The Journal of nutrition最新文献

Background: Human and animal studies report a blunted sense of taste in people who are overweight or obese, with heightened sensitivity also reported after weight loss. However, it is unknown if taste changes concurrently with weight gain.Objective: This study investigated the association of weight gain with changes in suprathreshold taste intensity perception in a free-living population of young adults.Methods: Taste response, anthropometric measures, and diet changes were assessed with a longitudinal study design in first-year college students 3 times throughout the academic year. At baseline, 93 participants (30 males, 63 females) were an average of 18 y old, with a body mass index (in kg/m²) of 21.9. Sweet, umami, salty, sour, and bitter taste intensities were evaluated at 3 concentrations by using the general Labeled Magnitude Scale. Ordinary least-squares regression models assessed the association of weight gain and within-person taste change, adjusting for sex, race, and diet changes.Results: Participants gained an average of 3.9% in weight, ranging from -5.7% to +13.8%. With each 1% increase in body weight, males perceived sweet and salty as less intense, with taste responses decreasing by 11.0% (95% CI: -18.9%, -2.3%; P = 0.015) and 7.5% (95% CI: -13.1%, -1.5%; P = 0.015) from baseline, respectively. Meanwhile, females did not experience this decrement, and even perceived a 6.5% increase (95% CI: 2.6%, 10.5%; P = 0.007) in sour taste with similar amounts of weight gain. Changes in the consumption of meat and other umami-rich foods also negatively correlated with umami taste response (-39.1%; 95% CI: -56.3%, -15.0%; P = 0.004).Conclusions: A modest weight gain is associated with concurrent taste changes in the first year of college, especially in males who experience a decrement in sweet and salty taste. This suggests that young-adult males may be susceptible to taste loss when gaining weight.

Background: Increased physical activity may be advantageous for weight loss.

Objective: We investigated the effects of an energy-restricted diet with and without moderate walking on body weight, body composition, resting energy expenditure (REE), and endocrine and cardiometabolic risk variables in overweight and obese participants.

Methods: A 12-wk, randomized, 2-arm, parallel, controlled, energy-restricted (500-800 kcal/d) dietary intervention study was conducted in 82 men and women [mean baseline characteristics: age, 39.4 y; weight, 99.3 kg; body mass index (in kg/m2), 31.9]. Participants were divided into 2 groups. One group received a hypoenergetic diet (DI) only (n = 44). The second group received the same DI and participated in a regular walking program of 2.5 h/wk (DI + walking; n = 38).

Results: After the 12-wk intervention, body weight was significantly decreased in the DI + walking group and the DI group (-8.8 compared with -7.0 kg, P = 0.064 for intergroup differences). The decrease in body weight was accompanied by a significant reduction in total fat mass, which was significantly more pronounced in the DI + walking group than in the DI group (-6.4 ± 3.1 compared with -4.8 ± 3.0 kg; P = 0.020). REE after 12 wk was not significantly different compared with the baseline REE. Diastolic blood pressure, mean arterial pressure, LDL cholesterol, and non-HDL cholesterol were similarly significantly improved by both interventions. In the DI + walking group, insulin and the homeostasis model assessment of insulin resistance index were also significantly reduced. Serum free triiodothyronine was significantly decreased and serum cortisol was significantly increased in both groups.

Conclusions: Participation in a 12-wk weight-loss study resulted in significant reductions in body weight and fat mass and was associated with significant improvements in biomarkers for cardiovascular disease risk. Moderate weight loss was not accompanied by a reduction in REE. Additional moderate walking enhanced the effects of a DI on fat loss and serum insulin. This trial was registered at www.germanctr.de/ and http://apps.who.int/trialsearch/ as DRKS00006827.

Background: Individuals with intrauterine growth restriction (IUGR) are prone to developing type 2 diabetes mellitus (T2DM). Dietary methionine restriction (MR) improves insulin sensitivity and glucose homeostasis in individuals with normal birth weight (NBW).Objective: This study investigated the effects of MR on plasma glucose concentration and hepatic and muscle glucose metabolism in pigs with IUGR.Methods: Thirty female NBW and 60 same-sex spontaneous IUGR piglets (Landrace × Yorkshire) were selected. After weaning (day 21), the piglets were fed diets with adequate methionine (NBW-CON and IUGR-CON) or 30% less methionine (IUGR-MR) (n = 6). At day 180, 1 pig with a body weight near the mean of each replication was selected for biochemical analysis.Results: The IUGR-CON group showed 41.6%, 68.6%, and 67.1% higher plasma glucose concentration, hepatic phosphoenolpyruvate carboxykinase activity, and glucose-6-phosphatase activity, respectively, than the NBW-CON group (P < 0.05). Muscle glycogen content and glycogen synthase activity were 36.9% and 38.8% lower, respectively, in the IUGR-CON than the NBW-CON group (P < 0.05), respectively, and there was decreased hepatic and muscle protein kinase B phosphorylation in the IUGR-CON group (P < 0.05). Compared with the IUGR-CON pigs, the IUGR-MR pigs had 28.7% lower plasma glucose concentrations (P < 0.05), which were similar to those of the NBW-CON pigs (P ≥ 0.05). The hepatic glycogen content and glycogen synthase activity of the IUGR-MR pigs were 62.9% and 50.8% higher than those of the IUGR-CON pigs (P < 0.05) and 53.5% and 84.3% higher than the NBW-CON pigs (P < 0.05), respectively. The IUGR-MR pigs' hepatic and muscle protein kinase B phosphorylation was higher than that of the IUGR-CON pigs (P < 0.05) and similar to that of the NBW-CON pigs (P ≥ 0.05).Conclusion: MR attenuates hyperglycemia in IUGR pigs by enhancing hepatic protein kinase B signaling and glycogen synthesis, implying a potential nutritional strategy to prevent type 2 diabetes mellitus in IUGR offspring.

Background: Magnesium influences hepatic lipid deposition in vertebrates, but the underlying mechanism is unknown.Objective: We used yellow catfish and their isolated hepatocytes to test the hypothesis that magnesium influences lipid deposition by modulating lipogenesis and lipolysis.Methods: Juvenile yellow catfish (mean ± SEM weight: 3.43 ± 0.02 g, 3 mo old, mixed sex) were fed a 0.14- (low), 0.87- (intermediate) or 2.11- (high) g Mg/kg diet for 56 d. Primary hepatocytes were incubated for 48 h in control or MgSO₄-containing medium with or without 2-h pretreatment with an inhibitor (AG490, GW6471, or Compound C). Growth performance, cell viability, triglyceride (TG) concentrations, and expression of enzymes and genes involved in lipid metabolism were measured. Results: Compared with fish fed low magnesium, those fed intermediate or high magnesium had lower hepatic lipids (18%, 22%) and 6-phosphogluconate dehydrogenase (6PGD; 3.7%, 3.8%) and malic enzyme (ME; 35%, 48%) activities and greater mRNA levels of the lipolytic genes adipose triacylglyceride lipase (atgl; 82% and 1.7-fold) and peroxisome proliferator-activated receptor (ppara; 18% and 1.0-fold), respectively (P < 0.05). Relative mRNA levels of AMP-activated protein kinase (ampk) a1, ampka2, ampkb1, ampkb2, ampkg1a, ampkg1b, Janus kinase (jak) 2a, jak2b, and signal transducers and activators of transcription (stat) 3 in fish fed high magnesium were higher (24% to 3.1-fold, P < 0.05) than in those fed low or intermediate magnesium. Compared with cells incubated with MgSO₄ alone, those incubated with MgSO₄ and pretreated with AG490, GW6471, or Compound C had greater TG concentrations (42%, 31%, or 56%), g6pd (98%, 59%, or 51%), 6pgd (68%, 73%, or 32%) mRNA expression, and activities of G6PD (35%, 45%, or 16%) and ME (1.5-fold, 1.3-fold, or 13%), and reduced upregulation (61%, 25%, or 45%) of the lipolytic gene, atgl (P < 0.05).Conclusions: Magnesium reduced hepatic lipid accumulation in yellow catfish and the variation might be attributed to inhibited lipogenesis and increased lipolysis. PPARA, JAK-STAT, and AMPK pathways mediated the magnesium-induced changes in lipid deposition and metabolism. These results offer new insight into magnesium nutrition in vertebrates.

Background: Ferritin and hepcidin are markers of iron status that typically increase during inflammation or infection. The postpartum period is a physiologically unique life stage in which the relations between these proteins and other markers of inflammation have not been extensively studied.Objective: We aimed to determine whether 2 markers of inflammation [high-sensitivity C-reactive protein (CRP) and α1-acid glycoprotein (AGP)] were associated with ferritin or hepcidin in postpartum women in California.Methods: This is a secondary analysis of a randomized controlled iron-intervention trial. Plasma CRP, AGP, ferritin, and hepcidin were analyzed at 2 and 17 wk postpartum in 114 lactating women. We examined Pearson correlation coefficients between all biomarkers at both time points and differences in mean values of ferritin and hepcidin between those with and without elevated CRP and/or AGP.Results: At 2 and 17 wk postpartum, 58% and 26% of women had CRP >5 mg/L and 78% and 29% had AGP >1 g/L, respectively. Neither CRP nor AGP was significantly correlated with ferritin (r = 0.07 and -0.06; n = 114 at 2 wk; -0.14 and -0.14; n = 95 at 17 wk) or hepcidin (r = 0.18 and -0.03 at 2 wk; -0.05 and -0.14 at 17 wk; P > 0.05 for all). At 2 wk, geometric mean plasma ferritin and hepcidin concentrations did not differ between women with and without elevated CRP or AGP (P > 0.5), but at 17 wk women with elevated CRP or AGP had lower mean (95% CI) ferritin and hepcidin than did women without either elevated CRP or AGP [ferritin: 30.3 ng/mL (23.4, 39.1 ng/mL) compared with 40.2 ng/mL (32.9, 49.2 ng/mL); P < 0.01; hepcidin: 44.3 ng/mL (32.3, 60.9 ng/mL) compared with 67.6 ng/mL (56.1, 81.5 ng/mL); P = 0.02].Conclusion: Lower ferritin and hepcidin among women with elevated CRP or AGP at 17 wk postpartum suggests that these markers of iron status react differently to physiologic immune activation than to pathologic inflammatory states.

Background: Emerging evidence suggests that the timing, amount at individual eating occasions, and distribution of protein and energy intakes throughout the day may affect health.Objective: We examined the timing, amounts, and distribution of protein and energy intakes throughout the day among participants aged 4-18 y in the United States in the context of chronobiology and nutrition.Methods: This cross-sectional analysis included 2532 participants aged 4-18 y who completed the first interviewer-administered 24-h dietary recall in NHANES 2013-2014. Descriptive statistics for intakes across the day were provided as percentiles, means ± SEMs, and percentages of nonconsumers. Statistical differences between intakes across the day were tested with the use of individual-level fixed-effects regression models. Cumulative distribution functions were used to examine the timing of the first and last caloric eating occasion.Results: Mean ± SEM protein (grams) and energy (percentage of the day) intakes were significantly higher (P < 0.05) in the evening than in the morning among all age groups. The percentage of participants aged 4-8, 9-13, and 14-18 y who had their first eating occasion at or after 1100 was 4%, 14%, and 20%, respectively, and the percentage who had their last eating occasion at or after 2100 was 8%, 19%, and 34%, respectively.Conclusions: Protein and energy intakes among participants aged 4-18 y in this study were largest in the evening and midday and smallest in the morning and afternoon. Clinical trials are needed to assess any potential impact such dietary behaviors may have on health outcomes related to metabolic dysfunction in children and adolescents.

Background: Maternal vitamin D insufficiency (plasma 25-hydroxyvitamin D [25(OH)D] <75 nmol/L) may play a role in ethnic disparities in rates of preterm and spontaneous preterm births.Objective: We explored the relation between maternal plasma 25(OH)D concentration in the first trimester (8-14 wk of gestation) and the risk of preterm and spontaneous preterm births (<37 wk of gestation) by ethnicity.Methods: We designed a case-control study that included 120 cases of preterm birth (<37 wk of gestation) and 360 term controls (≥37 wk of gestation) of singleton pregnancies from the 3D cohort, a multicenter study in 2456 pregnant women in Quebec, Canada. Plasma 25(OH)D was measured by LC-mass spectrometry. We compared the distribution of vitamin D status between cases and controls for 8 ethnic minority subgroups. We explored the association between maternal plasma 25(OH)D concentration and preterm and spontaneous preterm births with the use of splines in logistic regression by ethnicity.Results: The distributions of maternal vitamin D status (<50, 50-75, and >75 nmol/L) were different in preterm and spontaneous preterm birth cases compared with controls but only in women of ethnic minority (P-trend = 0.003 and 0.024, respectively). Among ethnic subgroups, sub-Saharan Africans (P-trend = 0.030) and Arab-West Asians (P-trend = 0.045) showed an inverse relation between maternal vitamin D status and the risk of preterm birth. Maternal plasma 25(OH)D concentrations of 30 nmol/L were associated with 4.05 times the risk of preterm birth in the total ethnic minority population (95% CI: 1.16, 14.12; P = 0.028) relative to participants with a concentration of 75 nmol/L. In contrast, there was no such association among nonethnic women (OR: 0.94; 95% CI: 0.48, 1.82; P = 0.85). There was no association when we considered only spontaneous preterm births in the total ethnic minority population (OR: 1.75; 95% CI: 0.39, 7.79; P = 0.46).Conclusion: Vitamin D insufficiency is associated with an increased risk of preterm birth in ethnic minority women in Canada.

Background: Antenatal anemia is a risk factor for adverse maternal and fetal outcomes and is prevalent in sub-Saharan Africa. Less than half of antenatal anemia is considered responsive to iron; identifying women in need of iron may help target interventions. Iron absorption is governed by the iron-regulatory hormone hepcidin.Objective: We sought to characterize changes in hepcidin and its associations with indexes of iron stores, erythropoiesis, and inflammation at weeks 14, 20, and 30 of gestation and to assess hepcidin's diagnostic potential as an index of iron deficiency.Methods: We measured hemoglobin and serum hepcidin, ferritin, soluble transferrin receptor (sTfR), and C-reactive protein (CRP) at 14, 20, and 30 wk of gestation in a cohort of 395 Gambian women recruited to a randomized controlled trial. Associations with hepcidin were measured by using linear regression, and hepcidin's diagnostic test accuracy [area under the receiver operating characteristic curve (AUC^ROC), sensitivity, specificity, cutoffs] for iron deficiency at each time point was analyzed.Results: The prevalence of anemia increased from 34.6% at 14 wk of gestation to 50.0% at 20 wk. Hepcidin concentrations declined between study enrollment and 20 wk, whereas ferritin declined between 20 and 30 wk of gestation. The variations in hepcidin explained by ferritin, sTfR, and CRP declined over pregnancy. The AUC^ROC values for hepcidin to detect iron deficiency (defined as ferritin <15 μg/L) were 0.86, 0.83, and 0.84 at 14, 20, and 30 wk, respectively. Hepcidin was superior to hemoglobin and sTfR as an indicator of iron deficiency.Conclusions: In Gambian pregnant women, hepcidin appears to be a useful diagnostic test for iron deficiency and may enable the identification of cases for whom iron would be beneficial. Hepcidin suppression in the second trimester suggests a window for optimal timing for antenatal iron interventions. Hemoglobin does not effectively identify iron deficiency in pregnancy. This trial was registered at www.isrctn.com as ISRCTN49285450.

Background: Choline is an important nutrient either obtained from a variety of foods or synthesized endogenously, and it is the precursor of betaine. We previously reported positive associations between plasma free choline and bone mineral density (BMD). Animal studies suggest an impact of dietary choline on bone metabolism, but the role of dietary intake of choline and betaine for human bone health is unknown.Objectives: The main aims were to examine the associations of dietary choline, choline species, and betaine with BMD and to study the relations between dietary and plasma free choline and betaine.Methods: Study subjects were participants in the Hordaland Health Study, including 2649 women and 1983 men (aged 46-49 or 71-74 y). BMD was measured by dual-energy X-ray absorptiometry, and dietary intake was obtained by using a validated 169-item food-frequency questionnaire. Risk associations were assessed by logistic regression and correlations by ρ (Spearman's bivariate rank order correlation).Results: Subjects in the lowest compared with the highest tertile of dietary total choline, free choline, glycerophosphocholine, phosphocholine, phosphatidylcholine, and sphingomyelin had a higher risk of low-femoral neck BMD, defined as the lowest BMD quintile. Particularly strong associations were found among middle-aged men for intake of free choline (OR: 1.83; 95% CI: 1.24, 2.69; P = 0.002) and glycerophosphocholine (OR: 2.13; 95% CI: 1.43, 3.16; P < 0.001) and among elderly women for total choline (OR: 1.96; 95% CI: 1.33, 2.88; P = 0.001) and phosphatidylcholine (OR: 1.94; 95% CI: 1.33, 2.84: P = 0.001) intake. No significant associations were observed between dietary betaine and BMD. Dietary total choline, free choline, glycerophosphocholine, phosphatidylcholine, and sphingomyelin correlated weakly with plasma free choline (ρ: 0.07, 0.05, 0.07, 0.07, and 0.05, respectively; P < 0.01). Dietary betaine correlated with plasma betaine (ρ: 0.23; P < 0.001).Conclusion: Dietary choline was positively associated with BMD in middle-aged and elderly participants.