Wednesday, November 02, 2005

Picky Eaters... A Cause For Concern?

Picky eating occurs on a continuum; there is no defined diagnostic cut-off for when it becomes pathologic. Picky eating that is brought to the attention of the pediatrician is probably best defined as an unwillingness to eat familiar foods or try new foods that is severe enough to interfere with daily routines and cause problems for the parent or child or disrupt the parent-child relationship.

About 20% to 30% of parents report that their preschool-aged child is a picky eater. Half of toddlers are described as not always hungry at mealtime, a third do not seem to enjoy meals, and a third have strong food preferences. One in four often refuses to eat, one in five requests specific foods and then refuses them, and nearly one in two tries to end a meal after a few bites. Almost two thirds of parents report one or more problems with their toddler's eating.

In a small (135 subjects) study comparing parental descriptions of picky preschoolers with those of nonpicky preschoolers, parents who described their child as a picky eater were more likely to report that their child eats a limited variety of foods (79% vs. 16%), wants the food prepared in specific ways (62% vs. 18%), does not accept new foods readily (90% vs. 39%), and has strong dislikes (97% vs. 63%). Vegetables are the foods most often rejected by preschoolers.

Children who are picky eaters seem to differ from nonpicky eaters in more than just eating behavior. Picky eaters are more likely to have negative temperamental traits1 and to be shy and anxious.

The most comprehensive study to date on nutrient intake and parental report of picky eating evaluated 74 children between 2 and 3 years old using questionnaires and diet diaries. Picky eaters were found to have significantly less variety in their diets than matched controls, but no significant differences in overall nutrient intake were noted. In another study, picky eaters between 3 and 5 years old ate significantly fewer foods than their nonpicky counterparts, but the actual difference was small—about 11 foods vs. 12 foods over the course of a day.

Why are children picky eaters?

It is unclear whether picky eating varies by gender, culture, socioeconomic status, or ethnicity. It does seem to peak during the preschool years and decline thereafter. One hypothesis holds that the developmental trajectory of picky eating has evolved as a protective mechanism. Specifically, picky eating seems to increase as children become more mobile. Some investigators theorize that children are "wired" for pickiness to protect them from eating potentially poisonous substances in the environment; children who are inherently reluctant to eat an unfamiliar food, or a variety of foods, will not "wander into the bush and eat a poison berry."

Human beings also seem to have some innate predisposition that guides which foods to accept and which to reject. All food rejections occur for essentially one of three reasons: dislike, fear, or disgust (see "Three reasons why people reject food"). Although children demonstrate some degree of disgust as young as 2 or 3 years old, disgust does not begin to cause food rejection in the adult form until 7 to 8 years of age.

Picky eating seems to run in families. Moderate correlation is seen between a mother's rating of pickiness and her child's rating,3 and high correlations are seen between twins in regard to picky eating.

Gathering the history

A few key interview questions can help rule out underlying medical problems in a child who is a picky eater and facilitate understanding of the family's perception of the problem and how they are dealing with it.

Tell me which foods your child won't eat. A pattern of refusing specific foods, such as milk products or foods with certain textures, raises the possibility of food allergy or intolerance or oral hypersensitivity.

Tell me what your child ate yesterday, starting with breakfast. A diet history can give you a sense of how picky the child is and open a discussion about what foods the child is given, how they are presented, and how the parents respond when the child refuses to eat foods.

What do you do when your child rejects a food at dinner? What sort of rules do the parents have about eating? If they answer that the child is required to remain at the table until his plate is clean, or reveal that the child is coerced to eat a particular food, that is an important finding. Neither approach has been shown to produce long-term improvement in picky eating. Both most likely add stress and negativity to the family mealtime.

What worries you the most about your child's eating? Parents often express concern that their child has a growth or vitamin deficiency. Reassuring them that their child is growing adequately and suggesting that they add a multivitamin with iron to the child's diet often assuages their worry.

Is anyone else in your family a picky eater? This question (to which the answer is nearly always "Yes") can open a discussion about the natural course of picky eating and may provide some insight into why the parent views the behavior as such a problem.

Is the child growing?

When a concern about picky eating is raised, the first and most important piece of information needed to guide management is the child's growth. Carefully measure weight and height (or length) and plot them on the gender-specific National Center for Health Statistics (NCHS) Growth Charts (http://www.cdc.gov/growthcharts/). Because evaluation of changes in percentiles over time is just as important as current position on the curve, longitudinal growth data are necessary.

A detailed discussion of the analysis of growth patterns with respect to acute and chronic undernutrition is outside the scope of this review. However, a body mass index (calculated as weight in kilograms divided by height in meters squared) or weight-for-length plotted at less than the 5th percentile on the age- and gender-specific NCHS Growth Charts should alert you that a child's picky eating may be a symptom of, or occur in conjunction with, an underlying medical problem. Such a child requires a thorough evaluation for failure to thrive. Discussion of the evaluation of failure to thrive may be found elsewhere.

Picky eaters should also be screened for constipation. The picky eater's diet is often low in fiber, and constipation can cause abdominal discomfort that only makes the eating behavior worse.

"Touching tonsils" may contribute to picky eating by causing a child to gag on large pieces of food, such as meat. Although this problem is relatively rare, it is worth considering because it is easily correctible by surgery.

In some cases, the child's eating behavior may be so far outside the range of normal that it deserves a psychiatric evaluation for "infantile anorexia." This term is applicable when underlying medical causes have been ruled out, and the child's food refusal is severe enough to result in malnutrition. Infantile anorexia typically requires consultation with a specialist for behavior modification in partnership with the parent and, sometimes, evaluation for parent-child interactional disturbances.

Considering the differential

As stated, the picky eater who is also not growing well warrants thorough evaluation because the differential diagnosis is broad. The same is true for a child whose picky eating is accompanied by other signs or symptoms of an underlying medical disorder. When picky eating occurs in an otherwise healthy child whose growth is normal and who has a normal physical exam and a negative review of systems, the differential diagnosis is relatively limited:

Food allergies or intolerance can lead to refusal of specific types of foods, such as eggs and milk. However, be very cautious about relying solely on the parent's history of an adverse reaction such as vomiting or irritability (or food refusal) to make the diagnosis. An appropriate work-up prevents unnecessary parental restriction of the child's diet, which can place the child at risk for nutritional deficiency.

Lactose intolerance causes abdominal discomfort, which can lead to refusal of lactose-containing foods. Lactase deficiency at birth is rare, but lactase activity begins to decline in non-Caucasian children between about 2 and 5 years of age.

Celiac sprue, an intolerance to gluten that occurs in 1% to 2% of the population, most often appears in children between 6 months and 2 years old. These children typically have a poor appetite but also exhibit associated signs and symptoms such as failure to thrive, diarrhea, and vomiting. Given the relatively high prevalence of the condition and the fact that the age of presentation often coincides with parental concern about picky eating, celiac sprue deserves special consideration in the differential diagnosis of picky eating.

Gastroesophageal reflux (GER). About 7% of 3- to 9-year-old children have at least occasional symptoms that suggest GER. Gastroesophageal reflux becomes gastroesophageal reflux disease (GERD) when it is severe or frequent enough to affect the child's daily life or cause associated medical problems, such as wheezing or esophageal injury.

Food refusal in children with GERD has been described as a conditioned aversion to eating caused by pain following ingestion. More recent evidence suggests that the aversion to eating is a conditioned response to nausea associated with the emetic reflex. Indeed, nausea seems to be a more potent cause of conditioned food aversion than pain. A single episode of nausea following ingestion of a particular food can cause an aversion to that food that persists for years. GERD is often found in association with failure to thrive, and severe GERD may well be a causative factor in some cases.

Oral hypersensitivity or post-traumatic feeding disorder of infancy. Some children refuse food because of a conditioned aversion to stimulation to the mouth created by previous adverse oral experiences, such as endotracheal intubation or nasogastric tube feeding. This type of feeding aversion occurs most often in former preterm infants or children with a history of multiple medical procedures. Many of these children have poor oral motor skills. They typically refuse textured foods. For them, diagnosis and treatment remain ill-defined; little or no empirical evidence for the efficacy of any technique can be found in the literature.

When the problem is diagnosed by a speech pathologist or occupational therapist, it is often termed "oral hypersensitivity," and treatment typically focuses on deconditioning—for example, with oral stimulation by brushing or exposure to various textures in association with positive reinforcement. The evidence for such classic behavior modification techniques is solid. The jury is still out, however, on the efficacy of sensory integration therapy for oral hypersensitivity disorders.

When diagnosed by a child psychiatrist, conditioned aversion to stimulation of the mouth is usually termed post-traumatic feeding disorder of infancy, a term coined by Chatoor and reviewed elsewhere. The psychiatric view of the problem is that classic behavior modification techniques have limited efficacy and that therapy should focus primarily on addressing the child's believed underlying anxiety and fear of eating. Unfortunately, the evidence for this type of intervention is also relatively limited.

Problems in parent-child interaction. An unusually strong focus within the family on the child's eating behavior or escalating negative affect in the mother and child may signal a larger problem in the parent-child relationship, which is often associated with separation-individuation and autonomy. Such families may benefit from an appropriate mental health referral.

Unrealistic parental expectations. In the study of eating behavior, it is often noted that no animal or human has ever been born with an inherent preference for bitter or irritating tastes. In other words, preferences for chili peppers and coffee are not inborn but learned. (Why humans should have a preference for exceedingly spicy or bitter foods at all remains an area of active research.) Parents who have a sense of culinary adventure and expect their 3-year-old to have the same zest for the spicier varieties of Chinese, Mexican, and Indian cuisine that they do are likely working against biology. Eating every food presented at the dinner table every evening is a goal that most children probably cannot meet.

Limited resources. It is always important to recognize that a substantial number of children in the United States live in households that are "food insecure"—meaning that they have inadequate access to enough food to lead an active, healthy life. Nearly half of children living in single-parent households in poverty are food insecure. The family may not have adequate financial resources to supply a range of palatable foods at each meal, and any food refusal that results in waste becomes a serious issue. Parents may be concerned that the child's picky eating, combined with a limited choice of foods, is affecting his or her health.

Will she outgrow it?

Pickiness seems to decline with age through early childhood. Children who are still described as picky after about 9 or 10 years old are likely to remain picky, however.

Parents are sometimes concerned that their child's picky eating foretells an impending adolescent eating disorder. A single prospective study of 659 children followed from 1 year to 21 years of age found that picky eating in early childhood (defined by maternal report as not eating enough, being choosy about or disinterested in food, and eating unusually slowly) predicted symptoms of anorexia nervosa in later adolescence. As reviewed by Jacobi and colleagues, however, more than 30 different characteristics have been identified as a possible risk factor for adolescent eating disorders. Because the number of studies describing picky eating as a risk factor is small, it is difficult to make firm statements about an association between picky eating and eating disorders in adolescence until additional research is completed.

What to do

A thorough history and clear definition of the problem are essential to plan intervention. If underlying medical problems and the diagnoses in the differential discussed earlier have been ruled out, the mainstay of management is to demystify the problem for parents. Picky eating, in most children, is a behavior that worsens during the toddler and preschool years and then begins to improve during the early elementary years. In other children, it can be seen as a personality trait. Either way, medical intervention is rarely indicated.

Behavioral interventions should be recommended only when parents are eager to put effort into modifying the behavior. Interventions must be benign and simple and should never be continued if they increase stress or discord at mealtimes. The Guide for Parents (www.contemporarypediatrics.com/contpeds/article/articleDetail.jsp?id=151500) lists some strategies you can suggest to parents who request them.

It is also important to remember that parents who are concerned about a child's picky eating may be identifying the eating as the problem when it is really a discrete symptom of an overarching concern: a difficult temperament. Although picky eating occurs on a continuum and is a "normal" behavior, do not minimize parents' worries. Helping the parent to understand the child's temperament, and how the picky eating is a symptom of it, will likely benefit the parent-child relationship in the long term.

Ashley, picky eater

In response to the concerns expressed by Ashley's mother at the outset of this article, you show her Ashley's normal growth parameters and growth pattern and reassure her that Ashley does not have signs or symptoms of the short list of possible disorders on the differential. Ashley is not constipated, and her mother already gives her an over-the-counter vitamin (which Ashley happily chews daily without resistance).

You briefly explain that picky eating naturally increases around this age in all children, then tends to diminish through the school years. Ashley's mother notes that her own mother is a very picky eater (but also an outstanding cook and beloved grandmother to Ashley); you acknowledge that, in some children, picky eating persists and is just another personality trait. You reassure her that predicting an eating disorder based on picky eating at 3 years old is impossible and that, because Ashley is suffering no health consequences from picky eating, there is really no cause for concern or need to push her to eat to the point where mealtime becomes unpleasant.

You offer a few suggestions to increase the likelihood that Ashley will accept an increased repertoire of foods. Her mother agrees to try them, pleased that she now has a plan of action that promises to be relatively benign.

Tincture of time

Picky eating is a common concern that parents bring to the pediatric office or clinic. If the history, review of systems, and physical exam (including growth parameters) are unrevealing, the differential diagnosis is short. Although picky eating typically declines with age, strategies to cope with the behavior can be offered to parents in the meantime. Research in children's eating behavior has improved our understanding of the variables that contribute to children's food choices. Translating these findings into advice for parents can be helpful.

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