Journal of Nutrition最新文献

Diet affects the intestinal microbiota. Increasingly, research is linking the intestinal microbiota to various human health outcomes. Consumption of traditional prebiotics (inulin, fructooligosaccharides, and galactooligosaccharides) confers health benefits through substrate utilization by select intestinal microorganisms, namely Bifidobacterium and Lactobacilli. A similar but distinct concept focused on microorganisms to support human health is through direct consumption of certain live microorganisms recognized as probiotics, which classically include Lactobacilli or Bifidobacterium strains. With advances in sequencing technologies and culturing techniques, other novel functional intestinal microorganisms are being increasingly identified and studied to determine how they may underpin human health benefits. These novel microorganisms are targeted for enrichment within the autochthonous intestinal microbiota through dietary approaches and are also gaining interest as next-generation probiotics because of their purported beneficial properties. Thus, characterizing dietary approaches that nourish select microorganisms in situ is necessary to propel biotic-focused research forward. As such, we reviewed the literature to summarize findings on dietary approaches that nourish the human intestinal microbiota and benefit health to help fill the gap in knowledge on the connections between certain microorganisms, the metabolome, and host physiology. The overall objective of this systematic review was to summarize the impact of dietary interventions with the propensity to nourish certain intestinal bacteria, affect microbial metabolite concentrations, and support gastrointestinal, metabolic, and cognitive health in healthy adults. Findings from the 17 randomized controlled studies identified in this systematic review indicated that dietary interventions providing dietary fibers, phytonutrients, or unsaturated fatty acids differentially enriched Akkermansia, Bacteroides, Clostridium, Eubacterium, Faecalibacterium, Roseburia, and Ruminococcus, with variable effects on microbial metabolites, and subsequent associations with physiological markers of gastrointestinal and metabolic health. These findings have implications for biotic-focused research on candidate prebiotic substrates as well as next-generation probiotics.

Background: Adding vitamin C-rich fruit to staples containing iron could be an effective strategy to improve iron bioavailability and thereby reduce iron-deficiency anemia in children.

Objectives: We aimed to assess the effect of consuming a mungbean-based meal with or without guava fruit on body iron stores, hemoglobin concentration, and anemia of children as part of a school feeding program.

Methods: We conducted a 7-mo randomized, controlled trial with 6- to 10-y-old school children (n = 200; 46% anemic, 71% iron-deficient) from a rural community in Haryana, North India. Children were assigned to 2 treatment groups to daily receive either a meal of mungbean dal only (3.0 mg iron; vitamin C:iron molar ratio ∼0.5:1), or mungbean dal with fresh guava (3.2 mg iron; ∼170 mg vitamin C; molar ratio ∼18:1). Meals were served every school day under supervision. The primary outcome was body iron stores, whereas concentrations of hemoglobin and other iron indicators were secondary outcomes.

Results: Daily consumption of mungbean dal along with guava did not result in an overall improvement of body iron stores [mean treatment effect: 0.65 mg/kg body weight; 95% confidence interval (CI): -0.34, 1.63; P = 0.197]. However, compared with children who consumed mungbean dal only, children in the guava group showed a larger increase in hemoglobin concentration (3.7 g/L; 95% CI: 1.6, 5.6; P = 0.001), and a larger drop in the prevalence of anemia (-51%; 95% CIs: -74, -10; P = 0.022) and iron-deficiency anemia (-56%, 95% CI: -83, 13; P = 0.087). These effects were more pronounced in children who were iron deficient at study start.

Conclusions: Addition of guava to a mungbean-based meal containing a moderate amount of iron increased hemoglobin and reduced anemia but did not provide enough additional absorbed iron to also increase body iron stores. Food-to-food fortification by inclusion of vitamin C-rich fruits in iron-containing school meals may help alleviate the burden of anemia in children.

Trial registration number: This trial was registered at https://clinicaltrials.gov/ct2/show/NCT01191463.

Current research studies point to an increased risk of diabetes with selenium (Se) intake beyond the physiological requirement used to prevent cancers. The existing hypothesis of "selenoprotein overexpression leads to intracellular redox imbalance" cannot clearly explain the U-shaped dose-effect relationship between Se intake and the risk of diabetes. In this review, it is speculated that metabolic remodeling based on the de novo biosynthesis of L-serine may occur in mammals at supranutritional or subtoxic levels of Se. It is also speculated that a large amount of L-serine is consumed by the body during insufficient Se intake, thus resulting in similar metabolic reprogramming. The increase in atypical ceramide and its derivatives due to the lack of L-serine may also play a role in the development of diabetes.

Background: Double-fortified salt (DFS; iron, iodine) improved iron status in randomized trials and was incorporated into India's social safety net programs, suggesting opportunities to address other micronutrient deficiencies.

Objectives: To evaluate the acceptability of quadruple-fortified salt (QFS; iron, iodine, folic acid, and vitamin B₁₂) in women and their households, using a randomized crossover trial design and triangle tests.

Methods: Women 18-49 y (n = 77) and their households were randomly assigned to receive QFS or DFS in a randomized crossover design over a 3-wk period (week 1: QFS/DFS, week 2: iodized salt, week 3: DFS/QFS). Each week, participants completed a 9-point hedonic questionnaire (1 = dislike extremely to 9 = like extremely) to evaluate 5 sensory domains (color, odor, taste, texture, and overall acceptability) of the intervention, and the remaining salt was weighed using a digital scale. Triangle tests were conducted among women to evaluate sensory discrimination of salt consumed in rice dishes prepared using standardized recipes. Mixed models were used to examine hedonic ratings and salt use; salt type, sequence, and period were included as fixed effects, and household was included as a random effect. Binomial tests were used to evaluate sensory discrimination of salt type in triangle tests.

Results: Mean hedonic ratings for most of the 5 sensory domains were ≥7 (like moderately) and did not differ by salt type [overall acceptability mean (SD): QFS: 7.8 (0.7) compared with DFS: 7.7 (1.2); P = 0.68]. Household salt use (weighed) did not differ by salt type. During the 3-wk intervention period, weighed salt use and hedonic ratings significantly increased, indicating a period effect independent of salt type or sequence. In triangle tests, rice samples prepared with QFS, DFS, or iodized salt were not distinguishable.

Conclusions: Acceptability of QFS was high, based on individual hedonic ratings and weighed household salt use. Rice dishes prepared with DFS, QFS, and iodized salt were not distinguishable. Findings informed the design of a randomized trial of QFS in this population. This trial was registered at clinicaltrials.gov as NCT03853304 and REF/2019/03/024479.

Background: Diet is critical for pregnant individuals and their offspring, but insight into diet during pregnancy mainly comes from questionnaires and recalls.

Objectives: To obtain detailed real-time dietary data during pregnancy to evaluate intra- and interindividual variation in intakes.

Methods: Pregnant individuals were recruited from a New York City health system December 2020-June 2023. Participants collected dietary intakes for 14 d (mean gestational weeks = 17.6) and again roughly 4 wk later (mean gestational weeks = 24.5). Participants logged each eating occasion using a smartphone and study-developed app, and wore a smartwatch capturing physiologic data.

Results: In total, 150 individuals completed ≥1 data collection round, with 134 completing both rounds. Mean daily eating window was 10.82 h, with weekends having a significantly shorter window than weekdays (P < 0.001). Eating window was correlated with energy intake (r = 0.401, P < 0.001), driven by later last eating occasions. There was high intraindividual variation in macro- and micronutrient intakes [intraclass correlation coefficient (ICC), range 0.11-0.40] and food type (ICC range: 0.08-0.34), and differences between weekdays and weekends (less protein and micronutrients on weekends). Few participants' mean intakes met daily recommended dietary allowances for key micronutrients (under 15% for iron, magnesium, vitamin D, and vitamin E; under 30% for calcium, folate, zinc, and vitamin A).

Conclusions: Dietary intakes varied substantially within and between individuals, and mean nutrient intake estimates did not capture nutrient adequacy for individuals or populations. Future work that examines individual daily dietary intakes throughout pregnancy among diverse populations is needed.

Background: Periconceptional folic acid supplementation (FAS) is widely recommended. However, the role of periconceptional FAS on neonatal birth weight remains unclear.

Objectives: This study aimed to explore the independent effects of periconceptional FAS on risks of small for gestational age (SGA) and large for gestational age (LGA) and to test the potential mediation role of maternal homocysteine (Hcy) during pregnancy on the above significant associations.

Methods: A large-scale prospective birth cohort was conducted in the Tongzhou Maternal and Child Health Hospital, Beijing, China, from June 2018 to August 2019. Periconceptional FAS was evaluated by a self-administered questionnaire on the day of recruitment in early pregnancy (<14th wk of gestation). FAS was defined as participants who had taken folic acid (FA) supplements, FA-containing multivitamins, or other FA-containing nutritional supplements. Neonatal birth weight was measured at delivery. Maternal serum Hcy concentrations were measured in early and late pregnancy. Logistic regression analyses were performed to assess the associations between FAS during preconception and/or early pregnancy and the occurrence of SGA or LGA. A mediation model was constructed to determine the role of maternal Hcy concentration on the above associations.

Results: FAS before pregnancy [risk ratios (RR), 0.819; 95% confidence interval (CI): 0.672, 1.000; P = 0.05], during early pregnancy (RR, 0.622; 95% CI: 0.451, 0.858), and from prepregnancy to early pregnancy (RR, 0.564; 95% CI: 0.371, 0.857) were associated with a lower risk of LGA. However, no significant association was found between periconceptional FAS and SGA birth. Maternal Hcy concentration in late pregnancy mediated the independent effects of maternal FAS during preconception and early pregnancy on risks of LGA birth.

Conclusions: Periconceptional FAS was associated with a lower risk of LGA, which may be mediated by the reduced serum Hcy concentration in late pregnancy. The current recommendation of periconceptional FAS should be complied with to reduce risks of LGA.

Background: There is a growing body of evidence on associations between one-carbon metabolism (OCM) and diabetes-related parameters. For this reason, we aimed to examine the associations of plasma choline, betaine, trimethylamine N-oxide (TMAO), glutathione (GSH), serum folate, vitamin B12, dihydrofolate reductase (rs70991108) genotype, methylenetetrahydrofolate reductase (MTHFR) (rs180113) genotype, methylenetetrahydrofolate dehydrogenase (MTHFD1) (rs2236225) genotype, and phosphatidylethanolamine N-methyltransferase (rs7946 and rs12325817) genotype with fasting glucose level, insulin level, and diabetes-related indices.

Methods: The study group consisted of 421 Polish adults aged 20-40 y. Food intake was assessed using a 3-d food diary. Plasma concentrations of choline, betaine, and TMAO were determined by ultra-high-performance liquid chromatography-electrospray ionization mass spectrometry. The total plasma GSH level was measured by high-performance liquid chromatography. Insulin, folate, and vitamin B12 concentrations were estimated by enzyme-linked immunosorbent assay method. Genotyping was performed with TaqMan probes.

Results: GSH level was negatively associated with insulin (β = -0.11, P < 0.05) and gamma-glutamyl transferase (GGTP) (β = -0.12, P < 0.05), and positively associated with fasting glucose (β = 0.11, P < 0.05). Betaine intake was negatively associated with serum insulin concentration (β = -0.13, P < 0.05) and HOMA-IR (β = -0.12, P < 0.05). Choline intake was negatively associated with insulin (β = -0.17, P < 0.01). Serum folate level was negatively associated with GGTP (β = -0.11; P < 0.05). The methylenetetrahydrofolate reductase (MTHFR) CC genotype was associated with higher serum insulin levels (β = 0.15; P < 0.01) and higher HOMA-IR (β = 0.15, P < 0.01), whereas the MTHFD1 AA genotype was negatively associated with Quantitative Insulin Sensitivity Check Index (β = -0.11, P < 0.05).

Conclusions: Our findings suggest that higher GSHL and higher intake of betaine, B₁₂, and choline, as well as the TT genotype of MTHFR and the AA genotype of MTHFD1, are associated with lower diabetes-related parameters among adults.

Background: Adipose tissue vitamin A (VA), that is, mainly retinol (RET) and its esters, comes from preformed VA and proVA carotenoids present in our food. Adipose tissue VA acts as hormonal cue maintaining essential aspects of adipocyte biology, which includes fat mobilization and catabolism, energy balance, and glucose homeostasis, and it is thus of particular interest to study its determinants, including genetic ones.

Objectives: This study aimed to identify genetic variations associated with adipose tissue VA concentration.

Methods: Forty-two healthy male adults received, in a randomized crossover design, 3 test meals. Periumbilical adipose tissue samples were collected on 6 occasions, that is, at fast and 8 h after consumption of each meal. RET concentration was measured in both plasma and the adipose tissue following saponification. Participants were genotyped using whole-genome microarrays. A total of 1305 single nucleotide polymorphism (SNPs) in or near 27 candidate genes were included for univariate analysis. Partial least squares (PLS) regression was carried out to find the best combination of SNPs associated with the interindividual variability in adipose tissue RET concentration.

Results: Adipose tissue RET concentration was not associated with plasma RET concentrations (r = -0.184, P = 0.28). Interindividual variability of adipose tissue RET concentration was high (CV = 62%). Twenty-nine SNPs were significantly (P < 0.05) associated with adipose tissue RET concentration and a PLS regression model identified 16 SNPs as explanatory variables of this concentration. The SNPs were in or near peroxisome proliferator activated receptor gamma, retinoid X receptor alpha, signaling receptor and transporter of retinol, cluster of differentiation 36, free fatty acid receptor 4, aldehyde dehydrogenase 1 family member A1, monoglyceride lipase, DGAT2, and polycystic kidney disease 1-like 2.

Conclusions: A combination of 16 SNPs has been associated with the interindividual of adipose tissue VA concentration in humans. This trial was registered at clinicaltrials.gov as NCT02100774.

Assessing nutrients' relative bioavailability value (RBV) in poultry nutrition has been a prominent subject in the scientific literature for several decades. This method of nutritional evaluation is commonly used to appraise emerging sources of trace minerals and amino acid chelates. References outlining the method for estimating RBV have been available since the 1970s. However, a simplified approach to RBV estimation using the slope-ratio method without preceding statistical considerations to ensure validity and meet fundamental requirements may yield misleading conclusions. Using the slope-ratio method, which involves dividing the regression slope of the test ingredient by that of the reference, can cause uncertainties regarding statistical significance if the model's probability is reported without confidence intervals (CIs) for the RBV estimates. Despite longstanding criticism regarding the misinterpretation and improper use of statistical tests and CIs, these issues persist in estimating RBV using the slope-ratio method. An additional concern is that the misuse of the slope-ratio method and the application of inappropriate statistical analyses can lead to the underestimation of the RBV of nutrients in poultry species. This means that improper application of these methods can cause inaccurately low RBV values, affecting the assessment of nutrient effectiveness. This review addresses the potential pitfalls in peer-reviewed articles within this field, with a particular focus on zinc bioavailability through a reevaluation of RBV data in broilers, laying hens, and honeybees.