American Journal of Clinical Nutrition最新文献

Medical nutritional therapy, an evidence-based application of the nutrition care process guided by a registered dietitian nutritionist, is an integral part of diabetes management, with emerging evidence suggesting distinct nutritional requirements in this population. A thorough review of the existing literature reveals an imperative to address the specific requirements for vitamins and minerals in this population. Current guidelines have given limited attention to micronutrients, despite the higher prevalence of deficiencies and the altered patterns of association between serum micronutrient levels and multiple health outcomes among individuals with type 2 diabetes (T2D). To enhance diabetes management, an international multidisciplinary panel of 20 experts from 12 countries participated in a modified Delphi process, which was informed by a narrative review conducted by the research team, to reach consensus on 18 statements, encompassing 11 nutrient-specific recommendations and 7 statements outlining future directions in diabetes nutrition therapy research. The plan for this consensus has been registered on the Practice Guideline Registration for Transparency (PREPARE) (Registration Number: PREPARE-2025CN1178). The expert panel proposed potential target serum levels, screening strategies, and micronutrient supplementation for people with T2D and that personalized nutritional strategies integrating individual characteristics, genetic information, and gut microbiota represent key areas for future research.

Background: Anthocyanin supplementation is a promising nutritional intervention for prediabetes, while the efficacy varies due to the heterogeneity of diseases. Efficacy of the anthocyanin supplementation in impaired glucose tolerance (IGT) is evaluated and possible mechanisms are further explored.

Objective: This study aimed to investigate the effect of anthocyanin supplementation on pancreatic islet function in individuals with IGT.

Methods: A 12-wk randomized, double-blind, placebo-controlled (anthocyanin 160 mg/day or placebo) trial was conducted with routine lifestyle guidance involving 68 IGT participants. The primary outcome was β-cell function: disposition index (DI). Secondary outcomes included other OGTT (oral glucose tolerance test)-derived indices, insulin sensitivity, anthropometric measures, and levels of skin advanced glycation end products (AGEs) measured by skin autofluorescence (SAF). Analyses followed intention-to-treat (ITT) principle.

Results: For the primary outcome, there were no significant between-group differences in DI, with the adjusted mean differences of 61.3 (95% CI: -27.4, 150.0; P = 0.174). The IGT reversion rate [defined as 2-h OGTT glucose <7.8 mmol/L] was significantly higher in the anthocyanin group than in the placebo group (55.9 % compared with 29.4%, P = 0.013). In parallel with a greater improvement in Matsuda index, with an adjusted difference of 4.6 (95% CI: 2.5, 6.7; P = 0.003). Additionally, skin AGEs decreased significantly only in the anthocyanin group. The reduction in skin AGEs was positively correlated with the decrease in postprandial glucose area under the curve (AUC) (r = 0.302, P = 0.001) and negatively with improved Matsuda index (r = -0.344, P < 0.001).

Conclusions: Anthocyanin supplementation could significantly reverse IGT by improving insulin sensitivity. The reduction of skin AGEs by anthocyanins might play a critical role in the dietary management of IGT.

Trial registration number: This trial was registered at the www.chictr.org.cn as ChiCTR2400079566.

Background: Some recent observational studies have linked higher blood linoleic acid (LA) with lower risk of cardiometabolic diseases. However, these associations have not been observed for other n-6 polyunsaturated fatty acids (PUFAs) which, in some settings have been linked to higher disease risk, and thus the controversy over the health effects of n-6 PUFAs remains. Dementia is a paradigmatic case of it.

Objectives: To investigate the association of linoleic acid and non-LA n-6 PUFAs with the risk of incident dementia.

Methods: We included 273,795 participants from the UK Biobank free of dementia at baseline for whom plasma n-6 PUFAs data were available. We modeled the relationships between LA and, separately, non-LA n-6 PUFAs and incident dementia by quintile (Q) and using continuous linear model using Cox proportional hazards models adjusting for variables reported to relate to incident dementia.

Results: A total of 5,799 incident dementia cases were ascertained (median follow-up: 15.06 years; 25^th and 75^th percentiles: 14.22-15.80 years). Compared to participants at Q1 (lowest quintile) of LA, those at Q5 (highest quintile) showed a lower risk of dementia (adjusted hazard ratio [95% confidence interval] = 0.82 [0.74, 0.91]). In contrast, participants at Q5 of plasma non-LA n-6 PUFAs were at a higher risk of incident dementia when compared to Q1 (1.21 [1.10, 1.33]). Similar patterns were observed when considering LA and non-LA n-6 PUFAs continuously.

Conclusions: We observed heterogeneous associations between different types of n-6 PUFAs and risk of dementia, supporting the increasing view that n-6 PUFAs should not be treated homogeneously. Future research should investigate whether dietary LA (which drives plasma LA levels) may help reduce risk for dementia.

Registration: This research has been conducted using the UK Biobank Resource under Application Number 85092.

Background: There have been multiple attempts to identify biological factors that predict long-term weight change. Previous investigators have theorized that variations in how humans metabolize dietary macronutrients (storage as opposed to oxidation) might be one of these characteristics, but to date there has been no effort to address this hypothesis.

Objective: We used a retrospective cohort study design to test the hypothesis that greater meal fat storage in subcutaneous adipose tissue would be associated with greater future weight gain.

Methods: Body composition, demographic, and meal fatty acid metabolism data was collated from 154 non-obese research volunteers who participated in studies conducted at Mayo Clinic between 1997 and 2012 that used either ¹⁴C- or ³H-triolein. At the time of the original studies, the participants were healthy, weight-stable, free of acute illnesses, and not taking any drugs that could affect the study outcomes. Using an electronic medical record search strategy, we identified satisfactory post-study weight data for 107 volunteers (54 males), over a mean follow up of 18 years. Regression analysis was used to test for relationships between adipose tissue meal fatty acid storage (and oxidation) and annualized weight change.

Results: The long-term (19 ± 7) years weight change for females was correlated with meal fat storage (P = 0.003, r=0.38) and meal fat oxidation measured using ¹⁴C-triolein (43 females P = 0.03, r = - 0.33). There was no significant relationship between meal fatty acid storage or oxidation and weight change for males.

Conclusions: The finding that weight change is correlated with dietary fatty acid metabolism for adult, non-obese females suggests that inter-individual variations in how women process dietary fat can influence long-term energy balance.

Clinical trial registration: NCT00254371; the other protocols were not considered clinical trials at the time they were conducted. https://clinicaltrials.gov/study/NCT00254371?term=testosterone&cond=%22Sarcopenia%22&viewType=Table&rank=9.

Background: Food processing has become an important focus in nutrition science due to its link to adverse health outcomes. Evaluating different classification systems provides valuable insights into how food processing is defined and its implications for nutrition research, cardiometabolic health, and food policy.

Objectives: We aim to compare the NOVA, International Agency for Research on Cancer (IARC), International Food Information Council (IFIC), and University of North Carolina (UNC) classification systems by evaluating their characteristics, reliability, and associations with nutrient intake and cardiometabolic risk factors.

Methods: Using data from 4,392 adult participants in the 2017-2018 National Health and Nutrition Examination Survey (NHANES) cycle, we categorized 4,605 food and beverage items according to four classification systems and harmonized processing levels into three categories: minimally processed, processed, and highly processed/formulated foods. Sociodemographic characteristics, nutrient profiles, and associations with cardiometabolic risk factors were analyzed using linear regression models that accounted for survey weights.

Results: The mean age of the population was 47 years, 52% were female, and 63% were white. Inter-rater agreement between two coders ranged from 68% to 86%. IARC classified the largest proportion of food and beverage items as highly processed/formulated, while IFIC classified the lowest. Across all systems, the top contributors to highly processed/formulated food intake were grain products; meat, poultry, fish, and mixtures; and sugars, sweets, and beverages. Greater intake of highly processed/formulated foods was consistently associated with younger age, White and Black race, lower education, and lower intake of protein, fiber, and several micronutrients. All systems linked greater highly processed/formulated food consumption to higher body mass index and elevated levels of log-transformed high-sensitivity C-reactive protein.

Conclusions: Despite differences in classification criteria across systems, associations with nutrients, sociodemographic, and cardiometabolic parameters were consistent. A standardized classification system is needed to ensure a unified understanding of ultra-processed food and its health implications.

Background: Although previous studies showed that heavy metal exposure and antioxidant micronutrient insufficiency were associated with cognitive impairment, their combined influence on cognitive function remain unclear.

Objectives: This study investigated the associations of blood lead, cadmium, selenium, erythrocyte folate, and serum 25(OH)D with cognitive performance and the interactions between heavy metals and micronutrients considered in a U.S. cross-sectional study.

Methods: Data from 2,858 participants aged ≥60 years in the National Health and Nutrition Examination Survey 2011-2014 were analyzed. Multivariable linear and logistic regression models were constructed to evaluate the main effects of heavy metals and micronutrients and their additive and multiplicative interactions on cognitive function.

Results: After adjustment for confounders, blood lead [β (95% CI): -1.67 (-3.32, -0.03)] and cadmium [-2.02 (-3.19, -0.85)] were inversely and serum 25(OH)D [2.23 (0.88, 3.59)] was positively associated with the Digit Symbol Substitution Test (DSST) score (a higher score indicating better cognitive function). Significant additive and multiplicative interactions between blood lead and erythrocyte folate, between blood lead and serum 25(OH)D, and between blood cadmium and erythrocyte folate in relation to low DSST score were detected. Compared with individuals in the first quartile of a weighted composite score of risk factors (defined as ≥median for 2 metals or

Conclusions: This study revealed that the neurodegenerative influence of heavy metals is more pronounced in individuals with lower micronutrient status. If the results of the present study are confirmed by future studies, reducing heavy metal exposure and improving micronutrient status may offer a novel and practical strategy for preventing cognitive decline and dementia.

Background: Folic acid (FA) fortification of cereal grains reduces the prevalence of folate insufficiency among adult females and related neural tube defects (NTDs) in their offspring. However, fortifiable cereal grains have limited reach in many lower-income countries, so additional fortification options need to be developed and evaluated.

Objectives: This study assessed the effects of folic acid fortification of iodized salt on women's discretionary salt intakes, biomarkers of folate and iodine status, and the occurrence of adverse events.

Methods: We conducted a community-based, three-arm, household-randomized dose-response trial among 360 non-pregnant Ethiopian females 18-49 years of age. We delivered iodized salts containing 32 parts per million (ppm) iodine and 99, 36, or 0 ppm FA to households bi-weekly for 26 weeks. We measured participants' fasting red blood cell (RBC) folate, serum folate, homocysteine, thyroglobulin, vitamin B12 biomarkers, glucose, and insulin, and urinary iodine/creatinine ratios before and during the intervention. We quantified participants' salt intakes using weighed food records, and we systematically recorded adverse events.

Results: The overall median (IQR) RBC folate concentration at baseline was 476 (371, 580) nmol/L. Participants' mean usual intakes of study salts (7.8±1.8 g/d) did not differ by study arm (p = 0.58). The final median (IQR) RBC folate concentrations were 1275 (1120, 1521) nmol/L, 1004 (819, 1212) nmol/L, and 468 (366, 596) nmol/L in the respective study arms (all significantly different, p<0.001). There were no group-wise differences in urinary iodine/creatinine ratios, serum thyroglobulin, insulin resistance, or reported adverse events.

Conclusions: FA fortification of salt is an effective and safe method to improve women's folate status and thereby reduce the risk of NTD-affected pregnancies.

Trial registration: This trial was registered on the ClinicalTrials.gov web site (registration number NCT06223854): https://clinicaltrials.gov/study/NCT06223854?term=Transcobalamin%20Deficiency&viewType=Table&rank=4.

Background: Early onset of puberty, often characterized by an accelerated linear growth spurt, is a recognized risk factor for a range of metabolic and cardiovascular conditions. While increased breastfeeding has been associated with later onset of puberty, the potential mediating role of pre-pubertal BMI in these associations remains poorly understood.

Objective: This study aims to examine the longitudinal associations of breastfeeding duration with adolescent growth parameters, including pubertal timing, and to assess whether pre-pubertal BMI mediates these associations.

Methods: Adolescent growth parameters were estimated from the height growth trajectories of 613 participants (312 females and 301 males) across six cohorts in the Environmental Influences on Child Health Outcomes Program. These parameters were derived by fitting the Preece-Baines growth model, a parametric growth curve fitted to longitudinal height data, in participants with at least three height measurements spanning the whole period of growth. Linear regression models were used to examine associations of breastfeeding duration with adolescent growth parameters. Mediation analysis was conducted to explore whether pre-pubertal BMI mediated the association between breastfeeding and pubertal timing.

Results: After adjusting for socioeconomic, maternal, and infant characteristics, children exclusively breastfed for at least three months reached age at peak velocity and age at maturation later than those who were not exclusively breastfed (β=0.32 years; 95% CI, 0.05-0.60, and β=0.30 years; 95% CI, 0.04-0.56, respectively). In adjusted models, each additional three months of any breastfeeding was associated with a later age at take-off (β=0.07 years; 95% CI, 0.00-0.15), and later age at peak velocity (β=0.11 years; 95% CI, 0.01-0.20). Pre-pubertal BMI did not significantly mediate these associations.

Conclusions: Exclusive breastfeeding and longer breastfeeding duration were associated with later onset of puberty in boys and girls. Pre-pubertal BMI did not mediate the observed associations.

Background: Excess sodium intake is a leading modifiable risk for non-communicable diseases. Despite some national sodium-reduction initiatives, no population-level updates to sodium-related KAB have been available since 2011.

Objective: To compare sodium-related KAB among Canadian adults in 2011 and 2024 and examine differences by sex and age, hypothesizing limited changes due to insufficient national sodium reduction initiatives.

Methods: Repeated cross-sectional national surveys were conducted in 2011 (n=2,603) and 2024 (n=3,267), readministering the same sodium KAB questions from the 2011 survey. Knowledge responses were coded as correct/incorrect, and 5-point Likert-scale items were recoded or dichotomized. Data were weighted to the Canadian Census. Rao-Scott adjusted χ², t-tests and regression models assessed changes over time, stratifying by sex and age.

Results: The proportion of adults actively limiting sodium intake declined from 57.4% in 2011 to 37.3% in 2024 (P < 0.001). Concurrently, engagement in nearly all sodium reduction behaviours decreased in 2024, including avoiding processed foods (69.3% to 52.3%), not adding salt at the table (69.2% to 58.1%), avoiding salt during cooking (62.3% to 43.4%) (all P < 0.001), and reading Nutrition Facts labels (54.2% to 49.6%, P = 0.005). Paradoxically, overall population sodium concern remained high and unchanged (66.3% to 65.9%, P = 0.812). Food label interpretation and awareness of recommended sodium intake improved (P < 0.001), but knowledge of health-related conditions linked to sodium such as blood pressure, heart disease and stroke decreased (all P < 0.001). Reported barriers to sodium reduction included cost, taste, time constraints, and lack of social support.

Conclusions: Many indices of sodium-related KAB deteriorated from 2011 to 2024 among Canadian adults, despite their continued concern about sodium intake. These findings highlight a widening knowledge-to-action gap and reinforce the need for comprehensive public health efforts to support population-wide dietary sodium reduction.

Background: Accurate methods for estimating resting energy expenditure (REE) are important to ensure adequate nutritional treatment in colorectal cancer (CRC) survivors.

Objective: To determine the agreement between REE estimated by commonly used predictive equations and by whole-room indirect calorimetry (WRIC).

Design: This cross-sectional study included 31 CRC survivors (age: 53-78 years; mean (standard deviation (SD)) body mass index (BMI) 28.7 (4.28) kg/m²), who underwent curative surgery. Body composition was measured by dual-energy x-ray absorptiometry (DXA). Predicted REE from equations in clinical use and derived from DXA and bioelectrical impedance analysis (BIA) were compared against REE measured by 30-min WRIC. Equations included Harris-Benedict, Mifflin-St. Jeor, FAO/WHO/UNU, Henry, Mifflin-St. Jeor_DXA, and FAO/WHO/UNU_BIA. Paired sample t-test, Lin's concordance correlation coefficient (CCC) and Bland-Altman analysis were used to determine the agreement between measured REE_WRIC and predicted REE. Accuracy was defined as the percentage of predicted REE values that fell within ± 10 % of REE_WRIC.

Results: Mean (SD) REE_WRIC was 1710 kcal/d (353), and respiratory quotient (RQ) was 0.79 (0.05). Most equations underestimated REE. On average, Harris-Benedict, Henry, and FAO/WHO/UNU_BIA showed the best overall agreement with REE_WRIC. However, these equations showed low accuracy with 65 %, 68 %, and 62 % of predicted REE values within ± 10 % of REE_WRIC, respectively.

Conclusions: Most predictive equations tended to underestimate REE in CRC survivors compared with REE_WRIC. The Harris-Benedict, Henry and FAO/WHO/UNU_BIA equations showed both best accuracy and agreement with WRIC. They were still inaccurate, with individual variability for a relevant part of the sample. Future studies need to develop improved predictive equations for CRC survivors.

Clinical trial registry number: https://clinicaltrials.gov/study/NCT01570010?locStr=Norway&country=Norway&cond=; Identifier: NCT01570010.