Hypothesis: could excessive fructose intake and uric acid cause type 2 diabetes?

Multitissue single-cell analysis reveals differential cellular and molecular sensitivity between fructose and high-fat high-sucrose diets

Metabolic syndrome (MetS), a conglomerate of dysregulated metabolic traits that vary between individuals, is partially driven by modern diets high in fat, sucrose, or fructose and their interactions with host genes in metabolic tissues. To elucidate the roles of individual tissues and cell types in diet-induced MetS, we performed single-cell RNA sequencing on the hypothalamus, liver, adipose tissue, and small intestine of mice fed high-fat high-sucrose (HFHS) or fructose diets. We found that hypothalamic neurons were sensitive to fructose, while adipose progenitor cells and macrophages were responsive to HFHS. Ligand-receptor analysis revealed lipid metabolism and inflammation networks among peripheral tissues driven by HFHS, while both diets stimulated synaptic remodeling within the hypothalamus. mt-Rnr2, a top responder to both diets, mitigated diet-induced MetS by stimulating thermogenesis. Our study demonstrates that HFHS and fructose diets have differential cell type and network targets but also share regulators such as mt-Rnr2 to affect MetS risk.

From Liver to Kidney: The Overlooked Burden of Nonalcoholic Fatty Liver Disease in Chronic Kidney Disease

Nonalcoholic fatty liver disease (NAFLD) is increasingly recognized as a contributor to chronic kidney disease (CKD), yet its impact remains underappreciated in clinical practice. Recent studies reveal a strong association between NAFLD and CKD progression, with evidence linking hepatic dysfunction to renal impairment through metabolic and inflammatory pathways. NAFLD not only increases the risk of CKD but also accelerates its progression, leading to worse cardiovascular outcomes and higher mortality, particularly in patients with advanced fibrosis. Despite this growing evidence, NAFLD often goes undiagnosed in CKD patients and routine hepatic evaluation is rarely integrated into nephrology care. Emerging diagnostic tools, including noninvasive biomarkers and imaging techniques, offer potential for earlier detection, yet their clinical implementation remains inconsistent. Although lifestyle modifications remain the foundation of treatment, pharmacotherapeutic strategies, including SGLT2 inhibitors and GLP-1 receptor agonists, have demonstrated potential in mitigating both hepatic and renal impairment. Recognizing the interplay between NAFLD and CKD is essential for improving patient outcomes. A multidisciplinary approach, integrating hepatology and nephrology expertise, is crucial to refining screening strategies, optimizing treatment, and reducing the long-term burden of these coexisting conditions.

Pacific Islands Families Study: Serum Uric Acid in Pacific Youth and the Associations with Free-Sugar Intake and Appendicular Skeletal Muscle Mass

BACKGROUND

Fructose (50% of sucrose/sugar) is one component of free-sugars and is metabolized to uric acid, which is a known risk factor for gout and metabolic syndrome. Pacific peoples in New Zealand experience a higher prevalence of gout, type 2 diabetes, and overweight/obesity than other ethnic groups. Interestingly, despite having a similar body mass index (BMI), they tend to have a higher proportion of appendicular skeletal muscle mass (ASMM) and less fat than other ethnic groups. Given this context, this study aimed to evaluate the associations between serum uric acid (SUA), free-sugar intake, and ASMM.

METHODS

In a nested sub-study from the Pacific Islands Families birth-cohort study, 101 boys and 99 girls (all aged 14 and 15 years) self-reported how often they had consumed foods containing sugar in the past month. Anthropometry, body fatness, and ASMM by dual-energy X-ray absorptiometry and metabolic risk factors, including SUA were measured.

RESULTS

Overall, 43% of girls and 57% of boys consumed 'sugary drinks' twice or more a day. When analyzed by group, ASMM was positively related to SUA for both boys and girls (r = 0.593, p < 0.0001). The effect of the intake of 'sugary drinks' on SUA (r = 0.176, p = 0.013) was reduced when ASMM was considered in the relationships.

CONCLUSIONS

This study shows high SUA levels in Pacific adolescents, with a positive association between ASMM and SUA in both genders. Sugary drink intake was positively associated with SUA in both boys and girls. High ASMM in Pacific people and an increased risk for raised SUA make it important to work with Pacific communities to reduce added sugar intake and adopt integrated, family-based, culturally centered, and life-course approaches to prevent chronic diseases, including gout.

The Impact of Fructose Consumption on Human Health: Effects on Obesity, Hyperglycemia, Diabetes, Uric Acid, and Oxidative Stress With a Focus on the Liver

Excessive fructose consumption, primarily through processed foods and beverages, has become a significant public health concern due to its association with various metabolic disorders. This review examines the impact of fructose on human health, focusing on its role in obesity, insulin resistance, hyperglycemia, type 2 diabetes, uric acid production, and oxidative stress. Fructose metabolism, distinct from glucose, predominantly occurs in the liver, where it bypasses normal insulin regulation, leading to increased fat synthesis through de novo lipogenesis. This process contributes to the development of non-alcoholic fatty liver disease and elevates the risk of cardiovascular disease. Furthermore, fructose-induced adenosine triphosphate depletion activates purine degradation, increasing uric acid levels and exacerbating hyperuricemia. The overproduction of reactive oxygen species during fructose metabolism also drives oxidative stress, promoting inflammation and cellular damage. By synthesizing recent findings, this review underscores the importance of regulating fructose intake, implementing public health policies, and adopting lifestyle changes to mitigate these adverse effects.

Dietary fructose: from uric acid to a metabolic switch in pediatric metabolic dysfunction-associated steatotic liver disease

Fructose consumption in pediatric subjects is rising, as the prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH). Despite increasing evidence supporting the detrimental effects of fructose in the development of Metabolic Syndrome (MetS) and its related comorbidities, the association between fructose intake and liver disease remains unclear, mainly in youths. The current narrative review aims to illustrate the correlation between fructose metabolism and liver functions besides its impact on obesity and MASLD in pediatrics. Fructose metabolism is involved in the liver through the classical lipogenic pathway via de novo lipogenesis (DNL) or in the alternative pathway via uric acid accumulation. Hyperuricemia is one of the main features of MALSD patients, underlining how uric acid is growing interest as a new marker of disease. Observational and interventional studies conducted in children and adolescents, who consumed large amounts of fructose and glucose in their diet, were included. Most of these studies emphasized the association between high fructose intake and weight gain, dyslipidemia, insulin resistance, and MASLD/MASH, even in normal-weight children. Conversely, reducing fructose intake ameliorates liver fat accumulation, lipid profile, and weight. In conclusion, fructose seems a potent inducer of both insulin resistance and hepatic fat accumulation.

Inhibitory effect of organogermanium compound 3-(trihydroxygermyl)propanoic acid on fructose-induced glycation of amino compounds

3-(Trihydroxygermyl)propanoic acid (THGP), a hydrolysate of poly-trans-[(2-carboxyethyl)germasesquioxane] (Ge-132, also known as repagermanium), can inhibit glycation between glucose/ribose and amino compounds. In addition, THGP may inhibit glycation by inhibiting reactions that occur after Amadori rearrangement and inducing the reversible solubilization of AGEs. In this study, we first investigated the effects and mechanisms on the glycation of fructose and amino compounds by THGP, as a greater reactivity was obtained with fructose than with glucose. Unlike other anti-glycation materials, THGP can form a complex with fructose, the initial compound of glycation. THGP also inhibited the production of AGEs and suppressed the reduction of fructose in a reaction between fructose and arginine. These results indicate that THGP forms a complex with cyclic fructose possessing a cis-diol structure at a reducing end, and that it suppresses the ring-opening of fructose and the progress of the initial glycation reaction. We next tried to evaluate the suppressive effect of glucosyl hesperidin (GHes) and THGP on the reaction of glycation between fructose and collagen. Both compounds effectively reduced the production of AGEs individually, and the combination of them led to a synergistic suppression. Therefore, through combination with other antiglycation materials, THGP may cooperatively exhibit glycation-inhibitory effects and be able to suppress the AGE production.

Association between Uric Acid Levels and the Consumption of Sugar-Sweetened Carbonated Beverages in the Korean Population: The 2016 Korea National Health and Nutrition Examination Survey

Elevated uric acid levels are linked with obesity and diabetes. Existing research mainly examines the relationship between sugar-sweetened carbonated beverage (SSB) consumption and uric acid levels. This study explored the association between the quantity and frequency of SSB consumption and elevated uric acid levels in Korean adults. Data from 2881 participants aged 19-64 years (1066 men and 1815 women) in the 2016 Korea National Health and Nutrition Examination Survey were analyzed. Serum uric acid levels were categorized into quartiles, with the highest defined as high uric acid (men, ≥6.7 mg/dL; women, ≥4.8 mg/dL). SSB consumption was classified into quartiles (almost never, <1 cup (<200 mL), 1-3 cups (200-600 mL), ≥3 cups (≥600 mL)) and frequency into tertiles (almost never, ≤1/week, ≥2/week). Multivariate logistic regression assessed the association, with separate analyses for men and women. Increased daily SSB consumption and frequency were significantly associated with high uric acid levels in men but not in women. After adjusting for sociodemographic and health characteristics, consuming ≥3 cups (≥600 mL) of SSBs per day and SSBs ≥ 2/week were significantly associated with high serum uric acid levels in men, but this association was not observed in women. The study concludes that increased SSB intake is linked to elevated uric acid levels in Korean men, but not in women.

Suboptimal diet quality is associated with the incidence of type 2 diabetes mellitus in middle-aged and older populations in China: evidence from a population-based cross-sectional study

The association between dietary quality and type 2 diabetes mellitus (T2DM) based on the Chinese Dietary Balance Index (DBI-16) is seldom reported. We hypothesized that poor dietary quality might increase the risk of T2DM in the middle-aged and older populations. A total of 1816 individuals (≥50 years) were included in the study. Demographic characteristics and dietary intake data were collected. Logistic regression and restricted cubic spline (RCS) analyses were conducted to explore the association between DBI-16 indexes and the risk of T2DM. The insufficient intake of vegetables and dairy might decrease the risk of T2DM (ORVegetable = 0.77, 95% CI = 0.60-0.97; ORDairy = 0.58, 95% CI = 0.35-0.96), but the individuals with insufficient intake of fruit were more likely to have a higher risk of T2DM (ORfruit = 2.26, 95% CI = 1.69-3.06). Compared with the subjects with the lowest quartile of Low Bound Score (LBS) or Diet Quality Distance (DQD), the individuals with Q2 and Q3 level of LBS (ORQ2 = 1.40, 95% CI = 1.03-1.90, P = .033; ORQ3 = 1.52, 95% CI = 1.11-2.08, P < .01) or DQD (ORQ2 = 1.45, 95% CI = 1.06-1.99, P = .021; ORQ3 = 1.64, 95% CI = 1.20-2.24, P < .01) showed increased risk of T2DM with a nonlinear association observed by RCS analysis. We concluded that imbalanced dietary intake, especially insufficient daily fruit intake, might predict an increased risk of T2DM in the middle-aged and elderly Chinese.

Hyperuricemia: An Intriguing Connection to Metabolic Syndrome, Diabetes, Kidney Disease, and Hypertension

PURPOSE OF THE REVIEW

Our review explores the epidemiology, physiology, and clinical data surrounding the connection between hyperuricemia and metabolic syndrome, chronic kidney disease, and hypertension.

RECENT FINDINGS

Compelling physiologic mechanisms have been proposed to explain a causal relationship between hyperuricemia and metabolic syndrome, chronic kidney disease, and hypertension but clinical studies have given mixed results in terms of whether intervening with hyperuricemia using urate-lowering therapy has any beneficial effects for patients with these conditions. Despite the large amount of research already put into this topic, more randomized placebo-controlled trials are needed to more firmly establish whether a cause-effect relationship exists and whether lowering uric acid levels in patients with these conditions is beneficial.

Elevated serum uric acid is a risk factor for progression to prediabetes in Japanese women: A 5-year retrospective chort study

AIMS/INTRODUCTION

The association between serum uric acid (SUA) levels and prediabetes risk remains poorly understood. The aim of this longitudinal retrospective study was to evaluate the association between SUA levels and prediabetes progression in Japanese individuals through sex-specific analysis.

MATERIALS AND METHODS

We enrolled 20,743 participants (11,916 men and 8,827 women) who underwent annual medical health checkups in 2017 (baseline) and 2022. None of the participants had diabetes and prediabetes or were taking SUA-lowering medications at baseline. Participants were divided into four groups according to the quartiles of SUA levels at baseline. Multivariable-adjusted Cox regression analysis was conducted to examine the risk of prediabetes progression. In addition, multivariate restricted cubic spline analysis was conducted to investigate the dose-response risk.

RESULTS

In women, compared with the lowest SUA quartile (Q1) group, the adjusted hazard ratios (95% confidence intervals) of prediabetes in the Q2, Q3, and Q4 groups were 1.03 (0.86-1.25), 1.41 (1.18-1.68), and 1.55 (1.30-1.84), respectively. However, in men, no significant association in the risk of prediabetes was found across quartiles of SUA. Furthermore, in women, restricted cubic spline analysis revealed the dose-response relationship between SUA and progression to prediabetes.

CONCLUSIONS

The results indicate that elevated serum SUA levels might be positively and independently associated with an increased risk of progression to prediabetes in Japanese women.

The Role of Uric Acid in Human Health: Insights from the Uricase Gene

Uric acid is the final product of purine metabolism and is converted to allantoin in most mammals via the uricase enzyme. The accumulation of loss of function mutations in the uricase gene rendered hominoids (apes and humans) to have higher urate concentrations compared to other mammals. The loss of human uricase activity may have allowed humans to survive environmental stressors, evolution bottlenecks, and life-threatening pathogens. While high urate levels may contribute to developing gout and cardiometabolic disorders such as hypertension and insulin resistance, low urate levels may increase the risk for neurodegenerative diseases. The double-edged sword effect of uric acid has resurrected a growing interest in urate's antioxidant role and the uricase enzyme's role in modulating the risk of obesity. Characterizing both the effect of uric acid levels and the uricase enzyme in different animal models may provide new insights into the potential therapeutic benefits of uric acid and novel uricase-based therapy.

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)'.

PFKFB3 Inhibits Fructose Metabolism in Pulmonary Microvascular Endothelial Cells

Pulmonary microvascular endothelial cells contribute to the integrity of the lung gas exchange interface, and they are highly glycolytic. Although glucose and fructose represent discrete substrates available for glycolysis, pulmonary microvascular endothelial cells prefer glucose over fructose, and the mechanisms involved in this selection are unknown. 6-Phosphofructo-2-kinase/fructose-2, 6-bisphosphatase 3 (PFKFB3) is an important glycolytic enzyme that drives glycolytic flux against negative feedback and links glycolytic and fructolytic pathways. We hypothesized that PFKFB3 inhibits fructose metabolism in pulmonary microvascular endothelial cells. We found that PFKFB3 knockout cells survive better than wild-type cells in fructose-rich medium under hypoxia. Seahorse assays, lactate and glucose measurements, and stable isotope tracing showed that PFKFB3 inhibits fructose-hexokinase-mediated glycolysis and oxidative phosphorylation. Microarray analysis revealed that fructose upregulates PFKFB3, and PFKFB3 knockout cells increase fructose-specific GLUT5 (glucose transporter 5) expression. Using conditional endothelial-specific PFKFB3 knockout mice, we demonstrated that endothelial PFKFB3 knockout increases lung tissue lactate production after fructose gavage. Last, we showed that pneumonia increases fructose in BAL fluid in mechanically ventilated ICU patients. Thus, PFKFB3 knockout increases GLUT5 expression and the hexokinase-mediated fructose use in pulmonary microvascular endothelial cells that promotes their survival. Our findings indicate that PFKFB3 is a molecular switch that controls glucose versus fructose use in glycolysis and help better understand lung endothelial cell metabolism during respiratory failure.

Effect of high-fructose consumption in pregnancy on the bone growth of offspring rats

Growing evidence suggests that bone health is programmed in early life. Maternal diet may influence the skeletal development of offspring. We aimed to determine the possible effects of high-fructose intake during pregnancy on different aspects of long bone morphology in the offspring of rats and to initially explore the possible mechanisms. Pregnant Sprague-Dawley rats were randomly divided into four groups and intragastrically administered the same dose of distilled water (CON, n = 12), 20 g/kg/day glucose (GLU, n = 12), 10 g/kg/day fructose (LFRU, n = 12), or 20 g/kg/day fructose (HFRU, n = 12) for 21 days during gestation. Computed tomography was used to analyze the cortical and cancellous bones of the distal femur of the offspring rats, and circulating bone metabolic biomarkers were measured using enzyme immunoassay. The results showed that high-fructose intake during pregnancy could decrease body weight, impair glucose metabolism, and increase serum leptin and uric acid in offspring. The offspring in the HFRU group had higher levels of the N-terminal propeptide of type I procollagen (PINP) and the C-telopeptide of type I collagen (CTX). The bone mean density (BMD), the total cross-sectional area inside the periosteal envelope (Tt.Ar), cortical bone area (Ct.Ar), medullary (or marrow) area (Ma.Ar), and trabecular mean density of the offspring in the HFRU group were lower than those in the CON group. Tartrate-resistant acid phosphatase (Trap) staining showed that high-fructose intake during pregnancy could increase the number of osteoclasts and increase the absorption area. Our results suggested that excessive fructose intake during pregnancy could inhibit skeletal development in offspring. Thus, attention to fructose intake during pregnancy is important for bone development in offspring.

Nonalcoholic Fatty Liver Disease and Chronic Kidney Disease Cross Talk

Nonalcoholic fatty liver disease is a multisystem condition with effects beyond the liver. The identification of chronic kidney disease as an independent mediator of nonalcoholic fatty liver disease or associated entity with shared cardiometabolic risk factors remains controversial and continues to draw scientific interest. With increasing prevalence of nonalcoholic fatty liver disease and lack of Food and Drug Administration approved therapies, these shared cardiometabolic risk factors have drawn significant attention. In this article, we review shared pathophysiological mechanisms between nonalcoholic fatty liver disease and chronic kidney disease along with current treatment strategies that might be useful for both disease processes.

Serum uric acid and the risk of gestational diabetes mellitus: a systematic review and meta-analysis

AIMS

Serum uric acid (SUA) is considered as a risk factor for gestational diabetes mellitus (GDM). However, current studies showed inconsistent results. This study aimed to explore the relationship between SUA levels and GDM risk.

METHODS

Eligible studies were retrieved from PubMed, Web of Science, Embase, China National Knowledge Infrastructure, and Wanfang databases up to November 1, 2022. The pooled standardized mean difference (SMD) and 95% confidence interval (CI) were used to represent the difference in SUA levels between GDM women and controls. The combined odds ratios (OR) and 95% CI were applied to assess association between SUA levels and GDM risk. Subgroup analyses were conducted on study continents, design, and quality, detection time of SUA, and GDM diagnostic criteria.

RESULTS

Totally 11 studies including five case-control and six cohort studies, in which 80,387 pregnant women with 9815 GDM were included. The overall meta-analysis showed that the mean SUA level in GDM group was significantly higher than in controls (SMD = 0.423, 95%CI = 0.019-0.826, p = .040, I² = 93%). Notably, pregnant women with elevated levels of SUA had a significantly increased risk of GDM (OR = 1.670, 95%CI = 1.184-2.356, p = .0035, I² = 95%). Furthermore, subgroup analysis performed on the detection time of SUA showed a significant difference in the association between SUA and GDM risk within different trimesters (1st trimester: OR = 3.978, 95%CI = 2.177-7.268; 1st to 2nd trimester: OR = 1.340, 95%CI = 1.078-1.667; p between subgroups <.01).

CONCLUSIONS

Elevated SUA was positively associated with GDM risk, particularly in the 1st trimester of pregnancy. Further studies with high quality are required to validate the findings of this study.

Elevated Serum Uric Acid Is Associated With Gestational Diabetes Mellitus: An Observational Cohort Study

CONTEXT

Elevated serum uric acid may be closely related to the occurrence of gestational diabetes mellitus (GDM).

OBJECTIVE

We aimed to elucidate the relationship between changes in serum uric acid before 24 weeks of gestation and the risk of GDM and associated adverse pregnancy outcomes and provide clinical epidemiological evidence for the involvement of uric acid in the etiology of GDM.

METHODS

We conducted a retrospective cohort study of 23 843 singleton pregnant women between February 2018 and June 2022. The exposure factor was serum uric acid before 24 weeks of gestation, primary outcome was gestational diabetes diagnosed at 24 to 28 weeks of gestation, and secondary outcomes were GDM A2 (GDM requiring pharmacotherapy), GDM combined with pre-eclampsia, preterm delivery, and large for gestational age infants. Adjusted risk ratios (RRs) were calculated using multivariate predictive marginal proportions from logistic regression models.

RESULTS

Among 23 843 singleton pregnant women, 3204 (13.44%) were diagnosed with GDM at 24 to 28 weeks of gestation, and elevated uric acid before 24 weeks of gestation was strongly associated with the risk of GDM. Compared with uric acid <240 µmol/L, the RR for GDM was 1.43 (95% CI 1.29-1.56) when uric acid was between 240 and 300 µmol/L; when uric acid was >300 µmol/L, the RR for GDM was 1.82 (95% CI 1.55-2.15). In secondary outcomes uric acid had a similar relationship with GDM A2, preterm birth, and GDM combined with pre-eclampsia.

CONCLUSION

Elevated uric acid levels before 24 weeks of gestation are associated with subsequent GDM; the best time to test for uric acid is before 18 weeks of gestation. Pregnant women with low and intermediate risk for GDM development may benefit more from serum uric acid measurements before 18 weeks of gestation.

Protective Effect of Hawthorn Fruit Extract against High Fructose-Induced Oxidative Stress and Endoplasmic Reticulum Stress in Pancreatic β-Cells

Hyperglycemia has deleterious effects on pancreatic β-cells, causing dysfunction and insulin resistance that lead to diabetes mellitus (DM). The possible causes of injury can be caused by glucose- or fructose-induced oxidative and endoplasmic reticulum (ER) stress. Hawthorn (Crataegus pinnatifida) fruit has been widely used as a hypolipidemic agent in traditional herbal medicine. The study aimed to investigate whether high fructose-induced pancreatic β-cell dysfunction could be reversed through amelioration of ER stress by the treatment of polyphenol-enriched extract (PEHE) from hawthorn fruit. The extract was partitioned using ethyl acetate as a solvent from crude water extract (WE) of hawthorn fruits, followed by column fractionation. The results showed that the contents of total polyphenols, flavonoids and triterpenoids in PEHE could be enhanced by 2.2-, 7.7- and 1.1-fold, respectively, in comparison to the original obtained WE from hawthorn fruit. In ER stress studies, a sharp increase in the inhibitory activity on the gene expression levels of GRP79, ATF6, IRE1α and CHOP involved in ER stress was evident when dosages of PEHE at 50–100 μg/mL were used against high-fructose (150 mM)-treated cells. HPLC–MS/MS analysis showed that polyphenols and flavonoids collectively accounted for 87.03% of the total content of PEHE.

High-Fructose Diet-Induced Hyperuricemia Accompanying Metabolic Syndrome-Mechanisms and Dietary Therapy Proposals

Fructose is often used as a food ingredient due to its low production costs and sweetening power. In recent years, it has been noticed that people on a Western diet high in fructose have high levels of uric acid in their blood. It was recognized that the specific metabolism of fructose in the body might cause increased production of uric acid, which then may affect the intensification of lipogenesis and the development of metabolic syndrome (MetS), insulin resistance, gout, cardiovascular diseases, leptin resistance, or non-alcoholic fatty liver disease. So far, to treat hyperuricemia, it has been recommended to use a low-purine diet characterized by limiting protein-containing products. However, this recommendation often leads to an increased intake of carbohydrate-rich foods that may contain fructose. Increased fructose consumption may enhance the secretion of uric acid again and, consequently, does not have therapeutic effects. Therefore, instead of a low-purine diet, using healthy diets, such as DASH or the Mediterranean diet, which can benefit metabolic parameters, could be a better proposal. This article provides an overview of this approach, focusing on MetS and hyperuricemia among high-fructose dieters.

Seeking Sweetness: A Systematic Scoping Review of Factors Influencing Sugar-Sweetened Beverage Consumption in Remote Indigenous Communities Worldwide

It is well-established that remote Indigenous communities have higher rates of sugar-sweetened beverage (SSB) consumption than non-Indigenous counterparts, which results in higher rates of chronic diseases such as type 2 diabetes mellitus (T2DM), obesity, and kidney disease. The aetiology leading to this behaviour remains understudied and overlooked. Therefore, the aim of this literature review is to understand the underpinning factors that contribute to SSB consumption in remote Indigenous communities. Studies were identified through five databases (n = 2529) and grey literature searching (n = 54). Following the PRISMA guidelines, each paper was assessed for eligibility, which left 34 studies for inclusion in the review. Within these papers, 37 different factors were found to influence SSB consumption in remote Indigenous communities. These were organised according to the Determinants of Nutrition and Eating (DONE) framework. SSB consumption was found to influence intake through each main level of the framework; individual (n = 9), interpersonal (n = 18), environmental (n = 9), and policy (n = 3). Preference was identified to be the most common factor to influence intake (n = 19), followed by health literacy (n = 15) and community availability (n = 12). Despite this, interventions to reduce SSB intake have never targeted this factor. This paper highlights the importance of a multi-level whole-of-system approach and suggests that an individual’s taste/preference should shape the direction of future research and intervention in this area.

Maternal fructose boosts the effects of a Western-type diet increasing SARS-COV-2 cell entry factors in male offspring

Fructose-rich beverages and foods consumption correlates with the epidemic rise in cardiovascular disease, diabetes and obesity. Severity of COVID-19 has been related to these metabolic diseases. Fructose-rich foods could place people at an increased risk for severe COVID-19. We investigated whether maternal fructose intake in offspring affects hepatic and ileal gene expression of proteins that permit SARS-CoV2 entry to the cell. Carbohydrates were supplied to pregnant rats in drinking water. Adult and young male descendants subjected to water, liquid fructose alone or as a part of a Western diet, were studied. Maternal fructose reduced hepatic SARS-CoV2 entry factors expression in older offspring. On the contrary, maternal fructose boosted the Western diet-induced increase in viral entry factors expression in ileum of young descendants. Maternal fructose intake produced a fetal programming that increases hepatic viral protection and, in contrast, exacerbates fructose plus cholesterol-induced diminution in SARS-CoV2 protection in small intestine of progeny.

Protective effect of melatonin on learning and memory impairment and hippocampal dysfunction in rats induced by high-fructose corn syrup

Objectives

We investigated the harmful effects of high fructose corn syrup (HFCS) on learning and memory in the hippocampus and the ameliorative effects of melatonin (Mel).

Materials and Methods

Thirty-six adult male Sprague Dawley rats were divided into three groups: Group I, control; Group II, HFCS; and Group III, HFCS+Mel. HFCS form F55 was prepared as a 20% fructose syrup solution. Rats in HFCS and HFCS+Mel groups were given drinking water for 10 weeks. Rats in the HFCS+Mel group have been given 10 mg/kg/day melatonin orally for the 6 weeks, in addition to HFCS 55. The Morris water maze (MWM) test was applied to all animals for 5 days to determine their learning and memory levels. After decapitation, one-half of the hippocampus samples were collected for western blot analysis, and another half of the tissues were collected for histopathological and immunohistochemical analyses.

Results

In the HFCS group, there was a significant difference between the time to find the platform in the MWM test and time spent in the quadrant between days 1 and 5 (P=0.037 and P=0.001, respectively). In addition, a decreased level of MT1A receptor, TNF-α, iNOS, osteopontin (OPN), and interleukin-6 (IL-6) expressions were significantly increased in the HFCS group. Melatonin treatment reversed MT1A receptor levels and TNF-α, iNOS, OPN, and IL-6 expressions. During the histopathological examination, increased neuronal degenerations were observed in the HFCS group. Melatonin ameliorated these changes.

Conclusion

Consumption of HFCS caused deterioration of learning and memory in adult rats. We suggest that melatonin is effective against learning and memory disorders.

Comparison of oral administration of fructose and glucose on food intake and physiological parameters in broiler chicks

Like glucose, fructose is a monosaccharide, but the mechanisms of its absorption and metabolism in the body are very different between the 2 molecules. In this study, we investigated the effects of oral administration of glucose and fructose on food intake, diencephalic gene expression, and plasma metabolite concentrations in broiler chicks. The animals used in this study were 4-day-old male broiler chicks (Ross 308). They were given glucose, fructose (200 mg/ 0.5 mL/ bird), or a similar volume of distilled water orally after 6 h fasting. After treatment, measurements of food intake (at 0, 30, and 60 min), and blood glucose as well as insulin concentrations were measured over time; however, diencephalic (hypothalamus) gene expression and plasma metabolites were measured at 30 min. The results showed that glucose administration suppressed food intake, but fructose administration did not suppress food intake and it was at the same level as distilled water administration. In addition, fructose administration did not increase plasma glucose and insulin levels as did glucose administration. In the diencephalon, expression levels of genes related to the melanocortin system were unaffected by the treatment, while gene expression levels related to intracellular energy regulation, such as AMP-activated protein kinase were affected by the glucose treatment in the fasted chicks. These results suggest that fructose administration does not suppress feeding behavior as a result of possible reduction in the energy levels in the diencephalon and associated energy metabolism.

Effects of Fructose and Stress on Rat Renal Copper Metabolism and Antioxidant Enzymes Function

The effects of a fructose-rich diet and chronic stress on copper metabolism in the kidneys are still understudied. We investigated whether fructose and/or chronic unpredictable stress modulate copper metabolism in a way that affects redox homeostasis, thus contributing to progression of metabolic disturbances in the kidney. We determined protein level of copper transporters, chaperones, and cuproenzymes including cytochrome c oxidase, as well as antioxidant enzymes function in the kidneys of male Wistar rats subjected to 20% liquid fructose supplementation and/or chronic stress. Liquid fructose supplementation increased level of copper chaperone of superoxide dismutase and decreased metallothionein level, while rendering the level of copper importer and copper chaperones involved in copper delivery to mitochondria and trans Golgi network unaffected. Stress had no effect on renal copper metabolism. The activity and expression of renal antioxidant enzymes remained unaltered in all experimental groups. In conclusion, fructose, independently of stress, decreased renal copper level, and modulated renal copper metabolism as to preserve vital cellular function including mitochondrial energy production and antioxidative defense, at the expense of intracellular copper storage.

Fasting serum fructose is associated with risk of gestational diabetes mellitus

Objective

To investigate the association of fasting serum fructose concentrations and the incidence of GDM.

Research design and methods

Five hundred twenty six pregnant women who attended the obstetric clinic of Xinhua Hospital, Chongming Branch were recruited prospectively from September 2019 to November 2020. Fasting serum fructose concentrations were measured by a validated liquid chromatography–tandem mass spectrometry method. GDM was diagnosed according to the criteria of the IADPSG. Independent sample t-test was used to compare the differences between groups. Multiple stepwise regression analysis was used to estimate the associations of serum fructose and other variables. Multivariate logistic regression models were adopted to evaluate the odds ratios (ORs) for GDM.

Results

Of the 526 pregnant women, 110 were diagnosed with GDM. Fasting fructose concentrations were increased significantly in GDM patients compared to those without GDM (1.30 ug/ml vs 1.16 ug/ml, p<0.001). Fasting fructose concentration was independently associated with GDM after adjusting the potential confounders, 1 ug/ml increase in fasting serum fructose level was associated with an 81.1% increased risk of GDM (1.811, [1.155-2.840]). Taking fructose <1.036 ug/ml as the reference, the OR for GDM was significantly higher in fructose ≥1.036 ug/ml group (OR, 1.669; 95% CI, 1.031–2.701) after all the potential confounders were adjusted.

Conclusions

Increased fasting serum fructose levels were independently associated with the incidence of GDM.

A Multivariate Analysis of “Metabolic Phenotype” Patterns in Children and Adolescents with Obesity for the Early Stratification of Patients at Risk of Metabolic Syndrome

Background: Metabolic syndrome (MS) is closely linked to obesity; however, not all individuals with obesity will develop obesity-related complications and a metabolically healthy obesity (MHO) group is also described. Objective: To perform a multivariate analysis (MVA) of the anthropometric and biochemical data in pediatric patients with obesity to reveal a “phenotype” predictive for MS. Methods: We analyzed 528 children with obesity (OB) and 119 normal-weight pediatric patients (NW). Adiposity indices were recorded, and MS was detected. MVA was performed. Results: Analysis of the structure of correlation of the variables showed that the variables of waist circumference (WC), body mass index (BMI), and estimated fat mass (eFM) were positively correlated with each other as a whole. In addition, the variables of the triglycerides (TG), triglyceride–glucose (TyG) index, and visceral adiposity index were positively correlated with each other as a whole, although none were correlated with the variables of BMI z-score, waist-to-height ratio, WC, eFM, or weight. The variables that related to insulin resistance (IR) and dyslipidemia were crucial for the early stratification of patients at risk of MS. Conclusions: Independently of body weight, IR, dyslipidemia, hypertriglyceridemia, and fat distribution seem to be the strongest MS risk factors. The early detection of and intervention in these modifiable risk factors are useful to protect children’s health.

The Association Between Frequent Sugar-Sweetened Beverage Intake and Sleep Duration in School Children: A Cross-Sectional Study

Background

Higher consumption of sugar-sweetened beverages (SSBs) maybe association with children's sleep pattern. However, few studies have considered this association in Asia, especially in school children. This study investigated the relationship between children's consumption frequency of such beverages and their sleep duration.

Methods

Participants aged 6–12 years were analyzed from two survey data in 2012 and 2013–2016 Nutrition and Health Surveys in Taiwan. A total of 2,628 participants were included in the analysis (2012, N = 1,267; 2013–2016, N = 1,361). Beverages weekly consumption were divided into low and high intake groups by medians cut-off points. The sleep variables were the sleep duration at night (including school days and weekends) and sleep debt. After controlling the confounders, the correlation between sugar-sweetened beverage consumption and sleep duration was examined using multinomial logistic regression analysis.

Results

The students slept for an average of 8.8 h on school days and 9.7 h on weekends. Relative to the low SSB intake group, the high intake group exhibited shorter sleep durations on school days (P < 0.001), greater sleep debt (P = 0.049). In logistic regression, high intake group were more likely to sleep for <8.5 h on school days (OR = 1.67, P = 0.002) and exhibit >2 h of sleep debt than low intake group (OR = 1.41, P = 0.022).

Conclusions

Children who had consumed sugar-sweetened beverages frequently slept for shorter durations at night on school days and exhibited greater sleep debt. The causal relationship was not clear. Nonetheless, these two factors are important in promoting children health.

The Sweet and Salty Dietary Face of Hypertension and Cardiovascular Disease in Lebanon

According to the World Health Organization (WHO), an estimated 1.28 billion adults aged 30–79 years worldwide have hypertension; and every year, hypertension takes 7.6 million lives. High intakes of salt and sugar (mainly fructose from added sugars) have been linked to the etiology of hypertension, and this may be particularly true for countries undergoing the nutrition transition, such as Lebanon. Salt-induced hypertension and fructose-induced hypertension are manifested in different mechanisms, including Inflammation, aldosterone-mineralocorticoid receptor pathway, aldosterone independent mineralocorticoid receptor pathway, renin-angiotensin system (RAS), sympathetic nervous system (SNS) activity, and genetic mechanisms. This review describes the evolution of hypertension and cardiovascular diseases (CVDs) in Lebanon and aims to elucidate potential mechanisms where salt and fructose work together to induce hypertension. These mechanisms increase salt absorption, decrease salt excretion, induce endogenous fructose production, activate fructose-insulin-salt interaction, and trigger oxidative stress, thus leading to hypertension. The review also provides an up-to-date appraisal of current intake levels of salt and fructose in Lebanon and their main food contributors. It identifies ongoing salt and sugar intake reduction strategies in Lebanon while acknowledging the country’s limited scope of regulation and legislation. Finally, the review concludes with proposed public health strategies and suggestions for future research, which can reduce the intake levels of salt and fructose levels and contribute to curbing the CVD epidemic in the country.

Dietary fructose and its association with the metabolic syndrome in Lebanese healthy adults: a cross-sectional study

BACKGROUND

Epidemiological studies investigating the association between dietary fructose intake and the metabolic syndrome (MetS) are scarce and have produced controversial findings. This study aimed at (1) assessing total dietary fructose intake in a sample of Lebanese healthy adults, and determining the intake levels of natural vs. added fructose; (2) investigating the association of dietary fructose with MetS; and (3) identifying the socioeconomic and lifestyle factors associated with high fructose intake.

METHODS

A cross-sectional survey was conducted on a representative sample of adults living in Beirut, Lebanon (n = 283). Anthropometric and biochemical data were collected, and dietary intake was assessed using a food frequency questionnaire. Intakes of naturally-occurring fructose from fructose-containing food sources, such as fruits, vegetables, honey, were considered as "natural fructose". Acknowledging that the most common form of added sugar in commodities is sucrose or High Fructose Corn Syrup (HFCS), 50% of added sugar in food products was considered as added fructose. Total dietary fructose intake was calculated by summing up natural and added fructose intakes. Logistic regression analyses were conducted to investigate the association of total, added and natural fructose intakes with the MetS and to identify the socioeconomic predictors of high fructose intake.

RESULTS

Mean intake of total fructose was estimated at 51.42 ± 35.54 g/day, representing 6.58 ± 3.71% of energy intakes (EI). Natural and added fructose intakes were estimated at 12.29 ± 8.57 and 39.12 ± 34.10 g/day (1.78 ± 1.41% EI and 4.80 ± 3.56% EI), respectively. Participants in the highest quartile of total and added fructose intakes had higher odds of MetS (OR = 2.84, 95%CI: 1.01, 7.94 and OR = 3.18, 95%CI: 1.06, 9.49, respectively). In contrast, natural fructose intake was not associated with MetS. Age, gender and crowding index were identified as factors that may modulate dietary fructose intakes.

CONCLUSIONS

The observed association between high added fructose intake and the MetS highlights the need for public health strategies aimed at limiting sugar intake from industrialized foods and promoting healthier dietary patterns in Lebanon.

Comparison of bovine serum albumin glycation by ribose and fructose in vitro and in vivo

Advanced glycation end products (AGEs) play a critical pathogenic role in the development of diabetic complications. Recent studies have shown that diabetes is associated with not only abnormal glucose metabolism but also abnormal ribose and fructose metabolism, although glucose is present at the highest concentration in humans. The glycation ability and contribution of ribose and fructose to diabetic complications remain unclear. Here, the glycation ability of ribose, fructose and glucose under a mimic physiological condition, in which the concentration of ribose or fructose was one-fiftieth that of glucose, was compared. Bovine serum albumin (BSA) was used as the working protein in our experiments. Ribose generated more AGEs and was markedly more cytotoxic to SH-SY5Y cells than fructose. The first-order rate constant of ribose glycation was found to be significantly greater than that of fructose glycation. LC-MS/MS analysis revealed 41 ribose-glycated Lys residues and 12 fructose-glycated residues. Except for the shared Lys residues, ribose reacted selectively with 17 Lys, while no selective Lys was found in fructose-glycated BSA. Protein conformational changes suggested that ribose glycation may induce BSA into amyloid-like monomers compared with fructose glycation. The levels of serum ribose were correlated positively with glycated serum protein (GSP) and diabetic duration in type 2 diabetes mellitus (T2DM), respectively. These results indicate that ribose has a greater glycation ability than fructose, while ribose largely contributes to the production of AGEs and provides a new insight to understand in the occurrence and development of diabetes complications.

Fructose Induces Insulin Resistance of Gestational Diabetes Mellitus in Mice via the NLRP3 Inflammasome Pathway

BACKGROUND

Insulin resistance (IR), which is affected by dietary factors, is the main pathology underlying of gestational diabetes mellitus (GDM). Fructose (Fru), a sugar found in fruits, honey, and food sweeteners, has been reported to induce IR and inflammation. This study explored the effects and mechanisms of Fru on IR of GDM in pregnant and postpartum mice and their offspring.

METHODS

The 6-week-old female C57BL/6J mice were randomly divided into control (Chow) and fructose (Fru) groups, with the latter receiving 20% (w/v) Fru in drinking water from 2 weeks before pregnancy to the end of pregnancy. The effects of Fru on IR and inflammation were determined using serum parameters, glucose metabolism tests, immunohistochemistry, and western blotting.

RESULTS

Compared with the Chow group mice, pregnant mice treated with Fru exhibited greater gestational weight gain, higher fasting blood glucose and insulin concentrations, and a higher homeostasis model of assessment (HOMA) for IR index, but a lower HOMA for insulin sensitivity index. Treatment with Fru also increased the concentrations of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), IL-17, and C-reactive protein in sera and the expression of IL-6, TNF-α, IL-17, and IL-1β mRNA in liver tissues of pregnant mice. Both CD68 and IL-1β positive cell were increased in Fru-treated mice compared with in Chow mice. Fru treatment also promoted IR and inflammation in mice at 4 weeks after delivery and in offspring mice. Mechanistically, Fru promoted the nuclear translocation of nuclear factor-kappa B (NF-κB) p65 to activate the nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome.

CONCLUSIONS

Exposure to Fru before and during pregnancy induced IR in pregnant mice, which continued at 4 weeks postpartum and affected the offspring. The effects of Fru may be associated with activation of the NF-κB-NLRP3 pathway.

Fructose-Rich Diet Is a Risk Factor for Metabolic Syndrome, Proximal Tubule Injury and Urolithiasis in Rats

Excessive consumption of fructose (FR) leads to obesity, metabolic syndrome (MS) and insulin resistance, which are known risk factors for kidney stones. The epidemiological study has suggested the association between fructose consumption and urolithiasis, but the precise mechanism is still not well understood. Male Wistar rats were assigned for 8 weeks to three groups with different FR content in diet: RD (n = 5)-regular diet with a FR < 3%; F10 (n = 6)-regular diet with an addition of 10% Fr in drinking water; F60 (n = 5)-60% FR as a solid food. Serum concentration of FR, creatinine (Cr), insulin (Ins), triglycerides (Tg), homocysteine (HCS), uric acid (UA), calcium (Ca), phosphate (Pi), magnesium (Mg) and sodium (Na) were measured. Based on 24 h urine collection the following tests were performed: urine pH, proteinuria (PCR), excretion of N-Acetyl-(D)-Glucosaminidase (NAG), monocyte chemoattractant protein (MCP-1), uric acid (uUAEx), phosphate (uPiEx), calcium (uCaEx), magnesium (uMgEx) and sodium (uNaEx). The creatinine clearance (CrCl) was calculated. Calcium deposits in kidney sections were examined using hematoxylin and eosin (HE) and von Kossa stains. The rats on F10 and F60, as compared to the RD diet, showed a tendency for lower CrCl, higher HCS level and some features of MS as higher Ins and TG levels. Interestingly, F10 (fluid) versus F60 (solid) diet led to higher serum Ins levels. F10 and F60 versus RD demonstrated higher urinary excretion of MCP-1 and NAG which were suggestive for inflammatory injury of the proximal tubule. F10 and F60 as compared to RD showed significantly lower uUAEx, although there were no differences in clearance and fractional excretion of UA. F60 versus RD induced severe phosphaturia (>30×) and natriuria (4×) and mild calciuria. F10 versus RD induced calciuria (3×), phosphaturia (2×) and mild natriuria. Calcium phosphate stones within the tubules and interstitium were found only in rats on FR diet, respectively, in two rats from the F10 group and another two in the F60 group. The rats which developed stones were characterized by significantly higher serum insulin concentration and urinary excretion of calcium and magnesium. A fructose-rich diet may promote development of calcium stones due to proximal tubule injury and metabolic syndrome.

Fructose Induces Visceral Adipose Tissue Inflammation and Insulin Resistance Even Without Development of Obesity in Adult Female but Not in Male Rats

Introduction: Obesity and related metabolic disturbances are frequently related to modern lifestyle and are characterized by excessive fructose intake. Visceral adipose tissue (VAT) inflammation has a central role in the development of insulin resistance, type 2 diabetes (T2D), and metabolic syndrome. Since sex-related differences in susceptibility and progression of metabolic disorders are not yet fully understood, our aim was to examine inflammation and insulin signaling in VAT of fructose-fed female and male adult rats. Methods: We analyzed effects of 9-week 10% fructose-enriched diet on energy intake, VAT mass and histology, and systemic insulin sensitivity. VAT insulin signaling and markers of VAT inflammation, and antioxidative defense status were also evaluated. Results: The fructose diet had no effect on VAT mass and systemic insulin signaling in the female and male rats, while it raised plasma uric acid, increased PPARγ level in the VAT, and initiated the development of a distinctive population of small adipocytes in the females. Also, adipose tissue insulin resistance, evidenced by increased PTP1B and insulin receptor substrate 1 (IRS1) inhibitory phosphorylation and decreased Akt activity, was detected. In addition, fructose stimulated the nuclear accumulation of NFκB, increased expression of proinflammatory cytokines (IL-1β, IL-6, and TNFα), and protein level of macrophage marker F4/80, superoxide dismutase 1, and glutathione reductase. In contrast to the females, the fructose diet had no effect on plasma uric acid and VAT inflammation in the male rats, but less prominent alterations in VAT insulin signaling were observed. Conclusion: Even though dietary fructose did not elicit changes in energy intake and led to obesity in the females, it initiated the proliferation of small-sized adipocytes capable of storing fats further. In contrast to the males, this state of VAT was accompanied with enhanced inflammation, which most likely contributed to the development of insulin resistance. The observed distinction could possibly originate from sex-related differences in uric acid metabolism. Our results suggest that VAT inflammation could precede obesity and start even before the measurable increase in VAT mass, making it a silent risk factor for the development of T2D. Our results emphasize that adipose tissue dysfunction, rather than its simple enlargement, could significantly contribute to the onset and development of obesity and related metabolic disorders.

Role of Glycation in Type 2 Diabetes Mellitus and Its Prevention through Nymphaea Species

The dysregulation of glucose metabolism that includes the modification of biomolecules with the help of glycation reaction results in the formation of advanced glycation end products (AGEs). The formation of AGEs may activate receptors for advanced glycation end products which induce intracellular signaling, ultimately enhancing oxidative stress, a well-known contributor to type 2 diabetes mellitus. In addition, AGEs are possible therapeutic targets for the treatment of type 2 diabetes mellitus and its complications. This review article highlights the antioxidant, anti-inflammatory, and antidiabetic properties of the Nymphaea species, and the screening of such aquatic plants for antiglycation activity may provide a safer alternative to the adverse effects related to glucotoxicity. Since oxidation and glycation are relatively similar to each other, therefore, there is a possibility that the Nymphaea species may also have antiglycating properties because of its powerful antioxidant properties. Herbal products and their derivatives are the preeminent resources showing prominent medicinal properties for most of the chronic diseases including type 2 diabetes mellitus. Among these, the Nymphaea species has also shown elevated activity in scavenging free radicals. This species has a load of phytochemical constituents which shows various therapeutic and nutritional value including anti-inflammatory and antioxidant profiles. To the best of our knowledge, this is the first article highlighting the possibility of an antiglycation value of the Nymphaea species by inhibiting AGEs in mediation of type 2 diabetes mellitus. We hope that in the next few years, the clinical and therapeutic potential may be explored and highlight a better perspective on the Nymphaea species in the inhibition of AGEs and its associated diseases such as type 2 diabetes mellitus.

Phylogenetic articulation of uric acid evolution in mammals and how it informs a therapeutic uricase

The role of uric acid during primate evolution has remained elusive ever since it was discovered over 100 years ago that humans have unusually high levels of the small molecule in our serum. It has been difficult to generate a neutral or adaptive explanation in part because the uricase enzyme evolved to become a pseudogene in apes thus masking typical signals of sequence evolution. Adding to the difficulty is a lack of clarity on the functional role of uric acid in apes. One popular hypothesis proposes that uric acid is a potent antioxidant that increased in concentration to compensate for the lack of vitamin C synthesis in primate species ∼65 million years ago (Mya). Here, we have expanded on our previous work with resurrected ancient uricase proteins to better resolve the reshaping of uricase enzymatic activity prior to ape evolution. Our results suggest that the pivotal death-knell to uricase activity occurred between 20-30 Mya despite small sequential modifications to its catalytic efficiency for the tens of millions of years since primates lost their ability to synthesize vitamin C, and thus the two appear uncorrelated. We also use this opportunity to demonstrate how molecular evolution can contribute to biomedicine by presenting ancient uricases to human immune cells that assay for innate reactivity against foreign antigens. A highly stable and highly catalytic ancient uricase is shown to elicit a lower immune response in more human haplotypes than other uricases currently in therapeutic development.

High Fructose Intake Contributes to Elevated Diastolic Blood Pressure in Adolescent Girls: Results from The HELENA Study

BACKGROUND

The association between high fructose consumption and elevated blood pressure continues to be controversial, especially in adolescence. The aim of this study was to assess the association between fructose consumption and elevated blood pressure in an European adolescent population.

METHODS

A total of 1733 adolescents (mean ± SD age: 14.7 ± 1.2; percentage of girls: 52.8%) were analysed from the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study in eight European countries. Blood pressure was measured using validated devices and methods for measuring systolic blood pressure (SBP) and diastolic blood pressure (DBP). Dietary data were recorded via repeated 24 h recalls (using specifically developed HELENA-DIAT software) and converted into pure fructose (monosaccharide form) and total fructose exposure (pure fructose + fructose from sucrose) intake using a specific fructose composition database. Food categories were separated at posteriori in natural vs. were non-natural foods. Elevated BP was defined according to the 90th percentile cut-off values and was compared according to tertiles of fructose intake using univariable and multivariable mixed logistic regression models taking into account confounding factors: centre, sex, age and z-score-BMI, MVPA (Moderate to Vigorous Physical Activity) duration, tobacco consumption, salt intake and energy intake.

RESULTS

Pure fructose from non-natural foods was only associated with elevated DBP (DBP above the 10th percentile in the highest consuming girls (OR = 2.27 (1.17-4.40); p = 0.015) after adjustment for cofounding factors.

CONCLUSIONS

Consuming high quantities of non-natural foods was associated with elevated DBP in adolescent girls, which was in part due to high fructose levels in these foods categories. The consumption of natural foods containing fructose, such as whole fruits, does not impact blood pressure and should continue to remain a healthy dietary habit.

Sugar sweetened beverages and increasing prevalence of type 2 diabetes in the Indigenous community of Australia

AIMS

The aim of this viewpoint was to discuss a profound health gap in type 2 diabetes that exists between Indigenous and non-Indigenous Australians.

DATA SYNTHESIS

In Australia, type 2 diabetes is ranked as the fastest growing chronic condition, with the rates of type 2 diabetes higher among Indigenous than non-Indigenous Australians. Improvements to diet could aid in reducing overweight and obesity in the Indigenous community, with sugar sweetened beverages (SSBs) examples of discretionary foods that contain a high amount of sugar. The marked increase in type 2 diabetes, obesity and consumption of SSBs in the Indigenous community may suggest that type 2 diabetes may result from weight gain caused by SSB consumption. Recent evidence suggests that higher consumption of SSBs was associated with greater incidence of type 2 diabetes independent of adiposity. Some determinants influencing increased SSBs consumption in the Indigenous population include advertising, marketing, availability and affordability.

CONCLUSIONS

The prevalence rates of type 2 diabetes continue to be higher among Indigenous than non-Indigenous Australians and overall, a link between SSBs and risk of type 2 diabetes is reported. Three solutions to high SSBs consumption in Indigenous communities include increased availability, affordability, and accessibility of healthy food and drink, engagement of Indigenous people in offering solutions including discussion of a sugar tax on SSBs framed with Indigenous input, and the provision of clean community water supply and water bubblers.

Association between sugar and starch intakes and type 2 diabetes risk in middle-aged adults in a prospective cohort study

OBJECTIVES

We aimed to investigate the association between sugar or starch intake and the risk of type 2 diabetes (T2D) in middle-aged Japanese adults.

SUBJECTS/METHODS

Participants comprised 27,797 men and 36,880 women aged 45-75 years with no history of diabetes and critical illness before the second survey in the Japan Public Health Center-based Prospective Study. We calculated sugar (total sugar, total fructose, and sugar subtypes) and starch intakes (% energy/d) using a validated 147-item food frequency questionnaire, to estimate the average dietary intake over the previous year. T2D onset was defined by validated self-reports. ORs adjusted for potential confounders were estimated using multiple logistic regression with categorical and cubic spline models.

RESULTS

During the 5-year follow-up, 690 men and 500 women were identified with T2D. In women, the quartiles of total sugar or total fructose intakes were not significantly associated with T2D risk; however, the spline curves showed an increased risk at extremely high intake levels (ORs [95% CI]: 1.88 [1.07-3.31] at 30% energy/d for total sugar and 1.87 [1.10-3.16] at 14% energy/d for total fructose). Starch intake was positively associated with T2D risk among women in the categorical and spline models (ORs [95% CI]: 1.55 [1.13-2.12] at 50% energy/d). In men, sugar and starch intakes were not associated with T2D risk.

CONCLUSIONS

In this large-scale population-based cohort study, starch intake was associated with an increased T2D risk in Japanese women. An increased risk with extremely high intake of total sugar or total fructose among women cannot be disregarded.

Exenatide-loaded inside-porous poly(lactic-co-glycolic acid) microspheres as a long-acting drug delivery system with improved release characteristics

The glucagon-like peptide-1 receptor agonist exenatide (EXT) is an effective treatment for type 2 diabetes. However, this peptide has a short biological half-life and the delayed release characteristic of current formulations limit its clinical application. Herein, we prepared EXT-loaded inside-porous poly(d,l-lactic-co-glycolic acid (PLGA) microspheres with outside layers (EXT-PMS) using a W₁/O/W₂ emulsion method with a microfluidic technique and its fabrication and formulation conditions were systematically investigated. In vitro dissolution experiments showed that the PLGA concentration, proportion of drug and oil phase, and the number and size of pores strongly affected the release behaviors of EXT-PMS. In vitro, the optimized EXT-PMS with large internal pores exhibited rapid and stable release without a lag phase. In a rat model, subcutaneous administration of the product yielded plasma concentrations of EXT that was sustained for 30 days with low burst and no delayed-release effect. The preparation of inside-porous microspheres is lighting up the development of long-acting drug delivery systems for other drugs with favorable release characteristics.

CRISPR-Cas9-mediated reactivation of the uricase pseudogene in human cells prevents acute hyperuricemia

The utility of CRISPR-Cas9 to repair or reverse diseased states that arise from recent genetic mutations in the human genome is now widely appreciated. The use of CRISPR to "design" the outcomes of biology is challenged by both specialized ethicists and the general public. Less of a focus, however, is the ability of CRISPR to provide metabolic supplements or prophylactic molecules that improve long-term human health by overwriting ancient evolutionary events. Here, we use CRISPR to genomically integrate a functional uricase gene that encodes an enzymatically active protein into the human genome. These uricase-producing cells are able to reduce or even eliminate high concentrations of exogenous uric acid despite the enzyme being localized to peroxisomes. Our evolutionary engineered cells represent the first instance of the primate ape lineage expressing a functional uricase encoded in the genome within the last 20 million years. We anticipate that human cells expressing uricase will help prevent hyperuricemia (including gout) as well as hypertension and will help protect against fatty liver disease in the future.

Vitamin D3 potentiates the nephroprotective effects of vildagliptin-metformin combination in a rat model of metabolic syndrome

The current study was conducted to investigate the nephroprotective effects of vildagliptin-metformin combination in an experimental model of fructose/salt-induced metabolic syndrome (MetS). A major aim was to evaluate the potential capacity of vitamin D3 to potentiate the pleiotropic nephroprotective effects of vildagliptin-metformin combination. MetS was induced in adult male Wistar rats by adding fructose (10%) to everyday drinking water and salt (3%) to the diet for 6 weeks. Along with the same concentrations of fructose/salt feeding, MetS rats were then treated orally with either vildagliptin (10 mg/kg/day)-metformin (200 mg/kg/day) combination, vitamin D3 (10 μg/kg/day), or the triple therapy for a further 6 weeks. The incidence of MetS was confirmed 6 weeks after fructose/salt consumption, when the rats exhibited significant weight gain, dyslipidemia, hyperuricemia, insulin resistance, hyperinsulinemia, and impaired glucose tolerance. At the end of the 12-week experimental period, MetS rats displayed significantly deteriorated renal function, enhanced intrarenal oxidative stress and inflammation together with exaggerated renal histopathological damages and interstitial fibrosis. The study has corroborated antioxidant, anti-inflammatory, and antifibrotic effects of vildagliptin-metformin combination, vitamin D3, and the triple collaborative therapy, conferring renoprotection in the setting of MetS. Due attention has been paid to the crucial role of dipeptidyl peptidase-4 inhibition and sirtuin-1/5' adenosine monophosphate-activated protein kinase activation as novel therapeutic targets to optimize renoprotection. The apparent potentiating effect, evoked upon coadministration of vitamin D3 with vildagliptin-metformin combination, may provide a cornerstone for further clinical investigations.

Different Food Sources of Fructose-Containing Sugars and Fasting Blood Uric Acid Levels: A Systematic Review and Meta-Analysis of Controlled Feeding Trials

BACKGROUND

Although fructose as a source of excess calories increases uric acid, the effect of the food matrix is unclear.

OBJECTIVES

To assess the effects of fructose-containing sugars by food source at different levels of energy control on uric acid, we conducted a systematic review and meta-analysis of controlled trials.

METHODS

MEDLINE, Embase, and the Cochrane Library were searched (through 11 January 2021) for trials ≥ 7 days. We prespecified 4 trial designs by energy control: substitution (energy-matched replacement of sugars in diets); addition (excess energy from sugars added to diets); subtraction (energy from sugars subtracted from diets); and ad libitum (energy from sugars freely replaced in diets) designs. Independent reviewers (≥2) extracted data and assessed the risk of bias. Grading of Recommendations, Assessment, Development, and Evaluation was used to assess the certainty of evidence.

RESULTS

We included 47 trials (85 comparisons; N = 2763) assessing 9 food sources [sugar-sweetened beverages (SSBs), sweetened dairy, fruit drinks, 100% fruit juice, fruit, dried fruit, sweets and desserts, added nutritive sweetener, and mixed sources] across 4 energy control levels in predominantly healthy, mixed-weight adults. Total fructose-containing sugars increased uric acid levels in substitution trials (mean difference, 0.16 mg/dL;  95% CI:  0.06-0.27 mg/dL;  P = 0.003), with no effect across the other energy control levels. There was evidence of an interaction by food source: SSBs and sweets and desserts increased uric acid levels in the substitution design, while SSBs increased and 100% fruit juice decreased uric acid levels in addition trials. The certainty of evidence was high for the increasing effect of SSBs in substitution and addition trials and the decreasing effect of 100% fruit juice in addition trials and was moderate to very low for all other comparisons.

CONCLUSIONS

Food source more than energy control appears to mediate the effects of fructose-containing sugars on uric acid. The available evidence provides reliable indications that SSBs increase and 100% fruit juice decreases uric acid levels. More high-quality trials of different food sources are needed. This trial was registered at clinicaltrials.gov as NCT02716870.

Impact of Coffee/Green Tea/Soft Drink Consumption on the Risk of Hyperuricemia: A Cross-Sectional Study

This cross-sectional study aimed to investigate the association between hyperuricemia and the frequency of coffee, tea, and soft drink consumption, based on data from the Korean Genome and Epidemiology Study (KoGES) (2004-2016). We used the KoGES health examinee data, obtained from urban residents aged ≥ 40 years. Information on the participants' medical history, nutrition (total calorie, protein, fat, and carbohydrate intake), frequency of alcohol consumption, smoking status, household income, and frequency of coffee/green tea/soft drink intake was collected. A logistic regression model was used to analyze the data. Subgroup analyses were performed according to the participant's age and sex. Among 173,209 participants, there were 11,750 and 156,002 individuals with hyperuricemia and non-hyperuricemia controls, respectively. In an adjusted model, frequent coffee and green tea consumption did not increase the risk of hyperuricemia, compared to the "no intake" reference group. However, an adjusted odds ratio of hyperuricemia was 1.23 (95% confidence interval, 1.11-1.35, p < 0.001) for participants who reported consuming soft drinks ≥ 3 times per day, compared to the respective "no drink" reference group. Even after adjusting for nutritional and sociodemographic factors, frequent soft drink intake was associated with an increased risk of hyperuricemia. Meanwhile, neither coffee nor green tea intake was associated with an increased risk of hyperuricemia.

Protective Effect of Jiang Tang Xiao Ke Granules against Skeletal Muscle IR via Activation of the AMPK/SIRT1/PGC-1α Signaling Pathway

The Jiang Tang Xiao Ke (JTXK) granule is a classic Chinese herbal formula that has been put into clinical use in the treatment of type 2 diabetes mellitus for decades. However, whether its ability to ameliorate skeletal muscle insulin resistance (IR) is through modulation of the AMPK/SIRT1/PGC-1α signaling pathway remains unknown. Therefore, we aimed to investigate the effects of JTXK granules on IR in skeletal muscle of high-fat diet-induced diabetic mice and C2C12 cells and analyze the underlying mechanisms. In the present study, we showed that JTXK granules attenuated body weight gain, reduced body fat mass, improved body lean mass, and enhanced muscle performance of diabetic mice. JTXK granules also improved glucose metabolism and skeletal muscle insulin sensitivity and partially reversed abnormal serum lipid levels, which might be related to the regulation of the AMPK/SIRT1/PGC-1α pathway, both in skeletal muscle tissue of diabetic mice and in C2C12 cells. Furthermore, drug-containing serum of JTXK granules was capable of enhancing glucose uptake and mitochondrial respiration in C2C12 cells, and AMPKα was proven to be closely involved in this process. Taken together, these results suggest that the JTXK granule ameliorates skeletal muscle IR through activation of the AMPK/SIRT1/PGC-1α signaling pathway, which offers a novel perspective of this formula to combat IR-related metabolic diseases.

Endogenous Fructose Metabolism Could Explain the Warburg Effect and the Protection of SGLT2 Inhibitors in Chronic Kidney Disease

Chronic low-grade inflammation underlies the pathogenesis of non-communicable diseases, including chronic kidney diseases (CKD). Inflammation is a biologically active process accompanied with biochemical changes involving energy, amino acid, lipid and nucleotides. Recently, glycolysis has been observed to be increased in several inflammatory disorders, including several types of kidney disease. However, the factors initiating glycolysis remains unclear. Added sugars containing fructose are present in nearly 70 percent of processed foods and have been implicated in the etiology of many non-communicable diseases. In the kidney, fructose is transported into the proximal tubules via several transporters to mediate pathophysiological processes. Fructose can be generated in the kidney during glucose reabsorption (such as in diabetes) as well as from intra-renal hypoxia that occurs in CKD. Fructose metabolism also provides biosynthetic precursors for inflammation by switching the intracellular metabolic profile from mitochondrial oxidative phosphorylation to glycolysis despite the availability of oxygen, which is similar to the Warburg effect in cancer. Importantly, uric acid, a byproduct of fructose metabolism, likely plays a key role in favoring glycolysis by stimulating inflammation and suppressing aconitase in the tricarboxylic acid cycle. A consequent accumulation of glycolytic intermediates connects to the production of biosynthetic precursors, proteins, lipids, and nucleic acids, to meet the increased energy demand for the local inflammation. Here, we discuss the possibility of fructose and uric acid may mediate a metabolic switch toward glycolysis in CKD. We also suggest that sodium-glucose cotransporter 2 (SGLT2) inhibitors may slow the progression of CKD by reducing intrarenal glucose, and subsequently fructose levels.

The Speed of Ingestion of a Sugary Beverage Has an Effect on the Acute Metabolic Response to Fructose

BACKGROUND

The consumption of sweetened beverages is associated with increased risk of metabolic syndrome, cardiovascular disease, and type 2 diabetes mellitus.

OBJECTIVE

We hypothesized that the metabolic effects of fructose in sugary beverages might be modulated by the speed of ingestion in addition to the overall amount.

DESIGN

Thirty healthy subjects free of any disease and medication were recruited into two groups. After overnight fasting, subjects in group 1 drank 500 mL of apple juice over an hour by drinking 125 mL every 15 min, while subjects in group 2 drank 500 mL of apple juice over 5 min. Blood samples were collected at time zero and 15, 30, 60, and 120 min after ingestion to be analyzed for serum glucose, insulin, homeostatic model assessment (HOMA-IR) score, fibroblast growth factor 21, copeptin, osmolarity, sodium, blood urea nitrogen (BUN), lactate, uric acid, and phosphate levels.

RESULTS

Serum glucose, insulin, HOMA-IR, fibroblast growth factor 21, copeptin, osmolarity, sodium, BUN, and lactate levels increased following apple juice ingestion. The increases were greater in the fast-drinking group, which were more significant after 15 min and 30 min compared to baseline. The changes in uric acid were not statistically different between the groups. Phosphate levels significantly increased only in the fast-drinking group.

CONCLUSION

Fast ingestion of 100% apple juice causes a significantly greater metabolic response, which may be associated with negative long-term outcomes. Our findings suggest that the rate of ingestion must be considered when evaluating the metabolic impacts of sweetened beverage consumption.

The high-fructose intake of dams during pregnancy and lactation exerts sex-specific effects on adult rat offspring metabolism

Experimental studies have demonstrated the effects of maternal fructose consumption during pregnancy and lactation on metabolic alterations in their offspring, especially male offspring. However, few studies have focused on female offspring after providing fructose in food to dam rats. Here, we studied whether offspring of both sexes were differentially affected by a maternal high-fructose diet (HFD). For this purpose, Sprague-Dawley rats were fed during pregnancy and lactation with a standard diet (SD) or a HFD (50% w/w). After weaning, offspring were fed an SD; 3 days later, dams were sacrificed, and their offspring were sacrificed on postnatal day 90. Body weight (BW), food and water intake (only for dams), and various biomarkers of metabolic syndrome were measured. When compared to the SD-fed dams, HFD-fed dams had a reduction in BW and food and water intake. Conversely, adiposity, liver weight, liver lipids, and plasma levels of glucose, insulin, cholesterol, triglycerides, and uric acid were increased in HFD-fed dams. Moreover, the BW, food consumption, weight of retroperitoneal fat pads, and liver lipids increased in female and male offspring of HFD-fed dams. Interestingly, the pups of HFD-fed mothers showed increased levels of leptin and insulin resistance and decreased levels of adiponectin which were more pronounced in male offspring than in female offspring. In contrast, a higher increase in BW was shown earlier in female offspring. Thus, high-fructose consumption by dams during pregnancy and lactation led to sex-specific developmental programming of the metabolic syndrome phenotype in adult offspring.

The relationship between excessive dietary fructose consumption and paediatric fatty liver disease

The global prevalence of non-alcoholic fatty liver disease (NAFLD) in children and adolescents is escalating and currently represents the most common chronic liver disease in the paediatric population. NAFLD is associated with high daily caloric intake and sedentary behaviour, with excessive consumption of added sugar emerging as an important contributor to NAFLD risk in children. This is a particularly important factor for adolescents with obesity, who are the heaviest consumers of added sugar. Table sugar, or sucrose, is a disaccharide comprised of fructose and glucose, yet only fructose has been strongly linked to NAFLD pathogenesis largely due to the unique characteristics of its metabolism and detrimental effects on key metabolic pathways. To date, the relationship between excessive fructose intake and risk of NAFLD in children and adolescents remains incompletely understood, and it is not yet known whether fructose actually causes NAFLD or instead exacerbates hepatic fat accumulation and possible hepatocellular injury only within the context of cardiometabolic factors. The purpose of this review is to summarize recent studies linking fructose consumption with NAFLD in the paediatric population and integrate results from interventional studies of fructose restriction in children and adolescents on NAFLD and related metabolic markers. Given the overall positive impact of lifestyle modifications in the management of paediatric NAFLD, reduction of added sugar consumption may represent an important, early opportunity to mitigate or prevent NAFLD in high-risk children and adolescents.