Complementary Feeding and Future Health: The Importance of Tailored Evidence-Based Recommendations

Complementary feeding (CF), introduced after exclusive breastfeeding, was defined by the World Health Organization (WHO) in 2002 [1]. The first 1,000 days are crucial for future health with breastfeeding being the most important factor [2]. Also, CF is important for future health but controversy exists about its timing and content. While evidence suggest for some benefit for introducing CF at 17 weeks of life at least in high-income countries, recommendations for the timing of introduction are discordant. In 2017, the European Society for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) recommended that CF should be introduced at 17 weeks of age [3]; however in 2023, the WHO released its own recommendations for CF [4] and this stirred a heated debate [5] as some of the WHO recommendations are not evidence based and the recommendations are universal while CF may need to be geographically tailored. The reader of this volume is encouraged to read the letter sent by multiple scientific societies to the WHO [6], the WHO response [7] and the multiple societies response to the WHO letter [8].

In this volume dedicated to CF we provide reviews on some aspects of CF introduction. The first review by Moreno [9] discusses CF and obesity. Globally, obesity in children is the most prevalent nutrition-related disorder [10]. Genetic susceptibility and obesogenic environment, contribute to obesity occurrence. As eating habits are imprinted early in life, the introduction of solid foods, becomes a critical period where these habits can be structured and modulated. The magnitude of the obesity epidemic with its long-term consequences turns prevention of obesity to be a high priority. This review [9] discusses obesity prevalence and trends, tracking into adulthood, consequences, and the economic burden. Methods of introduction of CF and obesity risk are reviewed such as BLISS (Baby-Led Introduction to Solids). The review shows that there is hope and provide data on successful programs for early obesity prevention.

Overall, it shows that the way we feed our infants after 6 months of life may affect their obesity risk, and that there are ways to reduce this risk. The second review [11] is a timely review on East and West perspectives since part of the controversy over the WHO recommendations stems from the WHO opinion that recommendations should be universal while allergy prevention strategies are relevant mainly to high-income western societies [6]. This review demonstrates that in western countries the prevalence has increased in recent decades and has plateaued in recent years though anaphylaxis rates have increased. While the prevalence recently began to stabilize in western countries, it started to rise in parts of Asia. Leung and Wong [11] discuss the different patterns of food allergy (FA) in the Eastern parts of the World compared to western parts, reflecting changes in economic status, urbanization and exposure to allergens. Thus, FA is becoming a universal problem with health risks, reduced quality of life and an economic burden worldwide. The reader is encouraged to read the discussion on various aspects of FA, including strategies for primary prevention such as early introduction of allergenic foods using an evidence-based approach [3, 6] showing that, if done appropriately, breastfeeding rates are not affected [12]. Overall, as recently suggested by many scientific societies [6], it calls for tailored FA prevention strategies rather than global recommendations.

In the review on factors impacting CF acceptance, Mennella [13] reiterates that we are born with preference to sweet and umami and later to salty foods and that exposure of the mother during pregnancy and while breastfeeding have a long lasting effect on dietary preferences. Overall, this emphasizes that there are multiple windows of opportunities to drive infants and toddlers toward a healthier diet during the CF period and beyond.

The last review by Verduci et al. [14] provides perspective to the previous three reviews and emphasizes the importance of exposure to CF after 17 weeks of age in high-income countries, highlighting difficulties in adapting the 2023 WHO recommendations [4]. Further, the review discusses developmental readiness for CF and consider the impact of practices on developing various diseases. The review ends with recommendations that are echoed throughout all reviews: recommendations should be tailored rather than universal and should be evidence based.