NAFLD, or metabolic dysfunction–associated steatotic liver disease, has increased in prevalence hand in hand with the rise in obesity and increased free sugars in the food supply. The causes of NAFLD are genetic in origin combined with environmental drivers of the disease phenotype. Dietary intake of added sugars has been shown to have a major role in the phenotypic onset and progression of the disease. Simple sugars are key drivers of steatosis, likely through fueling de novo lipogenesis, the conversion of excess carbohydrates into fatty acids, but also appear to upregulate lipogenic metabolism and trigger hyperinsulinemia, another driver. NAFLD carries a clinical burden as it is associated with obesity, type 2 diabetes, metabolic syndrome, and cardiovascular disease. Patient quality of life is also impacted, and there is an enormous economic burden due to healthcare use, which is likely to increase in the coming years. This review aims to discuss the role of dietary sugar in NAFLD pathogenesis, the health and economic burden, and the promising potential of sugar reduction to improve health outcomes for patients with this chronic liver disease.

Background: Metabolic dysfunction–associated steatotic liver disease (MASLD), formerly known as NAFLD, is the most common liver disease in children. Liver biopsy remains the gold standard for diagnosis, although more efficient screening methods are needed. We previously developed a novel NAFLD screening panel in youth using machine learning applied to high-resolution metabolomics and clinical phenotype data. Our objective was to validate this panel in a separate cohort, which consisted of a combined cross-sectional sample of 161 children with stored frozen samples (75% male, 12.8±2.6 years of age, body mass index 31.0±7.0 kg/m², 81% with MASLD, 58% Hispanic race/ethnicity). Methods: Clinical data were collected from all children, and high-resolution metabolomics was performed using their fasting serum samples. MASLD was assessed by MRI-proton density fat fraction or liver biopsy and cardiometabolic factors. Our previously developed panel included waist circumference, triglycerides, whole-body insulin sensitivity index, 3 amino acids, 2 phospholipids, dihydrothymine, and 2 unknowns. To improve feasibility, a simplified version without the unknowns was utilized in the present study. Since the panel was modified, the data were split into training (67%) and test (33%) sets to assess the validity of the panel. Results: Our present highest-performing modified model, with 4 clinical variables and 8 metabolomics features, achieved an AUROC of 0.92, 95% sensitivity, and 80% specificity for detecting MASLD in the test set. Conclusions: Therefore, this panel has promising potential for use as a screening tool for MASLD in youth.

Little is known about lipid changes that occur in the setting of metabolic-dysfunction-associated steatotic liver disease (MASLD) regression. We previously reported improvements in hepatic steatosis, de novo lipogenesis (DNL), and metabolomic profiles associated with oxidative stress, inflammation, and selected lipid metabolism in 40 adolescent boys (11–16 y) with hepatic steatosis ≥5% (98% meeting the definition of MASLD). Participants were randomized to a low-free-sugar diet (LFSD) (n = 20) or usual diet (n = 20) for 8 weeks. Here, we employed untargeted/targeted lipidomics to examine lipid adaptations associated with the LFSD and improvement of hepatic steatosis. Our LC-MS/MS analysis revealed decreased triglycerides (TGs), diacylglycerols (DGs), cholesteryl esters (ChE), lysophosphatidylcholine (LPC), and phosphatidylcholine (PC) species with the diet intervention (p < 0.05). Network analysis demonstrated significantly lower levels of palmitate-enriched TG species post-intervention, mirroring the previously shown reduction in DNL in response to the LFSD. Targeted oxylipins analysis revealed a decrease in the abundance of 8-isoprostane and 14,15-DiHET and an increase in 8,9-DiHET (p < 0.05). Overall, we observed reductions in TGs, DGs, ChE, PC, and LPC species among participants in the LFSD group. These same lipids have been associated with MASLD progression; therefore, our findings may indicate normalization of key biological processes, including lipid metabolism, insulin resistance, and lipotoxicity. Additionally, our targeted oxylipins assay revealed novel changes in eicosanoids, suggesting improvements in oxidative stress. Future studies are needed to elucidate the mechanisms of these findings and prospects of these lipids as biomarkers of MASLD regression.

Introduction Recently published studies support the beneficial effects of consuming fibre-rich legumes, such as cooked dry beans, to improve metabolic health and reduce cancer risk. In participants with overweight/obesity and a history of colorectal polyps, the Fibre-rich Foods to Treat Obesity and Prevent Colon Cancer randomised clinical trial will test whether a high-fibre diet featuring legumes will simultaneously facilitate weight reduction and suppress colonic mucosal biomarkers of colorectal cancer (CRC). Methods/design This study is designed to characterise changes in (1) body weight; (2) biomarkers of insulin resistance and systemic inflammation; (3) compositional and functional profiles of the faecal microbiome and metabolome; (4) mucosal biomarkers of CRC risk and (5) gut transit. Approximately 60 overweight or obese adults with a history of noncancerous adenomatous polyps within the previous 3 years will be recruited and randomised to one of two weight-loss diets. Following a 1-week run-in, participants in the intervention arm will receive preportioned high-fibre legume-rich entrées for two meals/day in months 1–3 and one meal/day in months 4–6. In the control arm, entrées will replace legumes with lean protein sources (eg, chicken). Both groups will receive in-person and written guidance to include nutritionally balanced sides with energy intake to lose 1–2 pounds per week. Ethics and dissemination The National Institutes of Health fund this ongoing 5-year study through a National Cancer Institute grant (5R01CA245063) awarded to Emory University with a subaward to the University of Pittsburgh. The study protocol was approved by the Emory Institutional Review Board (IRB approval number: 00000563). Trial registration number NCT04780477.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common liver disease worldwide, yet treatment remains “one size fits all,” despite phenotypic heterogeneity. We analyzed clinical and metabolomics data from 514 children (ages 5-18, 73% male) with biopsy-proven MASLD across three NASH Clinical Research Network studies. Unsupervised clustering of clinical data identified three distinct metabotypes: early-mild (49.4%, youngest, lowest lipids, liver enzymes, insulin resistance), cardiometabolic (36.8%, highest waist circumference, lipids, uric acid, SBP), and inflammatory-fibrotic (13.8%, highest liver enzymes, steatohepatitis, advanced fibrosis). Integrative network and pathway enrichment analyses revealed alterations in tryptophan metabolism within the inflammatory-fibrotic group, including elevated kynurenine pathway metabolites, which were significantly correlated with fibrosis stage. Branched-chain amino acid degradation, butanoate, and purine metabolism demonstrated greater enrichment in the cardiometabolic group. Here, we show that pediatric MASLD subtypes differ in clinical and metabolic features, providing a framework for targeted interventions, with validation needed in independent cohorts.

Plasma glutathione/glutathione disulfide (GSH/GSSG) and cysteine/cystine (Cys/CySS) redox couples undergo diurnal variation in adults and are more oxidized in obesity-related conditions, including metabolic dysfunction-associated steatotic liver disease (MASLD). There is limited research on redox in children and no data on redox responses to sugars, despite high sugar consumption in this population. This study aimed to describe the diurnal variation of redox couples in children, assess the impact of MASLD, and evaluate responses to fructose versus glucose beverages. In a 2-day randomized, controlled, crossover feeding study, 26 children (12 with MASLD, 14 controls; aged 10-18 years) consumed isocaloric meals with fructose beverages (FB) on one day and glucose beverages (GB) (set as control) on another, following a washout period. Blood was collected every 2 h over 24 h and analyzed for Cys/CySS and GSH/GSSG. Redox potentials, E_h(Cys/CySS) and E_h(GSH/GSSG), were calculated using the Nernst equation. Linear mixed models assessed diurnal variation and effects of MASLD and beverage type. Plasma E_h(GSH/GSSG) and E_h(CyS/CySS) varied significantly over time after both FB and GB (p < 0.05). With FB, E_h(GSH/GSSG) was significantly more oxidized in children with MASLD (p = 0.034); this was not observed with GB. Among children with MASLD, FB also led to greater E_h(GSH/GSSG) oxidation and lower GSH levels overnight (p < 0.05). While E_h(Cys/CySS) showed a similar trend, differences did not reach statistical significance. Our findings demonstrate that plasma redox states vary diurnally in children and are more oxidized in those with MASLD. Fructose intake increased oxidation of the GSH/GSSG redox couple and lowered GSH concentrations overnight, indicating heightened oxidative stress. These results identify fructose as a driver of redox imbalance in pediatric MASLD and support fructose reduction and glutathione restoration as therapeutic targets.