? On chi-squared tests for multiway contingency tables with cell proportions estimated from survey data. Then try again tomorrow. Breastfeeding and experience with variety early in weaning increase infantsacceptance of new foods for Sensitive period for introducing solid foods to two months. Effect of food texture on the development of chewing of children between six months and two years of age. Top of Page. So that's the argument for targeting the month time window: It might minimize your baby's risk of developing allergies, and reduce your child's risk of becoming fussy about food Harris and Mason You can look for these signs that your child is developmentally ready:. Spit-up is quite common and Sensitive period for introducing solid foods to be a symptom of an allergy. A step-by-step introduction to vegetables at the beginning of complementary feeding.

A sensitive period in development is one in which it is easier for learning to take place; the behaviour can however still be learned at a later stage, but with more difficulty.

  • Current dietary advice for children is that they should eat at least five portions of fruit and vegetables a day Department of Health.
  • For more information about how to know if your baby is ready to starting eating foods, what first foods to offer, and what to expect, watch these videos from 1, Days.
  • If I wait longer to introduce my baby to solid foods, will she be less likely to develop a food allergy?
  • Introducing solid foods to your baby is a messy, amusing, and sometimes frustrating business.

Children are best breast fed until at least a year and supplemented with solids. At times by months the child may not want breast milk, one must learn to follow the lead of the child. Prevention of feeding problems is essential when children get to the toddler phase and may often get picky with their food.

There is ideally a good variety and positive experience with food for the child. Tags: Sensitive Periods. I believe the information provided is just a bit outdated. Cows milk should not be given in place of mothers milk. That was the routine suggestion and now after more research we have learned this is not ideal. Also, I disagree that children cannot be independent while being dependent on mothers milk.

They form a secure attachment and they get a ton of good nutrition and anti bodies to fight off sickness. There are many indigenous people who practice extended nursing and their children are not dependent people who cannot find their independence.

Nursing has long been attacked in our culture and it needs to stop. For the health of our children and our mothers. In my personal experience my child weaned on their own at 2y4m with no pressure from me. In fact research suggests most children will wean around 2. Again, just new information after more research has been done. Our old beliefs need to be reconsidered in light of new research. Toddlers thrive on routines, so I would imagine it would be very difficult for a two-year-old child to suddenly decide that it is time to stop a part of their daily routine- especially one as special as breastfeeding.

I feel that breast milk does have amazing properties for a young child primarily the omega 3 to omega 6 ratio that is not found in many solid foods , and perhaps, a child should be given breast milk in a glass if the mother feels the child needs it nutritionally to balance out their diet, but I am certain that a child would not be happy about a change to a schedule that is so intimate as breastfeeding at the age of two. This is why I feel it is best to follow the WHO guidelines and Montessori Method, which suggests weaning or providing solid foods for texture and nutrition at around six months while slowly diminishing breast milk as the solitary food until about age 1 give or take.

By that time, most fruits and vegetables and some animal protein can be successfully digested by the child. He may drink anything in a glass ; juice, water etc but he never want to drink milk except in his old feeding bottle.

What can i do to stop this habit? There is no more nutritional value in breastfeeding for the child that age. Actually this is not true. Also to imply that they are somehow emotionally stunted and lacking in independence is also untrue. I love this site, but I am disappointed in this answer. The World Health Organization recommends feeding up to 2 yrs of age and there after until is mutually agreeable between mom and child. A lot of studies have been done on this issue and current research says the longer a child is attached to its primary caregiver the more independent they will be.

Montessori did talk about breastfeeding children. It of course depends on each child but that is a fair guideline age. World Health Organization advises that children be exclusively breast fed until 6 months of age for purposes of health and the developing immune system. Children do not need the nutrition that breast milk may be providing and all their nutritional needs should be provided by normal everyday food.

A mother need not be breastfeeding in order to have that same sort of closeness or special attachment that they have with their baby.

As the child gets older there are more age appropriate activities and hugs and kisses from parents will always be special. The direct contact that happens at this age is now solely for the pure enjoyment of direct contact without any need for any nourishment. The child learns about being their own person within the company of the mother. There is an appropriate time for everything. To stop breastfeeding is a natural way for detachment and independence to develop for the child if given the opportunity at the right time that it naturally occurs.

Is that still okay? Or is it more harmful to them? Did Montessori mention anything about this? This site uses Akismet to reduce spam. Learn how your comment data is processed. Sensitive Periods. Reply Lizelle February 1, at am. Reply Marissa August 17, at pm. Also, Ruth, I would love to see those studies you quoted so that I may further my own research. Reply valencia January 13, at pm.

Reply Tijana December 15, at pm. Reply Ruth September 22, at pm. Reply Halidsadee November 1, at pm. Reply Daily Montessori October 22, at pm. Reply Halidsadee October 17, at pm. Leave a Reply Cancel reply.

Toilet Learning Vs. Follow Daily Montessori. Daily Montessori.

Pin ellipsis More. Food flavors are also present in breast milk. The answer is that babies can mash soft, lumpy foods with their gums. Advances in Experimental Medicine and Biology. American Academy of Pediatrics. Discussion A nationally representative sample of infant feeding practices revealed specific social, demographic and behavioral factors associated with less than optimal feeding practices. Every child is different.

Sensitive period for introducing solid foods

Sensitive period for introducing solid foods

Sensitive period for introducing solid foods. Introduction

Given that these data are based on longitudinal reports, it could be that those introduced later to lumpy solids were more difficult to feed and more reluctant to accept textured foods. A further longitudinal questionnaire study [ 48 ] did observe a relationship between acceptance of a range of textured foods and feeding style, whether breast fed or formula fed. However, it was also noted that food acceptance was greater where family foods were given more often to the infant.

There is then a relationship between longer breastfeeding duration and the extent to which family foods, rather than pureed or commercially available baby foods, are fed to the infant as first foods [ 62 ], and this early and prolonged introductory period to real food tastes and textures generally influences subsequent texture acceptance.

One of the newer areas of interest in food acceptance is that of sensory hypersensitivity or hyper reactivity to sensory arousal. This denotes an over awareness and responsivity to stimuli, an over arousal which can give rise to an aversive reaction to normally non-threatening factors in the environment [ 63 ]. As this hypersensitivity would seem to be an innate trait, then it might also contribute to the reluctance of some infants in the early introductory period to accept new flavours, or more specifically textures; and, such an interaction has been observed between early experience and infant sensory sensitivity.

In infants introduced to complementary foods early or late within the 4- to 6-month period of introduction, and screened using the Dunn Infant Sensory Profile [ 69 ], it was found that infant sensory sensitivity predicted consumption of a new food. The higher the sensory reactivity the lower the consumption of a new food taste.

In addition, the relationship between tactile hypersensitivity and acceptance of the new food was moderated by the age of introduction to complementary food. A combination of breastfeeding with the timely introduction of complementary foods may confer a generalisation effect on the acceptance of new foods, and would seem the strategy which best predicts the subsequent acceptance of foods such as fruit and vegetables.

However, it is clear that whereas breastfeeding is not a necessary prequel to a wide food acceptance, the timely and frequent introduction of complementary foods of differing tastes and textures is. There are some data which would seem to support the idea of sensitive periods for the introduction of complementary foods according to both taste and texture, and this effect would appear to be more marked for those infants who are sensory hypersensitive.

We also know that there are innate differences between children which make some tastes and textures more difficult to accept and that these tastes and textures are those that are associated with vegetables and especially green leafy vegetables.

A generalisation effect has been noticed at all stages; the more variation in tastes and textures that are experienced the more willing the child is to try new foods. This gives rise to the advantage conferred by breastfeeding over formula feeding, but also means that complementary foods should be given with frequent taste variation, and that the early introduction of textured complementary foods other than smooth puree confers an advantage on the subsequent acceptance of other more complex textures, such as those found in most fruits and vegetables.

This article does not contain any studies with human or animal subjects performed by any of the authors. This article is part of the Topical Collection on Psychological Issues. Gillian Harris, Phone: , Email: ku. Helen Coulthard, Phone: , Email: ku. National Center for Biotechnology Information , U. Current Obesity Reports. Curr Obes Rep. Published online Mar 8. Gillian Harris and Helen Coulthard.

Author information Copyright and License information Disclaimer. Corresponding author. This article has been cited by other articles in PMC. Abstract Current dietary advice for children is that they should eat at least five portions of fruit and vegetables a day Department of Health.

Introduction Early Food and Taste Acceptance Infants are born with specific taste preferences and aversions; however, specific food preferences cannot be hardwired; humankind needs to be flexible about which foods can be accepted because different cultures depend upon a wide range of foodstuffs. Early Defining Exposure Experiences Amniotic Fluid There is some evidence that the experience of amniotic fluid, in turn affected by maternal diet, determines some preferences observed in the new born infant, but these observed preferences are for a specific odour.

Birth The infant is born with a preference for a sweet taste [ 3 , 20 ] and with a relatively neutral or positive response to salt and sour tastes, and possibly to umami, depending on the concentration used when testing. Early Milk Feeding Formulae Some flavour preferences might be learned from the intra-uterine environment, but they are also learned during the early stage of milk feeding; modified by exposure and to some extent predicting subsequent acceptance of foods.

Generalised Food Acceptance Therefore, although breast feeding would seem to confer some advantage over formula feeding in subsequent food acceptance, the effect is more that of the acceptance of taste change or taste variety.

Preference for Specific Foods The advantage of exposure to foods rather than flavours which pass through breast milk is that the tastes that are experienced are usually in the context and combination that will be carried on into adulthood. Generalisation Effect Two studies have looked specifically at generalisation effects; that is whether new foods are more likely to be accepted if a variety of foods are offered initially.

Long-Term Effects Long-term effects of the timing and type of complementary foods introduced have been reported in various studies, looking at children of different ages. Texture The concept of a sensitive period for the introduction of food of a texture other than puree was first suggested by Illingworth [ 54 ] and was based on case studies of hospitalised infants.

Sensory Sensitivity One of the newer areas of interest in food acceptance is that of sensory hypersensitivity or hyper reactivity to sensory arousal. Conclusion A combination of breastfeeding with the timely introduction of complementary foods may confer a generalisation effect on the acceptance of new foods, and would seem the strategy which best predicts the subsequent acceptance of foods such as fruit and vegetables.

Helen Coulthard declares that she has no conflict of interest. Human and Animal Rights and Informed Consent This article does not contain any studies with human or animal subjects performed by any of the authors. Department of Health. Prospective study of food preferences in childhood. Food Qual Prefer. Crook CK. Taste perception in the newborn infant.

Infant Behav Dev. Bits and pieces. Food texture influences food acceptance in young children. Predictors and consequences of food neophobia and pickiness in young girls. J Am Diet Assoc. Pliner P. Development of measures of food neophobia in children. Nicklaus S. Development of food variety in children.

A step-by-step introduction to vegetables at the beginning of complementary feeding. The effects of early and repeated exposure. Breastfeeding and experience with variety early in weaning increase infantsacceptance of new foods for up to two months. Clin Nutr. Exposure to vegetable variety in infants weaned at different ages. Predicting successful introduction of novel fruit to children. J Acad Nutr Diet. Specific social influences on the acceptance of novel foods in year-old children. Public Health Nutr.

Do food-related experiences in the first 2 years of life predict dietary variety in school age d children? J Nutr Educ Behav. Chem Senses. Hepper P. Inf Behav Dev. Long-term flavour recognition in humans with prenatal garlic experience. Dev Psychol. Developmental changes in the acceptance of the five basic tastes in the first year of life.

Br J Nutr. Rosenstein D, Oster H. Differential facial responses to 4 basic tastes in newborns. Child Dev. Longitudinal changes in sweet preferences in humans. Physiol Behav.

Sandal M, Breslin P. Variability in a tastes receptor gene determines whether we taste toxins in food. Curr Biol. Short-term vegetable intake by young children classified by 6-n-propylthoiuracil bitter-taste phenotype.

Am J Clin Nutr. Relationship of intake of plant-based foods with 6-n-propylthiouracil sensitivity and food neophobia in Japanese preschool children.

Eur J Clin Nutr. Genetic taste sensitivity to 6-n-propylthiouracil influences food preference and reported intake in preschool children. Provasi J, Polak EH. Odor sensitivity to geosmin enantiomers.

Heritability of food preferences in young children. Longitudinal study of nutrient and food intakes of infants aged 2 to 24 months. Flavor programming during infancy. Effect of hydrolysed formula feeding on taste preferences at 10 years. Flavor experiences during formula feeding are related to preferences during childhood.

Vegetable acceptance by infants: effects of formula flavors. Early Hum Dev. Differential transfer of dietary flavour compounds into human breast milk.

Phys Behav. Pediatr Res. Smoking and the flavor of breast milk. New Eng J Med. Infant dietary experience and acceptance of solid foods. Prenatal and postnatal flavor leaning by human infants. Early determinants of fruit and vegetable acceptance. Breastfeeding facilitates acceptance of a novel dietary flavour compound.

Demographic, familial and trait predictors of fruit and vegetable consumption by pre-school children. Relationship between parental report of food neophobia and everyday food consumption in 2—6-year-old children.

Arch Pediatr Adolesc Med. Smell differential reactivity, but not taste differential reactivity, is related to food neophobia in toddlers. From milk to solids: a reference standard for the transitional eating process in infants and preschool children in Japan. Associations between commercial complementary food consumption and fruit and vegetable intake in children.

Development of salt taste in infancy. Harris G, Booth DA. J Inf Reprod Psychol. Gerrish C, Mennella JA. Flavor variety enhances food acceptance in formula fed infants. Variety is the spice of life strategies for promoting fruit and vegetable acceptance during infancy.

Illingworth RS, Lister J. Berries, seeds, corn, and other foods can also be problematic. Some allergies fade as children mature. Wheat, milk, and egg allergies are the most commonly left behind by growing kids, while shellfish, fish, and peanut allergies tend to be lifelong.

While there is no cure for food allergies, scientists continue to study ways to lessen symptoms which helps children and adults tolerate problematic foods. A food allergy is a defensive reaction by the immune system to a specific protein in food, which can lead to respiratory or gastrointestinal problems. Being tested by a doctor or allergist is the best way to distinguish the symptoms and uncover the specific cause. On the other hand, intolerance to a specific food is a metabolic response, which is not related to the immune system.

Most often the response is to an enzyme in a food that the body cannot process. Lactose and gluten intolerances are two examples.

Exclusive breastfeeding to age six months is encouraged whenever possible. Hold off on offering your baby cow's milk until 12 months, regardless of when you stop breastfeeding, because the infant gut cannot digest it well.

It is okay to offer your baby yogurt and cheese, and use some milk in cooking for your baby. If you stop breastfeeding prior to your baby's first birthday, you'll need to give her formula. Does the order in which I introduce solids affect the likelihood of an allergy surfacing?

Jill Castle, MS, RD, LDN advises starting with nutrient-dense foods that are a good source of omega-3 fatty acids, zinc, and iron, including cooked pureed meat and fish. You can also offer some of the least-allergenic foods at first, such as oatmeal, root vegetables, avocados, bananas, and sweet potatoes, to ensure that your baby is getting a wide variety of nutrients, textures, and flavors.

Research suggests that early, regular exposure to these foods may reduce the risk of developing allergies to them. Be sure that the food is presented in developmentally appropriate forms: pureed, blended in with other foods, or as a safe finger food.

Should I stop breastfeeding or formula-feeding when I introduce my baby to solids? They are much more nutritionally and calorically dense than any amount of solid food your baby will initially be able to ingest.

Solids are a supplement to breast milk or formula. I did not eliminate any foods from my own diet while breastfeeding, and my baby has not shown any allergy symptoms. Doesn't that mean he isn't allergic to any solid foods? Not necessarily. Some food allergies do not surface until the child ingests the whole food directly.

Despite the uncertainty, it's unnecessary for moms to eliminate allergenic foods from their own diets in anticipation of an allergy, unless determined necessary by a doctor.

If your baby shows symptoms of a food allergy when you introduce solids, eliminate that food from your own diet until you have confirmed the source of the symptoms. Children of parents with allergies are 70 percent more likely to have a food allergy. Parents with asthma, eczema, or other allergic diseases are also more likely to have children with allergies. That said, many children with food allergies have no genetic disposition to them.

New research and guidelines suggest that offering allergenic food earlier to babies who are at higher risk from family history may help prevent them from developing food allergies. Should I introduce high-allergen foods to my child while at the doctor's office, in case she has a bad reaction? You wouldn't be the first to do it that way!

Introducing foods to babies is anxiety-inducing indeed, and many parents have approached exposing children to high-risk foods this way. If your family history points to the likelihood of an allergy, your doctor might suggest a Food Challenge, an allergy test during which a child is given a high-risk food to eat in a doctor's office in order to monitor any reaction. Otherwise, slow introduction and awareness should be sufficient to safely expose your child to new foods at home.

My baby is spitting up more after eating solids. Does this mean she is allergic to something she's eating? Babies usually spit up because their esophagus muscles aren't strong enough yet to close completely after swallowing. This improves as their digestive systems develop.

Spit-up is quite common and unlikely to be a symptom of an allergy.

A sensitive period in development is one in which it is easier for learning to take place; the behaviour can however still be learned at a later stage, but with more difficulty. This is in contrast to a critical period, a time at which a behaviour must be learned, and if this window of opportunity is missed, then the behaviour can never be acquired.

Both might determine food acceptance in childhood. There is evidence to support the idea of a sensitive period for the introduction of tastes, a critical period for the introduction of textures and for the development of oral motor function, and a possible critical period for the introduction of new foods but only in children where there is an innate disposition to develop early and extreme disgust responses.

There are both sensitive and critical periods in the acquisition of food preferences. A sensitive period is a limited period during which the brain is particularly receptive to the effects of experience. However, there is now some evidence that even processes not attained during a critical period can be attained in adulthood [ 3 ].

Critical and sensitive periods both need an age of onset and an age or stage at which learning can no longer occur or occur with such ease. We must also ask ourselves what might be the function of a sensitive, or even a critical period, for development in infancy, and the relevance of these stages to food acceptance.

Given that all mammals must be open to learning about changes in their environment and changes in their role within a social group as they age, why would a crucial period for learning new skills be of advantage to a species? The answer must lie in the way in which the brain develops, with neural networks set up in the young to facilitate necessary learned behaviours as other unnecessary pathways die off [ 3 ].

However, there are very few critical periods for learning in infancy in which this occurs; the most cited one of these is within the visual system, that of acquired stereoscopic vision [ 4 ]. Critical periods are not seemingly advantageous and relate to the manner in which neural circuits develop, but why might sensitive periods be advantageous?

This is because there are crucial periods during which the infant interacts with the environment; this interaction is determined by intrinsic factors, and the infant is primed to learn about stimuli that will facilitate development and contribute to subsequent survival. As human infants progressively need to eat food, then they need to learn very quickly which foods are safe, which foods are eaten by those around them, and their taste preferences need to be modified accordingly.

Food acceptance per se cannot be hard wired given the wide range of environments inhabited by the human race and the wide range of foods which provide the diet of different cultural groups. In the beginning, all food preferences need to be learned. Early research studies looking at isolation studies carried out on macaques seemed to show that there were critical periods during which social interaction skills had to develop.

However, subsequent research [ 5 ] demonstrated that it was not that the infant macaque could not interact with age mates when introduced to them after periods of isolation, but that other fear behaviours interfered to prevent this interaction. There are three points of development and domains at which this easy acceptance or later refusal might occur in relation to feeding and eating behaviour: taste and smell, tactile stimulation and texture, and visual appearance.

The mechanisms which are needed to sense taste and smell are more or less completely developed by birth and so acceptance post-natally in each of these domains [ 6 ] is related to exposure, with additional learned oral motor skills, and the development of the distaste-disgust response. Infants are exposed to flavours in utero and via breast milk. However, the flavours to which the infant is exposed by these routes can vary widely from mother to mother and from feed to feed [ 7 , 8 ], and although they might slightly prime the infant for subsequent acceptance of new foods, the advantages which they confer do not outweigh the mere introduction of tastes during the period of the introduction of complementary foods [ 9 ].

The infant is born with a preference for a sweet taste, and this may well be beneficial in that it directs the infant to ingest foods that might be a source of energy, and to reject water. The taste of bitter, however, is rejected at birth [ 10 , 11 ] because of the possible association between a bitter taste and toxicity. All other taste preferences are subsequently learned through exposure [ 9 , 10 ].

Early work carried out on the acceptance of tastes in food showed that there was an easy acceptance for a salt taste if this was added to a tasteless rice base and that this acceptance was dependent upon number of exposures rather than the amount eaten [ 12 , 13 ]. However, Johnson [ 15 ] looked at the acceptance of tastants added to rice-based cereal.

There was a clear and fast exposure effect for sour and salted rice; infants learned to like these flavours quickly and easily. For those infants given bitter tasting cereal, there was no exposure effect; those infants fed the bitter tasting cereal preferred the taste-free rice-based cereal. This effect might have been due to the bitter taste or due to the slightly later age of introduction, an effect noticed in infants fed bitter tasting proteinhydrolysate formulae [ 16 ].

This easy acceptance of a bitter tasting formula after early exposure continues into later childhood [ 18 ]. The taste preference learning was also exactly specific to the formula experienced [ 19 ]. Therefore, what was learned in this early sensitive period was that flavours initially linked with possible toxicity, if paired with good nutritional outcome, could be accepted. Anecdotally, many parents report that it is difficult to change their infant from any formula in later infancy once they have learned to accept a specific formula taste in early infancy.

There was some generalization noted from this early acceptance of a bitter tasting formula to the acceptance of bitter tasting food. But such taste preferences do not seem to generalize from liquid to solid food. Infants fed protein hydrolysates did not prefer broccoli, which is bitter, to carrots which are sweet [ 21 ].

It would seem therefore that early experience with both difficult tastes and textures has a facilitating effect. However, it should also be remembered that those introduced early, and to a variety of fruit and vegetables, probably live in an environment which generally facilitates the acceptance of a wider diet. There is also a generalization effect with all new foods and tastes. Difficult tastes are therefore not only better accepted if introduced earlier to the infant but also if they are introduced frequently [ 34 ].

It may also be advantageous if the infant experiences a continuation from taste to texture to appearance; that is they learn to recognize the food in all of its different presentations, as may well be the case with home prepared rather than with commercially produced introductory foods. Two studies of interest which add to this literature have been carried out with premature infants. In this latter study, the mean gestational age of the premature infants was The authors hypothesized that the premature infants would display more negative emotion when exposed to novel foods than would the full-term infants, but analysis of facial expression in response to the introduction of new foods showed a more positive acceptance by the pre-term infants.

The acceptance of a bitter taste is, however, more problematic; this is a taste often associated with toxicity and is therefore a taste to which it is appropriate for the infant to react and possibly subsequently reject. However, if the taste is associated in very early infancy with the only source of good nutrition, then this taste will be accepted at the earlier age, but not at the later age when other sources of good nutrition have been experienced. To a great extent, then the acceptance of food tastes is easier at an earlier age but not totally dependent upon developmental stage.

Tastes are learned in context and gradually associated with foods and food textures [ 37 ] which become increasing more complex. Unless the infant and child has innate taste aversions, such as an extreme response to bitter [ 6 , 38 ], then tastes can be accepted and modified throughout life [ 39 ].

However, in an adult, the motivation to try a new taste may be the defining characteristic determining whether or not that taste or taste modification is accepted. One study has recently shown that the age of introduction of new foods in the 4—6-month introductory period is more salient for those infants rated higher on tactile hypersensitivity. The concept of a sensitive period for the introduction of solid food was first suggested by Illingworth [ 44 p,] based on case studies of hospitalized infants.

If they are not given solids then as distinct from thickened feedings, which can be given any time after birth , they are very apt to be difficult about taking them later, failing to chew, refusing the solids, or vomiting.

A new born infant is born with a disposition to ingest, with sucking being the earliest means of receiving nutrition [ 45 ]. Early nutritive sucking comprises forward and backward movements of the tongue and is supported by both physiological and anatomical factors: rooting and sucking reflexes, the lips, tongue, and jaw acting as a single unit; the size of the oral cavity; sucking pads; and proximity of oral and laryngeal structures [ 45 — 47 ].

The difference between nutritive and non-nutritive sucking is that nutritive sucking requires the coordination of bursts of suck-swallow-breathe cycles whereas non-nutritive sucking is a burst of sucking and breathing with intermittent swallows.

Reviews of the literature on non-nutritive sucking have shown that the promotion of non-nutritive sucking in premature babies who require tube feeding, usually by the use of pacifiers, leads to a quicker transition to oral feeding and shorter stays in neonatal units [ 49 — 51 ].

While the benefits of non-nutritive sucking on the premature population are well researched, it is less clear whether these benefits continue in older infants who are unable to take nutrition orally during the early months of life. At first, sucking will be triggered automatically by any sort of stimulation of the lips and tongue but gradually, this reflex response comes under voluntary control. Morris and Klein [ 47 ] described how the baby develops separation of movement that enables the jaw, lips, and tongue to move separately and thus perform more complex oral motor tasks, an extension to the reflex suck and swallow.

The attainment of early oral motor skills needed to process more solid foods around the mouth shows a wide diversity across individuals. Carruth and Skinner [ 53 ] found that the mean age at which infants used the tongue to move food to the back of the tongue to swallow was 4. This variation may reflect normal differences in the development of the central nervous system and opportunities the infant has to practice skills [ 53 , 54 ].

The late introduction of textured solids that is foods that need to be processed with a side to side tongue movement is associated with poorer acceptance of these foods, and it has been suggested that there is at least a sensitive period for the acquisition of chewing skills [ 44 ].

The studies were, however, reported observations and other factors could have contributed to the later feeding difficulties.

Mature chewing is a complex combination of movements of the lips, tongue, and jaw, and fully mature chewing can take several years to develop [ 58 , 59 ]. At the same time, the tongue begins to move laterally, from centre to side. The poor acceptance of textured foods by children who are introduced to them after the first year of life would appear to have at least two components: firstly, a refusal to try unfamiliar foods as the child moves into the neophobic stage of food refusal in the second year of life and, secondly, an inability to manage the texture because chewing skills have not been acquired through practice [ 62 ].

Most researchers [ 63 ] agree that movement patterns, such as lateral tongue movements, are texture dependent and therefore do not emerge unless the child is given the particular textures requiring these skills. Another component in the acceptance of textured foods is that the side to side processing of food within the mouth serves to desensitize the inner sides of the cheeks. Lumpy textured food which lands onto the back of the tongue provokes a gag and retch reflex, which is aversive to the child.

In addition to this, children who do not process foods with a side to side tongue movement which positions food appropriately for processing become hypersensitive to any tactile stimulation and therefore find the experience of foods at the sides of the mouth aversive [ 64 , 65 ]. Parents may also respond to this gag response by further delaying the introduction of solid-textured foods [ 66 ].

Sensory-hypersensitive children are reluctant to allow food to go into the sides of the mouth and also reluctant to process the more difficult textures. Higher tactile sensitivity is particularly associated with rejection of foods of difficult texture [ 41 , 65 ].

However, before they get to the stage of foraging, in their second year, they need to know what their safe foods look like and need to attend quite closely to the detail of the appearance of that food. The neophobic stage, as it is defined for humans, describes a response of refusing food on sight [ 66 ]. The way that the food looks or the way in which the food is packaged predicts the safety of the food, and any deviation in the smallest detail will lead to this rejection [ 67 ].

Even foods that have been accepted prior to the onset of the neophobic stage might be refused if their appearance changes on subsequent presentations [ 68 ]. The onset of this stage also occurs at the time at which infants are showing contamination fears and therefore an early form of disgust [ 73 — 75 ]. A food that is liked might be refused if touched by a food that is disliked. Although it is relatively easy to get acceptance of a new taste or new food when that food has not previously been experienced, where there is motivation to try the food and where others are modelling the food [ 76 — 78 ], once a food has been deemed disgusting it would seem that it is almost impossible to get that food accepted into the diet [ 79 , 80 ].

Those children who are sensory hypersensitive are more likely to show strong neophobic responses and extreme disgust responses. In the extreme, some children form a strong disgust response to all new foods or variants of known foods [ 82 ]. In these children, the fear of new foods can remain until adulthood; new foods can evoke a disgust and fear response and texture refusal can worsen as the child becomes more orally defensive [ 64 , 83 ]. This may be an example, not of a critical period however, but of interfering or competing behaviours.

The formation of a disgust response towards foods that have not been accepted during the neophobic stage, perhaps necessary in early humans to prevent the ingestion of non-foods, blocks learning about new food tastes and textures. When no disgust or fear response has formed, then older children and adults can be motivated to try new foods that they deem safe to eat.

The defining factor here is the sensory hypersensitivity of the child; the experience of the food interacts with the innate disposition of the child to produce an extreme fear response and it is not that neural pathways can no longer form to promote food acceptance. However, acceptance of new tastes can be learned throughout life if the older child or adult is motivated to accept the repeated tastings that are required, not only for acceptance but also for pleasurable anticipation of the taste.

For some of course, those who are genetically programmed to dislike certain tastes such as bitter [ 38 ] or those who are sensory hypersensitive [ 84 ], then simply getting older will not change acceptance; there will be no increased motivation to try.

The factor of motivation is, however, an important one. Early childhood food preferences and experience predict later childhood and adult food preferences and dietary range [ 33 , 85 , 86 ]. So the sensitive period here is one of setting up habitual patterns of eating which may or may not be subject to later lifetime change. The response to texture may well be a function of innate differences, in that sensory-hypersensitive infants are less likely to accept different textures with ease [ 65 , 87 ], but it can also be delayed by lack of early experience.

Those infants who have not experienced textured foods in the first year of life find such foods difficult to accept and to process within the mouth. Similarly, in some, the development of the disgust response to specific foods is also a heightened innate response.

Sensitive period for introducing solid foods

Sensitive period for introducing solid foods