Contributions of enriched cereal-grain products, ready-to-eat cereals, and supplements to folic acid and vitamin B-12 usual intake and folate and vitamin B-12 status in US children: National Health and Nutrition Examination Survey (NHANES), 2003-2006

Metabolomic Effects of Folic Acid Supplementation in Adults: Evidence from the FACT Trial

BACKGROUND

Folic acid (FA) is the oxidized form of folate found in supplements and FA-fortified foods. Most FA is reduced by dihydrofolate reductase to 5-methyltetrahydrofolate (5mTHF); the latter is the form of folate naturally found in foods. Ingestion of FA increases the plasma levels of both 5mTHF and unmetabolized FA (UMFA). Limited information is available on the downstream metabolic effects of FA supplementation, including potential effects associated with UMFA.

OBJECTIVE

We aimed to assess the metabolic effects of FA-supplementation, and the associations of plasma 5mTHF and UMFA with the metabolome in FA-naïve Bangladeshi adults.

METHODS

Sixty participants were selected from the Folic Acid and Creatine Trial; half received 800 μg FA/day for 12 weeks and half placebo. Plasma metabolome profiles were measured by high-resolution mass spectrometry, including 170 identified metabolites and 26,541 metabolic features. Penalized regression methods were used to assess the associations of targeted metabolites with FA-supplementation, plasma 5mTHF, and plasma UMFA. Pathway analyses were conducted using Mummichog.

RESULTS

In penalized models of identified metabolites, FA-supplementation was associated with higher choline. Changes in 5mTHF concentrations were positively associated with metabolites involved in amino acid metabolism (5-hydroxyindoleacetic acid, acetylmethionine, creatinine, guanidinoacetate, hydroxyproline/n-acetylalanine) and 2 fatty acids (docosahexaenoic acid and linoleic acid). Changes in 5mTHF concentrations were negatively associated with acetylglutamate, acetyllysine, carnitine, propionyl carnitine, cinnamic acid, homogentisate, arachidonic acid, and nicotine. UMFA concentrations were associated with lower levels of arachidonic acid. Together, metabolites selected across all models were related to lipids, aromatic amino acid metabolism, and the urea cycle. Analyses of nontargeted metabolic features identified additional pathways associated with FA supplementation.

CONCLUSION

In addition to the recapitulation of several expected metabolic changes associated with 5mTHF, we observed additional metabolites/pathways associated with FA-supplementation and UMFA. Further studies are needed to confirm these associations and assess their potential implications for human health.

TRIAL REGISTRATION NUMBER

This trial was registered at https://clinicaltrials.gov as NCT01050556.

Neural tube defects: a review of global prevalence, causes, and primary prevention

Neural tube defects (NTDs) are common birth defects and contribute to life-long disabilities, high medical care costs, and perinatal and child mortality. This review is a primer on prevalence, causes, and evidence-based prevention strategies for NTDs. The estimated average global prevalence of NTDs is two cases per 1000 births, amounting to approximately 214,000-322,000 affected pregnancies worldwide annually. Prevalence and associated adverse outcomes are disproportionately high in developing countries. NTDs have multiple risk factors including genetic and non-genetic (i.e., maternal nutritional status, pre-pregnancy diabetes, early pregnancy exposure to valproic acid (anti-epileptic medication), and a previous pregnancy affected by a NTD) factors. Maternal folate insufficiency before and during early pregnancy is the most common risk factor and is preventable. Folic acid (vitamin B9) is required for formation of the neural tube early in pregnancy, around 28 days after conception, when most women are unaware of their pregnancies. Current guidelines recommend that all women planning or capable of pregnancy take a daily supplement containing 400-800 μg of folic acid. Mandatory folic acid fortification of staple foods (e.g., wheat flour, maize flour, rice) is safe, economical, and the effective intervention for primary prevention of NTDs. Currently, about 60 countries are implementing mandatory folic acid fortification of staple foods, preventing just a quarter of all preventable NTD cases worldwide. There is an urgent need for active champions, including neurosurgeons and other healthcare providers, to generate political will and promote effective mandatory food fortification with folic acid, and reach equitable primary prevention of NTDs in all countries.

Children Aged 5-6 Years in Vancouver, Canada Meet Dietary Recommendations for Folate and Vitamin B12 but not Choline

BACKGROUND

Choline, folate, and vitamin B12 are required for growth and development, but there is limited information on the intakes and relationships to biomarkers of status in children.

OBJECTIVES

The objective of this study was to determine the choline and B-vitamin intakes and relationship to biomarkers of status in children.

METHODS

A cross-sectional study was conducted in children (n = 285, aged 5-6 y) recruited from Metro Vancouver, Canada. Dietary information was collected by using 3 24-h recalls. Nutrient intakes were estimated by using the Canadian Nutrient File and United States Department of Agriculture database for choline. Supplement information was collected by using questionnaires. Plasma biomarkers were quantified by using mass spectrometry and commercial immunoassays, and relationships to dietary and supplement intake were determined by using linear models.

RESULTS

Daily dietary intakes of choline, folate, and vitamin B12 were [mean (SD)] 249 (94.3) mg, 330 (120) DFE μg, and 3.60 (1.54) μg, respectively. Top food sources of choline and vitamin B12 were dairy, meats, and eggs (63%-84%) and for folate, were grains, fruits, and vegetables (67%). More than half of the children (60%) were consuming a supplement containing B-vitamins, but not choline. Only 40% of children met the choline adequate intake (AI) recommendation for North America (≥250 mg/d); 82% met the European AI (≥170 mg/d). Less than 3% of children had inadequate folate and vitamin B12 total intakes. Some children (5%) had total folic acid intakes above the North American tolerable upper intake level (UL; >400 μg/d); 10% had intakes above the European UL (>300 μg/d). Dietary choline intake was positively associated with plasma dimethylglycine, and total vitamin B12 intake was positively associated with plasma B12 (adjusted models; P < 0.001).

CONCLUSIONS

These findings suggest that many children are not meeting the dietary choline recommendations, and some children may have excessive folic acid intakes. The impact of imbalanced one-carbon nutrient intakes during this active period of growth and development requires further investigation.

Heterologous Expression of SiFBP, a Folate-Binding Protein from Foxtail Millet, Confers Increased Folate Content and Altered Amino Acid Profiles with Nutritional Potential to Arabidopsis

The mechanism underlying folate degradation in foxtail millet grains remains unclear. Here, we identified SiFBP (Setaria italica folate-binding protein) from foxtail millet. A phylogenetic tree revealed that FBPs have close genetic relationships among cereal crop species. Docking analysis and heterologous expression of SiFBP in yeast showed that it could bind folic acid (FA). The SiFBP localized to the plasma membrane in tobacco mesophyll cells by transient expression. In Arabidopsis, it was expressed specifically in the roots and germinating seeds. Overexpressing SiFBP in yeast and Arabidopsis significantly increased folate contents. Untargeted metabolome analysis revealed differentially accumulated metabolites between the transgenic lines (TLs) and wild type (WT); these metabolites were mainly enriched in the amino acid metabolism pathway. The relative contents of lysine and leucine, threonine, and l-methionine were significantly higher in the TLs than in WT. Genes related to the folate and lysine synthesis pathways were upregulated in the TLs. Thus, SiFBP can be used for biofortification of folate and important amino acids in crops via genetic engineering.

Reduced Kidney Function Is Associated with Increasing Red Blood Cell Folate Concentration and Changes in Folate Form Distributions (NHANES 2011-2018)

Background: Current studies examining the effects of high concentrations of red blood cell (RBC) or serum folates assume that high folate concentrations are an indicator of high folic acid intakes, often ignoring the contributions of other homeostatic and biological processes, such as kidney function. Objective: The current study examined the relative contributions of declining kidney function, as measured by the risk of chronic kidney disease (CKD), and usual total folic acid intake on the concentrations of RBC folate and serum folate (total as well as individual folate forms). Design: Cross-sectional data from the National Health and Nutrition Examination Survey (NHANES) collected in 2-year cycles were combined from 2011 to 2018. A total of 18,127 participants aged ≥16 years with available folate measures, kidney biomarker data (operationalized as a categorical CKD risk variable describing the risk of progression), and reliable dietary recall data were analyzed. Results: RBC folate concentrations increased as CKD risk increased: low risk, 1089 (95% CI: 1069, 1110) nmol/L; moderate risk, 1189 (95% CI: 1158, 1220) nmol/L; high risk, 1488 (95% CI: 1419, 1561) nmol/L; and highest risk, 1443 (95% CI: 1302, 1598) nmol/L (p < 0.0001). Similarly, serum total folate concentrations increased as CKD risk increased: low risk: 37.1 (95% CI: 26.3, 38.0) nmol/L; moderate risk: 40.2 (95% CI: 38.8, 41.7) nmol/L; high risk: 48.0 (95% CI: 44.3, 52.1) nmol/L; the highest Risk: 42.8 (95% CI: 37.8, 48.4) nmol/L (p < 0.0001). The modeled usual intake of folic acid showed no difference among CKD risk groups, with a population median of 225 (interquartile range: 108−390) µg/day. Conclusion: Both RBC and serum folate concentrations increased with declining kidney function without increased folic acid intake. When analyzing associations between folate concentrations and disease outcomes, researchers may want to consider the confounding role of kidney function.

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.

Ready-to-eat cereal fortification: a modelling study on the impact of changing ready-to-eat cereal fortification levels on population intake of nutrients

OBJECTIVE

Ready-to-eat (RTE) cereal is an important source of nutrients in the American diet. Recent regulatory changes to labelling requirements may impact the fortification of RTE cereal. We used an evidence-based approach to optimize the fortification of RTE cereal considering current dietary patterns and nutrition policy.

DESIGN

A US modelling study of cross-sectional data from the National Health and Nutrition Examination Survey (NHANES) 2013-2014. The percentage of the population below the Estimated Average Requirement (EAR) and above the Upper Tolerable Intake Level (UL) was modelled under three scenarios: baseline, zero fortification and optimized fortification.

SETTING

USA.

PARTICIPANTS

Toddlers aged 1-3 years, n 559; children aged 4-12 years, n 1540; adolescents aged 13-18 years, n 992; and adults aged ≥19 years, n 576.

RESULTS

Comparing current with optimized fortification, nutrient/100 g RTE cereal decreased for vitamin A, thiamin, riboflavin, niacin, vitamin B6, folic acid, vitamin B12, Ca and Fe (by 2-82 %). The amount of vitamins C and D increased (by 13 and 50 %, respectively). Among RTE cereal eaters, these changes resulted in modest increases in the percentage of the population aged ≥1 year below the EAR (+0·5 to +11·5 percentage points). Decreases were observed in the percentage of the population above the UL.

CONCLUSIONS

Fortification of RTE cereal can be optimized to provide key nutrients and minimize the percentage of the population below the EAR and above the UL. Dietary intake modelling is useful to ensure that RTE cereal continues to help the population meet their nutrient needs.

Modeling the impact of folic acid fortification and supplementation on red blood cell folate concentrations and predicted neural tube defect risk in the United States: have we reached optimal prevention?

Background

The US CDC and the Institute of Medicine recommend that women capable of becoming pregnant consume ≥400 µg synthetic folic acid/d to prevent neural tube defects (NTDs). The United States has 3 sources of folic acid: fortified enriched cereal grain products (ECGPs), fortified ready-to-eat (RTE) cereals, and dietary supplements.

Objective

Our objectives were as follows: 1) to estimate the usual daily folic acid intake and distributions of red blood cell (RBC) folate concentrations among women consuming folic acid from different sources; 2) to assess the usual daily total folic acid intake associated with optimal RBC folate concentrations for NTD prevention; 3) to predict NTD prevalence; and 4) to estimate the number of preventable folate-sensitive NTDs.

Design

NHANES data (2007-2012) for nonpregnant women of reproductive age (12-49 y) were used to estimate usual daily intakes of synthetic folic acid and natural food folate. We applied existing models of the relation between RBC folate concentrations and NTD risk to predict NTD prevalence.

Results

Based on the distribution of overall RBC folate concentrations (4783 women), the predicted NTD prevalence was 7.3/10,000 live births [95% uncertainty interval (UI): 5.5-9.4/10,000 live births]. Women consuming folic acid from ECGPs as their only source had lower usual daily total folic acid intakes (median: 115 µg/d; IQR: 79-156 µg/d), lower RBC folate concentrations (median: 881 nmol/L; IQR: 704-1108 nmol/L), and higher predicted NTD prevalence (8.5/10,000 live births; 95% UI: 6.4-10.8/10,000 live births) compared with women consuming additional folic acid from diet or supplements. If women who currently consume folic acid from ECGPs only (48% of women) consumed additional folic acid sources, 345 (95% UI: 0-821) to 701 (95% UI: 242-1189) additional NTDs/y could be prevented.

Conclusions

This analysis supports current recommendations and does not indicate any need for higher intakes of folic acid to achieve optimal NTD prevention. Ensuring 400 µg/d intake of folic acid prior to pregnancy has the potential to increase the number of babies born without an NTD.

Folate supplementation in people with sickle cell disease

BACKGROUND

Sickle cell disease (SCD) is a group of disorders that affects haemoglobin, which causes distorted sickle- or crescent-shaped red blood cells. It is characterized by anaemia, increased susceptibility to infections and episodes of pain. The disease is acquired by inheriting abnormal genes from both parents, the combination giving rise to different forms of the disease. Due to increased erythropoiesis in people with SCD, it is hypothesized that they are at an increased risk for folate deficiency. For this reason, children and adults with SCD, particularly those with sickle cell anaemia, commonly take 1 mg of folic acid orally every day on the premise that this will replace depleted folate stores and reduce the symptoms of anaemia. It is thus important to evaluate the role of folate supplementation in treating SCD.

OBJECTIVES

To analyse the efficacy and possible adverse effects of folate supplementation (folate occurring naturally in foods, provided as fortified foods or additional supplements such as tablets) in people with SCD.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. We also conducted additional searches in both electronic databases and clinical trial registries.Date of last search of the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register: 17 November 2017.

SELECTION CRITERIA

Randomised, placebo-controlled trials of folate supplementation for SCD.

DATA COLLECTION AND ANALYSIS

Four review authors assessed We used the standard Cochrane-defined methodological procedures.Four review authors independently assessed the eligibility and risk of bias of the included trials and extracted and analysed the data included in the review. The quality of the evidence was assessed using GRADE.

MAIN RESULTS

One trial, undertaken in 1983, was eligible for inclusion in the review. This was a double-blind placebo-controlled quasi-randomised triaI of supplementation of folic acid in people with SCD. A total of 117 children with homozygous sickle cell (SS) disease aged six months to four years of age participated over a one-year period (analysis was restricted to 115 children).Serum folate measures, obtained after trial entry at six and 12 months, were available in 80 of 115 (70%) participants. There were significant differences between the folic acid and placebo groups with regards to serum folate values above 18 µg/L and values below 5 µg/L (low-quality evidence). In the folic acid group, values above 18 µg/L were observed in 33 of 41 (81%) compared to six of 39 (15%) participants in the placebo (calcium lactate) group. Additionally, there were no participants in the folic acid group with serum folate levels below 5 µg/L, whereas in the placebo group, 15 of 39 (39%) participants had levels below this threshold. Haematological indices were measured in 100 of 115 (87%) participants at baseline and at one year. After adjusting for sex and age group, the investigators reported no significant differences between the trial groups with regards to total haemoglobin concentrations, either at baseline or at one year (low-quality evidence). It is important to note that none of the raw data for the outcomes listed above were available for analysis.The proportions of participants who experienced certain clinical events were analysed in all 115 participants, for which raw data were available. There were no statistically significant differences noted; however, the trial was not powered to investigate differences between the folic acid and placebo groups with regards to: minor infections, risk ratio (RR) 0.99 (95% confidence interval (CI) 0.85 to 1.15) (low-quality evidence); major infections, RR 0.89 (95% CI 0.47 to 1.66) (low-quality evidence); dactylitis, RR 0.67 (95% CI 0.35 to 1.27) (low-quality evidence); acute splenic sequestration, RR 1.07 (95% CI 0.44 to 2.57) (low-quality evidence); or episodes of pain, RR 1.16 (95% CI 0.70 to 1.92) (low-quality evidence). However, the investigators reported a higher proportion of repeat dactylitis episodes in the placebo group, with two or more attacks occurring in 10 of 56 participants compared to two of 59 in the folic acid group (P < 0.05).Growth, determined by height-for-age and weight-for-age, as well as height and growth velocity, was measured in 103 of the 115 participants (90%), for which raw data were not available. The investigators reported no significant differences in growth between the two groups.The trial had a high risk of bias with regards to random sequence generation and incomplete outcome data. There was an unclear risk of bias in relation to allocation concealment, outcome assessment, and selective reporting. Finally, There was a low risk of bias with regards to blinding of participants and personnel. Overall the quality of the evidence in the review was low.There were no trials identified for other eligible comparisons, namely: folate supplementation (fortified foods and physical supplementation with tablets) versus placebo; folate supplementation (naturally occurring in diet) versus placebo; folate supplementation (fortified foods and physical supplementation with tablets) versus folate supplementation (naturally occurring in diet).

AUTHORS' CONCLUSIONS

One doubIe-blind, placebo-controlled triaI on folic acid supplementation in children with SCD was included in the review. Overall, the trial presented mixed evidence on the review's outcomes. No trials in adults were identified. With the limited evidence provided, we conclude that, while it is possible that folic acid supplementation may increase serum folate levels, the effect of supplementation on anaemia and any symptoms of anaemia remains unclear.If further trials were conducted, these may add evidence regarding the efficacy of folate supplementation. Future trials should assess clinical outcomes such as folate concentration, haemoglobin concentration, adverse effects and benefits of the intervention, especially with regards to SCD-related morbidity. Such trials should include people with SCD of all ages and both sexes, in any setting. To investigate the effects of folate supplementation, trials should recruit more participants and be of longer duration, with long-term follow-up, than the trial currently included in this review. However, we do not envisage further trials of this intervention will be conducted, and hence the review will no longer be regularly updated.

Breakfast and Breakfast Cereal Choice and Its Impact on Nutrient and Sugar Intakes and Anthropometric Measures among a Nationally Representative Sample of Australian Children and Adolescents

There is limited evidence in Australia that compares the nutritional impact of a breakfast cereal breakfast to a non-cereal breakfast, and includes the type of cereal. This study investigated the impact of breakfast choice and the total sugar content of breakfast cereal on nutrient intakes and anthropometric measures among Australian children and adolescents. Data from 2 to 18-year-old in the 2011–2012 National Nutrition and Physical Activity Survey were used (n = 2821). Participants were classified as breakfast cereal consumers (minimally pre-sweetened (MPS) or pre-sweetened (PS)), non-cereal breakfast consumers, or breakfast skippers. Foods consumed for breakfast, foods added to the cereal bowl, and the impact of breakfast choice on daily nutrient intakes and anthropometric measures were determined. Although only 9% of children skipped breakfast, 61% of skippers were aged 14–18 years. Among breakfast consumers, 49% had breakfast cereal, and 62% of these exclusively consumed MPS cereal. Breakfast skippers had a higher saturated fat intake than breakfast cereal consumers, and lower intakes of dietary fibre and most micronutrients (p < 0.001). Compared with non-cereal breakfast consumers, breakfast cereal consumers had similar added and free sugars intakes, lower sodium, and higher total sugars, carbohydrate, dietary fibre, and almost all other micronutrients (p < 0.001). The only difference in nutrient intakes between MPS and PS cereal consumers was higher folate among PS consumers. No associations between anthropometric measures and breakfast or breakfast cereal choice were found. The highest prevalence of breakfast skipping was among 14–18-year old. Breakfast cereal consumers had higher intakes of dietary fibre and most micronutrients compared with non-cereal breakfast consumers and skippers, and almost no differences were found between MPS and PS cereal consumers.

Trends in Food and Beverage Consumption Among Infants and Toddlers: 2005-2012

BACKGROUND

Nutritional guidance for infants and toddlers is lacking, and the diets of American children in the first 2 years of life are not well characterized.

METHODS

Cross-sectional data from the NHANES were used to describe the diets of 0- to 23-month-olds in the United States. Participants with complete dietary data were eligible for the analysis (N = 2359). Linear regression models were constructed to identify changes from 2005 to 2008 and from 2009 to 2012 in food and beverage consumption, both overall and within sociodemographic groups.

RESULTS

We observed several trends toward meeting early-feeding recommendations, such as a decline in the prevalence of complementary feeding among 0- to 5-month-olds. However, the prevalence of vegetable consumption was consistently lower than desired (∼25% of 6- to 11-month-olds and 20% of 12- to 23-month-olds had no reported vegetable consumption on dietary recall days in the 2009-2012 set). Subgroup analyses revealed that some trends were limited to certain populations (eg, a decline in juice consumption was observed among 6- to 11-month-old non-Hispanic whites and non-Hispanic blacks but not among Mexican Americans), and additional trends emerged within groups (eg, the prevalence of breast milk consumption declined among 0- to 5-month-old Mexican Americans).

CONCLUSIONS

Although there have been some improvements in the diets of 0- to 23-month-olds in recent years, there are areas in which this population continues to fall short of current recommendations. This underscores the need for additional policy guidance for providers and education for parents and caretakers on helping infants and toddlers achieve healthy diets.

Foods contributing to vitamin B6, folate, and vitamin B12 intakes and biomarkers status in European adolescents: The HELENA study

PURPOSE

To examine the association between food groups consumption and vitamin B6, folate and B12 intakes and biomarkers in adolescents.

METHODS

In total 2189 individuals participating in the cross-sectional Healthy Lifestyle in Europe by Nutrition in Adolescence study met the eligibility criteria for analysis of dietary intakes (46 % males) and 632 for biomarker analysis (47 % males). Food intakes were assessed by two non-consecutive 24-h recalls. Biomarkers were measured by chromatography and immunoassay. Food groups which best discriminated participants in the extreme tertiles of the distribution of vitamins were identified by discriminant analyses. Food groups with standardised canonical coefficients higher or equal to 0.3 were selected as valid discriminators of vitamins intake and biomarkers extreme tertiles. Linear mixed model elucidated the association between food groups and vitamins intakes and biomarkers.

RESULTS

Vitamin B6 intakes and biomarkers were best discriminated by meat (males and females), margarine and mixed origin lipids only in males and breakfast cereals (females). Breakfast cereals (males), and fruits, margarine and mixed origin lipids, vegetables excluding potatoes, breakfast cereals, and soups/bouillon (females) determined the most folate intakes and biomarkers. Considering vitamin B12 intakes and biomarkers, meat, and white and butter milk (males and females), snacks (males), and dairy products (females) best discriminated individual in the extremes of the distribution. Fewer associations were obtained with mixed model for biomarkers than for vitamins intakes with food groups.

CONCLUSIONS

Whereas B-vitamin intakes were associated with their food sources, biomarkers did with overall food consumption. Low-nutrient-density foods may compromise adolescents' vitamin status.

Effects of Ready-to-Eat-Cereals on Key Nutritional and Health Outcomes: A Systematic Review

BACKGROUND

In many countries breakfast cereals are an important component of breakfast. This systematic review assesses the contribution of consumption of ready-to eat cereal (RTEC) to the recommended nutrient intake. Furthermore, the effects of RTEC consumption on key health parameters are investigated as well as health promoting properties of RTEC.

METHOD

The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and CINAHL have been searched up till 16th of June 2015. Randomized controlled trials were excluded if RTEC were used during hypocaloric diets, if RTEC were eaten at other times than breakfast and if breakfasts included other products than RTEC, milk and fruit. Observational studies were excluded when "breakfast cereals" were not defined or their definition included cooked cereals. From cross-sectional studies only data concerning energy and nutrient intake as well as micronutrient status were used.

RESULTS

From 4727 identified citations 64 publications met the inclusion criteria of which 32 were cross-sectional studies, eight prospective studies and 24 randomized controlled trials. Consumption of RTEC is associated with a healthier dietary pattern, concerning intake of carbohydrates, dietary fiber, fat and micronutrients, however total sugar intake is higher. Persons consuming RTEC frequently (≥ 5 times/week) have a lower risk of inadequate micronutrient intake especially for vitamin A, calcium, folate, vitamin B 6, magnesium and zinc. Evidence from prospective studies suggests that whole grain RTEC may have beneficial effects on hypertension and type 2 diabetes. Consumption of RTEC with soluble fiber helps to reduce LDL cholesterol in hypercholesterolemic men and RTEC fortified with folate can reduce plasma homocysteine.

DISCUSSION

One of the review's strengths is its thorough ex/inclusion of studies. Limitations are that results of observational studies were based on self-reported data and that many studies were funded by food-industry.

CONCLUSION

Consumption of RTEC, especially of fiber-rich or whole grain RTEC, is implicated with several beneficial nutritional and health outcomes. The effect on body weight, intestinal health and cognitive function needs further evaluation. Of concern is the higher total sugar intake associated with frequent RTEC consumption.

Folate supplementation in people with sickle cell disease

BACKGROUND

Sickle cell disease is a group of disorders that affects haemoglobin, which causes distorted sickle- or crescent-shaped red blood cells. It is characterized by anaemia, increased susceptibility to infections and episodes of pain. The disease is acquired by inheriting abnormal genes from both parents, the combination giving rise to different forms of the disease. Due to increased erythropoiesis in people with sickle cell disease, it is hypothesized that they are at an increased risk for folate deficiency. For this reason, children and adults with sickle cell disease, particularly those with sickle cell anaemia, commonly take 1 mg of folic acid orally every day on the premise that this will replace depleted folate stores and reduce the symptoms of anaemia. It is thus important to evaluate the role of folate supplementation in treating sickle cell disease.

OBJECTIVES

To analyse the efficacy and possible adverse effects of folate supplementation (folate occurring naturally in foods, provided as fortified foods or additional supplements such as tablets) in people with sickle cell disease.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. We also conducted additional searches in both electronic databases and clinical trial registries.Date of last search: 07 December 2015.

SELECTION CRITERIA

Randomised, placebo-controlled trials of folate supplementation for sickle cell disease.

DATA COLLECTION AND ANALYSIS

Four review authors assessed the eligibility and risk of bias of the included trials and extracted and analysed the data included in the review. We used the standard Cochrane-defined methodological procedures.

MAIN RESULTS

One trial, undertaken in 1983, was eligible for inclusion in the review. This was a double-blind placebo-controlled quasi-randomised triaI of supplementation of folic acid in people with sickle cell disease. A total of 117 children with homozygous sickle cell (SS) disease aged six months to four years of age participated over a one-year period (analysis was restricted to 115 children).Serum folate measures, obtained after trial entry at six and 12 months, were available in 80 of 115 (70%) participants. There were significant differences between the folic acid and placebo groups with regards to serum folate values above 18 µg/l and values below 5 µg/l. In the folic acid group, values above 18 µg/l were observed in 33 of 41 (81 %) compared to six of 39 (15%) participants in the placebo (calcium lactate) group. Additionally, there were no participants in the folic acid group with serum folate levels below 5 µg/l, whereas in the placebo group, 15 of 39 (39%) participants had levels below this threshold. Haematological indices were measured in 100 of 115 (87%) participants at baseline and at one year. After adjusting for sex and age group, the investigators reported no significant differences between the trial groups with regards to total haemoglobin concentrations, either at baseline or at one year. It is important to note that none of the raw data for the outcomes listed above were available for analysis.The proportions of participants who experienced certain clinical events were analysed in all 115 participants, for which raw data were available. There were no statistically significant differences noted; however, the trial was not powered to investigate differences between the folic acid and placebo groups with regards to: minor infections, risk ratio 0.99 (95% confidence interval 0.85 to 1.15); major infections, risk ratio 0.89 (95% confidence interval 0.47 to 1.66); dactylitis, risk ratio 0.67 (95% confidence interval 0.35 to 1.27); acute splenic sequestration, risk ratio 1.07 (95% confidence interval 0.44 to 2.57); or episodes of pain, risk ratio 1.16 (95% confidence interval 0.70 to 1.92). However, the investigators reported a higher proportion of repeat dactylitis episodes in the placebo group, with two or more attacks occurring in 10 of 56 participants compared to two of 59 in the folic acid group (P < 0.05).Growth, determined by height-for-age and weight-for-age, as well as height and growth velocity, was measured in 103 of the 115 participants (90%), for which raw data were not available. The investigators reported no significant differences in growth between the two groups.The trial had a high risk of bias with regards to random sequence generation and incomplete outcome data. There was an unclear risk of bias in relation to allocation concealment, outcome assessment, and selective reporting. Finally, There was a low risk of bias with regards to blinding of participants and personnel. Overall the quality of the evidence in the review was low.There were no trials identified for other eligible comparisons, namely: folate supplementation (fortified foods and physical supplementation with tablets) versus placebo; folate supplementation (naturally occurring in diet) versus placebo; folate supplementation (fortified foods and physical supplementation with tablets) versus folate supplementation (naturally occurring in diet).

AUTHORS' CONCLUSIONS

One doubIe-blind, placebo-controlled triaI on folic acid supplementation in children with sickle cell disease was included in the review. Overall, the trial presented mixed evidence on the review's outcomes. No trials in adults were identified. With the limited evidence provided, we conclude that, while it is possible that folic acid supplementation may increase serum folate levels, the effect of supplementation on anaemia and any symptoms of anaemia remains unclear.Further trials may add evidence regarding the efficacy of folate supplementation. Future trials should assess clinical outcomes such as folate concentration, haemoglobin concentration, adverse effects and benefits of the intervention, especially with regards to sickle cell disease-related morbidity. Trials should include people with sickle cell disease of all ages and both sexes, in any setting. To investigate the effects of folate supplementation, trials should recruit more participants and be of longer duration, with long-term follow up, than the trial currently included in this review.

High folic acid consumption leads to pseudo-MTHFR deficiency, altered lipid metabolism, and liver injury in mice

BACKGROUND

Increased consumption of folic acid is prevalent, leading to concerns about negative consequences. The effects of folic acid on the liver, the primary organ for folate metabolism, are largely unknown. Methylenetetrahydrofolate reductase (MTHFR) provides methyl donors for S-adenosylmethionine (SAM) synthesis and methylation reactions.

OBJECTIVE

Our goal was to investigate the impact of high folic acid intake on liver disease and methyl metabolism.

DESIGN

Folic acid-supplemented diet (FASD, 10-fold higher than recommended) and control diet were fed to male Mthfr(+/+) and Mthfr(+/-) mice for 6 mo to assess gene-nutrient interactions. Liver pathology, folate and choline metabolites, and gene expression in folate and lipid pathways were examined.

RESULTS

Liver and spleen weights were higher and hematologic profiles were altered in FASD-fed mice. Liver histology revealed unusually large, degenerating cells in FASD Mthfr(+/-) mice, consistent with nonalcoholic fatty liver disease. High folic acid inhibited MTHFR activity in vitro, and MTHFR protein was reduced in FASD-fed mice. 5-Methyltetrahydrofolate, SAM, and SAM/S-adenosylhomocysteine ratios were lower in FASD and Mthfr(+/-) livers. Choline metabolites, including phosphatidylcholine, were reduced due to genotype and/or diet in an attempt to restore methylation capacity through choline/betaine-dependent SAM synthesis. Expression changes in genes of one-carbon and lipid metabolism were particularly significant in FASD Mthfr(+/-) mice. The latter changes, which included higher nuclear sterol regulatory element-binding protein 1, higher Srepb2 messenger RNA (mRNA), lower farnesoid X receptor (Nr1h4) mRNA, and lower Cyp7a1 mRNA, would lead to greater lipogenesis and reduced cholesterol catabolism into bile.

CONCLUSIONS

We suggest that high folic acid consumption reduces MTHFR protein and activity levels, creating a pseudo-MTHFR deficiency. This deficiency results in hepatocyte degeneration, suggesting a 2-hit mechanism whereby mutant hepatocytes cannot accommodate the lipid disturbances and altered membrane integrity arising from changes in phospholipid/lipid metabolism. These preliminary findings may have clinical implications for individuals consuming high-dose folic acid supplements, particularly those who are MTHFR deficient.

Fortification and health: challenges and opportunities

Fortification is the process of adding nutrients or non-nutrient bioactive components to edible products (e.g., food, food constituents, or supplements). Fortification can be used to correct or prevent widespread nutrient intake shortfalls and associated deficiencies, to balance the total nutrient profile of a diet, to restore nutrients lost in processing, or to appeal to consumers looking to supplement their diet. Food fortification could be considered as a public health strategy to enhance nutrient intakes of a population. Over the past century, fortification has been effective at reducing the risk of nutrient deficiency diseases such as beriberi, goiter, pellagra, and rickets. However, the world today is very different from when fortification emerged in the 1920s. Although early fortification programs were designed to eliminate deficiency diseases, current fortification programs are based on low dietary intakes rather than a diagnosable condition. Moving forward, we must be diligent in our approach to achieving effective and responsible fortification practices and policies, including responsible marketing of fortified products. Fortification must be applied prudently, its effects monitored diligently, and the public informed effectively about its benefits through consumer education efforts. Clear lines of authority for establishing fortification guidelines should be developed and should take into account changing population demographics, changes in the food supply, and advances in technology. This article is a summary of a symposium presented at the ASN Scientific Sessions and Annual Meeting at Experimental Biology 2014 on current issues involving fortification focusing primarily on the United States and Canada and recommendations for the development of responsible fortification practices to ensure their safety and effectiveness.

Discretionary fortification--a public health perspective

'Discretionary fortification' refers to the addition of vitamins and minerals to foods at the discretion of manufacturers for marketing purposes, but not as part of a planned public health intervention. While the nutrients added may correspond to needs in the population, an examination of novel beverages sold in Toronto supermarkets revealed added nutrients for which there is little or no evidence of inadequacy in the population. This is consistent with the variable effects of manufacturer-driven fortification on nutrient adequacy observed in the US. Nutrient intakes in excess of Tolerable Upper Intake Levels are now observed in the context of supplement use and high levels of consumption of fortified foods. Expanding discretionary fortification can only increase nutrient exposures, but any health risks associated with chronically high nutrient loads from fortification and supplementation remain to be discovered. Regulatory bodies are focused on the establishment of safe levels of nutrient addition, but their estimation procedures are fraught with untested assumptions and data limitations. The task of determining the benefits of discretionary fortification is being left to consumers, but the nutrition information available to them is insufficient to allow for differentiation of potentially beneficial fortification from gratuitous nutrient additions.

Vitamin and zinc status pretreatment and posttreatment in patients with inflammatory bowel disease

Vitamin deficiencies are common in inflammatory bowel disease. Here we present 5-year follow-up data of 61 patients. No folate or vitamin B12 deficiency was identified throughout the study. A daily multivitamin supplement was sufficient to replete 100% of vitamin A-deficient and vitamin E-deficient patients. A total of 52% of vitamin D-deficient patients corrected, but 15% who had normal vitamin D levels at diagnosis developed deficiency. A total of 63% of zinc-deficient patients normalized their zinc status, but 15% developed zinc deficiency at follow-up despite supplementation.

Fortified foods are major contributors to nutrient intakes in diets of US children and adolescents

BACKGROUND

Even in an era of obesity and dietary excess, numerous shortfall micronutrients have been identified in the diets of US children and adolescents. To help tailor strategies for meeting recommendations, it is important to know what foods contribute greatly to micronutrient intakes. Data are lacking on specific contributions made by added nutrients.

OBJECTIVE

Our aims were to examine the impact of fortification on nutrient adequacy and excess among US children and adolescents and to rank food sources of added nutrient intake and compare rankings with those based on total nutrient intake from foods.

DESIGN AND STATISTICAL ANALYSES

Data were from 7,250 respondents 2 to 18 years old in the National Health and Nutrition Examination Survey 2003-2006. Datasets were developed that distinguished nutrient sources: intrinsic nutrients in foods; added nutrients in foods; foods (intrinsic plus added nutrients); and total diet (foods plus supplements). The National Cancer Institute method was used to determine usual intakes of micronutrients by source. The impact of fortification on the percentages of children having intakes less than the Estimated Average Requirement and more than the Upper Tolerable Intake Level was assessed by comparing intakes from intrinsic nutrients to intakes from intrinsic plus added nutrients. Specific food sources of micronutrients were determined as sample-weighted mean intakes of total and added nutrients contributed from 56 food groupings. The percentage of intake from each grouping was determined separately for total and added nutrients.

RESULTS

Without added nutrients, a high percentage of all children/adolescents had inadequate intakes of numerous micronutrients, with the greatest inadequacy among older girls. Fortification reduced the percentage less than the Estimated Average Requirement for many, although not all, micronutrients without resulting in excessive intakes. Data demonstrated the powerful influence of fortification on food-source rankings.

CONCLUSIONS

Knowledge about nutrient intakes and sources can help put dietary advice into a practical context. Continued monitoring of top food sources of nutrients and nutrient contributions from fortification will be important.

National Athletic Trainers' Association position statement: evaluation of dietary supplements for performance nutrition

OBJECTIVES

To help athletic trainers promote a "food-first" philosophy to support health and performance, understand federal and sport governing body rules and regulations regarding dietary supplements and banned substances, and become familiar with reliable resources for evaluating the safety, purity, and efficacy of dietary supplements.

BACKGROUND

The dietary supplement industry is poorly regulated and takes in billions of dollars per year. Uneducated athletes need to gain a better understanding of the safety, eligibility, and efficacy concerns associated with choosing to take dietary supplements. The athletic trainer is a valuable athletic team member who can help in the educational process. In many cases, athletic trainers are asked to help evaluate the legality, safety, and efficacy of dietary supplements. For this position statement, our mission is to provide the athletic trainer with the necessary resources for these tasks.

RECOMMENDATIONS

Proper nutrition and changes in the athlete's habitual diet should be considered first when improved performance is the goal. Athletes need to understand the level of regulation (or lack thereof) governing the dietary supplement industry at the international, federal, state, and individual sport-participation levels. Athletes should not assume a product is safe simply because it is marketed over the counter. All products athletes are considering using should be evaluated for purity (ie, truth in labeling), safety, and efficacy.

Voluntary food fortification in the United States: potential for excessive intakes

BACKGROUND

Historically, the voluntary addition of micronutrients to foods in the United States has been regarded as an important means to lessen problems of nutrient inadequacy. With expanding voluntary food fortification and widespread supplement use, it is important to understand how voluntary food fortification has an impact on the likelihood of excessive usual intakes. Our objective was to investigate whether individuals in the United States with greater frequency of exposure to micronutrients from voluntarily fortified foods (vFF) are more likely to have usual intakes approaching or exceeding the respective tolerable upper intake levels (UL).

SUBJECTS/METHODS

The National Cancer Institute method was applied to data from the 2007-2008 National Health and Nutrition Examination Survey (NHANES) to estimate the joint distribution of usual intake from both vFF and non-vFF sources for 12 nutrients and determine the probability of consuming these nutrients from vFF on a given day. For each nutrient, we estimated the distribution of usual intake from all food sources by quintile of probability of consuming vFF and compared the distributions with ULs.

RESULTS

An increased probability of consuming zinc, retinol, folic acid, selenium and copper from vFF was associated with a greater risk of intakes above the UL among children. Among adults, increased probability of consuming calcium and iron from vFF was associated with a greater risk of intakes above the UL among some age/sex groups.

CONCLUSION

The high nutrient exposures associated with vFF consumption in some population subgroups suggest a need for more careful weighing of the risks and benefits of uncontrolled food fortification.

Modeling fortification of corn masa flour with folic acid: the potential impact on exceeding the tolerable upper intake level for folic acid, NHANES 2001-2008

Background

The Institute of Medicine set a tolerable upper intake level (UL) for usual daily total folic acid intake (1,000 µg). Less than 3% of US adults currently exceed the UL.

Objective

The objective of this study was to determine if folic acid fortification of corn masa flour would increase the percentage of the US population who exceed the UL.

Design

We used dietary intake data from NHANES 2001–2008 to estimate the percentage of adults and children who would exceed the UL if corn masa flour were fortified at 140 µg of folic acid/100 g.

Results

In 2001–2008, 2.5% of the US adult population (aged≥19 years) exceeded the UL, which could increase to 2.6% if fortification of corn masa flour occurred. With corn masa flour fortification, percentage point increases were small and not statistically significant for US adults exceeding the UL regardless of supplement use, sex, race/ethnicity, or age. Children aged 1–8 years, specifically supplement users, were the most likely to exceed their age-specific UL. With fortification of corn masa flour, there were no statistically significant increases in the percentage of US children who were exceeding their age-specific UL, and the percentage point increases were small.

Conclusions

Our results suggest that fortification of corn masa flour would not significantly increase the percentage of individuals who would exceed the UL. Supplement use was the main factor related to exceeding the UL with or without fortification of corn masa flour and within all strata of sex, race/ethnicity, and age group.

Association between vitamin B12intake and EURRECA's prioritized biomarkers of vitamin B12in young populations: a systematic review

Objective

To review evidence on the associations between vitamin B12intake and its biomarkers, vitamin B12intake and its functional health outcomes, and vitamin B12biomarkers and functional health outcomes.

Design

A systematic review was conducted by searching electronic databases, until January 2012, using a standardized strategy developed in the EURRECA network. Relevant articles were screened and sorted based on title and abstract, then based on full text, and finally included if they met inclusion criteria. A total of sixteen articles were included in the review.

Setting

Articles covered four continents: America (n4), Europe (n8), Africa (n1) and Asia (n3).

Subjects

Population groups included healthy infants, children and adolescents, and pregnant and lactating women.

Results

From the total number of 5815 papers retrieved from the initial search, only sixteen were eligible according to the inclusion criteria: five for infants, five for children and adolescents, and six for pregnant and lactating women.

Conclusions

Only one main conclusion could be extracted from this scarce number of references: a positive association between vitamin B12intake and serum vitamin B12in the infant group. Other associations were not reported in the eligible papers or the results were not provided in a consistent manner. The low number of papers that could be included in our systematic review is probably due to the attention that is currently given to research on vitamin B12in elderly people. Our observations in the current systematic review justify the idea of performing well-designed studies on vitamin B12in young populations.

Fortification of flours with folic acid reduces homocysteine levels in Brazilian women

Our hypothesis is that the fortification of flour with folic acid contributes to the reduction of plasma homocysteine (Hcy). We conducted a cross-sectional study covering 2 periods, before and after fortification (2002-2003 and 2008-2009, respectively), to assess the influence of the consumption of corn and wheat flours prefortification and postfortification with folic acid on Hcy levels and other biomarkers. In the total, 93 women (38 prefortification and 55 postfortification) were included. Levels of lipids and glucose, total Hcy and serum folate, and cobalamin were determined using commercial kits by colorimetric method, competitive immunoassay, and chemiluminescence, respectively The participants' average age was 48.1 ± 9.5 years for the prefortification group and 39.1 ± 4.1 years for the postfortification group (P < .001) but adjusted statistical tests by age. Both groups presented obesity class 1. In the prefortification group, 71.1% (n = 27) of women had a dietary intake of folate, which was lower than the current recommended for adults (< 400 μg/d), whereas in the postfortification group, only 16.4% (n = 9) of women had lower intakes than recommended. In the prefortification group, 42.1% (n = 16) of women had hyperhomocysteinemia (> 10 mmol/L) compared with only 9.1% (n = 5) in the postfortification group. Moreover, statistically significant differences were found between the 2 groups in total cholesterol, high-density lipoprotein, triglycerides, and dietary fiber. Our findings corroborate the hypothesis that fortification of wheat and corn flours with folic acid can possibly be associated with lower concentrations of plasma Hcy, providing probable greater cardiovascular protection in this group.

Mathematical modeling predicts the effect of folate deficiency and excess on cancer-related biomarkers

BACKGROUND

Folate is an essential B-vitamin that mediates one-carbon metabolism reactions, including nucleotide synthesis and others related to carcinogenesis. Both low- and high-folate status influences carcinogenesis.

METHODS

We used a mathematical model of folate-mediated one-carbon metabolism to predict the effect of a range of intracellular epithelial folate concentrations (0.25-15.0 μmol/L) on methylation rate and purine and thymidylate synthesis. We also examined the interaction of these folate concentrations with polymorphisms in two enzymes [methylene tetrahydrofolate reductase (MTHFR) and thymidylate synthase (TS)] in relation to the biochemical products.

RESULTS

TS enzyme reaction rate increased markedly in response to the modeled higher intracellular folate concentrations. Changes in methylation rate were modest, whereas purine synthesis was only minimally related to increases in folate concentrations with an apparent threshold effect at 5.0 to 6.0 μmol/L. The relationship between folate concentrations and thymidylate synthesis was modified by genetic variation in TS but less so by variation in MTHFR. These gene-folate interactions modestly influenced purine synthesis in a nonlinear manner but only affected methylation rate under conditions of very high MTHFR activity.

CONCLUSION

Thymidylate synthesis is very sensitive to changes in epithelial intracellular folate and increased nearly fivefold under conditions of high intracellular folate. Individuals with genetic variations causing reduced TS activity may present even greater susceptibility to excessive folate.

IMPACT

Our observation that thymidylate synthesis increases dramatically under conditions of very elevated intracellular folate provides biological support to observations that excessive folic acid intake increases risk of both precursor lesions (i.e., colorectal adenomas) and cancer.

Folic acid and primary prevention of birth defects

Birth defects (BDs) are an important public health problem, due to their overall incidence, occurring in 2-3% of live births in European Union. Neural tube defects (NTDs) are among major NTDs, due to their severity and relatively high incidence; in the meanwhile NTDs are also the most effectively preventable BDs to date. In particular, an adequate folic acid (FA) intake reduces both the occurrence and the recurrence of NTDs; FA is the synthetic form of folates, naturally occurring vitamins in a number of foods, especially vegetables. The daily intake of 0.4 mg of FA should be recommended to all women of childbearing age who plan to become pregnant. The Italian Network for Primary Prevention of BDs through FA Promotion has achieved a significant improvement in FA awareness and use in the periconceptional period. Nevertheless, primary prevention of BDs needs to make further progress; the Italian National Centre for Rare Diseases participates in european sureveillance of congenital anomalies (EUROCAT) Joint Action as coordinator of activities on the effectiveness of BDs prevention. Mandatory food fortification with FA has not been introduced in any European country. The health benefits of FA in reducing the risk of NTDs are undisputed; however mechanistic and animal studies suggest a relationship between high FA intakes and increased cancer promotion, while human studies are still inconsistent and inconclusive. A Working Group organized by the European Food Safety Authority pointed out significant uncertainties about fortification safety and the need for more studies; currently, FA intake from fortified foods and supplements should not exceed 1 mg/day in adults. In conclusion, based on up-to-date scientific evidence, the Italian Network strategy pivots on periconceptional supplementation integrated with promotion of healthy eating habits, support to health education, enhancing the role of women in managing life choices about their health and pregnancy and increasing the scientific knowledge about BDs primary prevention.

Folic acid food fortification-its history, effect, concerns, and future directions

Periconceptional intake of folic acid is known to reduce a woman’s risk of having an infant affected by a neural tube birth defect (NTD). National programs to mandate fortification of food with folic acid have reduced the prevalence of NTDs worldwide. Uncertainty surrounding possible unintended consequences has led to concerns about higher folic acid intake and food fortification programs. This uncertainty emphasizes the need to continually monitor fortification programs for accurate measures of their effect and the ability to address concerns as they arise. This review highlights the history, effect, concerns, and future directions of folic acid food fortification programs.