Consuming fructose-sweetened, not glucose-sweetened, beverages increases visceral adiposity and lipids and decreases insulin sensitivity in overweight/obese humans

MASH as an emerging cause of hepatocellular carcinoma: current knowledge and future perspectives

Hepatocellular carcinoma is one of the deadliest and fastest-growing cancers. Among HCC etiologies, metabolic dysfunction-associated fatty liver disease (MAFLD) has served as a major HCC driver due to its great potential for increasing cirrhosis. The obesogenic environment fosters a positive energy balance and results in a continuous rise of obesity and metabolic syndrome. However, it is difficult to understand how metabolic complications lead to the poor prognosis of liver diseases and which molecular mechanisms are underpinning MAFLD-driven HCC development. Thus, suitable preclinical models that recapitulate human etiologies are essentially required. Numerous preclinical models have been created but not many mimicked anthropometric measures and the course of disease progression shown in the patients. Here we review the literature on adipose tissues, liver-related HCC etiologies and recently discovered genetic mutation signatures found in MAFLD-driven HCC patients. We also critically review current rodent models suggested for MAFLD-driven HCC study.

Beyond Obesity and Overweight: The Clinical Assessment and Treatment of Excess Body Fat in Children : Part 1 - Insulin Resistance as the Root Cause of Pediatric Obesity

PURPOSE OF REVIEW

Pediatric obesity and comorbidities related to insulin resistance continue to be a growing public health crisis. If lifestyle measures are unsuccessful, pharmacological and surgical interventions are offered. In this paper, we describe the driving force of the obesity crisis: hyperinsulinemia and the development of insulin resistance. We give historical background of key policy issues which have contributed to this pandemic as well as the physiologic mechanisms of insulin resistance. The prevalence of obesity will continue to rise unless the root cause of hyperinsulinemia is addressed.

RECENT FINDINGS

Current research on insulin resistance demonstrates that a decreased consumption of carbohydrates is an effective first-line dietary intervention for the treatment of obesity and related metabolic diseases. Evidence shows it is safe and beneficial. A low-carbohydrate eating pattern can be helpful to address pediatric obesity. However, there must be policy guardrails in place to ensure that this is a sustainable and viable option for children and their families. There must be a change in the nutritional environment to help individuals battle the chronic disease of obesity.

Effects of dietary sugar restriction on hepatic fat in youth with obesity

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease in children. Like adults, children can develop the progressive form of NAFLD, nonalcoholic steatohepatitis (NASH), which is characterized by hepatic inflammation, often in the presence of fibrosis. Children with NAFLD are at higher risk of liver-related complications, metabolic dysfunction, and cardiovascular disease in adulthood. Many factors contribute to the escalating prevalence of NAFLD in the pediatric population, among which are an array of dietary patterns such as overnutrition, poor diet quality, and heavy consumption of fat and sugar, including fructose. Findings from an increasing number of epidemiological studies support a connection between high habitual sugar consumption and NAFLD, especially within the context of obesity, but these studies are not able to demonstrate whether sugar is a contributing factor or instead an indicator of an overall poor diet (or lifestyle) quality. To date, only four randomized controlled dietary interventions assessing the effects of sucrose/fructose restriction on hepatic fat fraction in youth with obesity have been published. The objectives of this review are to summarize the key findings from these dietary interventions to achieve a better understanding of the strength of the relationship between dietary sugar restriction and liver fat reduction, despite their inherent limitations, and to discuss the potential impact of weight loss and fat mass reduction on improvement in hepatic steatosis.

Intake of Sugar and Food Sources of Sugar and Colorectal Cancer Risk in the Multiethnic Cohort Study

BACKGROUND

The influence of sugar intake on the risk of colorectal cancer (CRC) remains controversial, and there is a need to investigate the heterogeneity of effects among racial and ethnic groups.

OBJECTIVES

To examine the association of intake of simple sugars and their food sources with CRC risk according to race/ethnicity in a Multiethnic Cohort Study.

METHODS

We analyzed data from 192,651 participants who participated in the Multiethnic Cohort Study comprising African-American, Japanese American, Latino, Native Hawaiian, and White older adults living in Hawaii and California with an average follow-up of 19 y. Intakes of total and specific types of sugars and sugary foods were estimated from a quantitative food frequency questionnaire completed by the participants in 1993-1996. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for CRC risk according to quintiles (Q) of sugar and food intakes using Cox models adjusted for potential confounders.

RESULTS

As of December 2017, 4403 incident CRC cases were identified. Among all participants, multivariable-adjusted CRC HRs for Q2, Q3, Q4, and Q5 compared with Q1 for total sugars were 1.03 (95% CI: 0.94, 1.13), 1.05 (95% CI: 0.96, 1.16), 1.12 (95% CI: 1.01, 1.24), and 1.13 (95% CI: 1.01, 1.27), respectively. A similar positive association was observed for total fructose, glucose, fructose, and maltose but not for added sugars and sugary foods. The increased risk appeared to be limited to colon cancer and to be strongest among younger participants (i.e., 45-54 y at baseline); an association with CRC was observed for sugar-sweetened beverages in the latter group. Among racial and ethnic groups, increased risk of CRC was most apparent in Latinos.

CONCLUSIONS

In this diverse cohort, intakes of total sugar, total fructose, glucose, fructose, and maltose were associated with an increased risk of CRC, and the association was strongest for colon cancer, younger participants, and Latinos.

Synergistic Amelioration of Letrozole-induced Polycystic Ovary Syndrome in Rats: A Therapeutic Approach with Apple Cider Vinegar and Metformin Combination

The present study was conducted to evaluate the combination effect of apple cider vinegar (ACV) and metformin against letrozole-induced polycystic ovary syndrome (PCOS). Female Wistar rats were administered letrozole (1 mg/kg/day, p.o) for 21 days, except for the control group of animals. On the 22nd day, PCOS-induced animals were segregated into 4 groups and administered with CMC, ACV, metformin, and a combination of ACV and metformin, respectively. The treatments were continued for 15 days, and on the 36th day, all the animals were sacrificed for biochemical (blood glucose, lipid profile), hormonal (sex hormones and adiponectin), and pro-inflammatory mediator estimations in blood samples. The ovarian tissue samples were used for oxidative stress parameters and histological alterations. The PCOS control animals showed a significant alteration in the estrous cycle. The administration of letrozole resulted in the alteration of hormonal balance and elevation of body weights, glycemic state, lipid profile, pro-inflammatory mediators in serum, and oxidative stress in ovarian samples. Individual treatment groups and combination treatment groups reversed the letrozole-induced alterations in PCOS animals, and more promising results were observed with combination therapy than with individual treatment groups. Further, the therapeutic potential of the combination treatment group was also confirmed by the histological observations in the ovarian samples. The study showed that the combination of ACV and metformin significantly alleviated letrozole-induced PCOS complications in rats. This might have been achieved by mitigating the hormonal imbalance, pro-inflammatory, hyperglycemic, and hyperlipidemic states in serum, and oxidative stress in the ovary samples.

Lutein and Zeaxanthin Enhance, Whereas Oxidation, Fructosylation, and Low pH Damage High-Density Lipoprotein Biological Functionality

High-density lipoproteins (HDLs) are key regulators of cellular cholesterol homeostasis but are functionally altered in many chronic diseases. The factors that cause HDL functional loss in chronic disease are not fully understood. It is also unknown what roles antioxidant carotenoids play in protecting HDL against functional loss. The aim of this study was to measure how various disease-associated chemical factors including exposure to (1) Cu2+ ions, (2) hypochlorous acid (HOCL), (3) hydrogen peroxide (H2O2), (4) sialidase, (5) glycosidase, (6) high glucose, (7) high fructose, and (8) acidic pH, and the carotenoid antioxidants (9) lutein and (10) zeaxanthin affect HDL functionality. We hypothesized that some of the modifications would have stronger impacts on HDL particle structure and function than others and that lutein and zeaxanthin would improve HDL function. HDL samples were isolated from generally healthy human plasma and incubated with the corresponding treatments listed above. Cholesterol efflux capacity (CEC), lecithin-cholesterol acyl transferase (LCAT) activity, and paraoxonase-1 (PON1) activity were measured in order to determine changes in HDL functionality. Median HDL particle diameter was increased by acidic pH treatment and reduced by HOCl, high glucose, high fructose, N-glycosidase, and lutein treatments. Acidic pH, oxidation, and fructosylation all reduced HDL CEC, whereas lutein, zeaxanthin, and sialidase treatment improved HDL CEC. LCAT activity was reduced by acidic pH, oxidation, high fructose treatments, and lutein. PON1 activity was reduced by sialidase, glycosidase, H2O2, and fructose and improved by zeaxanthin and lutein treatment. These results show that exposure to oxidizing agents, high fructose, and low pH directly impairs HDL functionality related to cholesterol efflux and particle maturation, whereas deglycosylation impairs HDL antioxidant capacity. On the other hand, the antioxidants lutein and zeaxanthin improve or preserve both HDL cholesterol efflux and antioxidant activity but have no effect on particle maturation.

Is stimulation of browning of human adipose tissue a relevant therapeutic target?

Brown adipose tissue (BAT) and beige adipose tissues are important contributors to cold-induced whole body thermogenesis in rodents. The documentation in humans of cold- and ß-adrenergic receptor agonist-stimulated BAT glucose uptake using positron emission tomography (PET) and of a decrease of this response in individuals with cardiometabolic disorders led to the suggestion that BAT/beige adipose tissues could be relevant targets for prevention and treatment of these conditions. In this brief review, we will critically assess this question by first describing the basic rationale for this affirmation, second by examining the evidence in human studies, and third by discussing the possible means to activate the thermogenic response of these tissues in humans.

Sex-dependent adipose glucose partitioning by the mitochondrial pyruvate carrier

Objective

The mitochondrial pyruvate carrier (MPC) occupies a critical node in intermediary metabolism, prompting interest in its utility as a therapeutic target for the treatment of obesity and cardiometabolic disease. Dysregulated nutrient metabolism in adipose tissue is a prominent feature of obesity pathophysiology, yet the functional role of adipose MPC has not been explored. We investigated whether the MPC shapes the adaptation of adipose tissue to dietary stress in female and male mice.

Methods

The impact of pharmacological and genetic disruption of the MPC on mitochondrial pathways of triglyceride assembly (lipogenesis and glyceroneogenesis) was assessed in 3T3L1 adipocytes and murine adipose explants, combined with analyses of adipose MPC expression in metabolically compromised humans. Whole-body and adipose-specific glucose metabolism were subsequently investigated in male and female mice lacking adipocyte MPC1 (Mpc1AD-/-) and fed either standard chow, high-fat western style, or high-sucrose lipid restricted diets for 24 weeks, using a combination of radiolabeled tracers and GC/MS metabolomics.

Results

Treatment with UK5099 or siMPC1 impaired the synthesis of lipids and glycerol-3-phosphate from pyruvate and blunted triglyceride accumulation in 3T3L1 adipocytes, whilst MPC expression in human adipose tissue was negatively correlated with indices of whole-body and adipose tissue metabolic dysfunction. Mature adipose explants from Mpc1AD-/- mice were intrinsically incapable of incorporating pyruvate into triglycerides. In vivo, MPC deletion restricted the incorporation of circulating glucose into adipose triglycerides, but only in female mice fed a zero fat diet, and this associated with sex-specific reductions in tricarboxylic acid cycle pool sizes and compensatory transcriptional changes in lipogenic and glycerol metabolism pathways. However, whole-body adiposity and metabolic health were preserved in Mpc1AD-/- mice regardless of sex, even under conditions of zero dietary fat.

Conclusion

These findings highlight the greater capacity for mitochondrially driven triglyceride assembly in adipose from female versus male mice and expose a reliance upon MPC-gated metabolism for glucose partitioning in female adipose under conditions of dietary lipid restriction.

Hepatic steatosis induced by nicotine plus Coca-Cola™ is prevented by nicotinamide riboside (NR)

Introduction

Cigarettes containing nicotine (Nic) are a risk factor for the development of cardiovascular and metabolic diseases. We reported that Nic delivered via injections or e-cigarette vapor led to hepatic steatosis in mice fed with a high-fat diet. High-fructose corn syrup (HFCS) is the main sweetener in sugar-sweetened beverages (SSBs) in the US. Increased consumption of SSBs with HFCS is associated with increased risks of non-alcoholic fatty liver disease (NAFLD). Nicotinamide riboside (NR) increases mitochondrial nicotinamide adenine dinucleotide (NAD+) and protects mice against hepatic steatosis. This study evaluated if Nic plus Coca-Cola™ (Coke) with HFCS can cause hepatic steatosis and that can be protected by NR.

Methods

C57BL/6J mice received twice daily intraperitoneal (IP) injections of Nic or saline and were given Coke (HFCS), or Coke with sugar, and NR supplementation for 10 weeks.

Results

Our results show that Nic+Coke caused increased caloric intake and induced hepatic steatosis, and the addition of NR prevented these changes. Western blot analysis showed lipogenesis markers were activated (increased cleavage of the sterol regulatory element-binding protein 1 [SREBP1c] and reduction of phospho-Acetyl-CoA Carboxylase [p-ACC]) in the Nic+Coke compared to the Sal+Water group. The hepatic detrimental effects of Nic+Coke were mediated by decreased NAD+ signaling, increased oxidative stress, and mitochondrial damage. NR reduced oxidative stress and prevented mitochondrial damage by restoring protein levels of Sirtuin1 (Sirt1) and peroxisome proliferator-activated receptor coactivator 1-alpha (PGC1) signaling.

Conclusion

We conclude that Nic+Coke has an additive effect on producing hepatic steatosis, and NR is protective. This study suggests concern for the development of NAFLD in subjects who consume nicotine and drink SSBs with HFCS.

Piloting a brief assessment to capture consumption of whole plant food and water: version 1.0 of the American College of Lifestyle Medicine Diet Screener (ACLM Diet Screener)

Background

Despite the availability of various dietary assessment tools, there is a need for a tool aligned with the needs of lifestyle medicine (LM) physicians. Such a tool would be brief, aimed at use in a clinical setting, and focused on a "food as medicine" approach consistent with recommendations for a diet based predominately on whole plant foods. The objective of this study is to describe the development and initial pilot testing of a brief, dietary screener to assess the proportion of whole, unrefined plant foods and water relative to total food and beverage intake.

Methods

A multidisciplinary study team led the screener development, providing input on the design and food/beverage items included, and existing published dietary assessment tools were reviewed for relevance. Feedback was solicited from LM practitioners in the form of a cross-sectional survey that captured information on medical practice, barriers, and needs in assessing patients' diets, in addition to an opportunity to complete the screener and provide feedback on its utility. The study team assessed feedback and revised the screener accordingly, which included seeking and incorporating feedback on additional food items to be included from subject matter experts in specific cultural and ethnic groups in the United States. The final screener was submitted for professional design, and scoring was developed.

Results

Of 539 total participants, the majority reported assessing diet either informally (62%) or formally (26%) during patient encounters, and 73% reported discussing diet with all or most of their patients. Participants also reported facing barriers (80%) to assessing diet. Eighty-eight percent believed the screener was quick enough to use in a clinical setting, and 68% reported they would use it.

Conclusion

The ACLM Diet Screener was developed through iterative review and pilot testing. The screener is a brief, 27-item diet assessment tool that can be successfully used in clinical settings to track patient dietary intakes, guide clinical conversations, and support nutrition prescriptions. Pilot testing of the screener found strong alignment with clinician needs for assessing a patient's intake of whole plant food and water relative to the overall diet. Future research will involve pilot testing the screener in clinical interventions and conducting a validation study to establish construct validity.

Metabolic Syndrome and Biotherapeutic Activity of Dairy (Cow and Buffalo) Milk Proteins and Peptides: Fast Food-Induced Obesity Perspective-A Narrative Review

Metabolic syndrome (MS) is defined by the outcome of interconnected metabolic factors that directly increase the prevalence of obesity and other metabolic diseases. Currently, obesity is considered one of the most relevant topics of discussion because an epidemic heave of the incidence of obesity in both developing and underdeveloped countries has been reached. According to the World Obesity Atlas 2023 report, 38% of the world population are presently either obese or overweight. One of the causes of obesity is an imbalance of energy intake and energy expenditure, where nutritional imbalance due to consumption of high-calorie fast foods play a pivotal role. The dynamic interactions among different risk factors of obesity are highly complex; however, the underpinnings of hyperglycemia and dyslipidemia for obesity incidence are recognized. Fast foods, primarily composed of soluble carbohydrates, non-nutritive artificial sweeteners, saturated fats, and complexes of macronutrients (protein-carbohydrate, starch-lipid, starch-lipid-protein) provide high metabolic calories. Several experimental studies have pointed out that dairy proteins and peptides may modulate the activities of risk factors of obesity. To justify the results precisely, peptides from dairy milk proteins were synthesized under in vitro conditions and their contributions to biomarkers of obesity were assessed. Comprehensive information about the impact of proteins and peptides from dairy milks on fast food-induced obesity is presented in this narrative review article.

Fructose overconsumption accelerates renal dysfunction with aberrant glomerular endothelial-mesangial cell interactions in db/db mice

For the advancement of DKD treatment, identifying unrecognized residual risk factors is essential. We explored the impact of obesity diversity derived from different carbohydrate qualities, with an emphasis on the increasing trend of excessive fructose consumption and its effect on DKD progression. In this study, we utilized db/db mice to establish a novel diabetic model characterized by fructose overconsumption, aiming to uncover the underlying mechanisms of renal damage. Compared to the control diet group, the fructose-fed db/db mice exhibited more pronounced obesity yet demonstrated milder glucose intolerance. Plasma cystatin C levels were elevated in the fructose model compared to the control, and this elevation was accompanied by enhanced glomerular sclerosis, even though albuminuria levels and tubular lesions were comparable. Single-cell RNA sequencing of the whole kidney highlighted an increase in Lrg1 in glomerular endothelial cells (GECs) in the fructose model, which appeared to drive mesangial fibrosis through enhanced TGF-β1 signaling. Our findings suggest that excessive fructose intake exacerbates diabetic kidney disease progression, mediated by aberrant Lrg1-driven crosstalk between GECs and mesangial cells.

Visceral Adipose Tissue: The Hidden Culprit for Type 2 Diabetes

Type 2 diabetes (T2D) is a chronic metabolic disorder characterized by insulin resistance in various tissues. Though conventionally associated with obesity, current research indicates that visceral adipose tissue (VAT) is the leading determining factor, wielding more influence regardless of individual body mass. The heightened metabolic activity of VAT encourages the circulation of free fatty acid (FFA) molecules, which induce insulin resistance in surrounding tissues. Individuals most vulnerable to this preferential fat deposition are older males with ancestral ties to Asian countries because genetics and sex hormones are pivotal factors for VAT accumulation. However, interventions in one's diet and lifestyle have the potential to strategically discourage the growth of VAT. This illuminates the possibility that the expansion of VAT and, subsequently, the risk of T2D development are preventable. Therefore, by reducing the amount of VAT accumulated in an individual and preventing it from building up, one can effectively control and prevent the development of T2D.

A preconception cohort study of sugar-sweetened beverage consumption and semen quality

BACKGROUND

Dietary factors, including high sugar intake, may have adverse effects on male reproduction. Studies of the association between sugar-sweetened beverage (SSB) intake and semen quality have reported inconsistent results.

OBJECTIVE

We estimated the effects of SSB consumption on semen quality in a North American preconception cohort study.

METHODS

We analyzed baseline data from 690 males (n = 1,247 samples) participating in Pregnancy Study Online (PRESTO) during 2015-2022. Participants aged ≥21 years completed a baseline questionnaire on which they reported information about intake of SSBs, including sodas, energy drinks, sports drinks, and fruit juices. After enrollment, we invited U.S. participants to a semen testing substudy, in which they collected and analyzed two samples using an at-home semen testing kit. We used linear regression models to estimate adjusted percent differences (%D) and 95% confidence intervals (CI) for associations of SSB intake with semen volume, sperm concentration, total sperm count (TSC), motility, and total motile sperm count (TMSC). We used modified Poisson regression models to estimate adjusted risk ratios (RRs) and 95% CIs for the association of SSB intake with World Health Organization semen parameter cut points.

RESULTS

Relative to non-consumers of SSBs, those who consumed ≥7 SSBs/week had lower semen volume (%D = -6, 95% CI: -13, 0), sperm concentration (%D = -22, 95% CI: -38, 0), TSC (%D = -22, 95% CI: -38, -2), motility (%D = -4, 95% CI: -10, 2), and TMSC (%D = -25, 95% CI: -43, -2). High SSB consumers also had greater risks of low sperm concentration (≤16 million/mL; RR = 1.89, 95% CI: 1.11, 3.21), low TSC (≤39 million; RR = 1.75, 95% CI: 0.92, 3.33), low motility (≤42%; RR = 1.23, 95% CI: 0.87, 1.75) and low TMSC (≤21 million; RR = 1.95, 95% CI: 1.12, 3.38). Associations were stronger among participants with body mass index ≥ 25 kg/m2 .

CONCLUSION

Greater SSB consumption was associated with reduced semen quality in a North American preconception cohort.

Liver fibrosis pathologies and potentials of RNA based therapeutics modalities

Liver fibrosis (LF) occurs when the liver tissue responds to injury or inflammation by producing excessive amounts of scar tissue, known as the extracellular matrix. This buildup stiffens the liver tissue, hinders blood flow, and ultimately impairs liver function. Various factors can trigger this process, including bloodborne pathogens, genetic predisposition, alcohol abuse, non-steroidal anti-inflammatory drugs, non-alcoholic steatohepatitis, and non-alcoholic fatty liver disease. While some existing small-molecule therapies offer limited benefits, there is a pressing need for more effective treatments that can truly cure LF. RNA therapeutics have emerged as a promising approach, as they can potentially downregulate cytokine levels in cells responsible for liver fibrosis. Researchers are actively exploring various RNA-based therapeutics, such as mRNA, siRNA, miRNA, lncRNA, and oligonucleotides, to assess their efficacy in animal models. Furthermore, targeted drug delivery systems hold immense potential in this field. By utilizing lipid nanoparticles, exosomes, nanocomplexes, micelles, and polymeric nanoparticles, researchers aim to deliver therapeutic agents directly to specific biomarkers or cytokines within the fibrotic liver, increasing their effectiveness and reducing side effects. In conclusion, this review highlights the complex nature of liver fibrosis, its underlying causes, and the promising potential of RNA-based therapeutics and targeted delivery systems. Continued research in these areas could lead to the development of more effective and personalized treatment options for LF patients.

The impact of taxing sugar-sweetened beverages on diabetes: a critical review

The global burden of type 2 diabetes is increasing at an alarming rate, fuelled by the obesity epidemic, with significant associated health and economic consequences and apparent inequalities. Sugar-sweetened beverages (SSBs) are a major source of added sugars in diets worldwide and have been linked to an increased risk of type 2 diabetes through a variety of mechanisms, including excess weight. Taxing SSBs has become a promising public health strategy to reduce consumption and mitigate the burden of type 2 diabetes. A substantial body of evidence suggests that SSB taxes lead to increased prices and subsequent reduced consumption, with a potentially greater effect among lower socioeconomic groups. This highlights the potential for tax policies to have an impact on type 2 diabetes and address health inequalities. Evidence from several ongoing SSB tax schemes, including sales and excise taxes, indicates positive effects on improving consumption patterns, and modelling studies point to health gains by averting type 2 diabetes and other cardiometabolic diseases. In contrast, evidence from empirical evaluation of the impact of SSB tax is scarce. Continued monitoring and the strengthening of evaluation research to develop context-tailored policies are required. In addition, there is a need to implement complementary efforts to amplify the impact of SSB taxation and effectively address the global burden of type 2 diabetes.

Acylation stimulating protein/C3adesArg in the metabolic states: role of adipocyte dysfunction in obesity complications

Adipose tissue, as an endocrine organ, secretes several adipocyte-derived hormones named 'adipokines' that are implicated in regulating energy haemostasis. Substantial evidence shows that white adipose tissue-derived adipokines mediate the link between obesity-related exogenous factors (like diet and lifestyle) and various biological events (such as pre- and postmenopausal status) that have obesity consequences (cardiometabolic disorders). One of the critical aetiological factors for obesity-related diseases is the dysfunction of adipokine pathways. Acylation-stimulating protein (ASP) is an adipokine that stimulates triglyceride synthesis and storage in adipose tissue by enhancing glucose and fatty acid uptake. ASP acts via its receptor C5L2. The primary objective of this review is to address the existing gap in the literature regarding ASP by investigating its diverse responses and receptor interactions across multiple determinants of obesity. These determinants include diet composition, metabolic disorders, organ involvement, sex and sex hormone levels. Furthermore, this article explores the broader paradigm shift from solely focusing on adipose tissue mass, which contributes to obesity, to considering the broader implications of adipose tissue function. Additionally, we raise a critical question concerning the clinical relevance of the insights gained from this review, both in terms of potential therapeutic interventions targeting ASP and in the context of preventing obesity-related conditions, highlighting the potential of the ASP-C5L2 interaction as a pharmacological target. In conclusion, these findings validate that obesity is a low-grade inflammatory status with multiorgan involvement and sex differences, demonstrating dynamic interactions between immune and metabolic response determinants.

Metabolic Effects of Selected Conventional and Alternative Sweeteners: A Narrative Review

Sugar consumption is known to be associated with a whole range of adverse health effects, including overweight status and type II diabetes mellitus. In 2015, the World Health Organization issued a guideline recommending the reduction of sugar intake. In this context, alternative sweeteners have gained interest as sugar substitutes to achieve this goal without loss of the sweet taste. This review aims to provide an overview of the scientific literature and establish a reference tool for selected conventional sweeteners (sucrose, glucose, and fructose) and alternative sweeteners (sucralose, xylitol, erythritol, and D-allulose), specifically focusing on their important metabolic effects. The results show that alternative sweeteners constitute a diverse group, and each substance exhibits one or more metabolic effects. Therefore, no sweetener can be considered to be inert. Additionally, xylitol, erythritol, and D-allulose seem promising as alternative sweeteners due to favorable metabolic outcomes. These alternative sweeteners replicate the benefits of sugars (e.g., sweetness and gastrointestinal hormone release) while circumventing the detrimental effects of these substances on human health.

Effect of various dietary fructose concentrations on the gallstone formation process in mice

Introduction

Background: little information is availaible on the effect of fructose on bile lipids. The first stage in the formation of gallstones corresponds to biliary cholesterol crystallization, derived from the vesicular transporters. The aim of this study was to investigate the influence of consuming diets with different fructose concentrations on serum lipids and their implications on gallstones formation. Methods: BALB/c mice divided into a control group as well as groups were treated with different fructose concentrations (10 %, 30 %, 50 % or 70 %) for different periods (1, 2 or 5 months). Blood, liver and bile samples were obtained. In bile samples, cholesterol and phospholipids levels were analyzed, and cholesterol transporters (vesicles and micelles) were separated by gel filtration chromatography. Results: treated animals showed: 1) increases in body weight similar to the control group; 2) a significant increase in plasma triglycerides only at very high fructose concentrations; 3) a significant increase in total serum cholesterol in the treatment for 1 month; 4) no variations in HDL-cholesterol; 5) a significant increase in serum glucose only at very high fructose concentrations in the second month of treatment; 6) no differences in the plasma alanine-aminotransferase activity; 7) a significant increase in liver triglyceride levels only at very high fructose concentrations; 8) no change in biliary lipid concentrations or in micellar and vesicular phospholipids. Conclusion: changes in plasma, liver and bile lipids were only observed at very high fructose concentrations diets. We conclude that fructose apparently does not alter the gallstone formation process in our experimental model.

Association between higher duodenal levels of the fructose carrier glucose transporter-5 and nonalcoholic fatty liver disease and liver fibrosis

BACKGROUND

An increased dietary fructose intake has been shown to exert several detrimental metabolic effects and contribute to the pathogenesis of nonalcoholic fatty liver disease (NAFLD). An augmented intestinal abundance of the fructose carriers glucose transporter-5 (GLUT-5) and glucose transporter-2 (GLUT-2) has been found in subjects with obesity and type 2 diabetes. Herein, we investigated whether elevated intestinal levels of GLUT-5 and GLUT-2, resulting in a higher dietary fructose uptake, are associated with NAFLD and its severity.

METHODS

GLUT-5 and GLUT-2 protein levels were assessed on duodenal mucosa biopsies of 31 subjects divided into 2 groups based on ultrasound-defined NAFLD presence who underwent an upper gastrointestinal endoscopy.

RESULTS

Individuals with NAFLD exhibited increased duodenal GLUT-5 protein levels in comparison to those without NAFLD, independently of demographic and anthropometric confounders. Conversely, no difference in duodenal GLUT-2 abundance was observed amongst the two groups. Univariate correlation analyses showed that GLUT-5 protein levels were positively related with body mass index, waist circumference, fasting and 2 h post-load insulin concentrations, and insulin resistance (IR) degree estimated by homeostatic model assessment of IR (r = 0.44; p = 0.02) and liver IR (r = 0.46; p = 0.03) indexes. Furthermore, a positive relationship was observed between duodenal GLUT-5 abundance and serum uric acid concentrations (r = 0.40; p = 0.05), a product of fructose metabolism implicated in NAFLD progression. Importantly, duodenal levels of GLUT-5 were positively associated with liver fibrosis risk estimated by NAFLD fibrosis score.

CONCLUSION

Increased duodenal GLUT-5 levels are associated with NAFLD and liver fibrosis. Inhibition of intestinal GLUT-5-mediated fructose uptake may represent a strategy for prevention and treatment of NAFLD.

Effects of Consuming Beverages Sweetened with Fructose, Glucose, High-Fructose Corn Syrup, Sucrose, or Aspartame on OGTT-Derived Indices of Insulin Sensitivity in Young Adults

(1) Background: Clinical results on the effects of excess sugar consumption on insulin sensitivity are conflicting, possibly due to differences in sugar type and the insulin sensitivity index (ISI) assessed. Therefore, we compared the effects of consuming four different sugars on insulin sensitivity indices derived from oral glucose tolerance tests (OGTT). (2) Methods: Young adults consumed fructose-, glucose-, high-fructose corn syrup (HFCS)-, sucrose-, or aspartame-sweetened beverages (SB) for 2 weeks. Participants underwent OGTT before and at the end of the intervention. Fasting glucose and insulin, Homeostatic Model Assessment-Insulin Resistance (HOMA-IR), glucose and insulin area under the curve, Surrogate Hepatic Insulin Resistance Index, Matsuda ISI, Predicted M ISI, and Stumvoll Index were assessed. Outcomes were analyzed to determine: (1) effects of the five SB; (2) effects of the proportions of fructose and glucose in all SB. (3) Results: Fructose-SB and the fructose component in mixed sugars negatively affected outcomes that assess hepatic insulin sensitivity, while glucose did not. The effects of glucose-SB and the glucose component in mixed sugar on muscle insulin sensitivity were more negative than those of fructose. (4) Conclusion: the effects of consuming sugar-SB on insulin sensitivity varied depending on type of sugar and ISI index because outcomes assessing hepatic insulin sensitivity were negatively affected by fructose, and outcomes assessing muscle insulin sensitivity were more negatively affected by glucose.

Current Perspectives: Obesity and Neurodegeneration - Links and Risks

Obesity is increasing in prevalence across all age groups. Long-term obesity can lead to the development of metabolic and cardiovascular diseases through its effects on adipose, skeletal muscle, and liver tissue. Pathological mechanisms associated with obesity include immune response and inflammation as well as oxidative stress and consequent endothelial and mitochondrial dysfunction. Recent evidence links obesity to diminished brain health and neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). Both AD and PD are associated with insulin resistance, an underlying syndrome of obesity. Despite these links, causative mechanism(s) resulting in neurodegenerative disease remain unclear. This review discusses relationships between obesity, AD, and PD, including clinical and preclinical findings. The review then briefly explores nonpharmacological directions for intervention.

Longitudinal Associations of Dietary Fructose, Sodium, and Potassium and Psychological Stress with Vascular Aging Index and Incident Cardiovascular Disease in the CARDIA Cohort

We explored how dietary behaviors (sucrose, fructose, sodium, and potassium consumption) and endured psychological stress in young adult males and females impact the vascular aging index (VAI) and CVD risk by mid-life. Data were obtained from the Coronary Artery Risk Development in Young Adults Study, an ongoing longitudinal study. The included participants (n = 2656) had undergone carotid artery ultrasound at year 20 allowing VAIs to be calculated. Demographics, dietary data, and depression scores were obtained at baseline and year 20 of follow-up. Regression analyses were used to assess the predictors of VAI. Cox regression analyses were conducted to assess the risk of CVD, stroke, and all-cause mortality. Predictors of vascular aging were found to be sex-specific. In females, depression scores at baseline were positively associated with VAI (B-weight = 0.063, p = 0.015). In males, sodium intake at year 20 positively predicted VAI (B-weight = 0.145, p = 0.003) and potassium intake inversely predicted VAI (B-weight = -0.160, p < 0.001). BMI significantly predicted CVD, stroke, and death. Fructose consumption at year 20 was a significant predictor of CVD risk while having high blood pressure at baseline was significantly associated with stroke risk. Our findings support the promotion of nutrient-specific behavior changes to prevent vascular aging in early adulthood and CVD risk in mid-life.

Lipid Metabolism in Metabolic-Associated Steatotic Liver Disease (MASLD)

Metabolic-associated steatotic liver disease (MASLD) is a cluster of pathological conditions primarily developed due to the accumulation of ectopic fat in the hepatocytes. During the severe form of the disease, i.e., metabolic-associated steatohepatitis (MASH), accumulated lipids promote lipotoxicity, resulting in cellular inflammation, oxidative stress, and hepatocellular ballooning. If left untreated, the advanced form of the disease progresses to fibrosis of the tissue, resulting in irreversible hepatic cirrhosis or the development of hepatocellular carcinoma. Although numerous mechanisms have been identified as significant contributors to the development and advancement of MASLD, altered lipid metabolism continues to stand out as a major factor contributing to the disease. This paper briefly discusses the dysregulation in lipid metabolism during various stages of MASLD.

Fructose: a modulator of intestinal barrier function and hepatic health?

PURPOSE

Consumption of fructose has repeatedly been discussed to be a key factor in the development of health disturbances such as hypertension, diabetes type 2, and non-alcoholic fatty liver disease. Despite intense research efforts, the question if and how high dietary fructose intake interferes with human health has not yet been fully answered.

RESULTS

Studies suggest that besides its insulin-independent metabolism dietary fructose may also impact intestinal homeostasis and barrier function. Indeed, it has been suggested by the results of human and animal as well as in vitro studies that fructose enriched diets may alter intestinal microbiota composition. Furthermore, studies have also shown that both acute and chronic intake of fructose may lead to an increased formation of nitric oxide and a loss of tight junction proteins in small intestinal tissue. These alterations have been related to an increased translocation of pathogen-associated molecular patterns (PAMPs) like bacterial endotoxin and an induction of dependent signaling cascades in the liver but also other tissues.

CONCLUSION

In the present narrative review, results of studies assessing the effects of fructose on intestinal barrier function and their impact on the development of health disturbances with a particular focus on the liver are summarized and discussed.

Charting the Chronology of Research on Added Sugars: A Scoping Review and Evidence Map

The objective of this study was to conduct a scoping review and produce a publicly available database characterizing the design and reporting elements of the literature on dietary added sugars and select health outcomes. Relevant studies published from 1990 to 2021 were identified to create a database containing information on study and population characteristics, reported added sugars source and concentrations, dietary energy balance, total energy intake, and outcome measures related to body composition, obesity, cardiovascular disease, and diabetes mellitus. There were 245 publications identified, 22% of which describe interventions, and 78% describe observational studies. Publications pertaining to added sugars have risen dramatically since 2010, led by studies primarily assessing body composition (36%) or cardiovascular health (32%), including adults (65%), measuring liquid-only sources of added sugars (56%). Over 65% of studies reported total energy intake, 61% controlled for total energy intake in the design and analysis, and fewer than 5% of studies reported the energy balance of subjects. There has been a significant increase in research on added sugars since 2010, with substantial heterogeneity across all facets of methodology-study designs, exposures and outcomes of interest, terminology, and reporting of dietary intake data-thus limiting the ability to synthesize evidence in this scope of the literature. This evidence map highlights gaps and important areas for improvement to strengthen the state of research and better inform future policies and dietary recommendations on added sugars.

Effects of Daily Ingestion of Two SunGold Kiwifruit for 6 Weeks on Metabolic and Inflammatory Biomarkers: A Randomized, Cross-Over, Exploratory Intervention Study

Kiwifruit contain many components, some considered beneficial, such as vitamins, phytochemicals and dietary fibre, and others potentially harmful, such as fructose and glucose in fruit sugars. In a 6-week, randomised, crossover study aimed at exploring the net effects of daily consumption of kiwifruit, 23 healthy participants consumed two Actinidia chinensis var. chinensis 'Zesy002' (marketed as Zespri™ SunGold™ Kiwifruit) per day as part of their customary diet (intervention) or without kiwifruit (control) as their customary diet for 6 weeks in a cross-over study. Anthropometric data, venous blood, and urine samples were collected at the start and end of the 6-week intervention and control periods for the measurement of physical changes, plasma glucose, insulin, glycated haemoglobin, short-chain fatty acids, blood lipids, uric acid, inflammatory biomarkers, and urinary ascorbic acid. Variables were measured between the start and finish of interventions, and between intervention and control periods. Food diaries were completed on the 3 days before blood sampling to estimate dietary ascorbic acid and dietary fibre intakes. Despite urinary vitamin C and food diaries indicating compliance, and good precision in measurements, there were no appreciable changes in biomarkers during the study, either within or between intervention and control periods, that would indicate a change in health status. Thus, the sizes of any effects of kiwifruit ingestion were too small to become significant under the test conditions used, indicating a high probability that daily ingestion of two SunGold kiwifruit is safe with respect to metabolic health.

Inflammation-induced TRIM21 represses hepatic steatosis by promoting the ubiquitination of lipogenic regulators

Nonalcoholic steatohepatitis (NASH) is a leading cause for chronic liver diseases. Current therapeutic options are limited due to an incomplete mechanistic understanding of how steatosis transitions to NASH. Here we show that the TRIM21 E3 ubiquitin ligase is induced by the synergistic actions of proinflammatory TNF-α and fatty acids in livers of humans and mice with NASH. TRIM21 ubiquitinates and degrades ChREBP, SREBP1, ACC1, and FASN, key regulators of de novo lipogenesis, and A1CF, an alternative splicing regulator of the high-activity ketohexokinase-C (KHK-C) isoform and rate-limiting enzyme of fructose metabolism. TRIM21-mediated degradation of these lipogenic activators improved steatosis and hyperglycemia as well as fructose and glucose tolerance. Our study identifies TRIM21 as a negative regulator of liver steatosis in NASH and provides mechanistic insights into an immunometabolic crosstalk that limits fatty acid synthesis and fructose metabolism during metabolic stress. Thus, enhancing this natural counteracting force of steatosis through inhibition of key lipogenic activators via TRIM21-mediated ubiquitination may provide a therapeutic opportunity to treat NASH.

Regulation of Macronutrients in Insulin Resistance and Glucose Homeostasis during Type 2 Diabetes Mellitus

Insulin resistance is an important feature of metabolic syndrome and a precursor of type 2 diabetes mellitus (T2DM). Overnutrition-induced obesity is a major risk factor for the development of insulin resistance and T2DM. The intake of macronutrients plays a key role in maintaining energy balance. The components of macronutrients distinctly regulate insulin sensitivity and glucose homeostasis. Precisely adjusting the beneficial food compound intake is important for the prevention of insulin resistance and T2DM. Here, we reviewed the effects of different components of macronutrients on insulin sensitivity and their underlying mechanisms, including fructose, dietary fiber, saturated and unsaturated fatty acids, and amino acids. Understanding the diet-gene interaction will help us to better uncover the molecular mechanisms of T2DM and promote the application of precision nutrition in practice by integrating multi-omics analysis.

Deciphering the role of gut metabolites in non-alcoholic fatty liver disease

Perturbations in microbial abundance or diversity in the intestinal lumen leads to intestinal inflammation and disruption of intestinal membrane which eventually facilitates the translocation of microbial metabolites or whole microbes to the liver and other organs through portal vein. This process of translocation finally leads to multitude of health disorders. In this review, we are going to focus on the mechanisms by which gut metabolites like SCFAs, tryptophan (Trp) metabolites, bile acids (BAs), ethanol, and choline can either cause the development/progression of non-alcoholic fatty liver disease (NAFLD) or serves as a therapeutic treatment for the disease. Alterations in some metabolites like SCFAs, Trp metabolites, etc., can serve as biomarker molecules whereas presence of specific metabolites like ethanol definitely leads to disease progression. Thus, proper understanding of these mechanisms will subsequently help in designing of microbiome-based therapeutic approaches. Furthermore, we have also focussed on the role of dysbiosis on the mucosal immune system. In addition, we would also compile up the microbiome-based clinical trials which are currently undergoing for the treatment of NAFLD and non-alcoholic steatohepatitis (NASH). It has been observed that the use of microbiome-based approaches like prebiotics, probiotics, symbiotics, etc., can act as a beneficial treatment option but more research needs to be done to know how to manipulate the composition of gut microbes.

Dietary Regulation of Hepatic Triacylglycerol Content-the Role of Eucaloric Carbohydrate Restriction with Fat or Protein Replacement

Accumulation of hepatic triacylglycerol (TG) is highly associated with impaired whole-body insulin-glucose homeostasis and dyslipidemia. The summarized findings from human intervention studies investigating the effect of reduced dietary carbohydrate and increased fat intake (and in studies also increased protein) while maintaining energy intake at eucaloric requirements reveal a beneficial effect of carbohydrate reduction on hepatic TG content in obese individuals with steatosis and indices of insulin resistance. Evidence suggests that the reduction of hepatic TG content after reduced intake of carbohydrates and increased fat/protein intake in humans, results from regulation of fatty acid (FA) metabolism within the liver, with an increase in hepatic FA oxidation and ketogenesis, together with a concomitant downregulation of FA synthesis from de novo lipogenesis. The adaptations in hepatic metabolism may result from reduced intrahepatic monosaccharide and insulin availability, reduced glycolysis and increased FA availability when carbohydrate intake is reduced.

Associations of dietary sugar types with coronary heart disease risk: a prospective cohort study

BACKGROUND

Higher intake of total sugar has been linked with coronary heart disease (CHD) risk, but the role of individual sugars, particularly fructose, is uncertain.

OBJECTIVES

This study aimed to investigate the associations of individual dietary sugars with CHD risk.

METHODS

In prospective cohort studies, we followed 76,815 women (Nurses' Health Study, 1980-2020) and 38,878 men (Health Professionals Follow-up Study, 1986-2016). Sugar and carbohydrate intake, including total fructose equivalents ([TFE] from fructose monosaccharides and sucrose), total glucose equivalents ([TGE] from glucose monosaccharides, disaccharides, and starch), and other sugar types, was measured every 2 to 4 y by semiquantitative food frequency questionnaires.

RESULTS

We documented 9,723 incident CHD cases over 40 years. In isocaloric substitution models with total fat as a comparison nutrient, comparing extreme quintiles of intake, hazard ratios (HRs), 95% confidence interval [CI]) for CHD risk were 1.31 (1.20 to 1.42; Ptrend < 0.001) for TGE and 1.03 (0.94 to 1.11; Ptrend = 0.25) for TFE. TFE from fruits and vegetables was not associated with CHD risk (Ptrend = 0.70), but TFE from added sugar and juice was associated with CHD risk (HR: 1.12, 95% CI: 1.04 to 1.20; Ptrend < 0.01). Intakes of total sugars and added sugar were positively associated with CHD risk (HRs: 1.16, 95% CI: 1.07 to 1.26, Ptrend < 0.001; 1.08, 95% CI: 0.99 to 1.16, Ptrend = 0.04).

CONCLUSIONS

Intakes of TGE, total sugar, added sugar, and fructose from added sugar and juice were associated with higher CHD risk, but TFE and fructose from fruits and vegetables were not.

High maternal adiposity during pregnancy programs an imbalance in the lipidome and predisposes to diet-induced hepatosteatosis in the offspring

BACKGROUND

Exposure to high maternal adiposity in utero is a significant risk factor for the later-life development of metabolic syndrome (MetS), including non-alcoholic fatty liver disease (NAFLD). We have previously shown that high pre-pregnancy adiposity programs adipose tissue dysfunction in the offspring, leading to spillover of fatty acids into the circulation, a key pathogenic event in obesity-associated MetS. Herein, we hypothesized that programming of adipose tissue dysfunction in offspring born to overweight dams increases the risk for developing NAFLD.

RESULTS

Females heterozygous for leptin receptor deficiency (Hetdb) were used as a model of high pre-pregnancy adiposity. Female wild-type (Wt) offspring born to Hetdb pregnancies gained significantly more body fat following high-fat/fructose diet (HFFD) compared with Wt offspring born to Wt dams. HFFD increased circulating free fatty acids (FFA) in male offspring of control dams, while FFA levels were similar in HFFD-fed offspring from Wt dams and CD or HFFD-fed Wt offspring from Hetdb dams. Despite female-specific protection from diet-induced FFA spillover, both male and female offspring from Hetdb dams were more susceptible to diet-induced hepatosteatosis. Lipidomic analysis revealed that CD-offspring of overweight dams had decreased hepatic polyunsaturated FA (PUFA) levels compared with control offspring. Changes to saturated FA (SFA) and the de novo lipogenic (DNL) index were diet driven; however, there was a significant effect of the intrauterine environment on FA elongation and Δ9 desaturase activity.

CONCLUSION

High maternal adiposity during pregnancy programs a susceptibility to diet-induced hepatosteatosis.

Discovery of a Novel Ketohexokinase Inhibitor with Improved Drug Distribution in Target Tissue for the Treatment of Fructose Metabolic Disease

Excessive fructose absorption and its subsequent metabolisms are implicated in nonalcoholic fatty liver disease, obesity, and insulin resistance in humans. Ketohexokinase (KHK) is a primary enzyme involved in fructose metabolism via the conversion of fructose to fructose-1-phosphate. KHK inhibition might be a potential approach for the treatment of metabolic disorders. Herein, a series of novel KHK inhibitors were designed, synthesized, and evaluated. Among them, compound 14 exhibited more potent activity than PF-06835919 based on the rat KHK inhibition assay in vivo, and higher drug distribution concentration in the liver. Its good absorption, distribution, metabolism, and excretion and pharmacokinetic properties make it a promising clinical candidate.

Controlled trial of a workplace sales ban on sugar-sweetened beverages

OBJECTIVE

To examine the effectiveness of a workplace sugar-sweetened beverage (SSB) sales ban on reducing SSB consumption in employees, including those with cardiometabolic disease risk factors.

DESIGN

A controlled trial of ethnically diverse, full-time employees who consumed SSB heavily (sales ban n 315; control n 342). Outcomes included standardised measures of change in SSB consumption in the workplace (primary) and at home between baseline and 6 months post-sales ban.

SETTING

Sutter Health, a large non-profit healthcare delivery system in Northern California.

PARTICIPANTS

Full-time employees at Sutter Health screened for heavy SSB consumption.

RESULTS

Participants were 66·1 % non-White. On average, participants consumed 34·7 ounces (about 1 litre) of SSB per d, and the majority had an elevated baseline BMI (mean = 29·5). In adjusted regression analyses, those exposed to a workplace SSB sales ban for 6 months consumed 2·7 (95 % CI -4·9, -0·5) fewer ounces of SSB per d while at work, and 4·3 (95 % CI -8·4, -0·2) fewer total ounces per d, compared to controls. Sales ban participants with an elevated BMI or waist circumference had greater post-intervention reductions in workplace SSB consumption.

CONCLUSIONS

Workplace sales bans can reduce SSB consumption in ethnically diverse employee populations, including those at higher risk for cardiometabolic disease.

Precision nutrition for targeting pathophysiology of cardiometabolic phenotypes

Obesity is a heterogenous disease accompanied by a broad spectrum of cardiometabolic risk profiles. Traditional paradigms for dietary weight management do not address biological heterogeneity between individuals and have catastrophically failed to combat the global pandemic of obesity-related diseases. Nutritional strategies that extend beyond basic weight management to instead target patient-specific pathophysiology are warranted. In this narrative review, we provide an overview of the tissue-level pathophysiological processes that drive patient heterogeneity to shape distinct cardiometabolic phenotypes in obesity. Specifically, we discuss how divergent physiology and postprandial phenotypes can reveal key metabolic defects within adipose, liver, or skeletal muscle, as well as the integrative involvement of the gut microbiome and the innate immune system. Finally, we highlight potential precision nutritional approaches to target these pathways and discuss recent translational evidence concerning the efficacy of such tailored dietary interventions for different obesity phenotypes, to optimise cardiometabolic benefits.

The fructose survival hypothesis for obesity

The fructose survival hypothesis proposes that obesity and metabolic disorders may have developed from over-stimulation of an evolutionary-based biologic response (survival switch) that aims to protect animals in advance of crisis. The response is characterized by hunger, thirst, foraging, weight gain, fat accumulation, insulin resistance, systemic inflammation and increased blood pressure. The process is initiated by the ingestion of fructose or by stimulating endogenous fructose production via the polyol pathway. Unlike other nutrients, fructose reduces the active energy (adenosine triphosphate) in the cell, while blocking its regeneration from fat stores. This is mediated by intracellular uric acid, mitochondrial oxidative stress, the inhibition of AMP kinase and stimulation of vasopressin. Mitochondrial oxidative phosphorylation is suppressed, and glycolysis stimulated. While this response is aimed to be modest and short-lived, the response in humans is exaggerated due to gain of 'thrifty genes' coupled with a western diet rich in foods that contain or generate fructose. We propose excessive fructose metabolism not only explains obesity but the epidemics of diabetes, hypertension, non-alcoholic fatty liver disease, obesity-associated cancers, vascular and Alzheimer's dementia, and even ageing. Moreover, the hypothesis unites current hypotheses on obesity. Reducing activation and/or blocking this pathway and stimulating mitochondrial regeneration may benefit health-span. This article is part of a discussion meeting issue 'Causes of obesity: theories, conjectures and evidence (Part I)'.

Consumption of Sugar-Sweetened Soft Drinks and Risk of Gastrointestinal Cancer: A Systematic Review and Meta-Analysis of Observational Studies

INTRODUCTION

Previous observational studies have reported inconsistent findings on the association between consumption of sugar-sweetened soft drinks (SSSDs) and the risk of gastrointestinal (GI) cancer. This study investigated the associations between SSSD consumption and the risk of GI cancer using a systematic review and meta-analysis.

METHODS

Observational epidemiological studies were searched from the PubMed and EMBASE databases until June 2021. We conducted a meta-analysis of all included studies and subgroup meta-analyses based on various factors.

RESULTS

In a meta-analysis of 27 studies with nine case-control studies and 18 cohort studies, the consumption of SSSDs was modestly associated with an increased risk of GI cancer (odds ratio [OR]/relative risk [RR]: 1.08; 95% confidence interval [CI]: 1.01-1.16), with a significant positive dose-response relationship. In the subgroup meta-analysis by study design, there was a significant positive association between the consumption of SSSDs and GI cancer in cohort studies (RR: 1.11; 95% CI: 1.03-1.20; n = 18), but not in case-control studies. In the subgroup meta-analysis by type of cancer, consumption of SSSDs was significantly associated with an increased risk of colorectal cancer (OR/RR: 1.13; 95% CI: 1.07-1.19).

CONCLUSIONS

This meta-analysis suggests that SSSD consumption significantly increases the risk of GI cancer, specifically colorectal cancer.

Sugar and Dyslipidemia: A Double-Hit, Perfect Storm

The availability of sugar has expanded over the past 50 years, due to improved industrial processes and corn subsidies, particularly in the form of sweetened beverages. This correlates with a surge in the prevalence of cardiometabolic disorders, which has brought this issue back into the spotlight for public health. In this narrative review, we focus on the role of fructose in the genesis of cardiometabolic dyslipidemia (an increase in serum triglyceride-rich lipoproteins (TRL): VLDL, chylomicrons (CM), and their remnants) bringing together the most recent data on humans, which demonstrates the crucial interaction between glucose and fructose, increasing the synthesis while decreasing the catabolism of these particles in a synergistic downward spiral. After reviewing TRL metabolism, we discuss the fundamental principles governing the metabolism of fructose in the intestine and liver and the effects of dysregulated fructolysis, in conjunction with the activation of carbohydrate-responsive element-binding protein (ChREBP) by glucose and the resulting crosstalk. The first byproduct of fructose catabolism, fructose-1-P, is highlighted for its function as a signaling molecule that promotes fat synthesis. We emphasize the role of fructose/glucose interaction in the liver, which enhances de novo lipogenesis, triglyceride (TG) synthesis, and VLDL production. In addition, we draw attention to current research that demonstrates how fructose affects the activity of lipoprotein lipase by increasing the concentration of inhibitors such as apolipoprotein CIII (apoCIII) and angiopoietin-like protein 3 (ANGPTL3), which reduce the catabolism of VLDL and chylomicrons and cause the building up of their atherogenic remnants. The end outcome is a dual, synergistic, and harmful action that encourages atherogenesis. Thus, considering the growing concerns regarding the connection between sugar consumption and cardiometabolic disease, current research strongly supports the actions of public health organizations aimed at reducing sugar intake, including dietary guidance addressing "safe" limits for sugar consumption.

Effect of quercetin on steroidogenesis and folliculogenesis in ovary of mice with experimentally-induced polycystic ovarian syndrome

Introduction

Polycystic Ovary syndrome (PCOS) affects the health of many women around theworld. Apart from fundamental metabolic problems connected to PCOS, focus of our study is on the role of quercetin on genes relevant to steroidogenesis and folliculogenesis.

Methods

Eighteen mature parkes strain mice (4-5 weeks old) weighing18-21 g were randomly divided into three groups of six each as follows: Group I serves as the control and was given water and a regular chow diet ad lib for 66 days; group II was given oral gavage administration of letrozole (LETZ) (6 mg/kgbw) for 21 days to induce PCOS and was left untreated for 45 days; For three weeks, Group III received oral gavage dose of LETZ (6 mg/kg), after which it received Quercetin (QUER) (125 mg/kg bw orally daily) for 45 days.

Results

In our study we observed that mice with PCOS had irregular estrous cycle with increased LH/FSH ratio, decreased estrogen level and decline in expression of Kitl, Bmp1, Cyp11a1, Cyp19a1, Ar, lhr, Fshr and Esr1 in ovary. Moreover, we observed increase in the expression of CYP17a1, as well as increase in cholesterol, triglycerides, testosterone, vascular endothelial growth factor VEGF and insulin levels. All these changes were reversed after the administration of quercetin in PCOS mice.

Discussion

Quercetin treatment reversed the molecular, functional and morphological abnormalities brought on due to letrozole in pathological and physiological setting, particularly the issues of reproduction connected to PCOS. Quercetin doesn't act locally only but it acts systematically as it works on Pituitary (LH/FSH)- Ovary (gonad hormones) axis. the Side effects of Quercetin have to be targeted in future researches. Quercetin may act as a promising candidate for medical management of human PCOS.

The impact of dietary fructose on gut permeability, microbiota, abdominal adiposity, insulin signaling and reproductive function

The excessive intake of fructose in the regular human diet could be related to global increases in metabolic disorders. Sugar-sweetened soft drinks, mostly consumed by children, adolescents, and young adults, are the main source of added fructose. Dietary high-fructose can increase intestinal permeability and circulatory endotoxin by changing the gut barrier function and microbial composition. Excess fructose transports to the liver and then triggers inflammation as well as de novo lipogenesis leading to hepatic steatosis. Fructose also induces fat deposition in adipose tissue by stimulating the expression of lipogenic genes, thus causing abdominal adiposity. Activation of the inflammatory pathway by fructose in target tissues is thought to contribute to the suppression of the insulin signaling pathway producing systemic insulin resistance. Moreover, there is some evidence that high intake of fructose negatively affects both male and female reproductive systems and may lead to infertility. This review addresses dietary high-fructose-induced deteriorations that are obvious, especially in gut permeability, microbiota, abdominal fat accumulation, insulin signaling, and reproductive function. The recognition of the detrimental effects of fructose and the development of relevant new public health policies are necessary in order to prevent diet-related metabolic disorders.

Diabetes websites lack information on dietary causes, risk factors, and preventions for type 2 diabetes

Introduction

Type 2 diabetes (T2D) is a growing public health burden throughout the world. Many people looking for information on how to prevent T2D will search on diabetes websites. Multiple dietary factors have a significant association with T2D risk, such as high intake of added sugars, refined carbohydrates, saturated fat, and red meat or processed meat; and decreased intake of dietary fiber, and fruits/vegetables. Despite this dietary information being available in the scientific literature, it is unclear whether this information is available in gray literature (websites).

Objective

In this study, we evaluate the use of specific terms from diabetes websites that are significantly associated with causes/risk factors and preventions for T2D from three term categories: (A) dietary factors, (B) nondietary nongenetic (lifestyle-associated) factors, and (C) genetic (non-modifiable) factors. We also evaluate the effect of website type (business, government, nonprofit) on term usage among websites.

Methods

We used web scraping and coding tools to quantify the use of specific terms from 73 diabetes websites. To determine the effect of term category and website type on the usage of specific terms among 73 websites, a repeated measures general linear model was performed.

Results

We found that dietary risk factors that are significantly associated with T2D (e.g., sugar, processed carbohydrates, dietary fat, fruits/vegetables, fiber, processed meat/red meat) were mentioned in significantly fewer websites than either nondietary nongenetic factors (e.g., obesity, physical activity, dyslipidemia, blood pressure) or genetic factors (age, family history, ethnicity). Among websites that provided "eat healthy" guidance, one third provided zero dietary factors associated with type 2 diabetes, and only 30% provided more than two specific dietary factors associates with type 2 diabetes. We also observed that mean percent usage of all terms associated with T2D causes/risk factors and preventions was significantly lower among government websites compared to business websites and nonprofit websites.

Conclusion

Diabetes websites need to increase their usage of dietary factors when discussing causes/risk factors and preventions for T2D; as dietary factors are modifiable and strongly associated with all nondietary nongenetic risk factors, in addition to T2D risk.

Glucose versus fructose metabolism in the liver measured with deuterium metabolic imaging

Chronic intake of high amounts of fructose has been linked to the development of metabolic disorders, which has been attributed to the almost complete clearance of fructose by the liver. However, direct measurement of hepatic fructose uptake is complicated by the fact that the portal vein is difficult to access. Here we present a new, non-invasive method to measure hepatic fructose uptake and metabolism with the use of deuterium metabolic imaging (DMI) upon administration of [6,6'-²H₂]fructose. Using both [6,6'-²H₂]glucose and [6,6'-²H₂]fructose, we determined differences in the uptake and metabolism of glucose and fructose in the mouse liver with dynamic DMI. The deuterated compounds were administered either by fast intravenous (IV) bolus injection or by slow IV infusion. Directly after IV bolus injection of [6,6'-²H₂]fructose, a more than two-fold higher initial uptake and subsequent 2.5-fold faster decay of fructose was observed in the mouse liver as compared to that of glucose after bolus injection of [6,6'-²H₂]glucose. In contrast, after slow IV infusion of fructose, the ²H fructose/glucose signal maximum in liver spectra was lower compared to the ²H glucose signal maximum after slow infusion of glucose. With both bolus injection and slow infusion protocols, deuterium labeling of water was faster with fructose than with glucose. These observations are in line with a higher extraction and faster turnover of fructose in the liver, as compared with glucose. DMI with [6,6'-²H₂]glucose and [6,6'-²H₂]fructose could potentially contribute to a better understanding of healthy human liver metabolism and aberrations in metabolic diseases.

Ketohexokinase-C regulates global protein acetylation to decrease carnitine palmitoyltransferase 1a-mediated fatty acid oxidation

BACKGROUND & AIMS

The consumption of sugar and a high-fat diet (HFD) promotes the development of obesity and metabolic dysfunction. Despite their well-known synergy, the mechanisms by which sugar worsens the outcomes associated with a HFD are largely elusive.

METHODS

Six-week-old, male, C57Bl/6 J mice were fed either chow or a HFD and were provided with regular, fructose- or glucose-sweetened water. Moreover, cultured AML12 hepatocytes were engineered to overexpress ketohexokinase-C (KHK-C) using a lentivirus vector, while CRISPR-Cas9 was used to knockdown CPT1α. The cell culture experiments were complemented with in vivo studies using mice with hepatic overexpression of KHK-C and in mice with liver-specific CPT1α knockout. We used comprehensive metabolomics, electron microscopy, mitochondrial substrate phenotyping, proteomics and acetylome analysis to investigate underlying mechanisms.

RESULTS

Fructose supplementation in mice fed normal chow and fructose or glucose supplementation in mice fed a HFD increase KHK-C, an enzyme that catalyzes the first step of fructolysis. Elevated KHK-C is associated with an increase in lipogenic proteins, such as ACLY, without affecting their mRNA expression. An increase in KHK-C also correlates with acetylation of CPT1α at K508, and lower CPT1α protein in vivo. In vitro, KHK-C overexpression lowers CPT1α and increases triglyceride accumulation. The effects of KHK-C are, in part, replicated by a knockdown of CPT1α. An increase in KHK-C correlates negatively with CPT1α protein levels in mice fed sugar and a HFD, but also in genetically obese db/db and lipodystrophic FIRKO mice. Mechanistically, overexpression of KHK-C in vitro increases global protein acetylation and decreases levels of the major cytoplasmic deacetylase, SIRT2.

CONCLUSIONS

KHK-C-induced acetylation is a novel mechanism by which dietary fructose augments lipogenesis and decreases fatty acid oxidation to promote the development of metabolic complications.

IMPACT AND IMPLICATIONS

Fructose is a highly lipogenic nutrient whose negative consequences have been largely attributed to increased de novo lipogenesis. Herein, we show that fructose upregulates ketohexokinase, which in turn modifies global protein acetylation, including acetylation of CPT1a, to decrease fatty acid oxidation. Our findings broaden the impact of dietary sugar beyond its lipogenic role and have implications on drug development aimed at reducing the harmful effects attributed to sugar metabolism.

Effects of Natural Alternative Sweeteners on Metabolic Diseases

The rising prevalence of obesity and diabetes is a significant health concern both in globally and is now regarded as a worldwide epidemic. Added sugars like sucrose and high-fructose corn syrup (HFCS) are a major concern due to their link with an increased incidence of diet-induced obesity and diabetes. The purpose of this review is to provide insight into the effects of natural sweeteners as alternatives to sucrose and HFCS, which are known to have negative impacts on metabolic diseases and to promote further research on sugar consumption with a focus on improving metabolic health. The collective evidences suggest that natural alternative sweeteners have positive impacts on various markers associated with obesity and diabetes, including body weight gain, hepatic fat accumulation, abnormal blood glucose or lipid homeostasis, and insulin resistance. Taken together, natural alternative sweeteners can be useful substitutes to decrease the risk of obesity and diabetes compared with sucrose and HFCS.

Nutrition interventions for adults with dyslipidemia: A Clinical Perspective from the National Lipid Association

Lifestyle habits can have a profound impact on atherosclerotic cardiovascular disease (ASCVD) risk. The National Lipid Association previously published recommendations for lifestyle therapies to manage dyslipidemia. This Clinical Perspective provides an update with a focus on nutrition interventions for the three most common dyslipidemias in adults: 1) low-density lipoprotein cholesterol (LDL-C) elevation; 2) triglyceride (TG) elevation, including severe hypertriglyceridemia with chylomicronemia; and 3) combined dyslipidemia, with elevations in both LDL-C and TG levels. Lowering LDL-C and non-high-density lipoprotein cholesterol are the primary objectives for reducing ASCVD risk. With severe TG elevation (≥500 mg/dL), the primary objective is to prevent pancreatitis and ASCVD risk reduction is secondary. Nutrition interventions that lower LDL-C levels include reducing cholesterol-raising fatty acids and dietary cholesterol, as well as increasing intakes of unsaturated fatty acids, plant proteins, viscous fibers, and reducing adiposity for patients with overweight or obesity. Selected dietary supplements may be employed as dietary adjuncts. Nutrition interventions for all patients with elevated TG levels include restricting intakes of alcohol, added sugars, and refined starches. Additional lifestyle factors that reduce TG levels are participating in daily physical activity and reducing adiposity in patients with overweight or obesity. For patients with severe hypertriglyceridemia, an individualized approach is essential. Nutrition interventions for addressing concurrent elevations in LDL-C and TG include a combination of the strategies described for lowering LDL-C and TG. A multidisciplinary approach is recommended to facilitate success in making and sustaining dietary changes and the assistance of a registered dietitian nutritionist is highly recommended.

Insulin Regulation of Hepatic Lipid Homeostasis

The incidence of obesity, insulin resistance, and type II diabetes (T2DM) continues to rise worldwide. The liver is a central insulin-responsive metabolic organ that governs whole-body metabolic homeostasis. Therefore, defining the mechanisms underlying insulin action in the liver is essential to our understanding of the pathogenesis of insulin resistance. During periods of fasting, the liver catabolizes fatty acids and stored glycogen to meet the metabolic demands of the body. In postprandial conditions, insulin signals to the liver to store excess nutrients into triglycerides, cholesterol, and glycogen. In insulin-resistant states, such as T2DM, hepatic insulin signaling continues to promote lipid synthesis but fails to suppress glucose production, leading to hypertriglyceridemia and hyperglycemia. Insulin resistance is associated with the development of metabolic disorders such as cardiovascular and kidney disease, atherosclerosis, stroke, and cancer. Of note, nonalcoholic fatty liver disease (NAFLD), a spectrum of diseases encompassing fatty liver, inflammation, fibrosis, and cirrhosis, is linked to abnormalities in insulin-mediated lipid metabolism. Therefore, understanding the role of insulin signaling under normal and pathologic states may provide insights into preventative and therapeutic opportunities for the treatment of metabolic diseases. Here, we provide a review of the field of hepatic insulin signaling and lipid regulation, including providing historical context, detailed molecular mechanisms, and address gaps in our understanding of hepatic lipid regulation and the derangements under insulin-resistant conditions. © 2023 American Physiological Society. Compr Physiol 13:4785-4809, 2023.

Total added sugar consumption is not significantly associated with risk for prediabetes among U.S. adults: National Health and Nutrition Examination Survey, 2013-2018

Prediabetes affects 38% of U.S. adults and is primarily linked to added sugars consumed from sugar-sweetened beverages. It is unclear if total dietary intake of added sugar also increases the risk for prediabetes. This study examined if total (g/day) and percent intakes of <10%, 10-15%, or >15% added sugar increase the odds for prediabetes in U.S. adults. A cross-sectional, secondary analysis using 2013-2018 NHANES data was conducted. This study included data from U.S. adults ≥ 20 years with normoglycemia (N = 2,154) and prediabetes (N = 3,152) with 1-2 days of dietary recall information. Prediabetes was defined as a hemoglobin A1c of 5.7%-6.4% or a fasting plasma glucose of 100-125 mg/dL. Survey-weighted logistic regression was used to estimate odds ratios of prediabetes based on usual intakes of added sugar (total and percent intakes) using the National Cancer Institute Method. Differences in prediabetes risk and total and percent intakes of added sugar were compared by race/ethnicity. The sample's total energy intake from added sugar was 13.9%. Total (unadjusted: OR: 1.01, 95% CI: .99-1.00, p = .26; adjusted: OR: 1.00, 95% CI: .99-1.00, p = .91) and percent intakes of added sugar (unadjusted [<10%: (ref); 10-15%: OR: .93, 95% CI: .77-1.12, p = .44; >15%: OR: 1.03, 95% CI: .82-1.28, p = .82] and adjusted [<10%: (ref); 10-15%: OR: .82, 95% CI: .65-1.04, p = .09; >15%: OR: .96, 95% CI: .74-1.24, p = .73]) were not significantly associated with an increased odds of prediabetes. Prediabetes risk did not differ by race/ethnicity for total (unadjusted model [p = .65]; adjusted model [p = .51]) or percent (unadjusted model [p = .21]; adjusted model [p = .11]) added sugar intakes. In adults ≥20 years with normoglycemia and prediabetes, total added sugar consumption did not significantly increase one's risk for prediabetes and risk estimates did not differ by race/ethnicity. Experimental studies should expand upon this work to confirm these findings.