INTRODUCTION — The goals of nutritional intervention in patients with food allergy are twofold: prevent acute and chronic food allergic reactions through allergen elimination and ensure optimal nutrition within the context of the allergen-restricted diet.

Nutritional management of food allergy requires careful planning to ensure that the nutrients inherent in the eliminated food(s) are adequately replaced. Nutrient-dense alternative food sources should be recommended when elimination diets are initiated. Follow-up to ensure that the alternative nutrient sources have been accepted and incorporated into the diet is also recommended.

This topic will focus on the prevention of nutritional problems that can arise with food elimination diets. Food allergen avoidance is discussed separately. (See "Management of food allergy: Avoidance" and "Patient education: Food allergen avoidance (Beyond the Basics)".)

The indications for nutrition assessment, clinical features of nutrition disorders, measurements of growth, and laboratory evaluation of nutritional status are also discussed separately. (See "Indications for nutritional assessment in childhood" and "Measurement of growth in children" and "Laboratory and radiologic evaluation of nutritional status in children" and "Dietary assessment in adults".)

REFERRAL — All patients with food allergy and their families would benefit from referral to a registered dietitian nutritionist (RDN) to learn how to avoid their allergens and how to substitute the eliminated food while minimizing the social impact of the allergy. Children in particular are at increased nutritional risk, and parents will need to plan avoidance strategies for a variety of settings, including those where the parent may not be present (eg, school, camps). Of note, an RDN has completed a minimum of a bachelor's degree from an Accreditation Council for Education in Nutrition and Dietetics (ACEND) approved program, an ACEND-approved internship, passed a written exam, and completed continuing professional education credits needed to maintain credentials. The term "nutritionist" is often free from governmental regulation and can be used by anyone without proof of qualification.

Major allergens that are staple foods (eg, milk, wheat) typically provide a large percentage of daily dietary intakes, contributing not only energy but also macronutrients (carbohydrates, protein, and fat) and micronutrients (vitamins and minerals). Other common allergens (eggs, soy, peanuts, tree nuts, fish, and shellfish) are nutritionally dense and, when eliminated, can impair intake of specific nutrients. Children with multiple food allergies or cow's milk allergy (CMA) appear to be at greatest nutritional risk, with a higher proportion exhibiting poor growth or overt malnutrition [1-6]. A registered dietitian nutritionist with food allergy expertise can provide patient-specific, practical advice on eliminating multiple and/or staple foods and address nutritional needs by recommending nutritionally appropriate replacements for eliminated foods as well as advice on skill-appropriate progression of complementary foods to avoid feeding difficulties [7].

GENERAL NUTRITION AND FOOD ALLERGY — Dietary limitations secondary to food allergy can lead to malnutrition, decreased growth velocity (height/length and weight), and/or deficiencies in specific macro and micronutrients [2]. Several studies have demonstrated that children with food allergies have lower intakes of total energy and macro/micronutrients than children without food allergy [2,8-10]. (See "Poor weight gain in children younger than two years in resource-abundant countries: Management" and "Poor weight gain in children older than two years in resource-abundant countries" and "Poor weight gain in children younger than two years in resource-abundant countries: Etiology and evaluation", section on 'Causes'.)

Pediatric clinicians should closely monitor the growth (height/length in addition to weight) of children with food allergy and refer such patients to a registered dietitian for evaluation [11,12]. In particular, height/length may be impacted, with one prospective international survey of over 430 children finding stunting more common than poor growth in children with food allergy [6]. (See 'Monitoring growth' below and "Normal growth patterns in infants and prepubertal children", section on 'Evaluation of growth'.)

Risk factors for nutritional deficiencies include dietary factors, such as multiple food allergies leading to a larger number of foods eliminated, altered weaning schedules, and elimination of foods with greater nutritional value; behavioral factors such as picky eating, refusal of supplemental formulas, and food refusal; and psychosocial and economic factors [13].

Energy — The patient with food allergies is at risk of insufficient energy intake due to inadequate substitution in the allergen elimination diet. Additionally, feeding problems such as food aversion and limited acceptance of a variety of foods may occur in children with food allergies and may significantly contribute to poor energy and overall nutrient intake. Certain food allergic disorders, such as eosinophilic esophagitis (EoE) and gastroenteritis, are more commonly accompanied by poor appetite, early satiety, and feeding difficulties, potentially contributing to decreased energy intake [14-16]. (See "Clinical manifestations and diagnosis of eosinophilic esophagitis" and "Eosinophilic gastrointestinal diseases".)

Estimated energy needs for those with food allergies are generally similar to energy needs of those without food allergies. (See "Introducing solid foods and vitamin and mineral supplementation during infancy", section on 'Infant nutritional requirements' and "Dietary recommendations for toddlers, preschool, and school-age children", section on 'Energy'.)

Energy is provided in the diet through three primary classes of macronutrients:

●Proteins

●Carbohydrates

●Fats

Acceptable macronutrient distribution ranges (AMDRs) indicate the range of intake for a particular energy source, expressed as a percentage of total caloric intake that is associated with reduced risk of chronic disease while providing adequate intakes of essential nutrients (table 1) [17].

Macronutrient intake should be considered in the nutritional assessment and recommendations for dietary modifications to ensure appropriate intake and distribution of carbohydrates, fats, and proteins. Finding a nutritional balance as well as meeting recommended dietary intakes can often be challenging when food groups are eliminated due to food allergies.

Protein — Many excellent sources of protein are also common allergens, including cow's milk, egg, soy, fish, shellfish, peanut, and tree nuts. Diets must be carefully planned to meet protein needs for optimal nutrition (and growth in children) when high-quality protein sources are eliminated from the diet.

Although rare in affluent countries when unrelated to chronic illness, cases of protein malnutrition have been reported in patients on elimination diets [18]. In a review of 12 cases of kwashiorkor referred to tertiary care centers in the United States (age range 1 to 22 months), one-half were the result of a deliberate deviation from a standard diet due to suspected food allergies without adequate protein in the diet [18]. Inadequate dietary protein intake may also contribute to decreased stature reportedly seen in children with food allergies [8,19,20]. (See "Malnutrition in children in resource-limited countries: Clinical assessment".)

Quality and quantity of dietary protein must be considered as well as total energy intake when assessing adequacy of protein in the diet [17]. The AMDR for protein is 5 to 20 percent for children 1 to 3 years of age, 10 to 30 percent for children 4 to 18 years of age, and 10 to 35 percent for adults. Dietary protein recommendations are based upon the assumption that energy intake is adequate. If energy intake is insufficient, free amino acids will be oxidized for energy, allowing for fewer available amino acids for anabolic and synthetic pathways [17]. The ideal protein-energy ratio for children with malnutrition (wasting) is higher, with recommendations from the World Health Organization (WHO) of between 8.9 and 11.5 percent [21].

Dietary protein recommendations are also based upon an estimated 65 to 70 percent of protein intake coming from sources of high biologic value, typically animal products, which contain a full complement of essential amino acids. Animal products are not necessary to provide optimal protein, but most alternative sources from plants (eg, legumes, grains, nuts, seeds, and vegetables) do not contain a full complement of essential amino acids. Thus, a diet without animal products requires greater dietary planning to ensure that a variety of plant-based foods are provided throughout the day to meet essential amino acid needs. It is not necessary to combine proteins in each meal. (See "Dietary history and recommended dietary intake in children" and "Vegetarian diets for children".)

Fat — Dietary fat is an important source of energy, supports the transport of fat-soluble vitamins, and provides the two essential fatty acids (EFAs), alpha-linolenic acid (ALA) and linoleic acid (LA). Assessing fat intake in the patient with food allergy is a simple but often overlooked step in the nutrition evaluation.

The AMDR for fat is 25 to 35 percent of total energy intake for older children and adults (30 to 40 percent for children one to three years of age). The risk of insufficient energy, vitamin E, and EFAs increases when fat intake falls below 20 percent of the total dietary energy intake [17,22]. The AMDR for LA and ALA is 5 to 10 percent and 0.6 to 1.2 percent, respectively, for children one year of age and older and adults. Although EFA deficiency is rare, the amount and type of dietary fat present in the diet will determine if fat intake is healthful. (See "Micronutrient deficiencies associated with malnutrition in children".)

To meet fat recommendations (AMDR), most dietary fats should come from monounsaturated and polyunsaturated sources (table 2). Intake of saturated should be limited to <10 percent of total energy intake in children >2 years and adults [23]. Trans fat intake should be kept as low as possible. (See "Dietary fat" and "Dietary recommendations for toddlers, preschool, and school-age children", section on 'Fat'.)

The recommended intake for LA is easily met as LA is abundant in most diets and is found in a wide variety of vegetable oils (table 2 and figure 1). ALA is less abundantly found, and the best sources tend to be from more commonly allergenic foods, such as fatty fish, certain nuts, and seeds.

Dietary fat is present in a wide variety of foods, such as dairy products, eggs, meat, fish, poultry, nuts, avocado, vegetable oils and margarines, and many convenience foods. Treatment of food allergy often results in the elimination of the allergen as well as many manufactured food products that contain the allergen. The resulting diet tends to come from primarily whole foods rather than processed foods, which may result in inadequate fat intake if additional fat is not added to the diet.

Replacement — Vegetable oils are easily added to the allergen-restricted diet when fat and EFA needs are not met (table 2 and figure 1). Refined oils (as opposed to unrefined or expeller-pressed oils) do not contain significant amounts of allergenic protein and therefore are a safe form of dietary fats for most patients with food allergies. The amount and type of oil used is individualized based upon current dietary intake and degree and type of dietary restrictions. Adding fats that are predominantly monounsaturated and polyunsaturated and those that contain at least 10 percent of daily EFA requirements are preferred. (See "Dietary recommendations for toddlers, preschool, and school-age children", section on 'Fat and cholesterol'.)

Carbohydrate — Carbohydrates make up the remaining energy sources and supply numerous vitamins, minerals, and trace elements. Individuals with grain allergies may have an especially difficult time ingesting sufficient carbohydrates without appropriate grain substitutions. In addition to grains, other foods that contribute carbohydrates in the diet are fruits, vegetables, milk products, and legumes. (See 'Wheat allergy' below.)

The AMDR for carbohydrate is between 45 to 65 percent of total caloric intake [24]. The recommended dietary allowance (RDA) is 130 grams/day for children one year of age and older and adults, based upon the role of carbohydrates as the primary source of energy for the brain [17].

Micronutrients — Micronutrients include vitamins, minerals, and trace elements. Variety in the diet contributes to adequacy of all nutrients provided. When a food group is eliminated, many nutrients provided by that food group must now be provided by other dietary sources.

Dietary reference intakes (DRIs) for micronutrients are available through the National Institutes of Health. (See "Dietary history and recommended dietary intake in children", section on 'Dietary reference intakes'.)

It is important to ensure adequate intake of all essential nutrients in children with food allergies. However, there is a greater risk of insufficiency of certain nutrients, depending upon the food allergen(s) avoided. These nutrients must be adequately replaced by other foods in the diet (table 3 and table 4 and table 5 and table 6).

Supplementation of micronutrients is considered when dietary modifications are inadequate to meet vitamin, mineral, and trace element needs. However, dietary supplements may contain or be contaminated with the very food allergen(s) the patient is trying to avoid. Thus, supplements should be assessed for allergen content prior to use [25].

MONITORING GROWTH — Growth in children is a good indicator of adequate energy and protein intake. Weight is the most sensitive measure of energy intake and is affected earlier and to a greater extent than stature by dietary inadequacies. However, stature may be negatively affected by food allergy even prior to changes in weight velocity [2,6]. Children with food allergies are at greater risk of inadequate growth and suboptimal nutrition than those without food allergies [1-4,8,9,19,20,26]. (See "Causes of short stature" and "Diagnostic approach to children and adolescents with short stature" and "Malnutrition in children in resource-limited countries: Clinical assessment" and "Poor weight gain in children older than two years in resource-abundant countries", section on 'Limited or inappropriate intake' and "Poor weight gain in children younger than two years in resource-abundant countries: Etiology and evaluation", section on 'Growth trajectory and proportionality'.)

Plotting a child's weight history on the appropriate growth chart (World Health Organization [WHO] growth charts for children younger than two years of age and Centers for Disease Control and National Center for Health Statistics growth charts for older children) provides a way to follow the typical growth patterns for that child as well as compare those patterns with that of the healthy reference population [27]. The reference lines on the WHO growth charts are either percentile lines or Z-scores. Z-scores are units of standard deviation from the mean. (See "Normal growth patterns in infants and prepubertal children", section on 'Evaluation of growth' and "The pediatric physical examination: General principles and standard measurements", section on 'Standard measurements' and "Measurement of growth in children", section on 'Recommended growth charts with calculators'.)

Dietary counseling can significantly improve nutritional intake and prevent nutritional deficiencies and growth failure [6,10,28]. Thus, children with food allergies, especially multiple food allergies or allergies to foods that are staples in the diet, such as milk, should be referred for nutritional counseling [11]. Recommending nutrient-dense alternatives to the eliminated food at diagnosis and ensuring that the alternative food is accepted and incorporated into the diet are essential preventative measures. The primary care provider may recommend a dietitian, or, in the United States, one may be found through the Academy of Nutrition and Dietetics. (See "Indications for nutritional assessment in childhood" and "Measurement of growth in children" and "Dietary history and recommended dietary intake in children".)

FOOD ELIMINATION DIETS — Long-term food elimination diets are essential to the management of patients with food allergy [11]. However, they should only be undertaken with close clinical supervision, preferably with the guidance of an allergy specialist and/or gastroenterologist to assure that elimination only includes those foods proven or highly likely to be causing symptoms. Foods should not be eliminated from the diet based upon results from unvalidated testing methods or based upon a "positive" validated test alone without correlation with the clinical history. (See "Management of food allergy: Avoidance" and "Patient education: Food allergen avoidance (Beyond the Basics)" and "History and physical examination in the patient with possible food allergy" and "Diagnostic evaluation of IgE-mediated food allergy", section on 'Unvalidated methods'.)

Food elimination diets may impact nutrient intake. Thus, care must be taken to ensure that the restricted diet continues to provide adequate nutrition. This is especially important in children, in whom nutritional deficits may impact growth and development. Rickets, vitamin and mineral deficiencies, and suboptimal growth and failure to thrive are all associated with food elimination diets [9,19,29-33]. (See "Overview of rickets in children" and "Micronutrient deficiencies associated with malnutrition in children" and "Poor weight gain in children older than two years in resource-abundant countries" and "Poor weight gain in children younger than two years in resource-abundant countries: Etiology and evaluation", section on 'Causes'.)

Eight foods/food groups are responsible for 90 percent of all food allergic reactions in the United States. The most common significant food allergens in adults are peanut, tree nuts, fish, and shellfish. Common food allergens of early childhood are cow's milk, hen's egg, wheat, soybean, and peanut [34,35]. Cow's milk allergy (CMA), wheat allergy, and multiple food allergies present the greatest nutritional challenges. (See "Management of food allergy: Avoidance".)

Cow's milk allergy — Adults with CMA are at risk of vitamin D and calcium deficiency because it is difficult to meet calcium needs through nondairy sources without careful substitution. The nutritional impact of cow's milk elimination in children is even greater since milk and milk products are the primary source not only of calcium and vitamin D, but also fat and protein for young children (table 7). Milk also provides vitamin B12, vitamin A, pantothenic acid (vitamin B5), riboflavin, and phosphorus. Finding a nutritionally dense substitute for cow's milk in the pediatric diet is essential. Alternative dietary sources for these nutrients are available (table 3). Vitamin D supplementation is discussed separately. (See "Milk allergy: Clinical features and diagnosis" and "Milk allergy: Management" and "Vitamin D insufficiency and deficiency in children and adolescents", section on 'Targets for vitamin D intake'.)

Breastfed infants — Maternal elimination of cow's milk protein is not necessary if the nursing infant is without symptoms and is growing well on an unrestricted maternal diet. However, nursing mothers of infants with CMA should do a trial of complete avoidance of milk protein in their diet if the infant has allergic symptoms and/or growth issues since immunologically recognizable proteins from the maternal diet can be found in breast milk [36]. The nutritional adequacy of the maternal diet may need to be assessed since complete milk elimination can compromise maternal nutrient intake [37]. Maternal concentrations of vitamin D, vitamin A, vitamin B6, vitamin B12, thiamin, niacin, selenium, iodine, and choline, in addition to the types of fatty acids present in the maternal diet, are reflected in breast milk [38]. Repletion in the maternal diet with a complete multivitamin mineral supplement can increase the content of these nutrients in breast milk when the maternal diet is otherwise deficient. Calcium content of breast milk is not affected by maternal calcium intake [39,40]. However, maternal dietary calcium replacement or calcium supplementation (1000 mg/day) is recommended to maintain maternal stores [41]. (See "Maternal nutrition during lactation" and 'Formula-fed infants' below.)

Formula-fed infants — Formula-fed infants with CMA need to avoid intact cow's milk protein formulas. Both extensively hydrolyzed cow's milk protein formulas (eHFs) and amino acid-based formulas (AAFs) are considered hypoallergenic [36]. For the vast majority of infants with CMA, an eHF is sufficient for symptom resolution. However, there is a subset of children who may require an AAF [42]. Another option that is available in Europe is extensively hydrolyzed rice protein-based formula (eRHF) [43,44]. Partially hydrolyzed cow's milk formulas (pHFs), such as Good Start (Nestle) and Gentlease (Enfamil), are not considered hypoallergenic in the United States and are not suitable options for infants with CMA [36]. Formulas from Europe labeled hypoallergenic (HA) are typically partially hydrolyzed and not suitable for management of CMA [45].

A summary report from an international consensus panel of allergy specialists (the Diagnosis and Rationale for Action against Cow's Milk Allergy [DRACMA]) provides conditional formula recommendations and advises that these should be interpreted with special attention to patient preference, cost, and clinical circumstance [41]:

●An eHF is recommended over an AAF or soy formula for the majority of patients with CMA since more than 90 percent of infants with CMA tolerate extensively hydrolyzed milk protein-based infant formulas (table 8).

●An AAF is recommended over an eHF in certain circumstances:

•Infants with immunoglobulin E (IgE)-mediated CMA at high risk of anaphylaxis who are not already on and tolerating an eHF.

•Any patient with eosinophilic esophagitis (EoE).

•Infants who continue to exhibit symptoms on eHFs.

•Infants with poor growth who have not improved on an eHF [42,46].

The DRACMA summary report recommends that soy formula not be given to infants with CMA during the first six months of life. Although soy formula is tolerated by approximately 85 percent of infants with IgE-mediated CMA, the prevalence of hypersensitivity to both soy and cow's milk is up to 60 percent for infants in the United States with non-IgE-mediated CMA, such as enterocolitis syndrome [36]. However, we generally do not switch infants with CMA to an eHF if they are already on a soy formula and tolerate it and/or if cost or taste preferences preclude the use of hypoallergenic formulas. (See "Introducing formula to infants at risk for allergic disease", section on 'Soy formula versus others' and "Introducing formula to infants at risk for allergic disease", section on 'Formula selection for the high-risk infant' and "Food protein-induced allergic proctocolitis of infancy".)

Children >1 year old — Infants are usually transitioned from a complete formula or breast milk to whole cow’s milk at approximately one year of age, usually around the time that at least two-thirds of the total daily caloric intake comes from a varied solid food diet. However, other criteria must be considered in the child with CMA, especially one with multiple food allergies, since a varied solid food diet may not be possible. Assessing the nutritional contribution of the solid food diet and the growth of the child as well as considering the nutritional benefits and pitfalls of the alternative beverages (table 7) before transitioning from a formula to a milk substitute is strongly advised. Hypoallergenic formulas or breast milk are the preferred substitute in children under two years of age [41].

Continued use of commercially prepared complete formulas beyond infancy is recommended for children with multiple food allergies on very limited diets or for those avoiding both milk and soy (table 9). Enriched alternative beverage sources (usually soy, nut, seed, or grain based) generally do not provide comparable nutrition with whole cow's milk or formulas (table 7). Thus, the DRACMA summary report recommends substituting a hypoallergenic formula or breast milk for cow's milk until two years of age [41]. The use of enriched alternative beverages for children between one and two years of age is not recommended in general, but they can be used on an individual basis after dietary assessment.

Enriched soy or pea protein beverages are appropriate alternatives for older toddlers, if tolerated, and provide dietary calcium, vitamin D, and protein sources similar to milk (table 7). It is important to confirm that the child is consuming an enriched version since unenriched alternative milk beverages are available. There is at least one reported case of a patient with rickets due to consumption of an unenriched soy beverage [30]. The risk of inadequate intake of calcium and vitamin D among children with CMA is decreased if a dairy-free enriched soy beverage or commercially prepared hypoallergenic infant/toddler formula is provided [8]. Soy beverage is generally lower in dietary fats, so additional fat in the form of vegetable oil may need to be added to the young toddler's diet. Pea protein milks are lower in carbohydrates.

For children with concomitant milk and legume allergy, enriched oat beverage provides calcium, vitamin D, vitamin B12, and phosphorus but is lower in protein and fat (table 7). Other enriched grain (eg, rice) and nut (eg, almond) beverages tend to be even lower in fat and protein than oat beverage. Enriched hemp beverage is seed based and would provide adequate fat but is low in protein. Protein requirements should be met entirely through solid foods in the diet before switching to enriched alternative grain or nut beverages. Fat intake may also need to be assessed. Additional fat in the form of vegetable oils may be required. When the child is ready to transition to an enriched alternative grain or nut beverage, intake should be limited to the amount required to meet calcium needs. Lastly, in addition to the poor nutritional quality of rice milk beverage, the presence of inorganic arsenic makes it a poor daily milk substitute for young children. Young children drink a relatively large amount of milk/milk substitute relative to their body weight. Although the US Food and Drug Administration (FDA) has not issued specific guidance for the use of rice beverage as a milk substitute in young children, the European Food Standards Agency does not recommend the use of rice beverage as a daily milk substitute for children under 4.5 years of age based on the poor nutritional quality and inorganic arsenic content [47].

Most alternative mammalian milks, such as goat's or sheep's milk, are also not suitable. Up to 92 percent of individuals with cow's milk protein allergies will also react to goat's milk [36]. Donkey's or mare's milk may be better tolerated in some cases, although these milks are generally not commercially available. (See "Food allergens: Overview of clinical features and cross-reactivity" and "Milk allergy: Clinical features and diagnosis" and "Milk allergy: Management".)

Calcium-fortified juices are often recommended to meet calcium needs. However, a one year old must drink 16 ounces per day of a highly fortified juice (30 percent of the daily value for calcium/serving) to consume adequate calcium. Excessive intake of a nutritionally inferior milk substitute or juice may displace nutrients from other dietary sources resulting in subsequent deficiencies, particularly protein, fat, and energy.

There are numerous other "dairy-free" products on the market, such as soy or coconut-based yogurt and soy or rice-based cheese. However, not all "dairy-free" products are milk protein free; therefore, reading all ingredient labels is imperative. As an example, casein is an ingredient in a rice cheese brand. Additionally, many of these products are manufactured on shared equipment with milk products and run the risk of cross contact with milk. It is possible to find some dairy-like products that are truly milk protein free and manufactured on dedicated equipment or in a suitable way to prevent cross contact. The nutritional contribution of these foods should be evaluated, however, as they are not comparable with the cow's milk versions. As an example, coconut yogurt is essentially protein free. In addition, these products typically are not enriched. (See "Management of food allergy: Avoidance", section on 'Food labeling'.)

Wheat allergy — Wheat contributes carbohydrates, the major source of energy in the diet, as well as many micronutrients. Four servings of wheat-based products, such as whole grain and enriched cereals or breads (eg, one-half cup hot cereal, one slice bread, 1 ounce uncooked pasta), generally provide greater than 50 percent of the recommended dietary allowance (RDA) for carbohydrate, iron, thiamine, riboflavin, and niacin for individuals one year of age and older and are a significant source of folic acid, vitamin B6, and magnesium. Whole-grain wheat products also contribute fiber to the diet. Alternative dietary sources of these macro- and micronutrients should be provided when wheat is eliminated from the diet (table 4). (See "Grain allergy: Allergens and grain classification".)

The patient with an allergy to wheat must avoid all wheat-containing foods, resulting in the elimination of many processed and manufactured products including bread, cereal, pasta, crackers, cookies, and cakes. Wheat is also commonly used as a minor ingredient in other commercial food products, such as condiments and marinades, cold cuts, soups, soy sauce, some low or nonfat products, hard candies, licorice, jelly beans, and gummies.

Many alternative grains and flours are available to patients with wheat allergy, including rice, corn, oat, barley, buckwheat, rye, amaranth, millet, quinoa, tree nuts, and legumes, if tolerated. Some of these alternatives to wheat flour come from other commonly allergenic foods, such as nuts, so caution is warranted. Additionally, 20 percent of individuals with one grain allergy may be clinically reactive to another grain [48]. Thus, use of these alternative products should be individualized and based upon tolerance as determined by the patient's allergy specialist. (See "Food allergens: Overview of clinical features and cross-reactivity".)

Alternative grains may improve the nutritional quality, variety, and convenience of the wheat-restricted diet. Many of these are commercially available as flours for home use. In addition, there are a wide variety of wheat-free and gluten-free products made from these grains. A gluten-free product will be free of wheat. However, the reverse may not be true, since rye and barley are also gluten-containing grains; therefore, a product made with barley may be wheat free but not gluten free. One issue is that many of these flours and products are not well fortified. Additionally, they may be lower in fiber. When choosing alternatives to wheat, the nutritional quality of the alternative flour or product should be considered. Choosing whole or enriched grains greatly improves the nutritional quality of the diet. When baking with unenriched alternative flour, a safe, fortified infant cereal can be substituted for a portion of the alternative flour used in baked products to increase the quantity of nutrients such as iron, thiamine, riboflavin, niacin, and zinc [25]. (See "Management of celiac disease in children" and "Management of celiac disease in adults".)

Egg allergy — Eggs contribute protein, vitamin B12, riboflavin, pantothenic acid, biotin, and selenium in the diet. Many foods supply the nutrients found in eggs, including milk, soy, meats, fish, and poultry (table 5). In addition, egg in the diet usually does not account for a large percentage of daily dietary intake. Thus, egg avoidance is unlikely to negatively impact nutritional intake. However, egg is a common ingredient in the Western diet; therefore, patients with egg allergy will need to learn how to replace egg in recipes (table 10). Many commercial egg substitutes are not suitable for the individual with egg allergy, since they contain egg protein; however, safe versions are available. (See "Egg allergy: Management".)

Soybean allergy — Soy is a nutritionally dense food containing protein, thiamine, riboflavin, pyridoxine, folic acid, calcium, phosphorus, magnesium, iron, and zinc. Soy generally does not appear in large quantities in the diet; therefore, the nutrients lost due to soy elimination are easily replaced (table 6). Exceptions to the minimal impact of soy elimination on nutritional status include concomitant milk allergy or other dietary patterns (such as vegetarianism) that limit food choices. In these cases, the diet should be carefully evaluated to ensure adequacy. (See "Vegetarian diets for children".)

Soy protein is found in a large assortment of products, including baked goods, cereals, crackers, canned tuna and soups, reduced-fat peanut butter, prebasted meat products, cold cuts, hot dogs, and many vegetarian-based products. Eliminating soy from the diet limits the variety of manufactured products that have diverse nutritional and social benefits. Studies show that the vast majority of individuals with soy allergy can tolerate highly refined soy oil and soy lecithin [49,50]. Soy oil and soy lecithin are present in many processed or manufactured foods, and avoidance of these two soy-derived ingredients may unnecessarily eliminate an extensive list of products.

Peanut, tree nut, fish, and shellfish allergies — Peanut, tree nut, fish, and shellfish allergies are the most common food allergens in adults. Although these foods contain valuable nutrients, they do not usually account for a large percentage of daily dietary intakes. Many foods supply the nutrients found in these foods, and substitutions are easily made when the allergy stands alone. However, meeting dietary needs may be more difficult when multiple food allergies occur or the diet is restricted for other reasons (eg, vegetarian diet). (See "Peanut, tree nut, and seed allergy: Management" and "Seafood allergies: Fish and shellfish" and "Food allergens: Overview of clinical features and cross-reactivity" and "Vegetarian diets for children".)

ONLINE RESOURCES — Online resources to help families manage food allergies are recommended:

●Food Allergy Research & Education (FARE)

●Kids with Food Allergies

●International Network for Diet and Nutrition in Allergy (INDANA)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Food allergy".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Beyond the Basics topic (see "Patient education: Food allergen avoidance (Beyond the Basics)")

SUMMARY

●The goals of nutritional intervention in patients with food allergy are to prevent allergic reactions through allergen elimination and to ensure adequate nutrition within the context of the allergen-restricted diet. (See 'Introduction' above.)

●Dietary limitations due to food allergy can lead to malnutrition due to deficits in total energy and/or deficiencies in specific macronutrients (protein, fat, carbohydrates) and micronutrients (vitamins, minerals, trace elements). The specific impact varies depending upon the food or foods avoided. Patients with food allergies should be referred to a registered dietitian familiar with food allergies to avoid these nutritional deficiencies. (See 'General nutrition and food allergy' above and 'Energy' above and 'Protein' above and 'Fat' above and 'Carbohydrate' above and 'Micronutrients' above and 'Referral' above.)

●Children with food allergies are at greater risk of inadequate growth than those without food allergies. Thus, their growth (both length/height and weight) should be monitored closely. (See 'Monitoring growth' above.)

●Measures that are essential to preventing inadequate growth and suboptimal nutrition include recommending nutrient-dense alternatives to the eliminated food at the time of diagnosis and following up to ensure that the alternative food is accepted and incorporated into the diet. (See 'Food elimination diets' above.)

●Alternative dietary sources are available for milk (table 7 and table 3 and table 8 and table 9), wheat (table 4), egg (table 5 and table 10), and soy (table 6). (See 'Cow's milk allergy' above and 'Wheat allergy' above and 'Egg allergy' above and 'Soybean allergy' above.)