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Background Moderate acute malnutrition (MAM) affects 33 million children annually. Investments in formulations of corn-soy blended flours and lipid-based nutrient supplements have effectively improved MAM recovery rates. Information costs and cost-effectiveness differences are still needed. Objectives We assessed recovery and sustained recovery rates of MAM children receiving a supplementary food: ready-to-use supplementary food (RUSF), corn soy whey blend with fortified vegetable oil (CSWB w/oil), or Super Cereal Plus with amylase (SC + A) compared to Corn Soy Blend Plus with fortified vegetable oil (CSB+ w/oil). We also estimated differences in costs and cost effectiveness of each supplement. Methods In Sierra Leone, we randomly assigned 29 health centers to provide a supplement containing 550 kcal/d for ∼12 wk to 2691 children with MAM aged 6–59 mo. We calculated cost per enrollee, cost per child who recovered, and cost per child who sustained recovery each from 2 perspectives: program perspective and caregiver perspective, combined. Results Of 2653 MAM children (98.6%) with complete data, 1676 children (63%) recovered. There were no significant differences in the odds of recovery compared to CSB+ w/oil [0.83 (95% CI: 0.64–1.08) for CSWB w/oil, 1.01 (95% CI: 0.78–1.3) for SC + A, 1.05 (95% CI: 0.82–1.34) for RUSF]. The odds of sustaining recovery were significantly lower for RUSF (0.7; 95% CI 0.49–0.99) but not CSWB w/oil or SC + A [1.08 (95% CI: 0.73–1.6) and 0.96 (95% CI: 0.67–1.4), respectively] when compared to CSB+ w/oil. Costs per enrollee [US dollars (USD)/child] ranged from $105/child in RUSF to $112/child in SC + A and costs per recovered child (USD/child) ranged from $163/child in RUSF to $179/child in CSWB w/oil, with overlapping uncertainty ranges. Costs were highest per sustained recovery (USD/child), ranging from $214/child with the CSB+ w/oil to $226/child with the SC + A, with overlapping uncertainty ranges. Conclusions The 4 supplements performed similarly across recovery (but not sustained recovery) and costed measures. Analyses of posttreatment outcomes are necessary to estimate the full cost of MAM treatment. This trial was registered at clinicaltrials.gov as NCT03146897.

Examining the role of environmental enteric dysfunction (EED) in child growth requires noninvasive, field-appropriate biomarkers. Alternatives to the traditionally used lactulose:mannitol (L:M) test have been explored, but few studies have compared the L:M test to host fecal mRNA transcripts. The objectives of this study were to examine whether 1) host fecal mRNA transcripts could predict presence and severity of EED, measured using the L:M test, and 2) EED modifies the effect of specialized nutritious foods (SNFs) on recovery from moderate acute malnutrition (MAM). This substudy was nested within a cluster randomized trial comparing four SNFs in the treatment of MAM among children 6 to 59 months in Sierra Leone. EED was assessed at enrollment using the L:M test and 15 host fecal mRNA transcripts on 522 children. Recovery from MAM was defined as achieving mid-upper arm circumference ≥ 12.5 cm within 12 weeks of supplementation. Random forest classification models were used to examine prediction of presence and severity of EED by host fecal mRNA transcripts. Logistic regression was used to test for effect modification by L:M test variables including % lactulose excreted (%L). Eight host fecal mRNA transcripts (AQP9, REG3A, IFI30, DECR1, BIRC3, SELL, PIK3AP1, DEFA6) identified EED (%L ≥ 0.2) and severe EED (%L ≥ 0.45) with high sensitivity and specificity. The L:M test variables did not modify the effect of SNFs on recovery from MAM. In this study, we found host fecal mRNA transcripts that could be biomarkers of EED but did not find EED to modify the effect of SNFs on MAM treatment.

Background Measures that better describe “healthy” and sustainable recovery during nutritional treatment of children with moderate acute malnutrition (MAM) are needed. Objectives We compared changes to body composition among children receiving 1 of 4 specialized nutritious food (SNFs) during treatment of MAM and by recovery and relapse outcomes. Methods The study was nested within a prospective, cluster-randomized, community-based, cost-effectiveness trial assessing 4 SNFs to treat children aged 6–59 mo with MAM [midupper arm circumference (MUAC) ≥11.5 cm and

Background There is evidence that Alzheimer's disease (AD) has significant cerebrovascular etiopathogenesis. Understanding potentially modifiable risk factors for vascular disease can help design long-term intervention strategies for controlling or preventing cognitive dysfunction attributable to cerebrovascular disease. Objective To evaluate the presence and severity of markers of cerebrovascular pathology, its relationship to diagnostic categories of dementia, including AD, and association with the metabolic biomarker homocysteine. Methods In a cross-sectional observational study, 340 community-dwelling elders received a clinical evaluation including brain MRI and neuropsychological tests. Dementia and mild cognitive impairment (MCI) were diagnosed by consensus committee. Fasting total plasma homocysteine was measured. Statistical analyses were adjusted for demographics and cerebrovascular risk factors. Results Nearly 25% of those diagnosed with AD had small vessel infarcts (SVI). Periventricular white matter hyperintensity (pvWMHI) was prevalent in participants with AD (61%) or MCI (amnesic 61% and non-amnesic 54%, respectively). Participants with SVI and/or pvWMHI also had greater brain atrophy. Homocysteine concentrations were higher in individuals with cerebrovascular findings than in those without. In individuals with cerebrovascular disease, homocysteine was inversely related to executive function (p = 0.022) and directly related to degree of brain atrophy (p = 0.009). Conclusions We demonstrated a significant prevalence of small vessel markers of cerebrovascular pathology in individuals diagnosed with AD, with a significant concurrence between cerebrovascular disease and brain and ventricular atrophy. While current research on AD has focused on amyloid-βpeptide deposition, tau-pathology, and microglial activation and inflammation, greater attention to the cerebrovascular contribution to this neurodegenerative disease presents an additional target for therapeutic prevention and intervention.

Background: There is a potential role of choline in cardiovascular and cerebrovascular disease through its involvement in lipid and one-carbon metabolism.Objective: We evaluated the associations of plasma choline and choline-related compounds with cardiometabolic risk factors, history of cardiovascular disease, and cerebrovascular pathology.Design: A cross-sectional subset of the Nutrition, Aging, and Memory in Elders cohort who had undergone MRI of the brain (n = 296; mean ± SD age: 73 ± 8.1 y) was assessed. Plasma concentrations of free choline, betaine, and phosphatidylcholine were measured with the use of liquid-chromatography-stable-isotope dilution-multiple-reaction monitoring-mass spectrometry. A volumetric analysis of MRI was used to determine the cerebrovascular pathology (white-matter hyperintensities and small- and large-vessel infarcts). Multiple linear and logistic regression models were used to examine relations of plasma measures with cardiometabolic risk factors, history of cardiovascular disease, and radiologic evidence of cerebrovascular pathology.Results: Higher concentrations of plasma choline were associated with an unfavorable cardiometabolic risk-factor profile [lower high-density lipoprotein (HDL) cholesterol, higher total homocysteine, and higher body mass index (BMI)] and greater odds of large-vessel cerebral vascular disease or history of cardiovascular disease but lower odds of small-vessel cerebral vascular disease. Conversely, higher concentrations of plasma betaine were associated with a favorable cardiometabolic risk-factor profile [lower low-density lipoprotein (LDL) cholesterol and triglycerides] and lower odds of diabetes. Higher concentrations of plasma phosphatidylcholine were associated with characteristics of both a favorable cardiometabolic risk-factor profile (higher HDL cholesterol, lower BMI, lower C-reactive protein, lower waist circumference, and lower odds of hypertension and diabetes) and an unfavorable profile (higher LDL cholesterol and triglycerides).Conclusion: Choline and its metabolites have differential associations with cardiometabolic risk factors and subtypes of vascular disease, thereby suggesting differing roles in the pathogenesis of cardiovascular and cerebral large-vessel disease compared with that of small-vessel disease.

OBJECTIVES: The objective of the study was to examine whether EED at enrollment modifies the effect of specialized nutritious foods (SNFs) on graduation from a moderate acute malnutrition (MAM) treatment program. METHODS: This sub-study was nested within a cluster randomized trial of MAM children 6–59 months of age supplemented with one of four SNFs: Super Cereal Plus w/amylase (SC + A), Corn Soy Blend Plus w/oil (CSB + w/oil - referent), Corn Soy Whey Blend w/oil (CSWB w/oil), and Ready to Use Supplementary Food (RUSF). Children with mid-upper arm circumference (MUAC) ≥11.5 cm and

OBJECTIVES: The objectives of the study were to 1) develop an EED score using fecal host mRNA transcripts, 2) compare three EED biomarkers, and 3) examine associations between EED biomarkers and growth outcomes and recovery from MAM. METHODS: In a study nested within a supplementary feeding program for children 6–59 months of age with MAM in Sierra Leone, EED was assessed in all children enrolled using: 1) lactulose: mannitol (L: M) test (n = 422), 2) fifteen host fecal mRNA transcripts (n = 441), and 3) host fecal proteins [alpha-1-anti trypsin (AAT), myeloperoxidase (MPO), neopterin (NEO)] (n = 200). Data were also collected on anthropometry and z scores computed for length-for-age (LAZ), and weight-for-length (WLZ). Length and weight gain were assessed over 2 weeks and recovery from MAM was defined as mid-upper arm circumference ≥12.5 cm. Factor analysis was used to identify EED scores using the mRNA transcripts and mixed effects regression was conducted to test for associations. RESULTS: The fifteen host fecal mRNA transcripts clustered into three scores using factor analysis (Eigen value >1). These were termed the Gut Inflammation (GI) score (Eigen value = 5.55), Gut Structure (GS) score (Eigen value = 2.48), and Gut Defense (GD) score (Eigen value = 2.22). We found agreement between the GI score and MPO (P

Background There is a variety of specialized nutritious foods available for use in programs targeting undernutrition, but evidence supporting the choice of product is limited. Objectives We compared the cost-effectiveness of 4 specialized nutritious foods to prevent stunting and wasting in children aged 6–23 mo in Burkina Faso. Methods Four geographic regions were randomly assigned to 1 of 4 intervention arms: Corn-Soy Blend Plus (CSB+) programmed with separate fortified vegetable oil (the reference food), Corn-Soy-Whey Blend (CSWB; a new formulation) with oil, SuperCereal Plus (SC+), and ready-to-use supplementary food (RUSF). We compared the effects of each intervention arm on growth (length-for-age z score (LAZ), weight-for-length z score (WLZ), end-line stunting (LAZ < −2), and total monthly measurements of wasting (WLZ < −2). Rations were ∼500 kcal/d, distributed monthly. Children were enrolled in the blanket supplementary feeding program at age ∼6 mo and measured monthly for ∼18 mo. Average costs per child reached were linked with effectiveness to compare the cost-effectiveness of each arm with CSB+ with oil. Results In our sample of 6112 children (CSB+, n = 1519; CSWB, n = 1503; SC+, n = 1564; RUSF, n = 1526), none of the foods prevented declines in growth. Children in the SC+ and RUSF arms were not significantly different than those in the CSB+ with oil arm. Children in the CSWB with oil arm experienced higher end-line (measurement at age 22.9–23.9 mo) stunting (OR: 2.07; 95% CI: 1.46, 2.94) and more months of wasting (incidence rate ratio: 1.29; 95% CI: 1.09, 1.51). CSB+ with oil was the least-expensive ration in all costing scenarios ($113–131 2018 US dollars/enrolled child) and similar in effectiveness to SC+ and RUSF, and thus the most cost-effective product for the defined purposes. Conclusions CSB+ with oil was the most cost-effective ration in the prevention of wasting and stunting in this trial. This trial was registered at clinicaltrials.gov as NCT02071563.

This report on vitamin B-12 (B12) is part of the Biomarkers of Nutrition for Development (BOND) Project, which provides state-of-the art information and advice on the selection, use, and interpretation of biomarkers of nutrient exposure, status, and function. As with the other 5 reports in this series, which focused on iodine, folate, zinc, iron, and vitamin A, this B12 report was developed with the assistance of an expert panel (BOND B12 EP) and other experts who provided information during a consultation. The experts reviewed the existing literature in depth in order to consolidate existing relevant information on the biology of B12, including known and possible effects of insufficiency, and available and potential biomarkers of status. Unlike the situation for the other 5 nutrients reviewed during the BOND project, there has been relatively little previous attention paid to B12 status and its biomarkers, so this report is a landmark in terms of the consolidation and interpretation of the available information on B12 nutrition. Historically, most focus has been on diagnosis and treatment of clinical symptoms of B12 deficiency, which result primarily from pernicious anemia or strict vegetarianism. More recently, we have become aware of the high prevalence of B12 insufficiency in populations consuming low amounts of animal-source foods, which can be detected with ≥1 serum biomarker but presents the new challenge of identifying functional consequences that may require public health interventions.

Factors associated with relapse among children who are discharged after reaching a threshold denoted ‘recovered’ from moderate acute malnutrition (MAM) are not well understood. The aim of this study was to identify factors associated with sustained recovery, defined as maintaining a mid-upper-arm circumference≥12·5 cm for 1 year after release from treatment. On the basis of an observational study design, we analysed data from an in-depth household (HH) survey on a sub-sample of participants within a larger cluster randomised controlled trial (cRCT) that followed up children for 1 year after recovery from MAM. Out of 1497 children participating in the cRCT, a subset of 315 children participated in this sub-study. Accounting for other factors, HH with fitted lids on water storage containers (P=0·004) was a significant predictor of sustained recovery. In addition, sustained recovery was better among children whose caregivers were observed to have clean hands (P=0·053) and in HH using an improved sanitation facility (P=0·083). By contrast, socio-economic status and infant and young child feeding practices at the time of discharge and HH food security throughout the follow-up period were not significant. Given these results, we hypothesise that improved water, sanitation and hygiene conditions in tandem with management of MAM through supplemental feeding programmes have the possibility to decrease relapse following recovery from MAM. Furthermore, the absence of associations between relapse and nearly all HH-level factors indicates that the causal factors of relapse may be related mostly to the child’s individual, underlying health and nutrition status.

Identification of modifiable risk factors provides a crucial approach to the prevention of dementia. Nutritional or nutrient-dependent risk factors are especially important because dietary modifications or use of dietary supplements may lower the risk factor level. One such risk factor is a raised concentration of the biomarker plasma total homocysteine, which reflects the functional status of three B vitamins (folate, vitamins B12, B6). A group of experts reviewed literature evidence from the last 20 years. We here present a Consensus Statement, based on the Bradford Hill criteria, and conclude that elevated plasma total homocysteine is a modifiable risk factor for development of cognitive decline, dementia, and Alzheimer’s disease in older persons. In a variety of clinical studies, the relative risk of dementia in elderly people for moderately raised homocysteine (within the normal range) ranges from 1.15 to 2.5, and the Population Attributable risk ranges from 4.3 to 31%. Intervention trials in elderly with cognitive impairment show that homocysteine-lowering treatment with B vitamins markedly slows the rate of whole and regional brain atrophy and also slows cognitive decline. The findings are consistent with moderately raised plasma total homocysteine (>11 μmol/L), which is common in the elderly, being one of the causes of age-related cognitive decline and dementia. Thus, the public health significance of raised tHcy in the elderly should not be underestimated, since it is easy, inexpensive, and safe to treat with B vitamins. Further trials are needed to see whether B vitamin treatment will slow, or prevent, conversion to dementia in people at risk of cognitive decline or dementia.

Flour fortification with folic acid, mandated for the prevention of neural tube defects (NTD), can be regarded as a positive public health intervention especially for women of childbearing age. However, the denial of the possibility of adverse effects related to interaction between high folic acid intake and vitamin B12 deficiency or the possibility that folic acid fortification and/or supplementation may be associated with adverse effects in some elderly racial/genetic subgroups is a major concern that is being overlooked. Denying the existence of these adverse effects will prevent further and more methodological studies to understand the mechanism and risk of adverse effects of adding folic acid in substantial amounts to any nation’s food supply by fortification and/or supplementation.

Background: Folate status has been positively associated with cognitive function in many studies; however, some studies have observed associations of poor cognitive outcomes with high folate. In search of an explanation, we hypothesized that the association of folate with cognition would be modified by the interaction of high-folate status with a common 19-bp deletion polymorphism in the dihydrofolate reductase (DHFR) gene. To our knowledge, the cognitive effects of this gene have not been studied previously. Objective: We examined the association between cognitive outcomes with the 19-bp deletion DHFR polymorphism, folate status, and their interaction with high or normal plasma folate. Design: This was a pooled cross-sectional study of the following 2 Boston-based cohorts of community living adults: the Boston Puerto Rican Health Study and the Nutrition, Aging, and Memory in Elders study. Individuals were genotyped for the DHFR 19-bp deletion genotype, and plasma folate status was determined. Cognitive outcomes included the Mini-Mental State Examination, Center for Epidemiologic Studies Depression Scale, and factor scores for the domains of memory, executive function, and attention from a set of cognitive tests. Results: The prevalence of the homozygous deletion (del/del) genotype was 23%. In a multivariable analysis, high folate status (>17.8 ng/mL) was associated with better memory scores than was normal-folate status (fourth–fifth quintiles compared with first–third quintiles: β ± SE = −0.22 ± 0.06, P < 0.01). Carriers of the DHFR del/del genotype had worse memory scores (β ± SE = −0.24 ± 0.10, P < 0.05) and worse executive scores (β = −0.19, P < 0.05) than did those with the del/ins and ins/ins genotypes. Finally, we observed an interaction such that carriers of the del/del genotype with high folate had significantly worse memory scores than those of both noncarriers with high-folate and del/del carriers with normal-folate (β-interaction = 0.26 ± 0.13, P < 0.05). Conclusions: This study identifies a putative gene-nutrient interaction that, if confirmed, would predict that a sizable minority carrying the del/del genotype might not benefit from high-folate status and could see a worsening of memory. An understanding of how genetic variation affects responses to high-folate exposure will help weigh risks and benefits of folate supplementation for individuals and public health.

Background Nutrition programs frequently approach wasting and stunting as 2 separate conditions with distinct causes and effects. Although several cross-sectional studies have identified an association between the 2 conditions, longitudinal studies are useful to quantify the risk of acute malnutrition based on the trajectory of linear growth. Objective We analyzed data from a longitudinal study to explore associations between linear growth and relapse to acute malnutrition in high-risk children during the year after recovery from moderate acute malnutrition (MAM). Methods This was a secondary data analysis from a cluster randomized trial involving 1487 Malawian children 6-62 mo old treated for MAM and enrolled upon recovery. Children were followed for 1 y, during which data were collected on anthropometric progress, symptoms of illness, and household food security. Multivariate fixed-effects logistic regression was used to identify associations between linear growth and relapse to acute malnutrition. Results Children who have recovered from MAM proved to be a high-risk population, with nearly half experiencing a decrease in height-for-age z score (HAZ) for 12 mo. Children whose HAZ was declining were more likely to relapse to MAM or SAM than were those whose linear growth rate maintained or increased their HAZ (P

Background: Objectives: Elevated plasma total homocysteine (tHcy) is associated with increased risk of cardiovascular disease, stroke and dementia. Results of clinical trials using B-vitamins to reduce the cognitive risks attributed to tHcy have been inconsistent. The high prevalence of both hyperhomocysteinemia and cognitive impairment among kidney transplant recipients makes them an important population in which to evaluate the effect of lowering homocysteine on cognitive function. We therefore evaluated whether B-vitamin therapy to lower tHcy would prevent cognitive-decline in a cohort of stable kidney transplant recipients. Design: The study was a longitudinal ancillary of the FAVORIT trial, a randomized, placebo-controlled multi-site trial of high-dose B vitamins to reduce cardiovascular and cerebrovascular events in clinically stable kidney transplant recipients with elevated tHcy. Participants: 584 participants from 18 sites across North America. Intervention: The intervention consisted of a daily multivitamin containing high-doses of folate (5.0 mg), vitamin B12 (1.0 mg) and vitamin B6 (50 mg). The placebo consisted of a daily multi-vitamin containing no folate and recommended daily allowances of vitamins B12 and B6 (0 mg folate; 2.0 µg vitamin B12; 1.4 mg vitamin B6). Measurements: Annual neuropsychological assessment for up to 5 years (mean 3.3 years) using a standardized test battery. Efficacy was analyzed on an intention-to-treat basis using end-of-trial data. Subgroup analyses included stratification for baseline plasma B-vitamin and tHcy concentrations. Results: At baseline, cognitive impairment was common with 61% of participants falling more than one standard deviation below published norms for at least one cognitive test. Fewer than 1% of participants had insufficient plasma folate < 5 ng/ml or vitamin B12 < 148 pmol/L. However, 44.6% had plasma B6 concentrations < 30 nmol/L. At follow-up, processing speed and memory scores were modestly but significantly better in the B-vitamin supplement group than in controls (p≤0.05). There was no interaction between baseline tHcy, B-vitamin status and treatment on the cognitive outcomes. Conclusions: High-dose B-vitamin supplementation provided modest cognitive benefit for kidney transplant recipients with elevated baseline tHcy. Since nearly all participants were folate and vitamin B12 sufficient at baseline, the potential cognitive benefits of folate and B12 supplementation in individuals with poor B-vitamin status remains to be determined.

OBJECTIVES: To determine differential changes in children's body composition—fat-free mass (FFM) and fat mass (FM)—after 4 weeks of treatment for moderate acute malnutrition (MAM) with one of 4 four specialized nutritious foods (SNFs). METHODS: This sub-study was nested within a larger cluster-randomized trial comparing the cost-effectiveness of 4 isocaloric SNFs in treating MAM among children 6–59 months in Pujehun District, Sierra Leone: Corn-Soy Blend Plus w/oil (CSB + w/oil), Super Cereal Plus w/amylase (SC + A), Corn-Soy-Whey Blend w/oil (CSWB w/oil) and Ready-to-use-Supplementary Food (RUSF). Children with mid-upper arm circumference (MUAC) ≥11.5 cm and

OBJECTIVES: This study compared the effectiveness of 4 specialized nutritious foods (SNFs) used for the treatment of moderate acute malnutrition (MAM) in children

We are worried by the following statement in a recent editorial on the safety of folic acid fortification: “No important adverse effects have been identified to date, probably because a modest level of fortification has proved very effective in preventing these devastating birth defects.”1 It is unusual in medicine to claim that a treatment is safe just because it is effective in treating or preventing one condition—objective evidence is needed on overall safety and the side effect profile in all people exposed to the “treatment,” not only those who benefit. It seems that WHO also has not fully assessed the possible harmful effects of folic acid because its guideline on folate and neural tube defects (NTDs) states: “high folic acid intake has not reliably been shown to be associated with negative health effects.”2 The editorial’s claim that half of all NTDs could be prevented by mandatory fortification in Europe is misleading, because the effectiveness of fortification depends on the baseline prevalence of NTDs, …

The recent increase in the intake of folic acid by the general public through fortified foods and supplements, has raised safety concern based on early reports of adverse health outcome in elderly with low B12 status who took high doses of folic acid. These safety concerns are contrary to the 2015 WHO statement that "high folic acid intake has not reliably been shown to be associated with negative healeffects". In the folic acid post-fortification era, we have shown that in elderly participants in NHANES 1999-2002, high plasma folate level is associated with exacerbation of both clinical (anemia and cognitive impairment) and biochemical (high MMA and high Hcy plasma levels) signs of vitamin B12 deficiency. Adverse clinical outcomes in association with high folate intake were also seen among elderly with low plasma B12 levels from the Framingham Original Cohort and in a study from Australia which combined three elderly cohorts. Relation between high folate and adverse biochemical outcomes were also seen in the Sacramento Area Latino Study on Aging (High Hcy, high MMA and lower TC2) and at an outpatient clinic at Yale University where high folate is associated with higher MMA in the elderly but not in the young. Potential detrimental effects of high folic acid intake may not be limited to the elderly nor to those with B12 deficiency. A study from India linked maternal high RBC folate to increased insulin resistance in offspring. Our study suggested that excessive folic acid intake is associated with lower natural killer cells activity in elderly women. In a recent study we found that the risk for unilateral retinoblastoma in offspring is 4 fold higher in women that are homozygotes for the 19 bp deletion in the DHFR gene and took folic acid supplement during pregnancy. In the elderly this polymorphism is associated with lower memory and executive scores, both being significantly worse in those with high plasma folate. These and other data strongly imply that excessive intake of folic acid is not always safe in certain populations of different age and ethnical/genetic background.

As the number of elderly continues to increase worldwide, age-related neurological disorders, such as Alzheimer’s disease and vascular dementia, are a growing concern. In some cases, vascular dementia and cognitive decline in aging are associated with nutritional status and elevated homocysteine, suggesting that improving nutritional status can play a meaningful role in the prevention of cognitive impairment. The research described in this chapter represents current understanding on the relationships of folate and vitamin B12 nutritional status with cognitive function and dementia in adults and elderly. Low B vitamin status is associated with increased homocysteine levels and there is evidence that insufficient B vitamin intake is associated with lower cognitive scores in comparison to adequate intake. However, higher rates of cognitive decline have been reported with high levels of folate and folic acid intake in adults, and memory performance may be impaired with high folate intake in individuals with low vitamin B12 status. Overall, studies reported lower folate blood levels and a higher prevalence of deficiency among subjects with dementia. In general, vitamin B12 serum levels were lower in patients with dementia relative to nondemented individuals; however, this relationship was not as consistent as that for folate. Subsequent to mandatory folic acid fortification, stroke mortality has decreased at a greater rate in the USA and Canada, suggesting a positive effect of fortification on cerebrovascular health. Interventions with folic acid and with combinations of B vitamins were able to improve cognitive function or prevent decline, especially in subjects with low nutrient status. As with the data for blood nutrient levels, evidence that vitamin B12 treatment improves cognitive function is conflicting and less positive.

We commend Semba et al. (2016) for examining child stunting in the context of protein and amino acids, which, beyond supplying essential nitrogen for protein synthesis, are involved in regulation of linear growth, an issue that has not been addressed sufficiently. The authors reported significant associations between low levels of serum amino acids and stunting in a cross-sectional study of young children in rural Malawi. As the authors note, studies of micronutrient and lipid supplements have failed to demonstrate improved linear growth in malnourished children. Furthermore, the ten most effective interventions recommended for scale up at the global level are likely to reduce stunting by only ~ 20% even at a coverage level of 90% (Bhutta et al., 2013). Thus, we are writing to comment on the findings of Semba et al., highlight relevant past and current research and advocate for further collaborative effort forward in the area of protein quality and childhood stunting. The results of Semba et al. raise a number of questions, including the interpretation of circulating amino acids. Plasma concentrations are static, representing the net effect of changes in production and utilization of an amino acid, unlike the dynamic flux. For example, plasma citrulline flux, which indicates enterocyte mass and function, is not reflected in its plasma concentration (Kao et al., 2016). Thus, among stunted children, are low circulating amino acids a biomarker of recent protein intake, the body's amino acid pool, acute protein deficiency, or simply a reflection of short-term physiological processes such as digestion and absorption (Cetin et al., 2015)? Or do the levels of circulating amino acids represent a response to entirely different biological processes such as presence of infection (Laurichesse et al., 1998) or a metabolic adjustment to preserve nutrients critical for maintaining lean body mass during periods of low intake of quality protein? What is clear from the novel approach used by Semba et al. is that physiological outcomes such as stunting and nutritional factors such as protein and amino acids and their metabolism and turnover are complex phenomena, and additional research will be required to answer these questions. While the emphasis from protein shifted to energy and micronutrients in the late 1970's, as noted by Semba et al., it was by no means an end to the work on protein quality; we would be remiss not to mention the decades of seminal work conducted since then through the leadership of the late Drs. Nevin Scrimshaw and Vernon Young. This included elucidating the relationship of protein and energy interactions, redefining protein and amino acid requirements within the context of high and low energy availabilities, and investigating the health impacts from improving protein quality via increased intake of essential amino acids (EAAs)—especially lysine, the most limiting EAA in cereal based diets. Dr. Scrimshaw's seminal protein work has continued through the Nevin Scrimshaw International Nutrition Foundation, which co-organized a workshop on the topic of protein quality and growth in 2012 (Suri et al., 2013). One reason that protein and amino acids are often overlooked in relation to stunting may be that while children in low-resource, developing country contexts appear to have adequate protein intake; however, there are two issues that may, in fact, put them at risk of inadequacy. First, failure to adjust for protein quality—a composite of the EAA profile as compared to the requirement pattern, and the “digestibility”, or absorption and utilization of the amino acids in foods, both of which can decrease the effective protein available to the body—results in overestimates of dietary protein adequacy. Second, the needs of children in these contexts are systematically underestimated; current protein and amino acid requirements do not account for conditions of energy deficit, and persistent or subclinical infections, which could be compounded by sub-optimal digestive and absorptive intestinal function; emerging research also suggests a connection with the microbiome (Kao et al., 2016). The link to dietary protein quality is of particular interest from a public health lens; as the authors note, “dietary intake of essential amino acids may be insufficient in children with stunting”. Previous research supports this hypothesis: An analysis of dietary and anthropometric data collected on Ghanaian children aged 2–13 years, found an association between dietary protein inadequacy (adjusting for quality) and risk of being stunted (Ghosh et al., 2010). A meta-analysis of consumption of conventional versus quality protein maize (higher in lysine and tryptophan) showed significantly higher rates of weight and height gain among young children with mild to moderate undernutrition from populations in which maize is the major staple food (Gunaratna et al., 2010). Additionally, an analysis of national food balance sheet data from developing countries found an inverse association between rates of stunting and the per capita availability of “utilizable” protein (adjusted for quality) but not total protein (Ghosh et al., 2012). Finally, the authors conclude, “randomized controlled trials would ultimately be required to determine whether essential amino acids…play a causal role in the pathogenesis of child stunting”. We whole-heartedly agree with this statement and point to some interesting findings emerging from an RCT recently completed in Ghana (Ghosh et al., 2014). This trial examined the effect of adding a protein quality and micronutrient-improved complementary food supplement to the diets of Ghanaian infants from age 6 to 18 months. Results show a dose response effect of receiving the supplement on HAZ scores at 18 months of age (unpublished). Biomarkers of inflammation, micronutrient status, and plasma amino acids were collected as well. We look forward to presenting the findings of this longitudinal analyses in comparison with the cross sectional association of stunting and amino acids as observed by Semba et al. Overall, the findings reported by Semba et al. add to evidence for the link between inadequate protein and amino acid intake and stunting in children. We expect that this important discussion on protein quality continue, in conjunction with newer research on the potential effects of the microbiome, enteric infections and chronic inflammation, in collaborative efforts to combat child stunting.