Effects of a low free sugar diet on the management of nonalcoholic fatty liver disease: a randomized clinical trial

NAFLD Fibrosis Progression and Type 2 Diabetes: The Hepatic-Metabolic Interplay

The bidirectional relationship between type 2 diabetes and (non-alcoholic fatty liver disease) NAFLD is indicated by the higher prevalence and worse disease course of one condition in the presence of the other, but also by apparent beneficial effects observed in one, when the other is improved. This is partly explained by their belonging to a multisystemic disease that includes components of the metabolic syndrome and shared pathogenetic mechanisms. Throughout the progression of NAFLD to more advanced stages, complex systemic and local metabolic derangements are involved. During fibrogenesis, a significant metabolic reprogramming occurs in the hepatic stellate cells, hepatocytes, and immune cells, engaging carbohydrate and lipid pathways to support the high-energy-requiring processes. The natural history of NAFLD evolves in a variable and dynamic manner, probably due to the interaction of a variable number of modifiable (diet, physical exercise, microbiota composition, etc.) and non-modifiable (genetics, age, ethnicity, etc.) risk factors that may intervene concomitantly, or subsequently/intermittently in time. This may influence the risk (and rate) of fibrosis progression/regression. The recognition and control of the factors that determine a rapid progression of fibrosis (or its regression) are critical, as the fibrosis stages are associated with the risk of liver-related and all-cause mortality.

Different dietary carbohydrate component intakes and long-term outcomes in patients with NAFLD: results of longitudinal analysis from the UK Biobank

BACKGROUND

This study aimed to investigate the association between the intake of different dietary carbohydrate components and the long-term outcomes of non-alcoholic fatty liver disease (NAFLD).

METHODS

We used prospective data from 26,729 NAFLD participants from the UK Biobank cohort study. Dietary information was recorded by online 24-hour questionnaires (Oxford WebQ). Consumption of different carbohydrate components was calculated by the UK Nutrient Databank Food Composition Table. Cox proportional hazards models were used to estimate the adjusted hazard ratio (HR) and 95% confidence interval (CI). A substitution model was used to estimate the associations of hypothetical substitution for free sugars.

RESULTS

During a median of 10.5 (IQR: 10.2-11.2) years and a total of 280,135 person-years of follow-up, 310 incident end-stage liver disease (ESLD) and 1750 deaths were recorded. Compared with the lowest quartile, the multi-adjusted HRs (95% CI) of incident ESLD in the highest quartile were 1.65 (1.14-2.39) for free sugars, 0.51 (0.35-0.74) for non-free sugars, and 0.55 (0.36-0.83) for fiber. For overall mortality, the multi-adjusted HRs (95% CI) in the highest quartile were 1.21 (1.04-1.39) for free sugars, 0.79 (0.68-0.92) for non-free sugars, and 0.79 (0.67-0.94) for fiber. Substituting free sugars with equal amounts of non-free sugars, starch or fiber was associated with a lower risk of incident ESLD and overall mortality.

CONCLUSIONS

A lower intake of free sugars and a higher intake of fiber are associated with a lower incidence of ESLD and overall mortality in NAFLD patients. These findings support the important role of the quality of dietary carbohydrates in preventing ESLD and overall mortality in NAFLD patients.

The Impact and Burden of Dietary Sugars on the Liver

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

Association between dietary glycemic index and non-alcoholic fatty liver disease in patients with type 2 diabetes mellitus

Objective

Managing dietary glycemic index (GI) deserves further attention in the interplay between non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM). This study aimed to evaluate the relationship between dietary GI and the odds of NAFLD in patients with T2DM.

Methods

A cross-sectional study was carried out between April 2021 and February 2022, including 200 participants with T2DM aged 18-70 years, of which 133 had NAFLD and 67 were in the non-NAFLD group. Cardiometabolic parameters were analyzed using standard biochemical kits and dietary intake was assessed using a validated food frequency questionnaire. Binary logistic regression was applied to explore odds ratios (ORs) and 95% confidence intervals (CIs) for NAFLD according to tertiles of dietary GI.

Results

Highest vs. lowest tertile (< 57 vs. > 60.89) of energy-adjusted GI was not associated with the odds of having NAFLD (OR 1.25, 95% CI = 0.6-2.57; P-trend = 0.54) in the crude model. However, there was an OR of 3.24 (95% CI = 1.03-10.15) accompanied by a significant trend (P-trend = 0.04) after full control for potential confounders (age, gender, smoking status, duration of diabetes, physical activity, waist circumference, HbA1c, triglycerides, total cholesterol, dietary intake of total carbohydrates, simple carbohydrates, fat, and protein).

Conclusion

High dietary GI is associated with increased odds of NAFLD in subjects with T2DM. However, interventional and longitudinal cohort studies are required to confirm these findings.

Vitamin E supplementation in the treatment on nonalcoholic fatty liver disease (NAFLD): Evidence from an umbrella review of meta-analysis on randomized controlled trials

OBJECTIVE

We conducted this umbrella review of meta-analysis on randomized controlled trials to clarify the effects of vitamin E administration on alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), degrees of steatosis and fibrosis in patients with nonalcoholic fatty liver disease (NAFLD).

METHODS

PubMed, MEDLINE, SCOPUS, EMBASE, and Web of Science were searched to identify pertinent articles published up to June 2023. To calculate the overall effect size (ES) and confidence intervals (CI), random-effects model was used.

RESULTS

Six meta-analyses were included in the umbrella review. By pooling ES based on the random-effects model, we found that vitamin E supplementation significantly decreased ALT (ES -6.47, 95% CI -11.73 to -1.22, P = 0.01), AST (ES -5.35, 95% CI -9.78 to -0.93, P = 0.01), degrees of fibrosis (ES -0.24, 95% CI -0.36 to -0.12, P < 0.001) and steatosis (ES -0.67, 95% CI -0.88 to -0.45, P < 0.001) in NAFLD patients, but had no effect on GGT. In the subgroup analyses, we detected that fibrosis scores notably decreased when vitamin E dosage was >600 IU/day (ES -0.25, 95% CI -0.41 to -0.10, P = 0.002) and when the treatment duration was ≥12 months (ES -0.24, 95% CI -0.37 to -0.12, P < 0.001).

CONCLUSION

Vitamin E administration improves ALT, AST, fibrosis, and steatosis in NAFLD subjects. Fibrosis scores were significantly reduced when vitamin E dosage exceeded 600 IU/day or with a treatment duration of at least 12 months.

Study protocol for a randomized, controlled trial using a novel, family-centered diet treatment to prevent nonalcoholic fatty liver disease in Hispanic children

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the leading liver disorder among U.S. children and is most prevalent among Hispanic children with obesity. Previous research has shown that reducing the consumption of free sugars (added sugars + naturally occurring sugars in fruit juice) can reverse liver steatosis in adolescents with NAFLD. This study aims to determine if a low-free sugar diet (LFSD) can prevent liver fat accumulation and NAFLD in high-risk children.

METHODS

In this randomized controlled trial, we will enroll 140 Hispanic children aged 6 to 9 years who are ≥50th percentile BMI and without a previous diagnosis of NAFLD. Participants will be randomly assigned to either an experimental (LFSD) or a control (usual diet + educational materials) group. The one-year intervention includes removal of foods high in free sugars from the home at baseline, provision of LFSD household groceries for the entire family (weeks 1-4, 12, 24, and 36), dietitian-guided family grocery shopping sessions (weeks 12, 24, and 36), and ongoing education and motivational interviewing to promote LFSD. Both groups complete assessment measures at baseline, 6, 12, 18, and 24 months. Primary study outcomes are percent hepatic fat at 12 months and incidence of clinically significant hepatic steatosis (>5%) + elevated liver enzymes at 24 months. Secondary outcomes include metabolic markers potentially mediating or moderating NAFLD pathogenesis.

DISCUSSION

This protocol describes the rationale, eligibility criteria, recruitment strategies, analysis plan as well as a novel dietary intervention design. Study results will inform future dietary guidelines for pediatric NAFLD prevention.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT05292352.

Nutritional and Lifestyle Therapy for NAFLD in People with HIV

HIV infection and nonalcoholic fatty liver disease (NAFLD) are two major epidemics affecting millions of people worldwide. As people with HIV (PWH) age, there is an increased prevalence of metabolic comorbidities, along with unique HIV factors, such as HIV chronic inflammation and life-long exposure to antiretroviral therapy, which leads to a high prevalence of NAFLD. An unhealthy lifestyle, with a high dietary intake of refined carbohydrates, saturated fatty acids, fructose added beverages, and processed red meat, as well as physical inactivity, are known to trigger and promote the progression of NAFLD to nonalcoholic steatohepatitis, liver fibrosis, and hepatocellular carcinoma. Furthermore, with no currently approved pharmacotherapy and a lack of clinical trials that are inclusive of HIV, nutritional and lifestyle approaches still represent the most recommended treatments for PWH with NAFLD. While sharing common features with the general population, NAFLD in PWH displays its own peculiarities that may also reflect different impacts of nutrition and exercise on its onset and treatment. Therefore, in this narrative review, we aimed to explore the role of nutrients in the development of NAFLD in PWH. In addition, we discussed the nutritional and lifestyle approaches to managing NAFLD in the setting of HIV, with insights into the role of gut microbiota and lean NAFLD.

Effects of various interventions on non-alcoholic fatty liver disease (NAFLD): A systematic review and network meta-analysis

Background: With the increasing prevalence of obesity and metabolic syndrome, the incidence of non-alcoholic fatty liver disease (NAFLD) is also increasing. In the next decade, NAFLD may become the main cause of liver transplantation. Therefore, the choice of treatment plan is particularly important. The purpose of this study was to compare several interventions in the treatment of NAFLD to provide some reference for clinicians in selecting treatment methods.

Methods: We searched Public Medicine (PubMed), Medline, Excerpta Medica Database (Embase), and Cochrane Library from January 2013 to January 2023 to identify randomized controlled trials (RCTs) published in English. The network meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Forty-three studies accounting for a total of 2,969 patients were included, and alanine aminotransferase (ALT), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL) were selected as outcome measures for analysis and comparison.

Results: We evaluated the results of drug, diet, and lifestyle interventions between the intervention and control groups. Curcumin (CUN) and probiotics (PTC) were selected for medication, the Mediterranean diet (MDED) was selected for special diet (SPD), and various kinds of exercise and lifestyle advice were selected for lifestyle interventions (LFT). The SUCRA was used to rank interventions according to the effect on ALT indicators (SUCRA: PTC 80.3%, SPD 65.2%, LFT 61.4%, PLB 32.8%, CUN 10.2%), TC indicators (SUCRA: PTC 89.4%, SPD 64%, CUN 34%, LFT 36.6%, PLB 17%), and LDL indicators (SUCRA: PTC 84.2%, CUN 69.5%, LFT 51.7%, PLB 30.1%, SPD 14.5%). The pairwise meta-analysis results showed that MDED was significantly better than NT in improving ALT [SMD 1.99, 95% CI (0.38, 3.60)]. In terms of improving TC and LDL, ATS was significantly better than NT [SMD 0.19, 95% CI (0.03, 0.36)] [SMD 0.18, 95% CI (0.01, 0.35)].

Conclusion: Our study showed that PTC is most likely to be the most effective treatment for improving NAFLD indicators. Professional advice on diet or exercise was more effective in treating NAFLD than no intervention.

Important food sources of fructose-containing sugars and adiposity: A systematic review and meta-analysis of controlled feeding trials

BACKGROUND

Sugar-sweetened beverages (SSBs) providing excess energy increase adiposity. The effect of other food sources of sugars at different energy control levels is unclear.

OBJECTIVES

To determine the effect of food sources of fructose-containing sugars by energy control on adiposity.

METHODS

In this systematic review and meta-analysis, MEDLINE, Embase, and Cochrane Library were searched through April 2022 for controlled trials ≥2 wk. We prespecified 4 trial designs by energy control: substitution (energy-matched replacement of sugars), addition (energy from sugars added), subtraction (energy from sugars subtracted), and ad libitum (energy from sugars freely replaced). Independent authors extracted data. The primary outcome was body weight. Secondary outcomes included other adiposity measures. Grading of Recommendations Assessment, Development, and Evaluation (GRADE) was used to assess the certainty of evidence.

RESULTS

We included 169 trials (255 trial comparisons, n = 10,357) assessing 14 food sources at 4 energy control levels over a median 12 wk. Total fructose-containing sugars increased body weight (MD: 0.28 kg; 95% CI: 0.06, 0.50 kg; P_MD = 0.011) in addition trials and decreased body weight (MD: -0.96 kg; 95% CI: -1.78, -0.14 kg; P_MD = 0.022) in subtraction trials with no effect in substitution or ad libitum trials. There was interaction/influence by food sources on body weight: substitution trials [fruits decreased; added nutritive sweeteners and mixed sources (with SSBs) increased]; addition trials [dried fruits, honey, fruits (≤10%E), and 100% fruit juice (≤10%E) decreased; SSBs, fruit drink, and mixed sources (with SSBs) increased]; subtraction trials [removal of mixed sources (with SSBs) decreased]; and ad libitum trials [mixed sources (with/without SSBs) increased]. GRADE scores were generally moderate. Results were similar across secondary outcomes.

CONCLUSIONS

Energy control and food sources mediate the effect of fructose-containing sugars on adiposity. The evidence provides a good indication that excess energy from sugars (particularly SSBs at high doses ≥20%E or 100 g/d) increase adiposity, whereas their removal decrease adiposity. Most other food sources had no effect, with some showing decreases (particularly fruits at lower doses ≤10%E or 50 g/d). This trial was registered at clinicaltrials.gov as NCT02558920 (https://clinicaltrials.gov/ct2/show/NCT02558920).

Eating, diet, and nutrition for the treatment of non-alcoholic fatty liver disease

Nutrition and dietary interventions are a central component in the pathophysiology, but also a cornerstone in the management of patients with non-alcoholic fatty liver disease (NAFLD). Summarizing our rapidly advancing understanding of how our diet influences our metabolism and focusing on specific effects on the liver, we provide a comprehensive overview of dietary concepts to counteract the increasing burden of NAFLD. Specifically, we emphasize the importance of dietary calorie restriction independently of the macronutrient composition together with adherence to a Mediterranean diet low in added fructose and processed meat that seems to exert favorable effects beyond calorie restriction. Also, we discuss intermittent fasting as a type of diet specifically tailored to decrease liver fat content and increase ketogenesis, awaiting future study results in NAFLD. Finally, personalized dietary recommendations could be powerful tools to increase the effectiveness of dietary interventions in patients with NAFLD considering the genetic background and the microbiome, among others.

Effects of time-restricted feeding (16/8) combined with a low-sugar diet on the management of non-alcoholic fatty liver disease: A randomized controlled trial

OBJECTIVES

Emerging studies have employed time-restricted feeding (TRF) and a low-sugar diet alone in the management of non-alcoholic fatty liver disease (NAFLD), but their combination has not been tested. The aim of this study was to investigate the effects of TRF combined with a low-sugar diet on NAFLD parameters, cardiometabolic and inflammatory biomarkers, and body composition in patients with NAFLD.

METHODS

A 12-wk randomized controlled trial was performed to compare the effects of TRF (16 h fasting/8 h feeding daily [16/8]) plus a low-sugar diet versus a control diet based on traditional meal distribution in patients with NAFLD. Changes in body composition, anthropometric indices, and liver and cardiometabolic markers were investigated.

RESULTS

TRF 16/8 with a low-sugar diet reduced body fat (26.7 ± 5.4 to 24.2 ± 4.9 kg), body weight (83.8 ± 12.7 to 80.5 ± 12.1 kg), waist circumference (104.59 ± 10.47 to 101.91 ± 7.42 cm), and body mass index (29.1 ± 2.6 to 28 ± 2.7 kg/m²), as well as circulating levels of fasting blood glucose and liver (alanine aminotransferase, 34 ± 13.9 to 21.2 ± 5.4 U/L; aspartate aminotransferase, 26.3 ± 6.2 to 20.50 ± 4 U/L; γ-glutamyl transpeptidase, 33 ± 15 to 23.2 ± 11.1 U/L; fibrosis score, 6.3 ± 1 to 5.2 ± 1.2 kPa; and controlled attenuation parameter, 322.9 ± 34.9 to 270.9 ± 36.2 dB/m), lipids (triacylglycerols, 201.5 ± 35.3 to 133.3 ± 48.7 mg/dL; total cholesterol, 190 ± 36.6 to 157.8 ± 33.6 mg/dL; and low-density lipoprotein cholesterol, 104.6 ± 27.3 to 84 ± 26.3 mg/dL), and inflammatory markers (high-sensitivity C-reactive protein, 3.1 ± 1.1 to 2 ± 0.9 mg/L; and cytokeratin-18, 1.35 ± 0.03 to 1.16 ± 0.03 ng/mL). These results were statistically significant (P < 0.05) compared with the control group.

CONCLUSIONS

TRF plus a low-sugar diet can reduce adiposity and improve liver, lipid, and inflammatory markers in patients with NAFLD.

Effect of Important Food Sources of Fructose-Containing Sugars on Inflammatory Biomarkers: A Systematic Review and Meta-Analysis of Controlled Feeding Trials

Background: Fructose-containing sugars as sugar-sweetened beverages (SSBs) may increase inflammatory biomarkers. Whether this effect is mediated by the food matrix at different levels of energy is unknown. To investigate the role of food source and energy, we conducted a systematic review and meta-analysis of controlled trials on the effect of different food sources of fructose-containing sugars on inflammatory markers at different levels of energy control. Methods: MEDLINE, Embase, and the Cochrane Library were searched through March 2022 for controlled feeding trials ≥ 7 days. Four trial designs were prespecified by energy control: substitution (energy matched replacement of sugars); addition (excess energy from sugars added to diets); subtraction (energy from sugars subtracted from diets); and ad libitum (energy from sugars freely replaced). The primary outcome was C-reactive protein (CRP). Secondary outcomes were tumour necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6). Independent reviewers extracted data and assessed risk of bias. GRADE assessed certainty of evidence. Results: We identified 64 controlled trials (91 trial comparisons, n = 4094) assessing 12 food sources (SSB; sweetened dairy; sweetened dairy alternative [soy]; 100% fruit juice; fruit; dried fruit; mixed fruit forms; sweetened cereal grains and bars; sweets and desserts; added nutritive [caloric] sweetener; mixed sources [with SSBs]; and mixed sources [without SSBs]) at 4 levels of energy control over a median 6-weeks in predominantly healthy mixed weight or overweight/obese adults. Total fructose-containing sugars decreased CRP in addition trials and had no effect in substitution, subtraction or ad libitum trials. No effect was observed on other outcomes at any level of energy control. There was evidence of interaction/influence by food source: substitution trials (sweetened dairy alternative (soy) and 100% fruit juice decreased, and mixed sources (with SSBs) increased CRP); and addition trials (fruit decreased CRP and TNF-α; sweets and desserts (dark chocolate) decreased IL-6). The certainty of evidence was moderate-to-low for the majority of analyses. Conclusions: Food source appears to mediate the effect of fructose-containing sugars on inflammatory markers over the short-to-medium term. The evidence provides good indication that mixed sources that contain SSBs increase CRP, while most other food sources have no effect with some sources (fruit, 100% fruit juice, sweetened soy beverage or dark chocolate) showing decreases, which may be dependent on energy control. Clinicaltrials.gov: (NCT02716870).

Low fat diet versus low carbohydrate diet for management of non-alcohol fatty liver disease: A systematic review

Although there is a consensus on beneficial effects of a low calorie diet in management of non-alcoholic fatty liver disease, the optimal composition of diet has not yet been elucidated. The aim of this review is to summarize the results of current randomized controlled trials evaluating the effects of low fat diet (LFD) vs. low carbohydrate diet (LCD) on NAFLD. This is a systematic review of all the available data reported in published clinical trials up to February 2022. The methodological quality of eligible studies was assessed, and data were presented aiming specific standard measurements. A total of 15 clinical trial studies were included in this systematic review. There is an overall lack of consensus on which dietary intervention is the most beneficial for NAFLD patients. There is also an overall lack of consensus on the definition of the different restrictive diets and the percentage of macronutrient restriction recommended. It seems that low calorie diets, regardless of their fat and carbohydrate composition, are efficient for liver enzyme reduction. Both LCD and LFD have similar effects on liver enzymes change; however, this improvement tends to be more marked in LFD. All calorie restrictive dietary interventions are beneficial for reducing weight, liver fat content and liver enzymes in individuals with NAFLD. Low fat diets seem to be markedly successful in reducing transaminase levels. Further research is needed to explore diet intensity, duration and long-term outcome.

Effects of the 5:2 intermittent fasting diet on non-alcoholic fatty liver disease: A randomized controlled trial

Background and aims

Dietary regimens are crucial in the management of non-alcoholic fatty liver disease (NAFLD). The effects of intermittent fasting (IF) have gained attention in this regard, but further research is warranted. Thus, we aimed to ascertain the overall effects of the 5:2 IF diet (5 days a week of normal food intake and 2 consecutive fasting days) in patients with NAFLD compared to a control group (usual diet).

Methods and results

A 12-week randomized controlled trial was performed to evaluate the effects of the 5:2 IF diet on anthropometric indices, body composition, liver indices, serum lipids, glucose metabolism, and inflammatory markers in patients with NAFLD. The IF group (n = 21) decreased body weight (86.65 ± 12.57–82.94 ± 11.60 kg), body mass index (30.42 ± 2.27–29.13 ± 1.95 kg/m²), waist circumference (103.52 ± 6.42–100.52 ± 5.64 cm), fat mass (26.64 ± 5.43–23.85 ± 5.85 kg), fibrosis (6.97 ± 1.94–5.58 ± 1.07 kPa), steatosis scores/CAP (313.09 ± 25.45–289.95 ± 22.36 dB/m), alanine aminotransferase (41.42 ± 20.98–28.38 ± 15.21 U/L), aspartate aminotransferase (34.19 ± 10.88–25.95 ± 7.26 U/L), triglycerides (171.23 ± 39.88–128.04 ± 34.88 mg/dl), high-sensitivity C-reactive protein (2.95 ± 0.62 −2.40 ± 0.64 mg/L), and cytokeratin-18 (1.32 ± 0.06–1.19 ± 0.05 ng/ml) values compared to the baseline and the end of the control group (n = 23)—p ≤ 0.05 were considered as significant. However, the intervention did not change the levels of high-density lipoprotein cholesterol, total cholesterol, low-density lipoprotein cholesterol, fasting blood sugar, insulin, HOMA-IR, and total antioxidant capacity.

Conclusion

Adhering to the 5:2 IF diet can reduce weight loss and related parameters (fat mass and anthropometric indicators of obesity), as well as hepatic steatosis, liver enzymes, triglycerides, and inflammatory biomarkers in patients with NAFLD.