Maximizing Recovery and Growth When Treating Moderate Acute Malnutrition with Whey-Containing Supplements

Abstract

Background:

Much debate exists about the utility of dairy ingredients in the supplementary foods used to treat childhood moderate acute malnutrition (MAM).

Objective:

To review the evidence regarding the effectiveness of dairy-containing supplements, particularly specially formulated foods containing whey permeate and whey protein concentrate, in treating children with MAM.

Methods:

A summary of a conference presentation regarding an overview of current evidence behind the use of whey in supplementary foods, including results of a randomized double-blinded clinical effectiveness trial involving 2259 Malawian children treated for MAM using either a soy ready-to-use supplementary food (RUSF) or a novel whey RUSF treatment.

Results:

While the majority of the evidence base only suggests potential benefits of including whey in supplementary foods to treat MAM, a recent study specifically demonstrates that a whey RUSF produced superior recovery and growth outcomes in treating children with MAM when compared with a soy RUSF.

Conclusions:

The use of whey ingredients has been shown to improve outcomes in the treatment of MAM; however, further research is needed to identify the ideal amount and type of dairy protein required to produce the best outcomes for the lowest cost.

Introduction

Moderate acute malnutrition (MAM) is a type of undernutrition caused by a lack of proper nutrient intake due to insufficient food availability or disease. ¹ Despite the overwhelming burden of MAM worldwide, affecting approximately 33 million children each year, ² there is currently no standardized approach to managing MAM. Although several supplementary food products have been developed and successfully used to treat MAM, ^3,4 the optimal quality, quantity, and source of protein needed in such products to optimize nutritional outcomes and survival are still debated. ⁵ Dairy products are known to be important for child growth, ⁶ but evidence is lacking regarding the necessity of dairy products or other animal source protein specifically in treating MAM. However, recent results from a randomized controlled clinical effectiveness trial in Malawi build on a growing body of knowledge regarding the role of dairy protein in the treatment of MAM. ⁷

Moderate Acute Malnutrition

Children with MAM have an increased risk of death, are more susceptible to infection, and are more likely to develop severe acute malnutrition (SAM) than healthy children. ⁸ Together, severe and moderate forms of acute malnutrition account for 11.5% of young child deaths worldwide. ⁹ If untreated, children with MAM who survive can stay moderately malnourished for several months, ¹⁰ likely having a negative effect on linear growth, cognitive development, and other lifelong consequences. ¹¹

MAM is characterized by a rapid loss of weight and is diagnosed anthropometrically, either by having a mid-upper arm circumference (MUAC) between 11.5 and 12.4 cm or a weight-for-height z-score (WHZ) < −2 and ≥ −3. Most of the programs designed to treat MAM consist of providing specially formulated foods in an outpatient-based supplementary feeding program (SFP). While in the SFP, children with MAM return weekly or biweekly for assessment and collection of the next ration of food until the child is discharged or reaches a maximum length of stay in the program. Recovery is typically defined by achieving a certain threshold in anthropometric size, measured by either MUAC or WHZ.

The 2 main types of specially formulated supplementary foods provided in SFPs are fortified blended foods, such as corn–soya or wheat–soya blend, and peanut-based ready-to-use supplementary foods (RUSF). Although both types of supplementary foods have been proven effective in treating MAM, RUSFs have led to faster recovery rates and improved MUAC and WHZ in children treated for MAM. ¹² Also, ready-to-use products are less likely to be shared with other family members than fortified blended foods. ¹³ Yet due to higher cost, RUSFs are less commonly used than fortified blended foods; an estimated 50 000 MAM children are treated with ready-to-use products compared with approximately 2 million MAM children treated with fortified blended foods worldwide each year. ¹⁴

Whey in the Treatment of MAM

Many of the traditional formulas for supplementary foods do not include any animal source protein. Recently, international nutrition experts have advocated for the increased use of dairy products, particularly whey, in supplementary foods administered to children with MAM. ¹⁵ Recommendations by Tufts University to the US Agency for International Development in the Food Aid Quality Review ¹⁵ include the addition of 3 g of whey protein concentrate (WPC) per 100 g of dry fortified blended food.

Whey is the liquid part of milk that is a coproduct of the cheese and curd manufacturing process. Whey proteins are fractionated from the whey and dried to make a WPC, which is typically 80% protein, 10% lactose, and minerals. ¹⁶ Whey is known for its high-quality amino acid profile and as an excellent source of branched-chain amino acids. ¹⁷ Branched-chain amino acids are metabolized by muscle, which in turn conserves the need to breakdown lean tissue for energy. This is important in the recovery from acute malnutrition, as one of the goals to recovery is building lean tissue mass. ¹⁸ Whey protein may also facilitate the retention of absorbed amino acids. ^16,17 Further, bioactive peptides present in whey have important biological functions related to growth and the immune system. ^16,19

After the extraction of whey proteins in the whey fractionation process, whey permeate remains. Whey permeate mostly comprises (at least 85%) lactose. Naturally found in milk, lactose is a primary energy source for breastfed infants and may also have a prebiotic effect that improves gut health. ^20,21 Also, a further benefit of lactose lies in its role facilitating the absorption of nutrients that support growth. ²²

Current Evidence behind the Inclusion of Whey in Supplementary Foods

Despite nutrition experts’ recommendations to include whey in supplementary foods and its potential benefits, a review in 2014 by Noriega and Lindshield ⁵ argues that the evidence behind the inclusion of whey in supplementary foods is weak, given the lack of studies specifically comparing different isocaloric and isonitrogenous supplementary foods to treat MAM.

Overall, the quality and quantity of protein are known to be important for growth in young children, and studies have suggested that animal source protein improves nutritional outcomes in undernourished populations. A prospective cohort study by Stein et al ²³ in 2003 followed Guatemalan women who received dried skimmed milk supplements in childhood and found they were more likely to be taller as adults than those who received a non–animal source protein supplement. Ackatia-Armah et al ²⁴ in Malawi found recovery rates to be higher among children who received treatment foods containing animal source protein (73% for whey-containing RUSF and 68% for corn–soy blend plus plus [CSB++] containing dried skimmed milk) than children receiving 1 of the 2 types of fortified cereal blends with no animal source protein (at 61% and 58%). Also, Karakochuk et al ²⁵ showed recovery rates of moderately malnourished children in Ethiopia were higher among those receiving a whey-containing RUSF (73%) than those receiving CSB with no animal source protein (67%). Although these studies demonstrate positive effects of consuming animal source protein, they do not allow for determining whether improved outcomes were due to the animal source protein or rather the total protein, total energy intake, and other factors that differed between the study and comparison foods.

Some intervention trials have investigated more comparable treatment foods that better isolate the effect of whey and other dairy protein in the treatment of wasting. A study by Oakley et al ²⁶ in Malawi found that treating children for SAM by substituting soy protein for dried skimmed milk in a ready-to-use therapeutic food (RUTF), lowering the milk content to only 10% of the total food weight, resulted in lower recovery rates and poorer growth outcomes than the recovery rates and growth outcomes for children who received RUTF with 25% milk. Similarly, another Malawian study by Bahwere et al ¹⁸ in 2014 substituted whey protein for dried skimmed milk in an RUTF for treating SAM and observed similar recovery rates across both groups of children receiving either the milk-based RUTF or the whey-based RUTF. These studies provide strong evidence supporting the effectiveness of using dairy products, particularly whey, in therapeutic foods for treating children with SAM.

More recently, a randomized, double-blind controlled clinical effectiveness trial was conducted in Malawi in 2013 to 2014, in which 2259 children with MAM were randomly assigned to receive 1 of 2 RUSFs and assessed for recovery. ⁷ A soy RUSF, containing no animal source protein, served as the control food. ^3,27 A novel whey RUSF, containing WPC and whey permeate (with no soy), was the intervention food. ⁷ Protein quality, measured by the Digestible Indispensable Amino Acid Score, was similar in both foods. The total amount of protein provided by the soy RUSF was approximately 50% higher than that of the whey RUSF in each dose the children received. The children who received the whey RUSF recovered at a successful rate (84%) compared with other SFPs demonstrating similar recovery rates, ^3,4 showing that the whey RUSF was effective in treating MAM. ⁷ The percentage of children with MAM who recovered was higher in the whey RUSF group than the soy RUSF group (81% vs 84%, for soy and whey RUSF, respectively, P = .039). ⁷ In addition, 5 of the 7 secondary growth outcomes were superior among the children who received the whey RUSF versus the soy RUSF. These secondary growth outcomes included MUAC at final visit, MUAC gain throughout treatment, WHZ at final visit, WHZ change throughout treatment, and weight gain throughout treatment. ⁷ Even though the whey RUSF contained less total protein and less total energy than the soy RUSF, it performed better in children with MAM.

Conclusion

The recent study demonstrating that a whey RUSF performed better than a soy RUSF in treating children with MAM provides the first specific evidence to support the inclusion of whey ingredients in RUSFs to treat MAM. These results help solidify the larger evidence base indicating potential beneficial outcomes of including whey and other dairy products in supplementary foods in the treatment of MAM. Although the 2 treatment foods in the recent Malawi trial ⁷ were neither isocaloric nor isonitrogenous, the whey RUSF performed better than the soy RUSF, even with lower caloric and total protein content, thus ultimately highlighting the additional benefits of whey. Still, further research is needed to identify the ideal amount and type of dairy protein required to produce the best outcomes for the lowest cost. When possible, studies comparing various types of proteins should involve isocaloric and isonitrogenous foods, possibly using dose–response study methodology, to better delineate the effects of the various components in animal source protein.