Enhancing protein quality by lysine and soy protein prevents growth suppression under protein, energy and micronutrient restriction in young male rats

Abstract

Malnutrition is linked to suppression of linear growth which leads to stunting of children in developing countries. Some evidence indicates that micronutrient supplementation prevents growth suppression, but dependence on poor quality dietary protein such as maize, may also be a risk factor. To understand the effect of dietary protein quality on the prevention of growth suppression, linear growth was compared in young male rats (4 week‐old) fed a 70% calorically restricted cornmeal (C), C+micronutrient (CM), CM+soy protein (CMS) or CMS+0.3% lysine (CMSK) for 3 weeks (n=5–6 per group). The total calorie intake was equivalent between the groups. The body weight of CM slightly increased compared to the C group, but addition of soy protein (CMS and CMSK) significantly increased body weight (C:15.8±2.6, CM:20.9±2.1, CMS:48.2±2.3 and CMSK:52.3±3.5g). Change in body length had the same tendency as the body weight in each group but was significantly larger in CMSK compared to CMS (C:1.7±0.4, CM:2.0±0.2, CMS:2.8±0.4 and CMSK:3.4±0.3cm,). The addition of protein and lysine altered muscle weight gain and adipose tissue deposition resulting in a decrease of total lean body mass. From these results, improvement of dietary protein quality by using plant source protein and amino acid could potentially prevent growth suppression such as stunting in weaning children in developing countries.