Folate content and retention in wheat grains and wheat-based foods: Effects of storage, processing, and cooking methods

Dietary folate intake and serum klotho levels in adults aged 40-79 years: a cross-sectional study from the national health and nutrition examination survey 2007-2016

Objective

This study aims to explore the relationship between dietary folate intake and serum Klotho levels in adults from aged 40 to 79 years in the United States, seeking to elucidate the intricacies of their interaction.

Methods

Analyzing data from the National Health and Nutrition Examination Survey (NHANES) spanning 2007 to 2016. The survey research determined folate intake through a 24-h dietary recall and nutrient density modeling, and assessed Klotho levels using enzyme-linked immunosorbent assay (ELISA). The relationship between folate intake and Klotho levels was evaluated using weighted linear regression, and complemented by analysis via smoothed curve models for nuanced understanding.

Results

The study encompassed 10,278 participants, with an average age of 57.64 years, revealing a noteworthy positive correlation between dietary folate and serum Klotho levels. The regression coefficient stood at 0.11 (95% confidence interval, 0.05, 0.18) post-adjustment for various covariates. When dietary folate intake was categorized into quartiles, the second, third, and fourth quartiles exhibited statistically significant differences compared to the lowest quartile. This indicates that higher folate intake correlates with increased serum Klotho levels. These findings underscore the potential benefits of elevating folate intake to enhance serum Klotho levels. Stratified analysis indicated that this association was more pronounced among males aged 60 years or older and individuals with hypertension.

Conclusion

The findings suggest a significant correlation between increased dietary folate intake and elevated serum Klotho levels in adults aged 40-79 years. Hinting at the potential nutritional influences on the aging process and associated health conditions. This calls for further exploration into the mechanisms and broader implications of this association.

Two maize homologs of mammalian proton-coupled folate transporter, ZmMFS_1-62 and ZmMFS_1-73, are essential to salt and drought tolerance

Folates are essential to the maintenance of normal life activities in almost all organisms. Proton-coupled folate transporter (PCFT), belonging to the major facilitator superfamily, is one of the three major folate transporter types widely studied in mammals. However, information about plant PCFTs is limited. Here, a genome-wide identification of maize PCFTs was performed, and two PCFTs, ZmMFS_1-62 and ZmMFS_1-73, were functionally investigated. Both proteins contained the typical 12 transmembrane helixes with N- and C-termini located in the cytoplasm, and were localized in the plasma membrane. Molecular docking analysis indicated their binding activity with folates via hydrogen bonding. Interference with ZmMFS_1-62 and ZmMFS_1-73 in maize seedlings through virus-induced gene silencing disrupted folate homeostasis, mainly in the roots, and reduced tolerance to drought and salt stresses. Moreover, a molecular chaperone protein, ZmHSP20, was found to interact with ZmMFS_1-62 and ZmMFS_1-73, and interference with ZmHSP20 in maize seedlings also led to folate disruption and increased sensitivity to drought and salt stresses. Overall, this is the first report of functional identification of maize PCFTs, which play essential roles in salt and drought stress tolerance, thereby linking folate metabolism with abiotic stress responses in maize.

How food matrices modulate folate bioaccessibility: A comprehensive overview of recent advances and challenges

The incomplete absorption of dietary folate makes it crucial to understand how food matrices affect folate bioaccessibility. Bioavailability encompasses bioaccessibility, which depicts the proportion that is liberated from the food matrix during digestion and becomes available for absorption. Bioavailability studies are expensive and difficult to control, whereas bioaccessibility studies utilize in vitro digestion models to parameterize the complex digestion, allowing the evaluation of the effect of food matrices on bioaccessibility. This review covers the folate contents in various food matrices, the methods used to determine and the factors affecting folate bioaccessibility, and the advances and challenges in understanding how food matrices affect folate bioaccessibility. The methods for determining bioaccessibility have been improved in the last decade. Current research shows that food matrices modulate folate bioaccessibility by affecting the liberation and stability of folate during digestion but do not provide enough information about folate and food component interactions at the molecular level. In addition, information on folate interconversion and degradation during digestion is scant, hindering our understanding of the impact of food matrices on folate stability. Moreover, the role of conjugase inhibitors should not be neglected when evaluating the nutritional value of food folates. Due to the complexity of food digestion, holistic methods should be applied to investigate bioaccessibility. By synthesizing the current state of knowledge on this topic, this review highlights the lack of in-depth understanding of the mechanisms of how food matrices modulate folate bioaccessibility and provides insights into potential strategies for accurate evaluation of the nutritional value of dietary folate.

Examination of Primary and Secondary Metabolites Associated with a Plant-Based Diet and Their Impact on Human Health

The consumption of plant-based diets has become a burgeoning trend, and they are increasingly consumed globally owing to their substantial energy intensity and dietetic advantages. Plants possess numerous bioactive components that have been recognized to exhibit manifold health-promoting assets. Comprehension of the synthesis of these primary and secondary metabolites by plants and their method of action against several chronic illnesses is a significant requirement for understanding their benefits to human health and disease prevention. Furthermore, the association of biologically active complexes with plants, humans, disease, medicine, and the underlying mechanisms is unexplored. Therefore, this review portrays various bioactive components derived from plant sources associated with health-promoting traits and their action mechanisms. This review paper predominantly assembles proposed plant-derived bioactive compounds, postulating valuable evidence aimed at perceiving forthcoming approaches, including the selection of potent bioactive components for formulating functional diets that are effective against several human disorders. This meticulous evidence could perhaps provide the basis for the advanced preemptive and therapeutic potential promoting human health. Hence, delivery opens possibilities for purchasers to approach the lucrative practice of plants as a remedy, produce novel products, and access new marketplaces.

Parental folic acid deficiency delays neurobehavioral development in rat offspring by inhibiting the differentiation of neural stem cells into neurons

Maternal folate status during pregnancy is associated with the neurodevelopment of offspring; however, study results on the association between paternal folate status and offspring neurodevelopment are inconsistent. This study aimed to explore whether parental folic acid deficiency affects the neurobehavioral development of offspring by affecting the differentiation of neural stem cells (NSCs) into neurons. In the present study, the offspring were divided into four groups: parental folic acid deficient group (D-D), maternal folic acid deficient and paternal folic acid normal group (D-N), maternal folic acid normal and paternal folic acid deficient group (N-D), and parental folic acid normal group (N-N). For in vivo study, neurobehavioral indexes, and neuron-specific nuclear protein (NeuN) and glial fibrillary acidic protein (GFAP) expression in the brain hippocampus and cerebral cortex of offspring were measured at different time points. For in vitro study, NSCs were cultured from the hippocampus and striatum, and neuronal and astrocytic differentiation were measured. The results demonstrated that parental folic acid deficiency decreased the brain folate level in offspring, delayed early sensory-motor reflex development, impaired spatial learning and memory ability in adolescence and adulthood, decreased differentiation of NSCs into neurons and increased differentiation of NSCs into astrocytes in vivo and in vitro. These impacts on the neurodevelopment of offspring were most pronounced in D-D group, followed by D-N group and N-D group. In conclusion, parental folic acid deficiency inhibits the neurobehavioral development of offspring, possibly by inhibiting the differentiation of NSCs into neurons.

Comparison of data-driven identified hypertension-protective dietary patterns among Chinese adults: based on a nationwide study

PURPOSE

Diet pattern (DP) is a key modifiable and cost-effective factor in hypertension (HTN) management. The current study aimed to identify and compare the hypertension-protective DPs among Chinese adults.

METHODS

52,648 participants aged over 18 years were included from China Nutrition and Health Surveillance (CNHS) 2015-2017. Reduced rank regression (RRR) and partial least square regression (PLS) was applied to identify the DPs. Multivariable-adjusted logistic regression was used to assess the association between the DPs and HTN.

RESULTS

DPs derived by RRR and PLS were both featured by higher consumption of fresh vegetables and fruits, mushrooms and edible fungi, seaweeds, soybeans and related products, mixed legumes, dairy products, fresh eggs, and lower of refined grain consumption. Compared to the lowest quintile, participants in the highest quintile had lower odds of HTN (RRR-DP: OR = 0.77, 95% CI = 0.72-0.83; PLS-DP: OR = 0.76, 95% CI = 0.71-0.82; all p < 0.0001). Simplified DP scores were observed the same protective tendencies (Simplified RRR-DP: OR = 0.81, 95% CI = 0.75-0.87; Simplified PLS-DP: OR = 0.79, 95% CI = 0.74-0.85; all p < 0.0001) and showed effective extrapolation in subgroups defined by gender, age, location, lifestyle, and different metabolic conditions.

CONCLUSIONS

The identified DPs had high conformity with East Asian dietary habits, and significantly negative associations with HTN among Chinese adults. The simplified DP technique also indicated the potential for improving the extrapolation of the results of DP analysis related to HTN.

B-vitamins and heat processed fermented starchy and vegetable foods in sub-Saharan Africa: A review

Micronutrient deficiency still occurs in sub-Saharan Africa (SSA) despite the availability of several food resources, particularly fermented foods and vegetables, with high nutritional potential. Fermentation enhances the quality of food in several aspects. Organoleptically, certain taste, aroma, and textures are developed. Health and safety are improved by inhibiting the growth of several foodborne pathogens and removing harmful toxic compounds. Furthermore, nutrition is enhanced by improving micronutrient contents and bioavailability from the food, especially vitamin B content. However, during processing and before final consumption, many fermented foods are heat treated (drying, pasteurization, cooking, etc.) to make the food digestible and safe for consumption. Heat treatment improves the bioavailability of B-vitamins in some foods. In other foods, heating decreases the nutritional value because some B-vitamins are degraded. In SSA, cooked starchy foods are often associated with vegetables in household meals. This paper reviews studies that have focused fermented starchy foods and vegetable foods in SSA with the potential to provide B-vitamins to consumers. The review also describes the process of the preparation of these foods for final consumption, and techniques that can prevent or lessen B-vitamin loss, or enrich B-vitamins prior to consumption.

Folate Enrichment of Whole-Meal Spaghetti Using Durum Wheat Debranning Fractions

Durum wheat debranning fractions (fine and coarse bran) were obtained and included as an ingredient in the formulation of whole-meal spaghetti to study their chemical-nutritional characteristics, in particular folate levels and sensorial properties. Experimental raw pasta had a higher folate content (40.5 µg/100 g) than commercial whole-meal pasta (28.3 µg/100 g), meeting the requirements for the health claim on folate (Reg. EU 432/2012) and for the nutritional claim on dietary fiber. After cooking, folate retention in pasta formulated with coarse bran was 80% and scored an overall "good" sensorial acceptability. Results indicate that whole-meal pasta formulated with folate-rich debranning fractions may represent a natural functional food that, integrated into the diet, could improve the health status of the population.

Effect of Milling on Nutritional Components in Common and Zinc-Biofortified Wheat

Biofortification is one of the most successful approaches to enhance the level of micronutrients in wheat. In the present study, wheats with zinc biofortification (foliar fertilization and breeding strategies) were milled into five components (whole flour, break flour, reduction flour, fine bran, and coarse bran) and their mineral content and nutritional components were evaluated. The results revealed that biofortification greatly increased the Zn concentration (by 30.58%-30.86%) and soluble Zn content (by 28.57%-42.86%) of whole flour after digestion. This improvement is mainly in break flour, reduction flour, and fine bran. Meanwhile, the contents of macronutrients including ash, lipids, and proteins and micronutrients containing iron, calcium, and vitamins (B₁, B₆, and B₉) increased after biofortification. In addition, there was a decline in the concentrations of vitamins B₂ and B₅. Although dietary fibers and starch are the major carbohydrates, total dietary fiber exhibited a declining trend in coarse bran, and starch exhibited a rising trend in break and reduction flour. There was a decrease in the molar ratio of phytates: zinc did not promote a significant improvement in zinc bioaccessibility. These results can be useful for generating wheat varieties rich in micronutrients as well as having better nutritional traits.

5-Methyltetrahydrofolate Is a Crucial Factor in Determining the Bioaccessibility of Folate in Bread

This study investigated the bioaccessibility of folate in wheat bread baked with different ingredients and processing methods. Next, different matrices were spiked with 5-methyltetrahydrofolate, gallic acid (GA), or both to investigate the stability of 5-methyltetrahydrofolate during in vitro digestion. The folate bioaccessibility in bread varied from 44 to 96%. The inclusion of whole-grain or faba bean flour significantly improved both folate content and bioaccessibility. Baking with yeast increased the folate content by 145% in bread but decreased folate bioaccessibility compared to the bread without added yeast because of the instability of 5-methyltetrahydrofolate. Spiking experiments confirmed oxidation as a critical reason for 5-methyltetrahydrofolate loss during digestion. However, GA protected this vitamer from degradation. Additionally, 5-methyltetrahydrofolate was less stable in whole-grain wheat matrices than other matrices. This study demonstrated that the stability of 5-methyltetrahydrofolate is crucial for folate bioaccessibility in bread, and methods for stabilizing this vitamer should be further studied.

Design of Cereal Products Naturally Enriched in Folate from Barley Pearling By-Products

Folate is a fundamental vitamin for human health in prevention of many diseases; however, unfortunately its deficiency is widespread, so a greater availability of folate rich foods is desirable. The aim of this study was to design new cereal products naturally enriched in folate using barley flour from pearling as ingredient. Folate content of unfortified and fortified commercial grain-based products was considered to identify the best ingredients for new formulation and for folate content comparisons. Nineteen Italian barley cultivars were evaluated for their folate content and Natura was chosen for its highest folate levels = 69.3 μg/100 g f.w. Application of pearling gave a by-product flour with a high folate level: 221.7 ± 7.0 μg/100 g; this flour was employed to design pasta and biscuits naturally enriched in folate: 87.1 μg/100 g and 70.1 ± 3.7 μg/100 g f.w., respectively. Folate content of new products is higher than commercial samples: 39.2 μg/100 g in refined pasta, 60.4 μg/100 g in wholemeal pasta, 62.1 μg/100 g in fortified biscuits and 10.4 μg/100 g in unfortified ones. Enriched pasta had higher folate retention (68.5%) after cooking compared to the fortified one (27.8%). This research shows promising results concerning the pearling technique to design new cereal products naturally enriched in folates.

Profiling of naturally occurring folates in a diverse soybean germplasm by HPLC-MS/MS

Soybean is a rich source of folates. We optimised the extraction and detection of folates from soybean seeds by HPLC-MS/MS and analysed the folate content and composition of 1074 accessions. Total folate content ranged from 64.51 to 691.24 μg/100 g fresh weight, with 10-fold variation, and 60 elite accessions with over 400 μg/100 g of total folate were identified. The most abundant component was 5-CHO-H4folate, which accounted for an average of 60% of total folate content. Seed-coat colour, seed weight, ecoregion, and accession type significantly affected soybean folate content. Furthermore, 5-CH3-H4folate correlated positively with seed protein (r = 0.24***) and negatively with oil (r = -0.26***). The geographical distribution of folate according to accession origin revealed that accessions from Northeast China contain higher amounts of total folate and 5-CHO-H4folate. This study provides comprehensive and novel insights into the folate profile of soybean, which will benefit soybean breeding for folate enhancement.

Agronomic Biofortification of Cayenne Pepper Cultivars with Plant Growth-Promoting Rhizobacteria and Chili Residue in a Chinese Solar Greenhouse

Agronomic biofortification of horticultural crops using plant growth-promoting rhizobacteria (PGPR) under crop residue incorporation systems remains largely underexploited. Bacillus subtilis (B1), Bacillus laterosporus (B2), or Bacillus amyloliquefaciens (B3) was inoculated on soil containing chili residue, while chili residue without PGPR (NP) served as the control. Two hybrid long cayenne peppers, succeeding a leaf mustard crop were used in the intensive cultivation study. Net photosynthesis, leaf stomatal conductance, transpiration rate, photosynthetic water use efficiency, shoot and root biomass, and fruit yield were evaluated. Derivatives of folate, minerals, and nitrate contents in the pepper fruits were also assessed. B1 elicited higher net photosynthesis and photosynthetic water use efficiency, while B2 and B3 had higher transpiration rates than B1 and NP. B1 and B3 resulted in 27–36% increase in pepper fruit yield compared to other treatments, whereas B3 produced 24–27.5% and 21.9–27.2% higher 5-methyltetrahydrofolate and total folate contents, respectively, compared to B1 and NP. However, chili residue without PGPR inoculation improved fruit calcium, magnesium, and potassium contents than the inoculated treatments. ‘Xin Xian La 8 F1’ cultivar had higher yield and plant biomass, fruit potassium, total soluble solids, and total folate contents compared to ‘La Gao F1.’ Agronomic biofortification through the synergy of Bacillus amyloliquefaciens and chili residue produced better yield and folate contents with a trade-off in the mineral contents of the greenhouse-grown long cayenne pepper.

Weighted gene co-expression network analysis unveils gene networks regulating folate biosynthesis in maize endosperm

Folates are essential elements for human growth and development, and their deficiency can lead to serious disorders. Waxy maize is a rich source of folates; however, the regulatory mechanism underlying folate biosynthesis in the endosperm remains unclear. Here, we examined changes in the folate content of maize endosperm collected at 15, 18, 21, 24, and 27 days after pollination (DAP) using liquid chromatograph-mass spectrometry and identified genes related to folate biosynthesis using transcriptome sequencing data. The results showed that 5-methyl-tetrahydrofolate and 5,10-methylene tetrahydrofolate were the main storage forms of folates in the endosperm, and their contents were relatively high at 21-24 days. We also identified 569, 3183, 4365, and 5513 differentially expressed genes (DEGs) in different days around milk stage. Functional annotation revealed 518 transcription factors (TFs) belonging to 33 families exhibiting specific expression in at least one sampling time. The key hub genes involved in folate biosynthesis were identified by weighted gene co-expression network analysis. In total, 24,976 genes were used to construct a co-expression network with 29 co-expression modules, among which the brown and purple modules were highly related to folate biosynthesis. Further, 187 transcription factors in the brown and purple modules were considered potential transcription factors related to endosperm folate biosynthesis. These results may improve the understanding of the molecular mechanism underlying folate biosynthesis in waxy maize and lead to the development of nutritionally fortified varieties.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-021-02974-7.

Vitamins in Cereals: A Critical Review of Content, Health Effects, Processing Losses, Bioaccessibility, Fortification, and Biofortification Strategies for Their Improvement

Around the world, cereals are stapled foods and good sources of vitamins A, B, and E. As cereals are inexpensive and consumed in large quantities, attempts are being made to enrich cereals using fortification and biofortification in order to address vitamin deficiency disorders in a vulnerable population. The processing and cooking of cereals significantly affect vitamin content. Depending on grain structure, milling can substantially reduce vitamin content, while cooking methods can significantly impact vitamin retention and bioaccessibility. Pressure cooking has been reported to result in large vitamin losses, whereas minimal vitamin loss was observed following boiling. The fortification of cereal flour with vitamins B1, B2, B3, and B9, which are commonly deficient, has been recommended; and in addition, region-specific fortification using either synthetic or biological vitamins has been suggested. Biofortification is a relatively new concept and has been explored as a method to generate vitamin-rich crops. Once developed, biofortified crops can be utilized for several years. A recent cereal biofortification success story is the enrichment of maize with provitamin A carotenoids.