Version July 2025
INTRODUCTION —
Vegetarian diets are recognized by the 2020-2025 Dietary Guidelines for America as one of three healthy dietary patterns [1]. There is increasing recognition that minimizing animal-based protein, particularly red meats, and maximizing plant-based options for protein provide combined benefits for health and the ability of this planet to continue providing enough food to feed the world's growing population [2]. In the broadest sense, vegetarian diets exclude meat and poultry, although there are a number of subcategories to vegetarianism (table 1).
As more people turn to vegetarian diets due to health, ecologic, and ethical considerations, it is important for clinicians to be equipped to answer questions for their patients and families. Like any diet, vegetarian diets require planning to optimize health, growth, and nutrient intake [3-7].
This topic review will outline the available evidence on vegetarian diets and discuss how to counsel families to ensure a well-planned diet with appropriate caloric and nutrient intake to support optimal growth. A well-planned vegetarian diet offers health benefits, while a poorly planned diet carries risks, particularly for infants, young children, and adolescents.
Overviews of healthy eating for children and adolescents are presented separately. (See "Dietary recommendations for toddlers and preschool and school-age children" and "Healthy eating for adolescents".)
PREVALENCE AND TRENDS —
Vegetarian diets are becoming increasingly popular in many countries, including among youth [3,8-10].
In the United States, approximately 5 percent of youth 8 to 17 years old describe themselves as vegetarian and 2 percent as vegan [11]. Among adults in the United States, approximately 6 percent follow some form of vegetarian diet and 3 percent follow a vegan diet [12]. When eating away from home, approximately one-half of Americans "sometimes or always" choose vegetarian meals and one-quarter "sometimes or always" choose vegan meals [11,12]. Vegetarian diets were reported by approximately 8 percent of adolescents in the United Kingdom [13] and 8 to 10 percent of adults in Germany, Austria, Italy, and the United Kingdom [14,15].
Interpretation of these surveys is complicated because of variations in definitions for the term "vegetarian" (table 1). Because the types and composition of vegetarian diets have important implications for the growth and development of children and adolescents, it is important for the clinician to discuss with their patients how they define vegetarianism for themselves and, specifically, which foods are included or excluded.
HEALTH CONSIDERATIONS —
Like any diet, vegetarian diets require planning to optimize health. The typical diet in the United States results in higher-than-needed caloric intake for protein in addition to lower-than-recommended intake for whole grains, fruits, and vegetables [16]. Dietary changes that decrease or eliminate animal-based proteins in favor of plant-forward proteins with increased intake of fresh fruits and vegetables align with recommendations of the US Food and Drug Administration and major nutritional societies [17-19]. Families new to these types of changes should be aware of how to achieve appropriate balance in nutrients to avoid a few important pitfalls, which are outlined below.
Overall diet quality — Surveys of pediatric populations indicate that those who follow a vegetarian diet are more likely to meet general targets for a healthy diet compared with those who do not follow a vegetarian diet. Several studies show that vegan children and adolescents generally have healthier food intake patterns, with the higher intakes of whole grains, vegetables, legumes, and nuts and the lower intakes of sweets and snack foods compared with omnivorous children [20-22]. They also had the highest intakes of vitamin E, vitamin B1, folate, vitamin C, magnesium, iron, and zinc and mean fiber intake, whereas the omnivorous group did not reach the dietary reference value of 14 g/1000 kcal for fiber. Another survey of adolescent schoolchildren in Minnesota compared self-reported dietary intake with the Healthy People 2010 nutritional objectives [23]. Adolescents who identified themselves as vegetarians were more likely than nonvegetarians to meet the objectives for total fat (70 versus 48 percent), saturated fat (65 versus 39 percent), daily servings of vegetables (26 versus 14 percent), and ≥5 servings of fruits or vegetables per day (39 versus 28 percent). The mean calcium intake in both groups was approximately 1100 mg/day, which is less than the recommended 1300 mg/day; only 30 percent of the students, regardless of dietary group, met the recommended target for calcium.
Potential effects on growth — Although children who follow a vegetarian diet tend to be somewhat leaner than their omnivore counterparts, their physical growth is usually within the normal range, provided that meal planning is adequate and sufficient food is made available [24-29]. By contrast, poorly planned or severely restricted diets can lead to nutrient deficiencies that may compromise or delay growth in children [30-32].
For children who have suboptimal growth while following a vegetarian diet, clinicians should review the diet composition and total caloric intake, with particular attention to ensuring sufficient fat content and avoiding excessive fiber. (See 'Energy' below and 'Fiber' below.)
Benefits for cardiovascular and metabolic health — Most available evidence on the benefits of vegetarian diets is for adults and shows an association with lower incidence of obesity, coronary heart disease, hypertension, and type 2 diabetes compared with consumption of a nonvegetarian diet [3,5,33-40]. While there are fewer studies specific for children, several studies show that establishing these patterns in childhood carries benefits into adulthood [6,41-43]. Additionally, studies show that vegetarian children generally have a lower risk of obesity; better lipid profiles; and decreased consumption of cholesterol, added sugars, and saturated fat. These benefits are accompanied by modest decreases in cardiovascular risk factors, including non-high-density lipoprotein cholesterol, blood pressure, and body mass index [5,44]. However, it is difficult to separate the effects of the diet from other characteristics of this population, including associated healthful behaviors (eg, regular exercise, avoidance of tobacco and alcohol products) or socioeconomic privilege. As a consequence, an independent effect of the diet on health outcomes or all-cause mortality has not been shown [45].
Benefits for the gut microbiota — Well-planned vegetarian diets appear to be beneficial to human health by promoting more diverse and stable gut microbiota [46]. The diversity of the microbiota has an important association with body mass index, obesity, and cardiovascular protection. Vegetarians have a microbiota rich in Prevotella and Ruminococcus and depleted in Bacteroides compared with omnivores. Plant fibers increase lactic acid bacteria such as Ruminococcus and Roseburia, which degrade complex carbohydrates into short-chain fatty acids and reduce disease-producing Clostridium and Enterococcus species. Plant fibers encourage the growth of microbiota that produce short-chain fatty acids, which improve immunity against pathogens and regulate intestinal function. Plant polyphenols increase Bifidobacterium and Lactobacillus, both of which have antiinflammatory effects. Thus, plant-based diets may be an effective way to promote a diverse ecosystem of beneficial microbes that support overall health.
OVERVIEW OF NUTRITIONAL COUNSELING
General considerations — Properly planned vegetarian diets can meet all nutrient needs for growth and development. Families new to vegetarian diets may benefit from counseling on energy, protein, iron, calcium, vitamin D, and vitamin B12 (cyanocobalamin) and, to a lesser extent, zinc, long-chain omega-3 fatty acids, and dietary fiber [3,47-50]. Nutritional counseling about these nutrients is detailed in the sections on each nutrient below.
The establishment of healthy eating patterns in childhood reduces the likelihood of developing chronic diseases later in life [51-54]. Thus, vegetarian children, like other children, should follow dietary guidelines that limit total fat, saturated fatty acids, and cholesterol and encourage complex carbohydrates, fiber, and antioxidants (eg, vitamins A and C, carotenoids, and phytochemicals) [1]. At the same time, the greatest risks for inadequate nutrient intake from a vegetarian diet occur during periods of growth. The more restrictive the vegetarian diet, the greater the risk of dietary inadequacy [55-57].
To address this, vegetarian or vegan diets should include a variety of nutrient-rich foods. Examples of foods include cooked legumes, whole-grain breads, enriched cereals, nuts and nut spreads (peanut, tahini, almond, cashew butter), nutlike seeds (soybeans, sunflower seeds, sesame seeds, flaxseeds, chia seeds, pumpkin seeds), avocados, and dried fruits. In addition, if dairy products are included in the vegetarian diet, they are a good source of energy, high-quality protein, calcium, potassium, vitamin B12, magnesium, and vitamin D (if fortified) [58,59].
The United States Department of Agriculture "MyPlate plan" is a tool depicting food groups and portion sizes and may serve as a useful reference guide. Food patterns with vegetarian options are provided for different calorie levels [60]. Similar tools for planning a vegetarian or vegan diet include VegPlate Junior (which meets Italian and United States dietary reference intakes) [61] and the "whole-food plant-based plate for healthy beginnings" from the American College of Lifestyle Medicine [62].
If there are concerns about a family's ability to follow through on a well-planned vegetarian diet, families may benefit from a referral to a dietitian to provide more extensive guidance.
Infancy and weaning — Breastfeeding mothers who are vegetarian should ensure adequate intake of vitamin B12, iron, vitamin D, and calcium (table 2). In particular, vitamin B12 content of breast milk reflects maternal vitamin B12 levels and severe deficiency can impair neurologic development in the infant [63]. Vegetarian and vegan mothers should be counseled on B12 supplementation. (See 'Vitamin B12' below.)
If the decision is made to feed an infant a plant-based formula, soy-based formulas are appropriate for full-term infants. Premature infants should be fed human milk if possible but, otherwise, a cow's milk-based premature formula because soy formula is associated with an increased risk of osteopenia [64,65]. Homemade formulas are never appropriate for an infant and should not be utilized [66].
When introducing solids for infants and weaning off of breast milk or formula, it is important to consider that vegetarian foods may have lower caloric density and higher fiber content, filling a smaller stomach without the calories needed for growth. This can be addressed by including higher-fat foods such as nut butters, soy foods, avocados, and oils. Additionally, infants should be offered iron-rich foods such as iron-fortified cereals, beans, dark green leafy vegetables, breads, and peas. Infants weaned to a vegetarian diet also require ongoing attention to ensure that they meet their vitamin B12 needs (0.5 mcg daily) through diet or a supplement.
Older children and adolescents — Understanding and affirming the patient's motivation for a vegetarian diet are valuable steps in counseling. In most cases, the motivation is for ethical or cultural reasons, for planetary or personal health, or for some combination of these.
For adolescents who are new to a vegetarian diet, the change in eating habits should be met with curiosity, both to answer any questions about the implications for health and to identify potential red flags that the change could be related to disordered eating. Adoption of a vegetarian diet during adolescence is not inherently a marker for disordered eating [67-69]. In some cases, ethical or environmental concerns are the key motivations for the dietary choice. In other cases, weight concerns are a primary motivation; this can also be a reasonable and healthy motivation but calls for additional monitoring to ensure that the diet is balanced and eating patterns and growth are appropriate. (See "Healthy eating for adolescents", section on 'Attitudes toward food and body image'.)
Counseling should include information about the nutritional implications of the diet, to set appropriate expectations and encourage the adolescent to make responsible food choices. If the adolescent endorses that their primary goal is to lose weight and/or if the dietary change was related to social or emotional problems, further screening for an eating disorder is appropriate, including a focused history, physical examination and psychological assessments. A patient with body mass index less than the 15th percentile and/or who has other features suggestive of an eating disorder (including disrupted menses or body image disturbances) is a candidate for referral for more intensive medical and psychological care. (See "Eating disorders: Overview of epidemiology, clinical features, and diagnosis" and "Healthy eating for adolescents" and "Healthy eating for adolescents", section on 'Pathologic dietary restriction ("dieting") and body image'.)
Plant-based beverages — For toddlers and preschool-aged children (<5 years), soy milk is an appropriate option in the place of cow-based milk as it has a similar profile in terms of protein, calcium, and vitamin D. Other plant-based beverages (such as oat- or almond-based "milks") should not be used as a primary source of energy and protein, given their lower caloric and protein content.
For school-aged children who avoid cow's milk, counsel families to select plant-based milk options that are fortified with calcium, B12, and vitamin D and do not have added sugar. Specific counseling is important because a wide variety of products are available and consumers may not be aware of the varying nutritional content of the many different plant-based milks. The nutrient profiles of plant-based beverages vary substantially, but they can be relatively low in protein, fat, and other nutrients [70-72]. Even when the beverages are fortified, the plant phytates may reduce the bioavailability of protein and minerals. (See 'Protein' below.)
There is emerging evidence that, in high-quality diets, higher consumption of dairy may have negative health effects. While existing nutritional guidance heavily favors dairy, it is important to recognize that plant-based options in a well-planned vegetarian diet may hold benefits in terms of endometrial and prostate cancer risks in particular, while higher dairy consumption is linked with lower colorectal cancer risk [73].
LABORATORY MONITORING —
Families or children following well-planned vegetarian or vegan diets do not need routine laboratory monitoring outside of the general guidance in primary care for all children. As examples:
●Iron deficiency – Anemia is a relatively common problem in children. Clinicians can help prevent iron deficiency anemia by counseling families about iron-rich foods and ways to improve absorption of iron. In addition, all children should have routine laboratory-based screening for iron deficiency anemia on one occasion for toddlers and adolescent females, with additional screening for those with risk factors including low dietary iron intake. (See "Iron deficiency in infants and children <12 years: Screening, prevention, clinical manifestations, and diagnosis", section on 'Screening recommendations' and "Iron requirements and iron deficiency in adolescents", section on 'Screening'.)
●Vitamin D – For patients with low estimated vitamin D intake (eg, those with little or no intake of fortified dairy products or plant-based beverages), check 25-hydroxyvitamin D at baseline, with follow-up testing as needed, depending on the result or to monitor supplementation. If a supplement is added, check the level approximately six months later and, if the result is normal, recheck approximately every two to three years. (See 'Vitamin D' below.)
●Vitamin B12 – For patients who follow a vegan diet, supplement empirically with vitamin B12. Measure serum vitamin B12 concentrations if there is a concern for deficiency, eg, question of nonadherence to the supplement or macrocytic anemia. (See 'Vitamin B12' below.)
ENERGY —
Approximate energy requirements for infants and children are shown in the tables (table 3 and table 4). Some young children who follow a vegetarian or vegan diet may have difficulty meeting their energy needs because of their relatively small stomach capacity and energy needs for growth [24,25,74,75]. A plant-based diet that has a high fiber content and low caloric density may provide a sense of fullness before an adequate amount of energy is ingested. This situation may be a significant problem in young children, who have small stomach capacities.
To meet energy needs, young children typically need three meals and three snacks per day. Both energy-dense and nutrient-dense foods should be included. Foods higher in healthy fats, such as nuts, seeds, nut and seed butters, and avocado, help meet nutrient and energy needs, especially for children who are underweight. The intake of fat should not be restricted in children younger than two years of age. (See "Dietary history and recommended dietary intake in children", section on 'Energy needs'.)
For adolescents who follow a vegetarian or vegan diet, the clinician should monitor growth and body weight to ensure that energy intake is appropriate. Adolescents who are overweight and who adopt a vegetarian diet as a means of weight management also should be monitored for evidence of disordered eating patterns and given anticipatory guidance to emphasize dietary variety and an appropriate energy intake for healthy weight management [76]. (See "Healthy eating for adolescents".)
PROTEIN
Requirements — Protein requirements for infants and children are listed in the tables (table 3 and table 4) [77]. The protein concentration varies among different foods, as shown in these protein foods tables from the MyPlate website.
These estimates are based on proteins from animal sources (meat, dairy, and eggs) or soy protein (eg, tofu), which are more than 90 percent digestible [78,79]. Diets that include these protein sources generally include sufficient protein, as long as the total energy intake is sufficient. This includes semi-vegetarian, pescatarian, or vegetarian diets that include milk, milk products, and/or eggs [80]. Note that the protein content of plant-based beverages is highly variable and generally less compared with cow's milk. (See 'Plant-based beverages' above.)
Proteins from legumes are 80 to 90 percent digestible, while proteins from grains and other plant foods are 70 to 90 percent digestible. Therefore, for vegetarians who rely on these protein sources, the protein requirement may be increased by 20 to 30 percent for children aged two to six years and by 15 to 20 percent for children aged six and older, in comparison with nonvegetarians [78].
Protein type
●Definitions – Proteins of plant and animal origin differ in their concentration of essential amino acids, which are necessary for growth and repair.
•Complete proteins – Animal proteins (including fish and dairy) and soy protein are considered "complete" because they supply all of the essential amino acids [81,82].
•Incomplete proteins – Other plant-based proteins are considered "incomplete" because they supply only some types of essential amino acids.
•Complementary proteins – Two types of vegetable proteins are considered "complementary" if the combination supplies all essential amino acids. As an example, grains are low in the essential amino acid lysine and high in methionine, whereas legumes and oily seeds are low in methionine and high in lysine. Together, they combine to make a high-quality protein source.
●Clinical implications – In clinical practice, it is rarely necessary to distinguish between these types of protein [83]. For most vegetarian diets, any type of protein can fill the protein requirement because the overall diet will contain ample essential amino acids, either from "complete" proteins or from a variety of "incomplete" proteins (typical intake of legumes or grain proteins).
An exception is a vegan diet that has low protein variety, especially if total protein intake is marginal. In this case, to avoid essential fatty acid deficiency, the protein requirement should be met with either soy protein (a complete protein) or from intentional combinations of complementary proteins (grains plus legumes or seeds). One need not consume complementary proteins at the same time or in the same meal [3,84].
VITAMINS AND MINERALS —
Nutritional counseling is important to ensure that the diet provides adequate vitamins and minerals, especially iron, calcium, vitamin D, and vitamin B12 (cyanocobalamin). If the diet cannot be adjusted to provide recommended amounts of each of these nutrients, supplements should be added to ensure adequate intake. In this case, we suggest a general multivitamin and mineral supplement that contains a broad range of water- and fat-soluble vitamins, minerals, and trace elements to ensure dietary intakes of micronutrients that approximate daily nutrient requirements for age (table 4).
Iron — Children who have rapid growth rates have increased iron needs and are at risk for iron deficiency with or without anemia [85-87]. The recommended dietary allowance (RDA) for iron is 7 mg in children 1 to 3 years old, 10 mg in children 4 to 8 years, 8 mg in children 9 to 13 years, and 11 mg for males and 15 mg for females aged 14 to 18 years. The RDA for pregnant adolescents is 27 mg/day [88]. (See "Iron deficiency in infants and children <12 years: Screening, prevention, clinical manifestations, and diagnosis" and "Iron requirements and iron deficiency in adolescents".)
●Potential deficits for a vegetarian diet – Iron deficiency is common among children in the United States and many other countries. Vegetarian and vegan children are potentially at higher risk for iron deficiency because milk and eggs are not good sources of absorbable iron, but the prevalence of iron deficiency varies widely [89]. Risk factors include a diet poor in plant-based iron-rich foods, periods of rapid growth, and menstruation [78,85,90,91]. In a study of 1100 children aged 4 to 18 years, female adolescents who reported being vegetarian were more likely to have low hemoglobin and serum ferritin values compared with their omnivorous peers [85]. One study of 43 lacto-ovovegetarian and 46 omnivorous children aged 4.5 to 9 years found lower serum hepcidin and ferritin levels in the vegetarian children, despite higher dietary intake of vitamin C, compared with the nonvegetarian children [92]. By contrast, a longitudinal study of young children in Toronto found no association between a vegetarian diet and biomarkers of iron deficiency [26].
Children who do not eat meat are at risk for iron deficiency because nonheme iron (from plants) is less readily absorbed compared with heme iron (from meat or fish) [85,88,93,94]. Absorption of heme iron is 15 to 35 percent, compared with 2 to 20 percent for nonheme iron. In addition, the absorption of nonheme iron is reduced greatly by other dietary components, whereas heme iron is little affected (table 5). In particular, tannins and polyphenols in tea and coffee form iron-tannate complexes that greatly reduce nonheme iron absorption [47,85,95]. Phytate found in legumes, nuts, seeds, whole grains, and soy protein also bind with nonheme iron to form insoluble complexes and reduce iron absorption [47,85,96,97]. In one study, absorption of iron from a variety of commonly eaten legumes (dried beans and peas) prepared as soups was only 1 to 2 percent [90].
●Nutritional counseling – For children who do not eat meat or fish, important strategies to increase iron absorption include intake of ascorbic acid (vitamin C) at each meal, avoidance of large intakes of tannin-containing teas, and increasing dietary iron content [47,85,87,98].
Iron supplements may be necessary for individuals with laboratory markers for iron deficiency (eg, low mean cell volume and mean corpuscular hemoglobin, microcytic anemia, and/or low ferritin) or those with low iron intake as estimated from a dietary recall. This is most likely for individuals eating restricted vegetarian diets with little or no meat or fish [3,47]. Adolescent girls are at increased risk for iron deficiency after menarche due to menstrual blood loss. (See "Iron deficiency in infants and children <12 years: Screening, prevention, clinical manifestations, and diagnosis" and "Iron requirements and iron deficiency in adolescents".)
Ascorbic acid (vitamin C) is a powerful promoter of nonheme iron absorption because it prevents the formation of less-soluble ferric compounds [90,99-101]. A 75 mg dose of ascorbic acid increases the absorption of nonheme iron three- to fourfold [96]. Because of its mechanism of action, ascorbic acid is effective only when consumed at the same time as the iron-containing food. Important sources of both vitamin C and other facilitators of iron absorption (eg, citric and malic acid) include citrus fruits and strawberries, broccoli, and tomatoes. By increasing absorption of nonheme iron, ascorbic acid helps to counteract the inhibitory effect of phytates in a plant-based diet.
Good plant sources of iron include whole or enriched breads or grains, iron-fortified cereals, legumes, green leafy vegetables, dried fruits, soy products, blackstrap molasses, bulgur, and wheat germ. The widespread fortification of enriched breads, cereals, and pasta products has helped increase iron intake for children.
Calcium — Adequate calcium intake is important throughout life to ensure peak bone mass accumulation, especially during periods of growth. Children with stronger bones may experience fewer fractures and may be more resistant to the development of osteoporosis in later life [102,103]. The recommended intake of calcium is approximately 700 mg for children 1 to 3 years of age, 1000 mg for children 4 to 8 years of age, and 1300 mg for those 9 to 18 years (table 4) [104]. (See "Bone health and calcium requirements in adolescents" and "Dietary recommendations for toddlers and preschool and school-age children", section on 'Dairy products'.)
●Potential deficits for a vegetarian diet – For children who consume lactovegetarian or lacto-ovovegetarian diets, most calcium needs can be met by milk and dairy products; these provide approximately 75 percent of the calcium in the average American diet [103,105]. Children who avoid dairy products, such as those following a vegan diet, have more difficulty meeting calcium needs. This is in part because they consume plant foods containing oxalates and phytates and because the calcium contents of typical vegetables, fruit, and cereal grains are relatively low [48,106-108]. Children who avoid dairy products generally require either substantial intake of calcium-fortified foods (eg, several servings daily of calcium-fortified soy milk) or a calcium supplement to meet the age-dependent recommended intake (table 4).
Estimates of calcium needs are imprecise because other dietary constituents also affect calcium balance: Oxalate and phytate decrease calcium absorption, while salt and protein increase calcium excretion [98,103,109]. Foods high in oxalate include spinach, beet greens, Swiss chard, and yams. Thus, the lower protein intake among vegetarians may decrease urinary calcium loss, which improves their net calcium balance and reduces their risk for calcium stone formation compared with omnivores [110]. (See "Kidney stones in adults: Epidemiology and risk factors", section on 'Protein'.)
●Nutritional counseling – Vegetarian children who do not drink milk should include at least one calcium-rich or calcium-fortified food with each meal and with several snacks each day. Children who follow a vegan diet can obtain calcium from calcium-fortified foods and beverages (such as fortified soy milk), foods naturally rich in calcium, calcium supplements, or a combination of these:
•Calcium-fortified foods include some types of soy milk, soy yogurt, and soy cheese, as well as calcium-precipitated tofu, many types of ready-to-eat cereals and some breakfast bars, pastas, waffles, and juices [111,112]. Calcium bioavailability in most of these sources is equivalent to milk. As an example, one 8-ounce glass of calcium-fortified orange juice provides 300 mg of calcium, equivalent to an 8-ounce glass of milk. In contrast, the bioavailability of calcium in soy milk is only 75 percent of that in cow's milk [113]. Ideally, these foods should also be fortified with vitamin D because vitamin D facilitates the absorption of calcium [114].
•Foods that are naturally rich in calcium and low in oxalate include kale, mustard greens, turnip greens, broccoli, bok choy, dried figs, and blackstrap molasses (table 6) [103]. Most of these foods have additional benefits because they provide other important nutrients. However, it is difficult to meet calcium requirements from these foods alone, even with large portions.
•Calcium supplements also can be used to provide adequate calcium intake. Consuming calcium supplements at the same time as iron or zinc supplements may interfere with the absorption and utilization of these minerals. (See "Bone health and calcium requirements in adolescents".)
The benefits of using fortified foods to increase calcium intake was demonstrated in a double-blind, placebo-controlled study of prepubertal girls with low spontaneous calcium intake who were randomly assigned to receive food products that were or were not fortified with 850 mg of calcium [115]. Calcium fortification increased mean bone mineral density in all girls, but the increase was greatest in those whose baseline calcium intake was less than 850 mg. The gains in bone mass persisted one year after discontinuation of treatment.
Vitamin D — Normal levels of vitamin D metabolites are necessary for adequate intestinal calcium, phosphate absorption, and bone formation [116-118]. Vitamin D is available through sunlight exposure and dietary intake (figure 1). Dietary intake of 15 mg (600 international units) daily is recommended for children one year and older. (See "Vitamin D insufficiency and deficiency in children and adolescents", section on 'Recommended vitamin D intake'.)
Sunlight exposure is an important source of vitamin D but is often insufficient, especially during the winter, for children with dark skin pigmentation, and for those who use sunscreen or clothing to protect their skin from sun damage. Maintenance of normal serum vitamin D concentrations requires exposure to the sun on hands, arms, and face for 10 to 15 minutes per day for fair-skinned individuals; individuals with dark skin pigmentation require 6 to 10 times as much exposure as a light-skinned individual [119]. (See "Vitamin D insufficiency and deficiency in children and adolescents", section on 'Skin pigmentation and low sun exposure'.)
●Potential deficits for a vegetarian diet – Few foods contain vitamin D. The principal dietary source of vitamin D for omnivores, lacto-ovovegetarians, and lactovegetarians is milk fortified with vitamin D (2.5 mg [100 international units] per 8 oz) [120]. Vegetarians who do not consume vitamin D-fortified cow's milk or plant-based beverage are at risk for vitamin D deficiency, which can lead to rickets in young children and osteomalacia in adults [121-124].
●Nutritional counseling – For children who do not drink cow's milk (eg, those following a vegan diet), a dietary alternative is fortified soy milk, other fortified alternative milk, or fortified breakfast cereal [114,116]. For children who eat fish (eg, a pescatarian or macrobiotic diet), consuming fatty fish (sardines, salmon, tuna, mackerel) or cod liver oils several times per week can provide sufficient vitamin D. Cheese and egg yolks provide small amounts of vitamin D [116].
To meet the recommended intake for vitamin D, children generally require either substantial intake of these vitamin D-rich foods (eg, several servings daily of fortified cow's milk or soy milk) and some additional vitamin D from sunlight exposure (eg, from participating in outdoor sports or active play). Otherwise, they will require a vitamin D supplement to meet the target, especially if they have risk factors for vitamin D deficiency such as dark skin pigmentation, low sun exposure, or residence in northern latitudes [125-127]. (See "Overview of vitamin D", section on 'Sources'.)
Vitamin B12 — Vitamin B12 (cobalamin) is only found in foods from animal sources (meat, fish, eggs, and dairy products) [48,128]. The RDA for cobalamin is 0.9 mcg for children 1 to 3 years of age, 1.2 mcg for 4 to 8 years, 1.8 mcg for 9 to 13 years, 2.4 mcg for 14 to 18 years, and 2.6 mcg for pregnant adolescents (table 7) [129]. Because substantial amounts of vitamin B12 are stored in the body (primarily in the liver), the deficiency develops gradually. Once vitamin B12 is removed from the diet, deficiency develops within four to six months in infants (eg, the breastfed infant of a mother with vitamin B12 deficiency) or one to two years in adults [129]. Vitamin B12 deficiency in infants can present with tremor, irritability, or spells (apneas, absences, and motor seizures) [63,130,131]. (See "Clinical manifestations and diagnosis of vitamin B12 and folate deficiency".)
●Potential deficits for a vegetarian diet – Lacto-ovovegetarians and lactovegetarians can, but do not always, consume sufficient amounts of vitamin B12 from eggs, milk, and milk products. Vegans, whose diets are based entirely on plant food, are at considerable risk for vitamin B12 deficiency [132,133]. For example, in one study, 10 of 25 vegans had vitamin B12 deficiency manifested by macrocytosis (picture 1) and low serum vitamin B12 [134]. In another report, serum vitamin B12 concentrations were determined in 83 volunteer subjects attending an American vegetarian society conference [135]. Among subjects who did not supplement their diets with vitamin B12 or multivitamin tablets, the percentage with serum vitamin B12 levels below the normal range was associated with the degree of dietary restriction:
•Vegans – 92 percent
•Lactovegetarians – 64 percent
•Lacto-ovovegetarians – 47 percent
•Semi-vegetarians – 20 percent
●Nutritional counseling – For children who eat fish (eg, those following a pescatarian diet), eating fish two to three times per week can provide a good source of vitamin B12. Vegan children and other vegetarians whose diet does not contain significant amounts of meat or fish should consume a regular and reliable source of the vitamin, either in fortified foods or an oral B12 supplement. Commonly used vitamin B12-fortified foods include most ready-to-eat cereals, many meat substitutes, some milk alternatives, and fortified nutritional yeasts [136]. Fortified soy milk is another good source of vitamin B12 for children [137]. Vitamin B12 supplements typically provide 6 to 9 mcg/day [133]. This dose is higher than the RDA to ensure adequate intake and because there are no adverse effects of the higher dose [129]. Of note, only cyanocobalamin is the active form of the vitamin and some listings of vitamin B12 content in foods do not differentiate between this form and its inactive analogs. As examples, much of the vitamin B12 present in spirulina, sea vegetables, tempeh, and miso is inactive and does not contribute to the vitamin B12 requirement [112,138]. Moreover, the inactive forms can compete with active forms for absorption.
Zinc — Recommended intake for zinc is 3 mg/day for children aged 1 to 3 years, 5 mg/day for children aged 4 to 8 years, 8 mg/day for children aged 9 to 13 years, 9 mg/day for adolescent females, and 11 mg/day for adolescent males (table 8).
●Potential deficits for a vegetarian diet – Children who do not consume dairy products are at risk of a suboptimal zinc status because of high requirements for growth, although the clinical significance of mild zinc deficiency is unclear. Severe zinc deficiency can be associated with impaired growth, taste, and smell, as well as impaired immunity, with an increased risk of infections, particularly diarrhea and pneumonia. Adult vegetarians do not typically develop zinc deficiency, because they have a compensatory increase in fractional absorption. (See "Zinc deficiency and supplementation in children".)
Zinc is found in foods of both animal and plant origin. Animal sources include oysters, shellfish, liver, meat, poultry, and dairy products [93,139]. The zinc in vegetarian diets has a lower bioavailability because of the high content of phytate and dietary fiber [47,78,140,141]. Certain food preparation techniques, such as the soaking of sprouting beans, grains, and seeds, as well as leavening breads, can mitigate this problem by reducing binding of zinc by phytates, thus increasing zinc bioavailability [3,142,143].
●Nutritional counseling – Milk and milk products are the primary source of zinc for children on vegetarian diets who also consume dairy products. For children who do not consume milk (eg, vegans), cereals are the primary source of zinc; secondary sources are meat substitutes (eg, legumes, nuts, and soy products). Plant sources of zinc include whole grains, legumes, wheat germ, and nuts.
Iodine — Iodine is essential for thyroid hormone synthesis, and iodine deficiency during pregnancy or infancy has an adverse effect on child development. Clinically significant iodine deficiency is uncommon in countries with universal salt iodization programs, including the United States. Other food sources include dairy products, eggs, fish, seafood, and fortified bread [144,145]. Plant-based foods typically have low iodine content (with the exception of seaweed). Accordingly, individuals following a vegan diet without iodized salt, fortified bread, or seaweed are at risk for iodine deficiency. In a systematic review of five studies, the median iodine status (as measured by urinary iodine concentrations) was below the threshold for iodine adequacy for all diets and was moderately deficient for all vegan cohorts, three-quarters of vegetarian cohorts, and none of the omnivore cohorts but with a wide range of iodine adequacy within each dietary group [145].
Iodine deficiency, iodine requirements, and iodine supplementation across the lifespan are described separately. (See "Iodine deficiency disorders".)
Omega-3 fatty acids — Dietary requirements for omega-3 fatty acids in infants, children, and adolescents have not been established [146]. However, indirect evidence suggests that they have some health benefits.
●Potential deficits for a vegetarian diet – Vegetarian diets generally are rich in omega-6 fatty acids but may be marginal in omega-3 fatty acids unless the diet includes fish, eggs, or generous amounts of algae. Omega-3 fatty acids, which include docosahexaenoic acid (DHA) or eicosapentaenoic acid (EPA), or their precursor alpha-linolenic acid (ALA), are important for cardiovascular health and eye and brain development [49,147,148]. Vegetarians, particularly vegans, have lower blood levels of EPA and DHA compared with nonvegetarians [3,149].
●Nutritional counseling – We suggest that vegetarian children include either oily fish or other good sources of omega-3 fatty acids in their diet, such as flaxseed, walnuts, canola oil, and soy. Infant formulas, soy milk, and breakfast bars that are fortified with DHA also are available [3]. For patients who do not consume fish regularly, consider counseling on an algae-based omega-3-supplement [150]. The evidence for benefit of omega-3 fatty acids supplements is based on limited evidence for cardiovascular risk protection in adults, with a low risk of harm [151]. (See "Fish oil: Physiologic effects and administration".)
FIBER —
Recommended fiber intake is 14 g/1000 kcal energy intake, which translates to approximately 14 g/day for ages 2 to 3 years, 17 to 20 g/day for 4 to 8 years, 22 to 25 g/day for 9 to 13 years, and 25 to 31 g/day for 14 to 18 years [1]. Because these targets are difficult to achieve, somewhat lower targets may be more realistic for children whose diets are not plant based [152].
The optimum level of dietary fiber for infants and children younger than two years of age is not known. For this age group, studies of weaning diets with increased fiber suggested that 5 g/day is beneficial and found no negative effect on the absorption of energy, zinc, and calcium or iron bioavailability [153,154]. However, other studies have shown that growth is poor among infants and toddlers weaned onto very high-fiber, low-calorie diets that often are deficient in vitamins and minerals [155,156]. (See "Dietary recommendations for toddlers and preschool and school-age children", section on 'Fiber'.)
●Potential issues for a vegetarian diet – Vegetarians tend to have a relatively high fiber intake compared with omnivores. In populations following a vegan diet, the average fiber intake is in a healthy range. In a study of 51 adults, average fiber intake among omnivores was 23 g, compared with 37 g among vegetarians and 47 g among vegans [157].
The consumption of a high-fiber diet in childhood promotes regular bowel movements and possibly reduces the risk of developing certain diseases in adulthood. However, during childhood, a diet with very high fiber content can compromise dietary energy intake and reduce the bioavailability of minerals such as iron, calcium, and zinc [3,47,78,158]. A small loss of energy, primarily as fat, and protein may occur with a high intake of dietary fiber. Daily fecal energy loss is estimated to increase by 1 percent for every 6 g increase in dietary fiber. This loss is unlikely to be significant in children who consume adequate energy.
The amount of dietary fiber recommended above, or even fiber intake that exceeds this recommendation, does not have an adverse effect on mineral bioavailability, provided that the dietary mineral intake is adequate. However, mineral bioavailability may be problematic in children who follow strict macrobiotic or vegan diets with low intake of calcium, iron, and zinc.
●Nutritional counseling – Most vegetarian children have a healthy intake of fiber. Because a very high-fiber diet can compromise energy intake and mineral absorption, vegetarian children should be monitored to ensure that they have adequate growth and adequate intake of minerals such as iron, calcium, and zinc.
Dietary fiber goals can be met best by eating a variety of fiber-rich fruits, vegetables, cereals, and grain products while consuming adequate energy intake for growth and development [158]. Fiber supplements are not recommended to meet dietary fiber goals.
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: Healthy diet in children and adolescents".)
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 5th to 6th 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 10th to 12th 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.)
●Basics topic (see "Patient education: Vegetarian or vegan diet (The Basics)")
SUMMARY AND RECOMMENDATIONS
●Overview – A well-planned vegetarian diet offers health benefits for children. Vegan diets can also offer benefits but require additional planning to ensure that all nutritional needs are met. In general, a lactovegetarian diet has greater health benefits and fewer health risks than a vegan diet (table 1). (See 'Benefits for cardiovascular and metabolic health' above.)
●Counseling
•Infants and young children – Breastfeeding mothers who are vegetarian or vegan should be counseled about B12 supplementation. The vitamin B12 content of breast milk reflects maternal vitamin B12 levels, and severe deficiency can impair neurologic development in the infant. When introducing solids and weaning an infant off of formula or breast milk, food choices should be high in fat and iron for the vegetarian child as vegetarian foods can have higher fiber and lower caloric density. Additional nutrients to counsel families about during this period include vitamin D, iron, zinc, folate, and calcium (table 2). Young children can be offered soy milk in the place of dairy, but other types of plant-based beverages are often lower in calories and protein and are not appropriate for periods of rapid growth. (See 'Infancy and weaning' above and 'Plant-based beverages' above.)
•Older children and adolescents – Many adolescents are turning to vegetarian diets for ethical or environmental concerns. Some older children or adolescents may choose a vegetarian diet as a means of weight control, and clinicians should be alert for evidence of inappropriate dietary restriction and other disordered eating behaviors. An adolescent whose body mass index is less than the 15th percentile and/or who has features suggestive of an eating disorder (including disrupted menses or body image disturbances) is a candidate for referral for more intensive medical and psychological care. (See 'Older children and adolescents' above.)
●Specific nutrients – Nutritional counseling is important to ensure that the diet provides adequate nutrients, especially energy, protein, iron, calcium, vitamin D, and vitamin B12 (cyanocobalamin). If the diet cannot be adjusted to provide recommended amounts of each of these nutrients, supplements should be added to ensure adequate intake.
•Iron – Children who do not eat meat or fish are at risk of iron deficiency, especially during periods of rapid growth and in menstruating girls. To enhance the absorption of nonheme iron (from plants), a source of ascorbic acid should be provided at each meal. Teas containing tannin should be limited. Iron supplements may be necessary for some individuals. (See 'Iron' above.)
•Calcium and vitamin D – Children who consume little or no dairy products are at risk for calcium and vitamin D deficiencies. Ready-to-eat cereals and alternative plant-based milks (such as soy milk) are good sources of these nutrients, provided that they are adequately fortified. However, the recommended intake for these nutrients is high and requires several servings daily of milk, fortified alternative milk, or fortified cereal. Many children require supplementation to meet their requirements. (See 'Calcium' above and 'Vitamin D' above.)
•Vitamin B12 – Children who follow a vegan diet are at risk for vitamin B12 (cobalamin) deficiency because animal products (meat, fish, and dairy products) provide the only dietary source of vitamin B12 (cobalamin) for humans. Individuals following a vegan diet should consume a regular and reliable source of the vitamin, either in fortified foods (soy milk or cereals) or an oral vitamin B12 supplement. (See 'Vitamin B12' above.)
ACKNOWLEDGMENT —
The UpToDate editorial staff acknowledges Kathleen J Motil, MD, PhD, and Debby Demory-Luce, PhD, RD, LD, who contributed to earlier versions of this topic review.
