Intake of Nuts and Seeds Is Associated with a Lower Prevalence of Nonalcoholic Fatty Liver Disease in US Adults: Findings from 2005-2018 NHANES

A Cross-Sectional Study on the Association of Walnut Consumption with Obesity and Relative Fat Mass among United States Adolescents and Young Adults in NHANES (2003-2020)

Background

Walnuts contain nutrients and phytochemicals that can promote metabolic health. However, the high energy content of walnuts along with other nuts raises the concern that consuming nuts promotes obesity.

Objectives

We sought to investigate the associations between consumption of walnuts as well as other nuts and measures of obesity in adolescents and young adults.

Methods

This study included 8874 adolescents (12-19 y) and 10,323 young adults (20-39 y) from 8 waves of National Health and Nutrition Examination Survey data (2003-2020). The associations of consumption of 1) walnuts only (WO); 2) walnuts with other nuts (WON); 3) other nuts (ON); and 4) no nuts (NN) with obesity status and relative fat mass (RFM) were assessed using logistic and linear regressions stratified by age group and sex. Sample weights were used in all statistical analyses.

Results

The mean daily intake of walnuts was not different between the 2 walnut consumption groups within each age group (adolescents: 2.18 [standard error (SE) 0.14] g; P = 0.917; young adults: 4.23 [0.37] g; P = 0.682). The WON group had the lowest prevalence of obesity (adolescents: 8.3%; young adults: 21.1%) while the NN group had the highest prevalence (adolescents: 24.1%; young adults: 35.4%). The models indicated lower odds of obesity in adolescent girls (odds ratio [OR]: 0.27; P < 0.05) and young adult women (OR: 0.58; P < 0.05) who consumed WON than in those who consumed NN. In both young women and girls, RFM was significantly lower in the WON and ON groups than the NN group (P < 0.001). In young men, WON consumption was also associated with a lower RFM (OR: -1.24; 95% confidence interval: -2.21, -0.28) compared with NN consumption.

Conclusions

For adolescents girls and young women, dietary intake of walnuts combined with other nuts has the strongest inverse association with measures of obesity.

Association between heavy metals exposure and persistent infections: the mediating role of immune function

Introduction

Persistent infections caused by certain viruses and parasites have been associated with multiple diseases and substantial mortality. Heavy metals are ubiquitous environmental pollutants with immunosuppressive properties. This study aimed to determine whether heavy metals exposure suppress the immune system, thereby increasing the susceptibility to persistent infections.

Methods

Using data from NHANES 1999-2016, we explored the associations between heavy metals exposure and persistent infections: Cytomegalovirus (CMV), Epstein-Barr Virus (EBV), Hepatitis C Virus (HCV), Herpes Simplex Virus Type-1 (HSV-1), Toxoplasma gondii (T. gondii), and Toxocara canis and Toxocara cati (Toxocara spp.) by performing logistic regression, weighted quantile sum (WQS) and Bayesian kernel machine regression (BKMR) models. Mediation analysis was used to determine the mediating role of host immune function in these associations.

Results

Logistic regression analysis revealed positive associations between multiple heavy metals and the increased risk of persistent infections. In WQS models, the heavy metals mixture was associated with increased risks of several persistent infections: CMV (OR: 1.58; 95% CI: 1.17, 2.14), HCV (OR: 2.94; 95% CI: 1.68, 5.16), HSV-1 (OR: 1.25; 95% CI: 1.11, 1.42), T. gondii (OR: 1.97; 95% CI: 1.41, 2.76), and Toxocara spp. (OR: 1.76; 95% CI: 1.16, 2.66). BKMR models further confirmed the combined effects of heavy metals mixture and also identified the individual effect of arsenic, cadmium, and lead. On mediation analysis, the systemic immune inflammation index, which reflects the host's immune status, mediated 12.14% of the association of mixed heavy metals exposure with HSV-1 infection.

Discussion

The findings of this study revealed that heavy metals exposure may increase susceptibility to persistent infections, with the host's immune status potentially mediating this relationship. Reducing exposure to heavy metals may have preventive implications for persistent infections, and further prospective studies are needed to confirm these findings.

Vegetarian diets and risk of nonalcoholic fatty liver disease: An observational study of National Health and Nutrition Examination Survey 2005-2018 using propensity score methods

BACKGROUND

Studies on the association between vegetarian diets and nonalcoholic fatty liver disease (NAFLD) are limited and have inconsistent results. This study aims to explore the association between vegetarian diets and NAFLD and compare the stage of fibrosis between vegetarians and nonvegetarians in a US representative sample.

METHODS

Cross-sectional data from 23,130 participants aged ≥20 years were obtained from the National Health and Nutrition Examination Survey, 2005-2018. Vegetarian status was classified based on two 24-h dietary recalls. We examined the association between vegetarian diets and the risk of NAFLD using the propensity score weighting method.

RESULTS

Vegetarian diets were significantly associated with decreases in hepatic steatosis index (HSI), US fatty liver index and nonalcoholic fatty liver disease fibrosis score with mean differences of -2.70 (95% confidence interval [CI]: -3.69, -1.70), -3.03 (95% CI: -7.15, -0.91) and -0.12 (95% CI: -0.26, -0.01), respectively. While modelling the risk of NAFLD, we estimated that vegetarians were 53% less likely to have NAFLD assessed by HSI (odds ratios [OR]: 0.47; 95% CI: 0.34, 0.65). The effect of vegetarian diets was higher among individuals with lower waist circumferences (OR: 0.20) than among those with higher waist circumferences (OR: 0.53,p interaction ${p}_{\text{interaction}}\,$ = 0.004). However, the association was largely attenuated after adjusting for body mass index and diabetes status. No significant association was identified between vegetarian diets and advanced fibrosis.

CONCLUSIONS

Vegetarian diets were associated with a lower prevalence of NAFLD among US adults, and the association appeared to be stronger in people with lower waist circumferences. Further studies are warranted to replicate our findings.

Dietary characteristics associated with the risk of non-alcoholic fatty liver disease and metabolic dysfunction-associated steatotic liver disease in non-obese Japanese participants: A cross-sectional study

Background and Aim

Dietary characteristics associated with non-alcoholic fatty liver disease (NAFLD) and metabolic dysfunction-associated steatotic liver disease (MASLD) in non-obese patients remain to be elucidated. This study examined the association of NAFLD and MASLD with dietary characteristics according to obesity status.

Methods

We performed a cross-sectional study of 15 135 participants (n = 7568 men and 7567 women) aged 35-74 years using data of annual health checks between 2008 and 2020. Obesity was defined as BMI ≥ 25 kg/m2. Diagnosis of fatty liver was based on abdominal ultrasonography. Fatty-liver-related dietary characteristics were assessed using a self-administered questionnaire.

Results

For non-obese participants, NAFLD was found in 31.0% of men and 19.4% of women. Non-obese MASLD was found in 27.6% of men and 18.1% of women. Multivariable-adjusted stepwise logistic regression analysis indicated that, in males, both non-obese NAFLD and non-obese MASLD were significantly and negatively associated with "often eat sesame/nuts", and positively associated with "often eat noodles/rice bowl" and "often eat evening meal" (P < 0.05). For non-obese women, both NAFLD and MASLD were significantly and positively associated with "often eat sweet buns/bread with fillings" (P < 0.05). Adjusted analyses showed that all dietary characteristics were not significantly associated with the risk of NAFLD/MASLD in obese men and women.

Conclusion

This cross-sectional study indicates the existence of sex and obesity differences in the association of NAFLD and MASLD with dietary characteristics. Our findings suggest that some dietary characteristics are associated with NAFLD and MASLD prevalence in non-obese Japanese participants.

Association of the habitual dietary intake with the fatty liver index and effect modification by metabotypes in the population-based KORA-Fit study

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is an emerging threat for public health with diet being a major risk factor in disease development and progression. However, the effects of habitual food consumption on fatty liver are still inconclusive as well as the proposed role of the individuals' metabolic profiles. Therefore, the aim of our study is to examine the associations between diet and NAFLD with an emphasis on the influence of specific metabotypes in the general population.

METHODS

A total of 689 participants (304 men and 385 women) of the KORA-Fit (S4) survey, a follow-up study of the population-based KORA cohort study running in the Region of Augsburg, Germany, were included in this analysis. Dietary information was derived from repeated 24-h food lists and a food frequency questionnaire. The intake of energy and energy-providing nutrients were calculated using the national food composition database. The presence of fatty liver was quantified by the fatty liver index (FLI), and metabotypes were calculated using K-means clustering. Multivariable linear regression models were used for the analysis of habitual food groups and FLI; for the evaluation of macronutrients, energy substitution models were applied.

RESULTS

A higher consumption of nuts and whole grains, and a better diet quality (according to Alternate Healthy Eating Index and Mediterranean Diet Score) were associated with lower FLI values, while the intake of soft drinks, meat, fish and eggs were associated with a higher FLI. The isocaloric substitution of carbohydrates with polyunsaturated fatty acids was associated with a decreased FLI, while substitution with monounsaturated fatty acids and protein showed increased FLI. Statistically significant interactions with the metabotype were observed for most food groups.

CONCLUSION

The consumption of plant-based food groups, including nuts and whole grains, and diet quality, were associated with lower FLI values, whereas the intake of soft drinks and products of animal origin (meat, fish, eggs) were associated with a higher FLI. The observed statistically significant interactions with the metabotype for most food groups could help to develop targeted prevention strategies on a population-based level if confirmed in independent prospective studies.

Non-linear associations of circulating total bilirubin concentration with the risk of nonalcoholic fatty liver disease and all-cause mortality

INTRODUCTION AND OBJECTIVES

Accumulating evidence has supported that mild elevated total bilirubin exerts antioxidant and anti-inflammatory properties in multiple metabolic diseases. We aimed to explore the association of circulating total bilirubin concentration with non-alcoholic fatty liver disease (NAFLD) risk and all-cause mortality and examine the potential nonlinear relationships between them.

MATERIAL AND METHODS

We used nationally representative data from the National Health and Nutrition Examination Survey (NHANES). NAFLD was assessed using the fatty liver index (FLI) and United States fatty liver index (USFLI), respectively.

RESULTS

A total of 35 912 and 17 329 participants were included in FLI-NAFLD (case with NAFLD was diagnosed by FLI) and USFLI-NAFLD (case with NAFLD was diagnosed by USFLI) groups, respectively. The mean age of total population was 46.25 years, and 48.51% were male. Compared to participants with lowest quintile of total bilirubin concentration, those with highest quintile had lower risk of NAFLD in both FLI-NAFLD (OR: 0.48, 95% CI: 0.40, 0.59) and USFLI-NAFLD (OR: 0.55, 95% CI: 0.43, 0.70) groups. Compared to participants with lowest quintile of total bilirubin concentration, the association between total bilirubin concentration and all-cause mortality was not significant among those with highest quintile of total bilirubin concentration (HR: 0.89, 95% CI: 0.66, 1.20). The restricted spline curves showed the nonlinear U-shaped association of total bilirubin concentration with NAFLD risk and all-cause mortality. The segmented linear regression analysis showed negative associations between total bilirubin concentration and risk of NAFLD in both FLI-NAFLD (OR: 0.94, 95% CI: 0.93, 0.95) and USFLI-NAFLD (OR: 0.95, 95% CI: 0.93, 0.96) groups when total bilirubin concentration was below the turning point (FLI-NAFLD: 18.81 μmol/L; USFLI-NAFLD: 15.39 μmol/L) and these associations were not significant when total bilirubin concentration was higher than the turning point. Furthermore, all-cause mortality decreased (OR: 0.97, 95%CI: 0.95, 1.00) with increased total bilirubin concentration up to the turning point (11.97 μmol/L), and then all-cause mortality increased with increasing total bilirubin concentration (OR: 1.03, 95%CI: 1.02, 1.04).

CONCLUSIONS

We found that higher circulating total bilirubin concentration within the physiological range was associated with decreased risk of NAFLD and all-cause mortality among NAFLD patients.

Nut and seed consumption is inversely associated with metabolic syndrome in females but not males: findings from the 2005-2018 NHANES data

PURPOSE

To assess the association between nut and seed consumption, both combined and separately, and metabolic syndrome and its components, including fasting glucose, triglycerides, high-density lipoprotein (HDL) cholesterol, central obesity, and blood pressure.

METHODS

This cross-sectional analysis used data from 22,687 adults (aged ≥ 18 years) involved in seven cycles (2005-2018) of the National Health and Nutrition Examination Survey (NHANES). Habitual nut and seed intakes were estimated by the Multiple Source Method using data from two 24-h dietary recalls. Metabolic syndrome was ascertained using biochemical data and self-reported medication use. Sex-specific effect estimates were obtained using logistic and linear regressions adjusting for lifestyle and socioeconomic confounders.

RESULTS

Compared to non-consumers, female, but not male, habitual consumers of either nuts or seeds had lower odds of having metabolic syndrome (OR: 0.83, 95% CI 0.71, 0.97). Both nut intake alone and seed intake alone were inversely associated with high fasting glucose and low HDL-cholesterol in females compared to non-consumers. When restricted to habitual consumers only, the combined intake of nuts and seeds at 6 g/day was associated with the lowest triglycerides and highest HDL-cholesterol in females. Combined consumption of nuts and seeds up to one ounce-equivalent (15 g) per day, but not in higher intake levels, was inversely associated with metabolic syndrome, high fasting glucose, central obesity, and low HDL-cholesterol in females.

CONCLUSIONS

Nut and seed consumption, both separately or combined, below 15 g/day was inversely associated with metabolic syndrome and its component conditions in females but not males.

Effect of Nut Consumption on Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis

Although previous epidemiological studies have been conducted to investigate the relationship between nut consumption and the risk of nonalcoholic fatty liver disease (NAFLD), the evidence remains inconclusive and contentious. The aim of our study was to further conduct a meta-analysis of observational studies to explore the latest evidence of the influence of nut consumption on NAFLD. This meta-analysis included a comprehensive search of all articles published in the PubMed and Web of Science online databases as of April 2023. A total of 11 articles were included, comprising 2 prospective cohort studies, 3 cross-sectional studies, and 7 case-control studies, and a random effects model was used to evaluate the relationship between nuts and NAFLD. Results showed that the odds ratio (OR) of NAFLD was 0.90 (95% CI: 0.81-0.99, p < 0.001) when comparing the highest and lowest total nut intake, indicating a significant negative correlation. Furthermore, subgroup analysis revealed that the protective effect of nuts on NAFLD was more significant in females (OR = 0.88; 95% CI: 0.78-0.98, I² = 76.2%). In summary, our findings provide support for a protective relationship between nut intake and risk of NAFLD. Further exploration of the association between other dietary components and NAFLD is an important avenue for future research.

MONITORING CHANGES IN THE VOLATILE FRACTION OF ROASTED NUTS AND SEEDS BY USING COMPREHENSIVE TWO-DIMENSIONAL GAS CHROMATOGRAPHY AND MATRIX TEMPLATES

Static headspace coupled with comprehensive two-dimensional gas chromatography and a flame ionization detector (HS-GC × GC-FID), has been applied to monitor changes in the volatile fraction of commercial edible nuts and seeds (peanuts, almonds, hazelnuts, and sunflower seeds). Effects of the roasting conditions (time, 5-40 min; temperature, 150-170 °C), which were employed under different combinations by using a ventilated oven, on target volatile fraction were examined to identify potential differences in relation to the roasting treatment of raw samples. In addition, reference templates were created, from the HS-GC × GC-FID method, for each of the four food matrices analyzed, and they were applied to characterize the samples according to the presence or absence of volatile compounds. Finally, these templates were successfully employed to make a quick distinction between different roasting conditions.•HS-GC × GC-FID was applied to study the volatile profile of edible nuts and seeds.•Reference templates (GC × GC-FID) were created for each of the four food matrices.•Rapid discrimination between raw and roasted samples was achieved.

Novel Lines of Research on the Environmental and Human Health Impacts of Nut Consumption

Nuts have formed part of human diets throughout the ages. In recent decades, research has shown they are key foods in dietary patterns associated with lower chronic disease risk. The current state of climate change, however, has introduced an imperative to review the impact of dietary patterns on the environment with a shift to plant-based diets. Nuts emerge as a significant source of protein in plant-based diets and are a minimally processed and sustainable food. Research in this area is evolving to drive better production methods in varying climate conditions. Nevertheless, nut consumption remains an important contributor to human health. The mechanisms of action can be explained in terms of the nutrients they deliver. Studies of nut consumption have linked components such as monounsaturated fatty acids, plant omega-3 fatty acids, antioxidants, and plant sterols to improved lipoprotein profiles, lower blood pressure, and reduced cardiovascular disease risk. Preliminary research also indicates possible beneficial effects of nut consumption on reproductive health. In any case, the ultimate effects of foods on health are the results of multiple interactive factors, so where nuts fit within dietary patterns is a significant consideration for research translation. This has implications for research methodologies, including categorization within food groups and inclusion in Healthy Dietary Indices. The aim of this narrative review is to outline new focal points for investigation that examine the environmental and some novel human health impacts of nut consumption and discuss future directions for research.

Plant-based diets in gastrointestinal diseases: Which evidence?

Plant-based diets (PBDs), rich in high-quality plant foods, offer multiple benefits for the overall and gastrointestinal health. Recently, it has been demostrated that the positive effects of PBDs on gastrointestinal health can be mediated by the gut microbiota, in particular, by inducing a greater diversity of bacteria. This review summarizes current knowledge on the relationship between nutrition, the gut microbiota, and host metabolic status. We discussed how dietary habits modify the composition and physiological activity of the gut microbiota and how gut dysbiosis affects the most prevalent gastrointestinal diseases, including inflammatory bowel diseases, functional bowel disorders, liver disorders, and gastrointestinal cancer. The beneficial role of PBDs is being increasingly recognized as potentially useful in the management of most diseases of the gastrointestinal tract.

A Healthful Plant-Based Diet Is Associated with Lower Odds of Nonalcoholic Fatty Liver Disease

There is little evidence for the associations of the overall plant-based diet index (PDI), the healthful PDI (hPDI), and the unhealthful PDI (uPDI) with the odds of nonalcoholic fatty liver disease (NAFLD). We present a nationwide cross-sectional study among US adults aged 18 years or older. Diet was assessed by 24-h recalls. Overall PDI, hPDI, and uPDI were constructed based on 18 food groups. NAFLD was defined based on controlled attenuation parameter derived via transient elastography (TE) in the absence of other causes of chronic liver disease. Among 3900 participants with eligible TE examination, 1686 were diagnosed with NAFLD. The overall PDI was not associated with NAFLD prevalence (comparing extreme tertiles of PDI score OR = 1.03, 95% CI 0.76, 1.38, ptrend = 0.609). However, hPDI was inversely (OR = 0.50, 95% CI 0.35, 0.72, ptrend < 0.001), while uPDI was positively associated with odds of NAFLD (OR = 1.37, 95% CI 0.93, 2.02, ptrend = 0.009) in the multivariable-adjusted models without body mass index (BMI). After further adjustment for BMI, only the association of hPDI with NAFLD remained statistically significant (OR = 0.64, 95% CI 0.46, 0.87, ptrend = 0.006). Such inverse association appeared stronger in non-Hispanic whites, but not in other racial/ethnic groups (pinteraction = 0.009). Our findings suggest that a plant-based diet rich in healthy plant foods might be associated with lower odds of NAFLD, particularly among US non-Hispanic whites. Clinical trials and cohort studies to validate our findings are needed.

Perspective: Is it Time to Expand Research on "Nuts" to Include "Seeds"? Justifications and Key Considerations

The health benefits of nuts reported throughout the literature are extensive and well established for reducing the risk of, and managing several chronic conditions such as cardiovascular disease, type 2 diabetes, nonalcoholic fatty liver disease, and cognition. Despite their comparable nutrient profile to nuts, seeds are often not assessed in clinical and epidemiological studies. Interestingly, dietary guidelines and recommendations often refer to "nuts and seeds" collectively, even though they are not consistently examined together in nutrition research when determining associated health benefits. The purpose of this review is to call for future nutrition research to consider combining nuts and seeds. This review provides justification for this proposal by summarizing current definitions for nuts and seeds and highlighting the similarities or dissimilarities in their nutrient compositions. Following this, we summarize current evidence on the health benefits of nuts and seeds, research gaps that should be addressed, and considerations for future research using both epidemiological and interventional study designs.

Diet in Scleroderma: Is There a Need for Intervention?

Systemic sclerosis (SSc) patients exhibit a plethora of risk factors for nutritional decline, including the presence of chronic inflammation and the progressive nature of disease-related multisystem involvement. The prevalence and consequences of nutritional decline in scleroderma are frequently underestimated, its management currently remaining a subject of debate. The main objective of the present study was to perform a detailed assessment of scleroderma patients' diet as well as their eating habits and to describe the relationships with weight loss and malnutrition risk in the absence of professional nutritional counseling.

METHODS

We used a translated and validated version of the EPIC-Norfolk FFQ (European Prospective Investigation into Cancer and Nutrition Norfolk Food Frequency Questionnaire) to evaluate the patients' diet and MUST (Malnutrition Universal Screening Tool) to investigate the risk of malnutrition. Disease activity was estimated using the EUSTAR-AI (European Scleroderma Trials and Research group Activity Index).

RESULTS

We included 69 patients with SSc, of which 42 underwent a detailed dietary assessment. Dietary factors were connected to body composition and digestive symptoms. We found high sodium intake and frequent suboptimal energy consumption in our study group, including patients with cardiopulmonary involvement. Liver transaminases were inversely correlated with the consumption of nuts and seeds. Malnutrition and weight loss were significantly associated with pulmonary hypertension, heart failure, albumin levels, and the extent of skin fibrosis, but not advanced age. Although the patients with EUSTAR-AI ≥ 2.5 were more frequently included in the moderate and high malnutrition risk categories, these results did not reach statistical significance.

CONCLUSIONS

Currently, there is an unmet need for longitudinal and interventional research focusing on the long-term significance, ramifications, and management of nutritional impairment in SSc patients with various clinical manifestations. Our results indicate that scleroderma patients could benefit from personalized nutritional counseling in an interdisciplinary setting.