Tyrosine requirement during the rapid catch-up growth phase of recovery from severe childhood undernutrition

Cereals and pulse-based ready-to-use therapeutic food as an alternative to the standard milk- and peanut paste-based formulation for treating severe acute malnutrition: a noninferiority, individually randomized controlled efficacy clinical trial

BACKGROUND

The cost of current standard ready-to-use therapeutic food (RUTF) is among the major obstacles to scaling up community-based management of acute malnutrition (CMAM), an important child survival strategy. Identifying a cheaper alternative is a global public health priority.

OBJECTIVE

We sought to compare the efficacy of soya-maize-sorghum RUTF (SMS-RUTF) with that of standard peanut paste-based RUTF (P-RUTF).

DESIGN

We used a nonblinded, parallel-group, simple randomized controlled trial along with a day care approach that enrolled 2 groups of children aged 6-23 and 24-59 mo, respectively, with severe acute malnutrition (SAM).

RESULTS

Intention-to-treat (ITT) and per-protocol (PP) analyses showed noninferiority of SMS-RUTF compared with P-RUTF for the recovery rate [ITT: Δ = -2.0% (95% CI: -7.6%, 3.6%); PP: -1.9% (95% CI: -5.3%, 1.4%)], weight gain [Δ = -0.7 g · kg(-1)· d(-1)(95% CI: -1.3, 0.0 g · kg(-1)· d(-1))], and length of stay [Δ = 2.0 d (95% CI: -1.7, 5.8 d)] in children ≥24 mo of age. In children ≤23 mo of age, the recovery rate of SMS-RUTF was inferior to that of P-RUTF [ITT: Δ = -20.8% (95% CI: -29.9%, -11.7%); PP: -17.2% (95% CI: -25.6%, -8.7%)]. Treatment with SMS-RUTF resulted in a greater increase in hemoglobin [0.670 g/dL (95% CI: 0.420, 0.921 g/dL);P< 0.001]. Treatment with both RUTFs resulted in the replenishment of all of the amino acids tested except for methionine. There were no differences at discharge between RUTF groups in fat mass [Δ = 0.3 kg (95% CI: -0.6, 1.6 kg);P= 0.341] or fat mass index [Δ = 0.4 kg/m(2)(95% CI: -0.3, 1.1 kg/m(2));P= 0.262]. By contrast, comparisons of fat-free mass indicated lower concentrations than the community controls after treatment with either of the 2 RUTFs [Δ = -1.3 kg (95% CI: -2.4, -0.1 kg) andP= 0.034 for comparison between community controls and the SMS-RUTF group; Δ = -1.8 kg (95% CI: -2.9, -0.6 kg) andP= 0.003 for comparison between community controls and the P-RUTF group].

CONCLUSION

SMS-RUTF can be used to treat SAM in children aged ≥24 mo to reduce the costs of CMAM programs. More research is required to optimize SMS-RUTF for younger children. This trial was registered in the Pan African Clinical Trial Registry as PACTR201303000475166.

Progressive Changes in the Plasma Metabolome during Malnutrition in Juvenile Pigs

Severe acute malnutrition (SAM) is one of the leading nutrition-related causes of death in children under five years of age. The clinical features of SAM are well documented, but a comprehensive understanding of the development from a normal physiological state to SAM is lacking. Characterizing the temporal metabolomic change may help to understand the disease progression and to define nutritional rehabilitation strategies. Using a piglet model we hypothesized that a progressing degree of malnutrition induces marked plasma metabolite changes. Four-week-old weaned pigs were fed a nutrient-deficient maize diet (MAL) or nutritionally optimized reference diet (REF) for 7 weeks. Plasma collected weekly was subjected to LC-MS for a nontargeted profiling of metabolites with abundance differentiation. The MAL pigs showed markedly reduced body-weight gain and lean-mass proportion relative to the REF pigs. Levels of eight essential and four nonessential amino acids showed a time-dependent deviation in the MAL pigs from that in the REF. Choline metabolites and gut microbiomic metabolites generally showed higher abundance in the MAL pigs. The results demonstrated that young malnourished pigs had a profoundly perturbed metabolism, and this provides basic knowledge about metabolic changes during malnourishment, which may be of help in designing targeted therapeutic foods for refeeding malnourished children.

Amino acid requirements in children and the elderly population

The factorial approach is used to measure the dietary indispensable amino acid (IAA) requirements in children, although recent measurements based on the indicator amino acid oxidation (IAAO) method have begun to generate more direct evidence. Difficulties with the factorial method are that it depends on accurate estimates of the maintenance protein requirement, as well as of protein deposition during growth. Also, a value for the efficiency of utilizing dietary protein for deposition has to be selected, based on published Nitrogen (N) balance studies. In the recent 2007 WHO/FAO/UNU report, the amino acid requirement pattern for infants was taken to be similar to the amino acid composition of breast milk. For pre-school and older children, the factorial method gave values for the scoring pattern of protein that were fairly close to the earlier 1985 WHO/FAO/UNU report for children, since growth progressively became a smaller component of the factorial calculation as age progressed. However, given that there are several assumptions in the derivation of factorial estimates, direct experimental measurements of the amino acid requirement are desirable. The IAAO method, as it is non-invasive, as made it possible to measure the IAA requirements in children. Over the last decade, some of the IAA requirements have been determined by using the IAAO method in healthy school age children; however, the data on IAA requirements in developing country populations are still being conducted. In the elderly, there are not enough data to make a separate recommendation for IAA requirements from that of adults.

Methods to assess amino acid requirements in humans

PURPOSE OF REVIEW

There are now different stable isotopic methods to measure minimum daily human indispensable amino acid (IAA) requirements. There has been debate on the appropriateness of statistical methods used to define the nature of change in the response.

RECENT FINDINGS

Current isotopic methods measure daily amino acid oxidation and balance of the IAA under test, or of a selected indicator amino acid, to graded intakes of the test IAA. A key concern is how response curves of oxidation/balance are analyzed to find the inflection point (breakpoint) at which the intake requirement is identified. Evaluating the pattern of the response to identify a breakpoint by a two-phase regression appears best. The indicator amino acid oxidation method has also been shortened and developed into a noninvasive protocol suitable for different populations and age groups.

SUMMARY

The indicator amino acid oxidation and balance method might be considered the best approach currently available, but it is challenging. The short-term indicator oxidation method is noninvasive and nondemanding. IAA requirements, based on these methods, have implications for the quality of protein in the dietary intake of populations. Methods that assess the IAA requirements to support optimal body function also need to be developed.