Fasting Glucose

It is estimated that about 150,000 to 200,000 individuals under the age of 20 have diabetes. As opposed to the epidemiology in adults, most children with diabetes have type 1 diabetes. However, over the past 20 years, the rate of type 2 diabetes in children and adolescents has increased significantly, especially in some at-risk groups. Children with type 2 diabetes are frequently more than 10 years old, obese, and have a family history of type 2 diabetes. Rates are higher in some racial/ethnic groups, such as Asian/Pacific Islander, Native American, Black, and Hispanic descent children. Rates of undiagnosed type 2 diabetes and “prediabetes” (impaired fasting glucose (>100 mg/dL; 5.6 mmol/L) in young persons are not well defined, though it is assumed the official statistics only identify a portion of the affected persons. Using fasting glucose levels and primary care provider diagnosis of diabetes from NHANES 1999–2000 to 2007–2008, May and colleagues (2012) reported that the prevalence of prediabetes/diabetes among adolescents aged 12 to 19 years old has increased from 9 percent to 23 percent. A study using NHANES 1999–2000 to 2007–2008 data predicted that the number of youth with type 1 diabetes and type 2 diabetes may increase by 23 percent and 49 percent, respectively. Overweight and obese children less than 18 years with two or more other risk factors (Table 4-6) should be screened for type 2 diabetes every 2 to 3 years. A fasting plasma glucose assessment (>125 mg/dL is consistent with diabetes; 101 to 125 mg/dL defines impaired fasting glucose or prediabetes) is most commonly used as a screening test for children, adolescents, and adults. In the evolution of type 2 diabetes, post-prandial glucose increases earlier than fasting glucose; some experts therefore recommend determining plasma glucose two hours after a standard glucose load or two hours after a meal. Thus, significant elevations in non-fasting glucose tests, especially those >200 mg/dL should be further evaluated. Diabetes screening recommendations for children and adolescents are shown in Table 4-6. Though in adults, screening tests for diabetes and prediabetes include hemoglobin A1C, or a 2-hour plasma glucose level as part of an oral glucose tolerance test, such recommendations have not been broadly applied to children. Similarly, though HbA1C is now considered as a good tool for screening and monitoring for T2DM in adults, there are concerns about the use of A1C to evaluate children and adolescents for T2DM. Given that cardiovascular disease risk factors tend to cluster together, screening for other such risk factors (e.g. hypertension, dyslipidemia) should be considered for children and adolescents at risk for developing type 2 diabetes.

Elevated glucose levels, especially in the hospital setting, may occur at times of significant stress and acute illness, such as infection or sepsis, or as a side effect of some medications, such as steroids. Such secondary causes should be considered when assessing a child with hyperglycemia. Low glucose levels related to malnutrition are relatively rare, and usually occur in late stage, severe malnutrition. Neonates and premature infants are among higher risk groups for low and high glucose levels at times of stress.

Lipids

Encouraging a healthy lifestyle and consideration of cardiovascular disease risk factors should start relatively early in life. Screening for hypercholesterolemia should start around 3 years of age, and target children with a positive family history of early atherosclerotic vascular disease (AVD) or parental dyslipidemia. (Table 4-7 and Figures 4-2 and 4-3). A positive family history of early AVD is defined as a parent, grandparent, aunt/uncle, or sibling with a heart attack, sudden death thought to be related to AVD, angina, angioplasty, peripheral vascular disease, or cerebrovascular disease before age 55 in males or before 65 in females. Screening should also be considered in children at higher risk for developing adult heart disease, such as those with diabetes, hypertension, and obesity. Children with high cholesterol levels tend to become adults with high cholesterol levels. However, as tracking of lipid levels over time is not perfect, not all the hypercholesterolemic children will become hypercholesterolemic adults. Screening in high-risk children should consist of the average of two fasting lipid profiles obtained on two separate occasions. Low-density lipoprotein cholesterol (LDL-C) > 130 mg/dL or triglycerides >110 mg/dL are generally considered elevated and should be evaluated further for secondary causes and potential intervention (see Table 4-7 and Figures 4-2 and 4-3). The initial intervention in children with primary hypercholesterolemia is dietary and lifestyle assessment and intervention.

Universal screening is recommended for children 9 to 11 years old, and can consist of a non-fasting non-high-density lipoprotein cholesterol (non-HDL-C) assessment. Children with non-HDL-C greater than 145 mg/dL and/or HDL-C less than 40 mg/dL should be considered for further assessment, including fasting lipid profiles. A general summary of the National Heart, Lung, and Blood Institute expert panel’s recommendations regarding lipid screening is shown in Table 4-7 and Figures 4-2 and 4-3, and further details are available at http://www.nhlbi.nih.gov/guidelines/cvd_ped/summary.htm. Guidelines are also available for the management of patients with obesity and dyslipidemia.

Iron Status

Though significant progress has been made in decreasing rates of iron deficiency in children in the United States over the past several decades, iron deficiency is likely the most common micronutrient deficiency in the United States. Iron deficiency is usually due to inadequate dietary intake of iron, especially during times of rapid growth or increased blood loss, such as infancy and early childhood, and during adolescence (especially for girls). Pre-term infants and infants with intrauterine growth retardation are also born with decreased iron stores and thus should receive iron supplements. Adolescent athletes, for reasons that are not totally clear, are another at-risk group. A higher prevalence of iron deficiency has also been observed in obese children across a broad age range. Even in the absence of anemia, iron deficiency is associated with poor growth and neuro-cognitive development in infants and behavioral and learning problems in older children and adolescents. Iron deficiency and iron-deficiency anemia are also associated with decreased exercise capacity and physical endurance. Thus it is very important to identify and treat iron deficient children.

As specific measures of iron stores (e.g., serum ferritin, transferrin, iron binding capacity, free erythrocyte protoporphyrin) are costly and not widely available, hemoglobin and red blood cell indices (derived from a simple CBC) are the laboratory parameters most commonly used to evaluate children for iron deficiency. However, these are relatively insensitive measures of true iron status. It should be noted that transient decreases in hemoglobin levels are relatively common with infections, thus a single low hemoglobin level should be confirmed or assessed further before initiating therapy. An alternative to more specialized testing is providing a therapeutic iron supplement challenge. An iron deficient child should respond to such a challenge with a reticulocytosis and increase in hemoglobin within a few weeks. Screening for iron deficiency should thus focus on at-risk children, as noted above, and especially those at-risk children who have not been receiving iron-sufficient diets, or iron supplements, as appropriate.

Vitamin D

Vitamin D deficiency, defined based on the serum or plasma measurement of 25-hydroxyvitamin D [25(OH)D], is a common and poorly recognized condition that occurs in infants, children, adolescents, and adults. Many affected children are dark skinned and have limited exposure to UV light, are fed unfortified “health food” milk alternatives, or are breastfed without vitamin D supplementation by mothers with vitamin D insufficiency or deficiency.

As reviewed by the Institute of Medicine (IOM) taskforce in 2011, vitamin D is essential for skeletal health but there is currently a lack of convincing evidence to link vitamin D supplements with benefits for other nonskeletal outcomes such as cardiovascular disease, death, cancer, and quality of life. There is no additional benefit currently identified for levels of 25(OH)D above 20 ng/mL (50 nmol/L), therefore the IOM considered the 20-ng/ml level as the upper range of human requirements, meeting the needs of most individuals in the general populations (regardless of other factors such as skin color). However, these guidelines are not specific for individuals with underlying conditions or diseases. The United States Institute of Medicine Recommended Dietary Allowance of vitamin D is 400 IU per day for children younger than 1 year of age, 600 IU per day for children at least 1 year of age and adults up to 70 years, and 800 IU per day for older adults. The AAP recommendations for children is similar to the IOM but that of the pediatric endocrine society is not. Premature infants, dark-skinned infants and children, and children who reside at higher latitudes (particularly above 40°) may require larger amounts of vitamin D supplementation, especially in the winter months. The principal source of vitamin D is solar UV-B (wavelengths of 290–315 nm) irradiation. Dietary sources of vitamin D other than vitamin supplements are limited and include oily fish, some fish oils, and egg yolks. Although some foods in the United States are vitamin D fortified, including milk, some cereals, orange juice, some yogurts, and margarine, most United States children do not eat sufficient quantities of vitamin D-containing foods to provide adequate vitamin D intake.

Although 25(OH)D serum/plasma levels are considered the gold standard to identify vitamin D deficiency, this may be a poor marker in chronic conditions such as obesity and conditions with inflammation. Youth who are obese tend to have 25(OH)D levels in the deficient range but studies of bone density in this population are similar to reference populations, thus there is currently no evidence that these lower vitamin D levels in obese children have a demonstrable effect on bone health . New screening and treatment guidelines for obese children with low vitamin D levels have not been developed.

Breast or Bottle

Lactation is discussed in Chapter 3.

The AAP states that breastfeeding and human milk are the normative standard and recommends exclusive breastfeeding up to approximately 6 months for almost all infants (see iron and vitamin D section above for recommendations regarding supplements for breastfed infants). Breastfeeding is associated with numerous medical and neurocognitive advantages. Though true contraindications to breastfeeding are rare, there are significant obstacles to breastfeeding in the United States, including lack of knowledge, limited experience with breastfeeding, lack of support for breastfeeding mothers at home or in the workplace, and misguided social “norms”. All healthcare providers, including hospitals, obstetricians, and pediatricians, and all pediatric care providers should encourage breastfeeding whenever possible, and work to encourage community-based supports for breastfeeding mothers. Certified breastfeeding counselors and breastfeeding support groups should be used when appropriate to help establish and support effective breastfeeding. Interventions to overcome problems with breastfeeding must be considered as relatively urgent, to avoid interruptions in the mother’s milk supply or other problems which may interfere with longer term success with breastfeeding. The WHO/Unicef Baby Friendly Initiative launched in 1991 and revised in 2006 has contributed to increased rates of exclusive breastfeeding and improved infant health and survival.

Except for special formulas, manufacturers of infant formulas try to approximate the composition of human breast milk. For example, formula manufacturers add omega-3 and omega-6 fatty acids, docosahexaenoic acid (DHA), and arachidonic acid (ARA) to infant formulas, as these fatty acids are found in breast milk and support normal brain and eye development.

Iron and Vitamin D Supplementation

Even though breast milk is lower in iron than cow’s milk, the iron in breast milk is more readily absorbed. Pre-term infants and infants with intrauterine growth retardation are born with decreased iron stores and thus should receive iron supplements (for breastfed infants 2 mg/kg per day elemental iron is recommended as a supplement; formula-fed infants should receive iron fortified formula and 1 mg/kg per day elemental iron as a supplement is appropriate). Recommendations for breastfed infants, beginning around 4 to 6 months, include 1 mg/kg per day of iron. For older infants, iron supplements may be required if adequate intake from complementary foods is not assured.

Supplementation with 400 IU of vitamin D should be initiated within days of birth for all breastfed infants, and for non-breastfed infants and children who do not ingest at least 1 litre of vitamin D-fortified formula or milk daily, and consideration should be given to supplementing with up to 800 IU of vitamin D per day.

Weaning Babies from Breast Milk or Formulas

Infants should remain on breast milk or formula until the age of 1 year, as the AAP recommends that cow’s milk not be given to children under 1 year of age. Most healthcare providers feel that cow’s milk is an important source of calories, protein, and calcium for children over 1 year of age. Earlier introduction of cow’s milk is associated with gastrointestinal blood loss due to a milk protein-induced inflammatory reaction in the small bowel. This blood loss may be sufficient to deplete iron stores and to produce anemia. In addition, cow’s milk has a higher protein and phosphorus content than breast milk or infant formula. These components present a solute load that exceeds the capacity of the immature kidney and may precipitate dehydration and electrolyte imbalance in infants.

Introducing Solid Food

Recommendations concerning the introduction of solid food have changed considerably over the years. In the past, many children ate a wide variety of foods as early as the first month of life. The consensus among healthcare providers is to delay the introduction of solid foods until the child is at least 4 months old. The AAP and WHO both recommend breast milk as the sole nutrient source until 6 months of age.

Infants are not physiologically ready to accept solid foods from a spoon until they are at least 4 months of age. It is around this time that the oral extrusion reflex becomes extinguished and infants develop sufficient head and neck control and coordination of the oral musculature to begin taking solid foods. Recent data also suggests that early introduction of solid foods (defined as before 4 months of age in this study) may predispose the child to excess weight gain and obesity.

The introduction of solid foods marks the beginning of a critical period during which the infant learns to master eating from a spoon and to accept different tastes and textures. Not coincidentally, an infant’s readiness for these experiences generally corresponds to a physiologic need to supplement the amounts of calories and nutrients available from breast milk or formula. However, breast milk, formula, or a combination should still continue to be the major source of calories and nutrients during the remainder of the infant’s first year.

Preventing and Managing Food Allergies

Introducing solid foods earlier in an infant’s life may stimulate the development of food allergies. Infants from families with known food allergies are most at risk. Food allergies – actually, food hypersensitivity reactions – occur in 2 to 8 percent of children less than 3 years of age. Approximately 90 percent of food allergies are associated with the following group of eight foods: peanuts, tree nuts (such as walnuts or cashews), eggs, milk, fish, shellfish, soy, and wheat. Approximately 2.5 percent of infants will experience allergic reactions to cow’s milk in the first 3 years of life, 1.5 percent to egg, and 0.6 percent to peanuts. Many children outgrow food allergies during the first few years of life. Approximately 85 percent of children with reactions to milk and eggs become tolerant to them by 5 years of age. Even a peanut allergy may remit in up to 20 percent of children. It should be noted that celiac disease is related to a reaction to gluten, may cause symptoms similar to food allergies (diarrhea, abdominal pain), but is not an allergy, and does not remit with time.

General Guidelines for Introducing New Foods

Most experts agree that new foods should be introduced gradually, with an interval of at least 3 days between successive new food introductions. Following this procedure makes it easier to detect a child’s inability to tolerate a newly introduced food. Table 4-8 summarizes how to feed an infant during the first year of life and is often very helpful to hand out to parents of infants.

Cereals For formula-fed infants, iron-fortified cereals are the first recommended solid food. Generally offered first at 6 months of age, rice cereal is fortified with iron, is generally non-allergenic, and is usually well tolerated. Begin with 1 to 2 tablespoons in the morning, mixed with formula or breast milk. The cereal should be mixed to a consistency similar to that of applesauce. Cereal can be thickened as the child grows older. Feeding cereal from a spoon helps the baby learn this new skill, which takes a few weeks. Parents should be advised to avoid putting cereal in a bottle, as it does not, as commonly believed, help children to sleep through the night. Furthermore, the need to make a larger hole in the nipple to prevent clogging may cause a rapid intake of this viscous mixture and lead to choking.

Vegetables Cooked, strained vegetables, without added salt, either homemade or as commercially prepared baby food, are appropriate to start at 6 to 8 months of age. The importance of avoiding salt should be stressed. Infants do not require extra sodium, and adding salt may encourage a greater salt intake later in life. Raw vegetables that are soft or cooked (steamed) may be introduced at 1 year of age. Hard vegetables such as raw carrots should not be introduced until the child’s top and bottom molars have erupted and she can adequately chew and swallow these items without choking. It is advised that vegetables be introduced prior to fruits, because infants are likely to prefer the sweet taste of fruits to vegetables. Introducing vegetables first gives them a better chance of being accepted by the child.

Fruits and Fruit Juice Cooked and strained or pureed fruits, either homemade or purchased baby food without added sugar, may be started after rice cereal and vegetables. Fresh, mashed bananas also may be introduced at this time. Peeled, soft fruits such as peaches and pears may be cut into small pieces and started at 8 to 10 months of age. It is recommended that foods that are harder to chew, such as apples, should be deferred until the child has a greater capacity to chew. Juices made from 100 percent fruit, such as apple juice, may also be offered at this time. According to the AAP, no juice should be given to babies younger than 6 months of age. Juice intake should be limited to less than 4 ounces per day for children over 6 months to ensure adequate intake of other foods. Encourage parents to dilute juice with water and to only offer 100 percent juice without added sugars.

Parents who do not themselves eat a wide range of fruits and vegetables may hesitate to offer such foods to their infants. Research suggests that taste preferences are inherited, so if a parent does not like broccoli, there is an increased chance that the child will also not like it. However, as noted below, repeated offering of a new food may overcome a child’s initial resistance or rejection of an unfamiliar taste or texture.

Eggs In the past, experts recommended that cooked egg yolks be introduced to infants over the age of 6 months, but that the introduction of egg whites should be delayed until the child reaches 1 year of age because of the potential risk of inducing an allergy to eggs in younger infants. However, recent recommendations from the AAP state that there is no convincing evidence that delaying the introduction of highly allergenic foods, such as eggs, has a significant protective effect on the development of atopic disease.

Meat Red meat can be an important source of iron. For breastfed and partially breastfed infants, smooth preparations of single meat (beef, veal, lamb, turkey, chicken) are suggested as the first solid food. Recent research indicates that the early consumption of meats improves the iron and zinc status of the older infant. Meats should be well puréed to avoid the risk of choking. Iron supplementation of vegetarian breastfed babies who will not be given meat should be considered (elemental iron 1 mg/kg per day) if dietary sources of iron are not adequate.

Starch/Carbohydrates Children tend to like pasta, spaghetti, noodles, and dry cereal. However, other essential foods with higher nutrient density should be introduced first during the meal to ensure that the child’s diet is complete and balanced. Whole grains are recommended over their white counterparts for added nutrients and fiber and introducing whole grains early may help children to acquire a life-long taste for them.

Fats High saturated fat intake is associated with a greater risk of AVD and other conditions in adults. However, the high caloric density of fat makes it an important source of calories for the rapidly growing infant. Unfortunately, cases have been reported of failure to thrive, in which young children were fed an inappropriate, very low-fat, calorically inadequate diet, so it is important to provide guidance to ensure that children are receiving a nutritionally adequate diet if modification of fat intake is implemented. A longitudinal study has reported normal growth and development over more than 10 years in a group of children whose parents were counseled to follow a lower fat, nutritionally adequate diet starting in infancy.

To be prudent, the AAP recommends that dietary fat should not be limited before age 2. However, in order to support the development of healthy eating habits, children should not have the opportunity to eat popular high-fat foods such as french fries, chicken nuggets, pizza, macaroni, and cheese, every day.

Beverages Soft drinks such as soda (regular and diet) are acidic and contribute to dental caries in children by demineralizing and eroding tooth enamel. In addition, the sugar content of these beverages sustains bacterial growth around the teeth, which also produces acidic by-products that demineralize teeth and cause cavities. Soda and other sweetened beverages, such as juice drinks, iced teas, and sports drinks, can contribute to excess calorie intake. It is recommended that children and adults alike avoid consumption of such beverages. These beverages as well as 100 percent fruit juices may contribute to obesity. They should not be given to young children and only provided in limited amounts to older children. Juices provide nutrients, but commonly contain as many calories as soda.

Choking Hazards Parents and caregivers should be warned not to feed infants foods that pose a hazard for choking or aspiration. These include nuts, popcorn, grapes, raisins, raw carrots or celery, and hot dogs.

Potential Feeding Problems

Children begin expressing personal preferences at an early age and simultaneously develop mechanisms for self-control. Parents must therefore take care to strike a balance between helping guide a child’s food choices to develop healthy eating habits and providing sufficient opportunities for experimentation and control. Over-controlling parental behaviors have been associated with a child’s decreased ability to appropriately control his/her own caloric intake. Children of authoritarian parents (those who set limits, but respect their child’s likes and dislikes) do best with regulating their own intake. Parents should provide children with a healthy selection of food and children should be allowed to determine how much food they need to eat. Children who consume a variety of foods over time and demonstrate appropriate growth are likely to be consuming an adequately balanced diet. Allowing children to dictate what and when they will eat likely promotes poor eating habits. Parents who worry that their child is not eating enough and allow the child to eat anything and at any time of the day simply to ensure that he or she eats something may be promoting poor eating habits.

Problems also surface when parents engage in power struggles with their children over eating issues. Toddlers and young children may experience “food jags” where they want to eat the same food for days at a time. Meeting the child’s request, while offering other healthy foods alongside the desired food, may be a better response than turning mealtime into a battle. Left on their own, children eventually will tire of the same food, but if winning each mealtime struggle is in the balance, these episodes may worsen.

Confusion and rushing at mealtimes, as well as distractions such as television, may also disrupt the formation of appropriate eating habits. The following are recommended best practices for caregivers feeding young children:

• Offer meals and snacks around the same time each day. Eating opportunities should be 2 to 4 hours apart. This allows the child to regulate his/her own hunger.
  
• Allow children to have only water between scheduled meals and snacks. Do not allow “grazing”.
  
• Sit with children at the table and eat together as often as possible. Engage in pleasant mealtime conversation as a family. Be a role model by eating healthful foods in front of young children
  
• Do not allow the child to dictate what will be served at meals and snacks. Caregivers are responsible for making this decision and should not short-order cook to cater to the likes of each child. However, ensuring that at least one food item offered is accepted by the child can make mealtimes easier.
  
• Do not force children to eat. Similarly, do not restrict them to only set portions. Healthy children are able to regulate their own hunger.
  
• Do not use food for bribing, rewarding, or punishing children.

Requirements for Growth

Adolescents’ energy and nutrient needs increase as they enter their pubertal growth spurt, but on a per kilogram basis, are generally lower than those of infants and children. Infants typically double their body weight over a few months, whereas older children and adolescents may double their weight over a period of 6 to 9 years. However, the energy needs of adolescents may vary considerably – between those whose activity level decreases considerably as they transition from a younger child who plays a lot to inactive “couch potatoes” and internet surfers, or those who are active multiple sport participants. The iron requirements of adolescent girls also increase as they begin to menstruate.

Lifestyle Issues

Adolescence marks a time of psychological, physical, and social changes that may influence eating habits. In particular, adolescents commonly have (1) a tendency to skip meals (especially breakfast and lunch); (2) sufficient money and opportunities to purchase foods (including fast foods) on their own outside the home or school environment; (3) increased consumption of “junk food” and sweetened beverages (adolescent males in particular); (4) a tendency to diet, particularly adolescent girls; (5) changes in physical activity including increased activity among adolescents participating in competitive sports or, conversely, decreased physical activity such as with non-athletic adolescents.

Some adolescents also explore restrictive dietary practices, fad diets, or vegetarianism that may put them at risk for vitamin, mineral, and trace element deficiencies. Eating disorders such as anorexia nervosa and bulimia nervosa also become a concern in adolescence. They occur across all major ethnic groups and all socioeconomic levels, and teen athletes may be at higher risk of developing an eating disorder, especially those participating in sports where low weight, a weight target or limiting weight gain is encouraged. Common features of eating disorders include dysfunctional eating habits, body image misperception, and rapid weight loss. Eating disorders are generally classified as mental health problems, therefore a team approach to treatment that includes medical management, psychological interventions, and nutritional counseling is recommended (see Chapter 4: Case 3).