Date Published: January 12, 2017
Publisher: Public Library of Science
Author(s): Anne-Louise Hother, Mikkel Lykke, Torben Martinussen, Hanne Damgaard Poulsen, Christian Mølgaard, Per Torp Sangild, André Briend, Christian Fink Hansen, Henrik Friis, Kim F. Michaelsen, Thomas Thymann, Christopher James Johnson.
Phosphorus (P) levels in refeeding diets are very important as undernourished children are at risk of hypophosphatemia during refeeding. For this reason, conventional corn-soy-blends (CSB) have been reformulated by the World Food Programme to obtain a mono-calcium-phosphate fortified product (CSB+) and a product further fortified with skim milk powder (CBS++).
Using a piglet model of undernourished children, we hypothesized that feeding of CSB+, CSB++ or CSB+ with added whey permeate (CSB+/wp) would help to prevent refeeding hypophosphatemia. Pigs were weaned at 4 weeks of age and undernutrition was induced with a nutritionally inadequate pure maize diet for 7 weeks, after which they were refed for 3 weeks with either CSB+ (n = 10), CSB++ (n = 10) or CSB+/wp (n = 10). For reference, a fourth group continued on the maize diet (REF, n = 10).
Following induction of undernutrition, body weight and length were 29±5% and 67±4% (means±SD) of values in age-matched pigs fed a nutritionally adequate diet, and the mean serum P level was 1.77±0.34 mmol/l. During the first week of refeeding, P levels in the CSB+ pigs decreased to 55% of values before refeeding (P < 0.05) while values in the CSB++ and CSB+/wp pigs were able to maintain their plasma phosphate at a similar level as before refeeding. We conclude that fortification of CSB with only monocalcium-phosphate does not prevent hypophosphatemia. Dairy products like skim milk powder or whey permeate may represent relevant sources of phosphorus during refeeding. The content and form of phosphorus in such diets need to be carefully evaluated, and the undernourished piglet may be used to test the efficacy of such diets.
Worldwide, 50 million children suffer from acute malnutrition , which is a major cause of morbidity and mortality [2,3]. Food aid distribution is a key short-term approach to prevent and treat malnutrition, and corn-soy-blend (CSB) is one of the main food aid products used [4,5]. Accordingly, it has been estimated that at least 2 million moderately wasted children receive corn-soy-blend every year [5,6]. Corn-soy-blend is served as porridge and consists of precooked flour from maize and soybean grains fortified with vitamins and minerals . However, recent focus on dietary management of children with moderate malnutrition and development of guidelines for recommended nutrient intakes  have shown that these diets may be inadequate for this target group.
The study was approved by the Danish Animal Experiments Inspectorate (2009/561-173 1), which is in accordance with the guidelines from Directive 2010/63/EU of the European Parliament.
To our knowledge this is the first study to evaluate the effect of the improved formulations of fortified blended foods on serum phosphate. We observed a marked drop in serum phosphate during the first week of refeeding in pigs fed CSB+. A similar drop was not seen in the pigs fed maize indicating that the drop in serum phosphate was not due to malnutrition per se, but may instead be due to an increased demand for phosphate during refeeding, and that CSB+ was insufficient to meet this higher demand for phosphate. We found that further diet fortification with phosphorus sources like skimmed milk powder or whey permeate improves the plasma status and therefore represent diets that may potentially be useful during refeeding to improve plasma phosphate status.