Body Composition Changes in Children during Treatment for Moderate Acute Malnutrition: Findings from a 4-Arm Cluster-Randomized Trial in Sierra Leone.

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 <12.5 cm without bipedal edema] in Sierra Leone. Biweekly SNF rations (1 of 3 fortified-blended foods or a lipid-based nutrient supplement) were given until children recovered (MUAC ≥12.5 cm), or up to 7 rations (∼12 wk). Deuterium dilution was used to estimate fat-free mass (FFM) and fat mass (FM) at enrollment and after 4 wk of treatment to ensure similar treatment exposure among the participants. Another MUAC measurement was performed among recovered children 4 wk after program exit to determine whether recovery was sustained. ANOVA, paired t tests, and linear regression models were used to determine significant differences in changes from baseline to 4 wk. RESULTS: Among 312 analyzed participants, mean baseline weight comprised ∼80% FFM; mean weight gained after 4 wk comprised ∼82% FFM. Changes in FM and FFM among 4 SNFs were similar. Children who recovered gained more weight (241%), FFM (179%), and weight-for-height z score (0.44 compared with 0) compared with those who did not recover; sustainers gained 150% more weight. FM gains were positive among recovered children and sustainers, as well as negative among those who did not recover or sustain recovery, but not significantly different. CONCLUSIONS: Four SNFs had similar effects on body composition in children after 4 wk of treatment for MAM, showing a healthy pattern of weight gain, the majority being FFM. Differential responses to treatment underscore a need for further research to provide targets for healthy, sustainable recovery. This trial was registered at clinicaltrials.gov as NCT03146897.

Biomarkers of Nutrition for Development (BOND): Vitamin B-12 Review.

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.

Children with Poor Linear Growth Are at Risk for Repeated Relapse to Wasting after Recovery from Moderate Acute Malnutrition.

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 < 0.001). Mean changes of +0.15, -0.03, -0.17, and -0.53 in HAZ were observed for those who sustained recovery, relapsed to MAM once, relapsed to MAM multiple times, and developed SAM, respectively. Conclusion: Our results add to the body of evidence suggesting that acute wasting is a harbinger of subsequent stunting. Children who experience poor linear growth after MAM are more likely to experience relapse. Given this bidirectional relation between wasting and stunting, supplementary feeding programs should consider both when designing protocols, aiming to optimize linear growth and achieve acute weight gain, as a means of reducing relapse. This trial was registered at clinicaltrials.gov as NCT02351687.

Household-level factors associated with relapse following discharge from treatment for moderate acute malnutrition.

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.

Environmental enteric dysfunction: pathogenesis, diagnosis, and clinical consequences.

Stunting is common in young children in developing countries, and is associated with increased morbidity, developmental delays, and mortality. Its complex pathogenesis likely involves poor intrauterine and postnatal nutrition, exposure to microbes, and the metabolic consequences of repeated infections. Acquired enteropathy affecting both gut structure and function likely plays a significant role in this outcome, especially in the first few months of life, and serve as a precursor to later interactions of infection and malnutrition. However, the lack of validated clinical diagnostic criteria has limited the ability to study its role, identify causative factors, and determine cost-effective interventions. This review addresses these issues through a historical approach, and provides recommendations to define and validate a working clinical diagnosis and to guide critical research in this area to effectively proceed. Prevention of early gut functional changes and inflammation may preclude or mitigate the later adverse vicious cycle of malnutrition and infection.

Implications of acquired environmental enteric dysfunction for growth and stunting in infants and children living in low- and middle-income countries.

Changes in small bowel function early in infancy in developing countries are increasingly being demonstrated, probably accompanied by altered mucosal architecture in most individuals, including reduced enterocyte mass and evidence of immune activation and inflammation in the mucosa. These alterations appear to be the result of factors of uncertain nature in the environment, and may be a cause of growth faltering and stunting in young children. For these reasons, this constellation of findings is being referred to as environmental enteropathy, or as we propose herein, environmental enteric dysfunction. If the causes were known and effective interventions were available, strategies and policies to intervene at--or possibly before--birth could be developed and promoted in order to prevent subsequent malnutrition and recurrent infection, which are known to interact in a cyclical and synergistic manner in a downward clinical course often ending in death. Resources would be mobilized and applied differently, and the emphasis would change from treatment to prevention. In order to move in this highly desired direction, investments in research will be required to establish the criteria to assess environmental enteric dysfunction, determine its predictive value for growth faltering and stunting, identify the causes, and propose and test potential interventions. The concepts and tools are available. What is required is the decision to move forward along this pathway to better health for infants and children in low-income countries.

Status of vitamins B-12 and B-6 but not of folate, homocysteine, and the methylenetetrahydrofolate reductase C677T polymorphism are associated with impaired cognition and depression in adults.

The C677T polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene differs in frequency in various ethnic groups that have differing prevalence of age-related cognitive impairments. We used a series of neuro-psychological tests to examine the association of the MTHFR C677T polymorphism with cognition and depression and also to assess whether genotype modifies the association of folate and homocysteine with these outcomes. This study analyzed pooled cross-sectional data from 2 ethnically diverse cohorts of community-living adults: the Boston Puerto Rican Health Study (n = 939) and the Nutrition, Aging, and Memory in Elders study (n = 1017). Individuals in both cohorts underwent anthropometric and laboratory measurements and dietary and health assessments using validated questionnaires between the years 2003 and 2007. Cognitive outcomes included measures of global cognition [Mini-Mental Status Exam (MMSE)], depression (Center for Epidemiological Studies Depression Scale), and 3 factor scores for the domains of attention, executive function, and memory that were derived from a detailed set of neuropsychological tests. Low plasma vitamin B-12 concentrations were associated with poorer MMSE scores and higher depression scores, and low vitamin B-6 concentrations were associated with lower MMSE and worse attention and executive function in the multivariate analysis. In contrast, MTHFR genotype, folate, and homocysteine were not associated with cognition or depression in either ethnicity-pooled or stratified analysis. The current study did not find evidence of an association between the MTHFR C677T TT genotype and impaired cognition or depression in a population with adequate folate status and a high prevalence of cognitive impairment and depression.

A history of the isolation and identification of folic acid (folate).

In the 1930s, Lucy Wills identified a 'new hemopoietic factor' in yeast and liver which cured tropical macrocytic anemia in humans and experimental anemia in monkeys. Janet Watson and William B. Castle named the unknown substance, which would ultimately become a form of folate, 'Wills' factor'. Further studies with this unknown substance showed that it was active against nutritional pancytopenia in monkeys and experimental anemia in chicks, leading to various designations such as vitamin M (monkey) and vitamin B(c) (chick). Other factors with growth-promoting activity for microorganisms such as Lactobacillus casei were given the interim names including folic acid - in recognition of extracts from leafy greens. Competing pharmaceutical research groups headed by Robert Stokstad at Lederle Laboratories and Joseph John Pfiffner at Parke-Davis Research Laboratory independently isolated factors bearing the biological properties of Wills' factor and other unknown related factors including folic acid, Lederle Laboratories from a bacterial culture and Parke-Davis Laboratory from yeast and liver as a conjugate of folate. The new vitamin then was crystallized, chemically identified, and synthesized as pteroylglutamic acid and named folic acid between 1943 and 1945. Further studies of the monoglutamic folic acid and the yeast isolate polyglutamyl folate followed through the 1950s and to the present.

A history of the isolation and identification of vitamin B(6).

In the 1930s, Rudolf Peters showed that young rats kept on a semi-synthetic diet with added thiamin and riboflavin but no other supplement developed 'rat acrodynia', a condition characterized by severe cutaneous lesions. In 1934, Paul György showed that the factor which cured 'rat acrodynia' was vitamin B(6). Other studies soon showed that vitamin B(6) deficiency produced convulsions in rats, pigs, and dogs, and a microcytic anemia in certain animals. Samuel Lepkovsky isolated and crystallized vitamin B(6) in 1938. The following year, Leslie Harris and Karl Folkers, and Richard Kuhn and his associates independently showed that vitamin B(6) was a pyridine derivative, 3-hydroxy-4,5-dihydroxy-methyl-2-methyl-pyridine. György proposed the term pyridoxine for this derivative. Esmond Snell developed a microbiological growth assay in 1942 that led to the characterization of pyridoxamine, the animated product of pyridoxine, and pyridoxal, the formyl derivative of pyridoxine. Further studies showed that pyridoxal, pyridoxamine, and pyridoxine have largely equal activity in animals and owe their vitamin activity to the ability of the organism to convert them into the enzymatically active form pyridoxal-5-phosphate. Pyridoxal-5-phosphate plays a role in a wide variety of enzyme systems, especially in the metabolic utilization and transformation of amino acids.

Cognitive dysfunction and depression in adult kidney transplant recipients: baseline findings from the FAVORIT Ancillary Cognitive Trial (FACT).

OBJECTIVE: Hyperhomocysteinemia and B-vitamin deficiency may be treatable risk factors for cognitive impairment and decline. Hyperhomocysteinemia, cognitive impairment, and depression are all common in individuals with kidney disease, including kidney transplant recipients. Accordingly, we assessed the prevalence of cognitive impairment and depressive symptoms in transplant recipients and their association with kidney function, plasma total homocysteine, and B-vitamin concentrations. SETTING: Cross-sectional analysis of baseline data from the Folic Acid for Vascular Outcome Reduction In Transplantation (FAVORIT) Ancillary Cognitive Trial (FACT), which included 183 participants in FAVORIT who underwent detailed neuropsychological assessment before the study intervention. RESULTS: The mean age was 54.0 ± 9.5 years (range: 7 to 386 months). Men comprised 55.2% of the cohort, and the mean time between the current transplant and cognitive testing was 7.0 ± 5.8 years. Twenty-four percent of participants reported neurological or psychiatric complaints, and 30% exhibited symptoms of mild to severe depression. Testing revealed evidence of significant and selective deficits in this population: 33% performed more than 1 standard deviation (SD) below normed means on a memory test, 58% fell lower than 1 SD below the norms on a test of attention and mental processing speed, and 33% to 42% fell lower than 1 SD below the norms on several tests of executive function. Lower estimated glomerular filtration rate and lower folate were associated with poorer performance on tests of memory and executive function. CONCLUSIONS: These observations confirm previous reports of mood and cognitive impairments in adult kidney transplant recipients. Further research is needed to determine the benefit of B-vitamin supplementation and other interventions in this patient population.

B-vitamin deficiency causes hyperhomocysteinemia and vascular cognitive impairment in mice.

In older adults, mildly elevated plasma total homocysteine (hyperhomocysteinemia) is associated with increased risk of cognitive impairment, cerebrovascular disease, and Alzheimer's disease, but it is uncertain whether this is due to underlying metabolic, neurotoxic, or vascular processes. We report here that feeding male C57BL6/J mice a B-vitamin-deficient diet for 10 weeks induced hyperhomocysteinemia, significantly impaired spatial learning and memory, and caused a significant rarefaction of hippocampal microvasculature without concomitant gliosis and neurodegeneration. Total hippocampal capillary length was inversely correlated with Morris water maze escape latencies (r = -0.757, P < 0.001), and with plasma total homocysteine (r = -0.631, P = 0.007). Feeding mice a methionine-rich diet produced similar but less pronounced effects. Our findings suggest that cerebral microvascular rarefaction can cause cognitive dysfunction in the absence of or preceding neurodegeneration. Similar microvascular changes may mediate the association of hyperhomocysteinemia with human age-related cognitive decline.

Biomarkers of environmental enteric dysfunction are differently associated with recovery and growth among children with moderate acute malnutrition in Sierra Leone.

BACKGROUND: Environmental enteric dysfunction (EED) may influence growth during and recovery from moderate acute malnutrition (MAM), however, biomarkers to assess these relations have yet to be identified. OBJECTIVES: The objectives of this study were to: 1) develop a score for EED based on host fecal mRNA transcripts, 2) compare biomarkers of EED with each other, and 3) examine associations between the EED biomarkers and recovery from MAM and growth outcomes. METHODS: In a cohort of 520 Sierra Leonean MAM children, biomarkers of EED included the lactulose: mannitol (L: M) test, 15 host fecal mRNA transcripts, and host fecal proteins [α-1-antitrypsin (AAT), myeloperoxidase (MPO), neopterin (NEO)]. Anthropometry data were also collected and z scores were computed for length-for-age (LAZ) and weight-for-length (WLZ). Recovery from MAM was defined as midupper 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 15 host fecal mRNA transcripts were clustered into 3 scores: gut inflammation (GI) score, gut structure (GS) score, and gut defense (GD) score. We found agreement between certain inflammation markers (GI score and MPO), and permeability markers (GS score and AAT; AAT and the L: M excretion ratio). Antimicrobial gut defense (GD score) was inversely associated with percent lactulose excreted, a measure of intestinal permeability. LAZ (ß: -0.08; 95% CI: -0.14, -0.02) and WLZ (ß: -0.03; 95% CI: -0.06, -0.01) were negatively associated with GI score. A high GD score (ß: 0.36; 95% CI: 0.08, 0.64) and low AAT (ß: -1.35; 95% CI: -2.35, -0.36) were associated with recovery from MAM. CONCLUSIONS: Scores derived from host fecal mRNA transcript variably correlated with the L: M test and host fecal proteins. Markers of intestinal inflammation, permeability, and defense were associated with growth outcomes and recovery from MAM.

Host Fecal mRNAs Predicted Environmental Enteric Dysfunction among Children with Moderate Acute Malnutrition in Sierra Leone.

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.

Effectiveness and cost-effectiveness of 4 supplementary foods for treating moderate acute malnutrition: results from a cluster-randomized intervention trial in Sierra Leone.

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.

Community-level micronutrient fortification of school lunch meals improved vitamin A, folate, and iron status of schoolchildren in Himalayan villages of India.

Anemia and micronutrient deficiencies are common among Indian schoolchildren. We assessed the effectiveness of micronutrient fortification of meals cooked and fortified at school on anemia and micronutrient status of schoolchildren in Himalayan villages of India. In this placebo-controlled, cluster-randomized study, 499 schoolchildren (6-10 y) received either multiple micronutrients (treatment group) or placebo (control group) as part of school meals (6 d/wk) for 8 mo. Both groups were dewormed at the beginning of the study. The micronutrient premix provided 10 mg iron, 375 microg vitamin A, 4.2 mg zinc, 225 microg folic acid, and 1.35 microg vitamin B-12 for each child per day (approximately 75% recommended dietary allowance). Blood samples drawn before and after the intervention were analyzed for hemoglobin, ferritin, retinol, zinc, folate, and vitamin B-12. Baseline prevalence of anemia (37%), iron deficiency anemia (10%), low serum ferritin (24%), retinol (56%), zinc (74%), folate (68%), and vitamin B-12 (17%) did not differ between groups. Postintervention, fewer in the treatment group had lower serum retinol [odds ratio (OR) (95% CI): 0.57 (0.33-0.97)] and folate [OR (95% CI): 0.47 (0.26-0.84)] than the control group. The serum vitamin B-12 concentration decreased in both groups, but the magnitude of change was less in the treatment than in the control group (P < 0.05). Total body iron (TBI) increased in both groups; however, the change was greater in the treatment than in the control group (P < 0.05). Micronutrient fortification of school meals by trained school personnel was effective in improving vitamin A, folate, and TBI status while also reducing the magnitude of a decrease in vitamin B-12 status.

Considering the case for vitamin B12 fortification of flour.

Reasons to fortify flour with vitamin B12 are considered, including the high prevalence of depletion and deficiency of this vitamin that occurs in persons of all ages in resource-poor countries and in the elderly in wealthier countries, and the adverse functional consequences of poor vitamin B12 status. From a global perspective, the main cause of inadequate intake and status is a low intake of animal-source foods; even lacto-ovo vegetarians have lower serum vitamin B12 concentrations than omnivores, and for various reasons many populations have limited consumption of animal-source foods. Infants are vitamin B12-depleted from early infancy if their mothers' vitamin B12 status and intake are poor during pregnancy and lactation. Even in the United States, more than 20% of the elderly have serum vitamin B12 concentrations that indicate depletion, and an additional 6% have deficiency, primarily due to gastric atrophy, which impairs the absorption of the vitamin from food but usually not from supplements or fortified foods. Although the evidence is limited, it shows that fortified flour, consumed as bread, can improve vitamin B12 status. Where vitamin B12 fortification is implemented, the recommendation is to add 20 microg/kg flour, assuming consumption of 75 to 100 g flour per day, to provide 75% to 100% of the Estimated Average Requirement; the amount of the vitamin that can be added is limited by its cost. The effectiveness of this level of addition for improving vitamin B12 status in programs needs to be determined and monitored. In addition, further research should evaluate the bioavailability of the vitamin from fortified flour by elderly people with food cobalamin malabsorption and gastric atrophy.

Knowledge gaps in understanding the metabolic and clinical effects of excess folates/folic acid: a summary, and perspectives, from an NIH workshop.

Folate, an essential nutrient found naturally in foods in a reduced form, is present in dietary supplements and fortified foods in an oxidized synthetic form (folic acid). There is widespread agreement that maintaining adequate folate status is critical to prevent diseases due to folate inadequacy (e.g., anemia, birth defects, and cancer). However, there are concerns of potential adverse effects of excess folic acid intake and/or elevated folate status, with the original concern focused on exacerbation of clinical effects of vitamin B-12 deficiency and its role in neurocognitive health. More recently, animal and observational studies have suggested potential adverse effects on cancer risk, birth outcomes, and other diseases. Observations indicating adverse effects from excess folic acid intake, elevated folate status, and unmetabolized folic acid (UMFA) remain inconclusive; the data do not provide the evidence needed to affect public health recommendations. Moreover, strong biological and mechanistic premises connecting elevated folic acid intake, UMFA, and/or high folate status to adverse health outcomes are lacking. However, the body of evidence on potential adverse health outcomes indicates the need for comprehensive research to clarify these issues and bridge knowledge gaps. Three key research questions encompass the additional research needed to establish whether high folic acid or total folate intake contributes to disease risk. 1) Does UMFA affect biological pathways leading to adverse health effects? 2) Does elevated folate status resulting from any form of folate intake affect vitamin B-12 function and its roles in sustaining health? 3) Does elevated folate intake, regardless of form, affect biological pathways leading to adverse health effects other than those linked to vitamin B-12 function? This article summarizes the proceedings of an August 2019 NIH expert workshop focused on addressing these research areas.