There is no good reason not to introduce meats, vegetables, and fruits as the first complementary foods, according to Dr. Frank R. Greer, a member of the American Academy of Pediatrics's Committee on Nutrition.
Introducing these foods early and often promotes healthy eating habits and preferences for these naturally nutrient-rich foods, said Dr. Greer, who is a professor of pediatrics at the University of Wisconsin in Madison.
Rice cereal has traditionally been the first complementary food given to American infants, but ?Complementary foods introduced to infants should be based on their nutrient requirements and the nutrient density of foods, not on traditional practices that have no scientific basis,? Dr. Greer said in an interview.
In fact, the AAP's Committee on Nutrition is working on a statement that will include these new ideas, Dr. Greer said in an interview. Currently, there are no official AAP recommendations for introduction of complementary foods. ?There are suggestions of what complementary foods to introduce in various AAP-sponsored publications, which are based on the traditional introduction of solid foods starting with infant iron-fortified cereals and progressing through vegetables and then fruits.?
Complementary foods are any nutrient-containing solid or liquid foods other than breast milk or formula given to infants, excluding vitamin and mineral supplements. By 6 months of age, human milk becomes insufficient to meet the requirements of an infant for energy, protein, iron, zinc, and some fat-soluble vitamins (J. Pediatr. Gastroenterol. Nutr. 2008;46:99?110).
Rice cereal has been the first complementary food given to infants in the United States for many reasons, including cultural tradition. By the 1960s, most U.S. infants (70%?80%) were fed cereal by 1 month of age. By 1980, rice cereal predominated, as it was considered to be well tolerated and ?hypoallergenic??given growing concerns about food allergies, he said. (See box.)
However, newer thinking is that the emphasis for complementary foods should be on naturally nutrient-rich foods. This includes protein and fiber, along with vitamins A, C, D, and E and the B vitamins. In addition, saturated and trans fats should be limited, as should sugar, said Dr. Greer.
In light of this thinking, rice cereal is a less than perfect choice for the first complementary food given to infants, he said. Rice cereal is low in protein and high in carbohydrates. It is often mixed with varying amounts of breast milk or formula. Although most brands of formula now have added iron, zinc, and vitamins, iron is poorly absorbed?only about 7.8% of intake is incorporated into red blood cells.
In contrast, meat is a rich source of iron, zinc, and arachidonic acid. Consumption of meat, fish, or poultry provides iron in the form of heme and promotes absorption of nonheme iron, noted Dr. Greer. Red meat and dark poultry meat have the greatest concentration of heme iron. Heme iron is absorbed intact into intestinal mucosal cells and is not affected by inhibitors of nonheme iron from the intestinal tract. Iron salts present in infant cereal are generally insoluble and poorly absorbed.
Another issue is when to begin introducing complementary foods, said Dr. Greer. This varies by nationality. In Germany for example, complementary foods are introduced to 16% of infants by 3 months. A third (34%) of infants in Italy and half (51%) of infants in the United Kingdom are introduced to complementary foods by 4 months. In the United States, 18% of infants are introduced to complementary foods?cereal?by 3 months, 40% by 4 months, 71% by 5 months, and 81% by 6 months.
Those complementary food choices for infants aren't always the most nutritious either. By 6 months, roughly a third of U.S. infants have been introduced to fruit (71%) and vegetables (73%), but only 21% have been introduced to meat. In a 2008 study in Pediatrics, researchers reported that 15% of infants have less than one serving of fruit or vegetable per day by 8 months of age (Pediatrics 2008;122[suppl. 2]:S91?7). In contrast, half of 10-month-old infants had eaten at a fast food restaurant, 22% had eaten carryout food, and 28% had eaten restaurant or carryout food at least twice in the previous week.
Early experiences promote healthy eating patterns, said Dr. Greer. It's known that food flavors are transmitted to breast milk; infants whose mothers eat fruits and vegetables during lactation will have greater consumption of fruits and vegetables during childhood (Public Health Nutr. 2004;7:295?302). It's also been shown that infants are more accepting of food after repeated exposure (Am. J. Clin. Nutr. 2001;73:1080?5).
Dr. Greer reported that he has no relevant financial conflicts of interest.
Delaying or avoiding the introduction of allergenic foods during a critical window in the first year of life doesn't appear to prevent the development of food allergies and may even put children at increased risk, according to Dr. Greer.
There is a lack of evidence to support food allergen avoidance in infants, he said. Any benefits appear to be largely in the first 3?4 months of life, when exclusive breastfeeding is of the greatest benefit for prevention of atopic disease.
Oral tolerance is an antigen-driven process and depends on regular exposure to food antigens during a critical early window. Allergen avoidance may be unsuccessful or detrimental in allergy prevention in infants, he said. There is some evidence that continued breastfeeding during new food introduction is beneficial in preventing atopic disease.
In 2008, the AAP recommended that complementary foods should not be introduced before 4?6 months and noted that there is no indication that delayed introduction of certain foods, including allergenic foods such as wheat, fish, egg, and peanut-containing products, protects against atopic disease(Pediatrics 2008;121:183?91).
Likewise, the European Society for Paediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN) recommended in 2008 that complementary foods should be introduced between 17 and 26 weeks.
The group also recommended against the avoidance or late introduction of allergenic foods such as wheat, fish, egg, and peanut (J. Pediatr. Gastroenterol. Nutr. 2008;46:99?110).
Most allergic reactions to foods (90%) are due to eight food types: milk, eggs, peanuts, tree nuts, fish, shellfish, soy, and wheat. However, studies generally have not supported a protective effect for a maternal exclusionary diet during pregnancy; a diet excluding cow's milk, eggs, peanuts, and fish has not been found to protect against the development of atopic disease in infants.
Dietary food allergens, including peanuts, cow's milk protein, and egg, can be detected in breast milk. In the majority of studies, especially those with follow-up beyond 4 years of age, there is no convincing evidence that restricting the maternal diet results in long-term prevention of atopic disease in infants.