Growth of malnourished infants and children: how is inflammation involved?

Abstract

Malnutrition may be classified as acute or chronic and by severity into mild, moderate, and severe forms. Features of chronic malnutrition include diminished weight gain, stunted growth, mental apathy, and developmental delay. Acute protein-energy malnutrition (PEM) manifests itself most commonly as marasmus (adapted form) but also as kwashiorkor; however, some children may have signs of both (marasmic kwashiorkor). The occurrence of nutritional edema in the two latter forms heralds a state of decompensation (mal-adapted form). One diagnoses marasmus when weightfor-height (WFH) is more than 3 SDs below the mean for age and sex (weight-for-height Z score [WHZ] of less than −3), whereas kwashiorkor is characterized by pitting pedal edema, independent of height or weight. Children may also present with marasmic kwashiorkor, with edema superimposed upon on severe wasting. Similarly, severe stunting is a height (or length) of more than 3 SDs below that expected for age (height-for-age Z-score [HAZ] of <−3). In addition, children with kwashiorkor exhibit behavioral symptoms such as lethargy and apathy when left alone, with increased irritability with physical contact [1]. Moderate malnutrition is defined by anthropometric values between −3 and −2 SDs from the expected. Mild or ‘at-risk’ malnutrition is considered if any of the above-described indexes fall below 1 standard deviation less than the median value for the reference population (Z score <−1 SD). The midupper-arm circumference (MUAC) is considered a measure of lean body mass and correlates strongly with WHZ. It is a strong predictor of mortality [1,2]. Nutritional stunting may occur at several epochs of an individual’s life history: in utero, caused by insufficient maternal nutrition and/or intrauterine undernutrition; during infancy by a lack of breastfeeding until 6 months of age, or during later infancy due to the delayed introduction of complementary feeding, inadequate (quantity and quality) complementary feeding, or impaired absorption of nutrients, especially due to multiple episodes of infectious diseases [3]. The consequences of child stunting may be both immediate and longer term. They include increased morbidity and mortality, poor child development and learning capacity, increased risk of infections and non-communicable diseases, increased susceptibility to accumulate central fat, lower fat oxidation, lower energy expenditure, insulin resistance and a higher risk to develop diabetes, hypertension, dyslipidemia, lowered working capacity, and unfavorable maternal reproductive outcomes in adulthood. Furthermore, stunted children, who experienced rapid weight gain after 2 years, have an increased risk of becoming overweight or obese later in life (components of the metabolic syndrome) [2–4].