Long-term nuts intake and metabolic syndrome: A 13-year longitudinal population-based study

The association between dietary patterns and metabolic syndrome among Iranian adults, a cross-sectional population-based study (findings from Bandare-Kong non-communicable disease cohort study)

BACKGROUND

Metabolic syndrome is a cluster of metabolic disorders increasing the risk of cardiovascular disease and diabetes. Dietary patterns are supposed to be important and controllable factors in developing metabolic syndrome. The purpose of this study was to investigate the association of dietary patterns with metabolic syndrome and its components.

SUBJECTS/METHODS

Cross-sectional data were extracted from the Bandare-Kong cohort study conducted on 4063 people aged 35 to 70. Dietary patterns were extracted using principal component analysis based on thirty-eight pre-defined food groups. Multivariable logistic regression was conducted to investigate the association between metabolic syndrome and its components with quintiles of dietary patterns in crude and adjusted models.

RESULTS

Three major dietary patterns were identified (healthy, western, and traditional) in the final analysis of 2823 eligible individuals. After adjusting for covariates, the odds of metabolic syndrome were significantly decreased by 46% in subjects with the highest adherence to the healthy dietary pattern compared to those with the lowest adherence quintile. Results from fully adjusted models on individual metabolic syndrome components showed an inverse association between higher adherence to the healthy dietary pattern and the odds of increased blood glucose, high waist circumference, and elevated blood pressure. However, in fully adjusted models, no significant association was observed between the western and traditional dietary patterns with odds of metabolic syndrome and its components.

CONCLUSIONS

Adherence to a healthy dietary pattern containing high amounts of fruits, vegetables, nuts, low-fat dairy products, and legumes, could be recommended to prevent and control metabolic syndrome.

The relationship between nut consumption and premature coronary artery disease in a representative sample of Iranians: Iran-premature coronary artery disease (IPAD) study

OBJECTIVE

The cardioprotective effects of nuts are well established. However, the positive impacts of nuts in preventing CVD at a younger age, a condition known as premature coronary artery disease (PCAD), is still debated. Therefore, we aim to determine the association between nuts and PCAD occurrence and its severity in different Iranian ethnicities.

DESIGN

This case-control study was conducted within the framework of the Iran-premature coronary artery disease (I-PAD) study, an ongoing multi-centric study on Iranian patients of different ethnicities.

SETTING

This multi-centric case-control study was conducted in among 3253 persons under the age of 70 years in women and 60 years in men from different ethnicities in Iran.

PARTICIPANTS

Information on nut consumption was collected using a validated FFQ. Subjects were selected from among the candidates for angiography. Cases were those whose coronary angiography showed stenosis of more than 75 % in at least one vessel or more than 50 % of the left main artery, while the control group participants had normal angiography results.

RESULTS

In the crude model, compared to the first quartile, the highest quartile of nut consumption was significantly associated with a lower risk of PCAD (OR = 0·26, 95 % CI (0·21, 0·32); Pfor trend = 0·001). In the top quartile of nut intake, a substantial decrease in PCAD was observed after controlling for putative confounders (OR = 0·32; 95 % CI (0·24, 0·43); Pfor trend = 0·001). Additionally, a 75 % decrease in the risk of severe PCAD was observed in the participants in the highest quartile of nut intake.

CONCLUSION

A significant inverse association was observed between nut intake and the risk and severity of PCAD in the Iranian population. Large-scale clinical trials are required to confirm these findings.

Legumes and nuts intake in relation to metabolic health status, serum brain derived neurotrophic factor and adropin levels in adults

There is controversial evidence about the relationship between consumption of legumes and nuts with metabolic disturbances. The present study was undertaken to explore the association of legumes and nuts intake with metabolic health status among Iranian adults. This cross-sectional study was conducted on 527 adults (45.7% female, aged 20-65 years) chosen through a multistage cluster random-sampling approach. Dietary intakes of individuals were assessed using a validated food frequency questionnaire. Fasting blood samples were gathered to evaluate biochemical parameters. Metabolic health status of subjects was determined according to the criteria defined by Wildman. Data of covariates were collected using pre-tested procedures. The overall prevalence of metabolic unhealthy (MU) phenotype was 42.5%. After controlling all confounders, participants with highest intake of legumes and nuts had lower odds of MU status, compared with the lowest intake (OR 0.35; 95% CI 0.18-0.71). This association was stronger in normal-weight rather than overweight/obese adults and also in women rather than men. Higher consumption of legumes and nuts was additionally related to decreased odds of hyperglycemia, hypertriglyceridemia, and hypertension. A marginally inverse association was observed between legumes and nuts intake with low brain-derived neurotrophic factor (BDNF) levels, in fully-adjusted model (ORT3 vs. T1 0.50; 95% CI 0.25-1.01). Each tertile increase in legumes and nuts intake was marginally related to higher adropin levels ([Formula: see text] = 4.06; P = 0.07). In conclusion, this study demonstrated that higher intake of legumes and nuts is associated with lower chance of MU both in normal weight and overweight/obese adults. The association may be facilitated through serum BDNF and adropin.

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.

MIND dietary pattern adherence is inversely associated with visceral adiposity and features of metabolic syndrome

The effects of following the Mediterranean-Dietary Approaches to Stop Hypertension (DASH) Intervention for Neurodegenerative Delay (MIND) diet on metabolic health remains understudied. This cross-sectional analysis of 163 adults investigated associations between adherence to the MIND, Mediterranean, DASH, and Healthy Eating Index (HEI-2015) diets and metabolic syndrome (MetS) features and visceral adiposity. We hypothesized that the MIND diet would show the most beneficial associations with MetS risk factors. Diet adherence was assessed using the Dietary History Questionnaire II. Visceral adipose was assessed using dual-energy X-ray absorptiometry. Waist circumference and systolic and diastolic blood pressures were obtained. Fasting blood triglycerides, high-density lipoprotein cholesterol, and glucose concentrations were determined. Stepwise regression analyses were applied. Waist circumference was inversely associated with DASH (β = -0.21, P < .01), HEI-2015 (β = -0.18, P = .01), and MIND (β = -0.19, P < .01). Triglycerides were inversely associated with DASH (β = -0.19, P = .01), HEI-2015 (β = -0.18, P = .02), and MIND (β = -0.23, P < .01). High-density lipoprotein cholesterol was positively associated with Mediterranean (β = 0.18, P = .02) and MIND (β = 0.21, P < .01). Systolic blood pressure was inversely associated with Mediterranean (β = -0.18, P = .02), DASH (β = -0.30, P < .01), HEI-2015 (β = -0.24, P < .01), and MIND (β = -0.25, P < .01). Diastolic blood pressure was inversely associated with Mediterranean (β = -0.26, P < .01), DASH (β = -0.34, P < .01), HEI-2015 (β = -0.24, P < .01), and MIND (β = -0.31, P < .01). Fasting glucose was inversely associated with MIND (β = -0.19, P = .02). Visceral adiposity was inversely associated with Mediterranean (β = -0.19, P < .01), DASH (β = -0.22, P < .01), HEI-2015 (β = -0.22, P < .01), and MIND (β = -0.28, P < .01). Although each diet exhibited potential benefits for metabolic outcomes, only greater MIND diet adherence was associated with lower visceral adiposity and each MetS feature in adults.

Inverse association of a traditional Korean diet composed of a multigrain rice-containing meal with fruits and nuts with metabolic syndrome risk: The KoGES

Background

Hansik, a traditional Korean diet, may have a beneficial impact on metabolic syndrome (MetS) risk as dietary westernization increases its prevalence. We examined the hypothesis that adherence to the hansik diet may be inversely associated with the risk of MetS and its components and sought to understand the gender differences in 58,701 men and women aged over 40.

Materials and methods

Hansik was defined using 14 components from which the Korean dietary pattern index (K_diet-index) was generated by summing their scores. Low-hansik intake was defined as the K_diet-index with <8. MetS was categorized based on the 2005 revised NCEP-ATP III criteria modified for Asians.

Results

The K_diet-index score was negatively associated with the dietary inflammation index and showed that the high intake of a meal with multigrain rice, fruits, and their products, and nuts, and low intake of fried foods were inversely associated with MetS by 0.707, 0.864, 0.769, and 0.918 times, respectively, after adjusting for covariates. More women and participants with more educated and lower income belonged to the high-hansik group, and participants with high self-rated health scores consumed more hansik. All participants on a high-hansik diet were associated with a 0.87 time lower risk of MetS. Specifically, the association between hansik intake and MetS risk was not significant among men following stratification by gender. Body composition, including the body mass index, waist circumference, and fat mass, was inversely associated with hansik intake, while the skeletal muscle mass index was positively associated with the hansik intake in each gender and all participants. In all the participants in the high-hansik group, no significant changes were seen in the serum glucose and HDL concentration. However, a high-hansik intake showed lower blood pressure and serum LDL and triglyceride concentrations only in men and a higher glomerular filtration rate in both genders.

Conclusions

Hansik intake might improve MetS risk, with its primary beneficial effects on body composition, dyslipidemia, and blood pressure gender-dependently.

Effect of nuts on components of metabolic syndrome in healthy adults with overweight/obesity: A systematic review and meta-analysis

AIMS

Randomized controlled trials evaluating the effects of nut consumption on the metabolic profile of healthy adults with overweight/obesity have yielded conflicting results. This systematic review and meta-analysis aimed to summarize the effects of incorporating nuts into the diet on serum lipid profile, glycemic markers, and blood pressure in healthy adults with overweight/obesity.

DATA SYNTHESIS

PubMed, Embase, Scopus, Web of Science, and Cochrane Library were searched up to April 2021. The random-effects model was used to determine the pooled effect sizes expressed as weighted mean difference (WMD) with % 95 confidence intervals (CIs). Ten eligible RCTs (with 12 arms) were included in the meta-analysis. The meta-analysis revealed that nut intake significantly decreased serum triglycerides (TG) (WMD: -13.19 mg/dL, 95% CI: - 25.90, - 0.48). Furthermore, subgroup analysis showed a significant reduction in serum LDL-cholesterol (LDL-C) following adherence to normocaloric, nut-enriched diets (WMD: - 4.56 mg/dL, 95% CI: - 8.24, - 0.88). However, nuts did not affect serum total cholesterol, high-density lipoprotein cholesterol, glycemic markers, and blood pressure.

CONCLUSIONS

Overall, incorporating nuts into the diet of healthy adults with overweight/obesity have favorable effects on serum TG and LDL-C. Thus, nuts might exert protective effects against dyslipidemia in this population.

REGISTRY NUMBER

PROPSPERO CRD42021250662.

The Regular Consumption of Nuts Is Associated with a Lower Prevalence of Abdominal Obesity and Metabolic Syndrome in Older People from the North of Spain

BACKGROUND

The aim of this study was to relate the adherence to nut consumption (30 g) three or more days per week to the prevalence of abdominal obesity and metabolic syndrome (MetS) in an elderly population from the north of Spain.

METHODS

The study consists of an observational, descriptive, cross-sectional, and correlational study conducted in 556 non-institutionalised individuals between 65 and 79 years of age. To define the consumption recommendation of nuts the indication of the questionnaire MEDAS-14 was followed. The diagnosis of MetS was conducted using the International Diabetes Federation (IDF) criteria.

RESULTS

In 264 subjects aged 71.9 (SD: ±4.2) years old, 39% of whom were men, the adherence to nut consumption recommendations was 40.2%. Of these individuals, 79.5% had abdominal obesity. The prevalence of MetS was 40.2%, being 47.6% in men and 35.4% in women (p < 0.05). A nut consumption lower than recommended was associated with a 19% higher prevalence of abdominal obesity (Prevalence Ratio: 1.19; 95% CI: 1.03-1.37; p < 0.05) and a 61% higher prevalence of MetS (Prevalence Ratio: 1.61; 95% CI: 1.16-2.25; p = 0.005) compared to a consumption of ≥3 servings per week.

CONCLUSION

An inverse relationship was established between nut consumption and the prevalence of abdominal obesity and metabolic syndrome.

Socioeconomic and lifestyle factors modifies the association between nut consumption and metabolic syndrome incidence

BACKGROUND & AIMS

The aim of this study was to evaluate the association of nut consumption and its various types with metabolic syndrome (MetS) risk and to investigate whether lifestyle factors (physical activity and smoking status) and socioeconomic status (education and occupation) modulate the association of nut consumption and the risk of MetS.

METHODS

We prospectively studied 1915 participants of the Tehran Lipid and Glucose study, among whom 591 were diagnosed with MetS during 8.9 years of follow-up. Nut consumption and its various types were assessed using a validated semi-quantitative food frequency questionnaire. Multivariable adjusted Cox regression was used to estimate Hazard Ratios (HRs) for MetS events across tertiles of nut consumption and its various types. Regarding interaction between nut consumption and physical activity levels, education levels, and smoking status on the risk of MetS, using joint classification, the effect modification of lifestyle factors and socioeconomic status on the association between nut consumption (<median and ≥ median) and risk of MetS was assessed by Cox regression.

RESULTS

Nut consumption was inversely associated with MetS risk in multivariable-adjusted models. The highest tertiles of the constituents of nuts including fiber, polyphenol, MUFA and PUFA reduced MetS risk compared with the lowest tertiles, after adjustment for confounders. Among various types of nuts, the multivariable-adjusted HRs of MetS were 0.78 (0.63-0.96) for walnuts, and 0.77 (0.63-0.94) for pistachios, compared with the lowest intake. Among adult population, consuming nuts higher than the median and having moderate to high physical activity levels resulted in significant reduction in the MetS risk (HRs: 0.74, CI: 0.55-0.98 for moderate and HRs: 0.63, CI: 0.47-0.86 for high physical activity level). Participants who did not smoke had lower risk of MetS regardless of their amount of nuts consumption (HRs: 0.67, CI: 0.47-0.94 for intakes < median and HRs: 0.71, CI: 0.53-0.93 for intakes ≥ median). Stratification based on education status resulted in reduction in the risk of MetS in participants consuming nuts ≥ median in both educated and not-educated group (HRs: 0.81, CI: 0.66-0.98 for the non-educated group and HRs: 0.63, CI: 0.47-0.84 for the educated group).

CONCLUSIONS

Incorporating nuts, especially walnuts, into dietary patterns reduced the risk of MetS, especially among individuals with more physical activity levels.

Longitudinal Association of Nut Consumption and the Risk of Cardiovascular Events: A Prospective Cohort Study in the Eastern Mediterranean Region

Background and Aim: There are few pieces of evidence on the association between nut consumption and the risk of cardiovascular disease (CVD) in the Eastern Mediterranean Region. This study investigated the relationship of nut consumption with the risk of CVD and all-cause mortality in the Iranian population.

Methods and Results: This population-based prospective cohort study was carried out in 6,504 randomly selected participants aged ≥35 years in central Iran (2001–2013) in the framework of the Isfahan Cohort Study. Dietary data were collected by a validated 48-item food frequency questionnaire. Subjects or their next of kin were interviewed biannually, looking for the possible occurrence of cardiovascular events and all-cause mortality. During the median follow-up of 135 months and 52,704.3 person-years, we found a total of 751 CVD events. In unadjusted model, participants in the highest quartile of nut intake had a lower CVD risk {hazard ratio (HR) [95% confidence interval (CI)]: 0.57(0.47–0.70); P for trend < 0.001}, CVD mortality [HR (95% CI): 0.54 (0.33–0.72); P for trend < 0.001], and all-cause mortality [HR (95% CI): 0.24 (0.14–0.42); P for trend < 0.001]. In the fully adjusted model, the association was diluted, and no significant relationship was found between nut intake and CVD events and all-cause mortality, except for CVD mortality in the highest quartile vs. the lowest one [HR (95% CI): 0.55 (0.30–0.98)].

Conclusion: Nut intake had an inverse association with the risk of CVD mortality. It is suggested to perform studies to examine the association of individual types of nuts and different preparation methods on CVD risk and mortality.

Long-term association of red meat consumption and lipid profile: A 13-year prospective population-based cohort study

OBJECTIVES

The long-term associations between red meat consumption and lipid profile are not completely known. This longitudinal study assessed the association of red meat consumption with lipid profile in healthy Iranian adults using repeated measurements of red meat intake.

METHODS

The population-based longitudinal study was conducted within the framework of the Isfahan Cohort Study on a subsample of 1376 healthy adults, aged ≥35 y, for whom complete information was available in all three phases of the study. A simplified qualitative 48-item food frequency questionnaire, blood pressure, anthropometric measurements, and fasting serum lipids and blood sugar were evaluated in three phases. Mixed-effects linear regression was applied to examine the longitudinal associations between red meat consumption and lipid profile.

RESULTS

After adjustment for potential confounders, each single-serving increase in red meat and organ meat consumption was significantly associated with an increment in triacylglycerol (β = 6.30; 95% confidence interval [CI], 3.97-8.63), total cholesterol (β = 3.03; 95% CI, 2.02-4.04), low-density lipoprotein (β = 3.40; 95% CI, 2.64-4.17), high-density lipoprotein (β = 0.60; 95% CI, 0.28-0.93), ratio of low-density to high-density lipoprotein (β = 0.03; 95% CI, 0.01-0.05), and non-high-density lipoprotein (β = 2.42; 95% CI, 1.41-3.43). However, processed meat consumption had no significant association with lipid profile.

CONCLUSIONS

Total red meat intake had a significant, direct association with lipid profile after a 13-year follow-up period in a cohort of the healthy Iranian population.

Replacing white rice bars with peanuts as snacks in the habitual diet improves metabolic syndrome risk among Chinese adults: a randomized controlled trial

BACKGROUND

Observational studies have suggested that intake of nuts is associated with lower risk of cardiometabolic diseases, whereas refined grain consumption has been linked to higher risk. Little is known about whether substituting white rice, a refined grain, with nuts may confer benefit among adults at high risk of cardiometabolic diseases.

OBJECTIVES

We aimed to evaluate isocaloric substitution of peanuts for white rice bars as snacks on changes in fasting glucose, lipid profile, body weight, as well as changes in metabolic syndrome (MetS) status among participants with MetS or at risk of MetS.

METHODS

This parallel-arm randomized controlled trial included 224 participants either with MetS (according to the International Diabetes Federation criteria for Chinese adults, n = 163) or at risk of MetS (central obesity plus 1 additional MetS risk factor, n = 61). Participants were randomly assigned to either the peanut arm (56 g/d as snacks, n = 113) or the control arm (isocaloric white rice bars, n = 111) for 12 wk.

RESULTS

A total of 209 participants (93.3%) completed the 12-wk intervention with a compliance rate > 85% among all participants. No between-group differences were found for improvements in fasting glucose, HDL cholesterol, waist circumference, and body weight. Participants in the peanut group had a significantly higher MetS reversion rate (no longer meeting MetS criteria after the 12-wk trial) than those in the control group (RR: 2.33; 95% CI: 1.10, 4.89; P = 0.026).

CONCLUSIONS

Including peanuts as a snack in the habitual diet in place of a refined-grain snack did not significantly change glycemic or lipid parameters, but improved overall MetS risk without promoting weight gain among Chinese adults at high risk of cardiometabolic diseases. Further larger-scale trials are needed to confirm these findings and elucidate underlying biological mechanisms.This trial was registered at clinicaltrials.gov as NCT03194152.

Metabolic Syndrome Features and Excess Weight Were Inversely Associated with Nut Consumption after 1-Year Follow-Up in the PREDIMED-Plus Study

BACKGROUND

High nut consumption has been previously associated with decreased prevalence of metabolic syndrome (MetS) regardless of race and dietary patterns.

OBJECTIVES

The aim of this study was to assess whether changes in nut consumption over a 1-y follow-up are associated with changes in features of MetS in a middle-aged and older Spanish population at high cardiovascular disease risk.

METHODS

This prospective 1-y follow-up cohort study, conducted in the framework of the PREvención con DIeta MEDiterránea (PREDIMED)-Plus randomized trial, included 5800 men and women (55-75 y old) with overweight/obesity [BMI (in kg/m2) ≥27 and <40] and MetS. Nut consumption (almonds, pistachios, walnuts, and other nuts) was assessed using data from a validated FFQ. The primary outcome was the change from baseline to 1 y in features of MetS [waist circumference (WC), glycemia, HDL cholesterol, triglyceride (TG), and systolic and diastolic blood pressure] and excess weight (body weight and BMI) according to tertiles of change in nut consumption. Secondary outcomes included changes in dietary and lifestyle characteristics. A generalized linear model was used to compare 1-y changes in features of MetS, weight, dietary intakes, and lifestyle characteristics across tertiles of change in nut consumption.

RESULTS

As nut consumption increased, between each tertile there was a significant decrease in WC, TG, systolic blood pressure, weight, and BMI (P < 0.05), and a significant increase in HDL cholesterol (only in women, P = 0.044). The interaction effect between time and group was significant for total energy intake (P < 0.001), adherence to the Mediterranean diet (MedDiet) (P < 0.001), and nut consumption (P < 0.001). Across tertiles of increasing nut consumption there was a significant increase in extra virgin olive oil intake and adherence to the MedDiet; change in energy intake, on the other hand, was inversely related to consumption of nuts.

CONCLUSIONS

Features of MetS and excess weight were inversely associated with nut consumption after a 1-y follow-up in the PREDIMED-Plus study cohort. This trial was registered at isrctn.com as ISRCTN89898870.

Does Nut Consumption Reduce Mortality and/or Risk of Cardiometabolic Disease? An Updated Review Based on Meta-Analyses

Aim We aimed to determine if nut consumption decreases mortality and/or the risk of cardiometabolic diseases based on updated meta-analyses of epidemiological and intervention studies. Methods. An updated electronic search was conducted in PubMed/MEDLINE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and the Cochrane Library databases for original meta-analyses to investigate the effects of nut consumption on cardiometabolic disease in humans. Results. Seven new meta-analyses were included in this updated review. Findings similar to our previous review were observed, showing that nut consumption significantly decreased cardiovascular disease (CVD) mortality (−19% to −25%; n = 4), coronary heart disease (CHD) mortality (−24% to −30%; n = 3), stroke mortality (−17% to −18%; n = 3), CVD incidence (−15% to −19 %; n = 4), CHD [or coronary artery disease (CAD)] incidence (−17% to −34%; n = 8), and stroke incidence (−10% to −11%; n = 6) comparing high with low categories of nut consumption. Fasting glucose levels (0.08 to 0.15 mmol/L; n = 6), total cholesterol (TC; 0.021 to 0.30 mmol/L; n = 10), and low-density lipoprotein cholesterol (LDL-C; 0.017 to 0.26 mmol/L; n = 10) were significantly decreased with nut consumption compared with control diets. Body weight and blood pressure were not significantly affected by nut consumption. Conclusion. Nut consumption appears to exert a protective effect on cardiometabolic disease, possibly through improved concentrations of fasting glucose, total cholesterol, and LDL-C.

The association between metabolic syndrome and peanuts, pine nuts, almonds consumption: The Ansan and Ansung Study

BACKGROUND

Previous studies reported an inverted relationship between nut consumption and the incidence of metabolic syndrome (MetS). The present study investigated the incidental risk for MetS according to peanut, almond, and fine nut consumption in the Korean population.

METHODS

In a community-based Korean cohort, 5306 Korean adults were divided into four groups according to their peanut, almond, and fine nut intake (<1/month, 1/month-0.5/week, 0.5-1/week, and ≥1/week, in which one serving = 15 g) and were followed-up for 10 years. A Cox proportional hazard model was used to evaluate the hazard ratios (HRs) with confidence intervals (CI) for MetS in each study group. Age subgroup (≥50 or <50 years) analysis was also conducted.

RESULTS

The age and multivariable-adjusted HRs with 95% CIs for MetS showed a significant inverse dose-response relationship between peanut, almond, and fine nut intake and the incidence of MetS in men and women (multivariable-adjusted HRs [95% CI] in men; 0.91 [0.76-1.09] in 1/month-0.5/week, 1.03 [0.80-1.31] in 0.5-1/week, 0.72 [0.56-0.93] in ≥1/week and in women; 0.81 [0.65-1.003] in 1/month-0.5/week, 0.76 [0.54-1.07] in 0.5-1/week, 0.57 [0.41-0.79] ≥1/week)). Subgroup analysis showed a significant difference in middle-aged men (≥1/week) and old-aged women (≥0.5/week).

CONCLUSION

The results of the present study suggested that peanut, almond, and fine nut intake (≥15 g/week) may be inversely related to incidence risk of MetS in the Korean general population. Additionally, the association between nut consumption and MetS incidence risk may differ in sex and age subgroups.

Relationship Between Nut Consumption and Metabolic Syndrome: A Meta-Analysis of Observational Studies

Objective: Our aim was to examine the relationship between nut consumption and metabolic syndrome (MetS). Methods: The electronic databases of PubMed, Web of Science, and Embase were searched up to November 2018 for observational studies on the relationship between nut consumption and MetS. The pooled relative risk (RR) of MetS for the highest versus lowest category of nut consumption, as well as their corresponding 95% confidence intervals (CIs) were calculated. Results: A total of 11 observational studies (6 cross-sectional and 5 prospective cohort studies), which involved a total of 89,224 participants, were identified for this meta-analysis. The overall multivariable adjusted RR showed that nut consumption was negatively associated with MetS (RR = 0.84; 95% CI, 0.76-0.92; p < 0.001). Of interest, subgroup analysis confirmed that such findings existed in tree nuts (RR = 0.97; 95% CI, 0.94-1.00; p = 0.04), but not in peanuts (RR = 1.01; 95% CI, 0.96-1.06; p = 0.68). Conclusions: The existing evidence suggested that nut consumption was negatively associated with MetS. However, such an inverse relationship only existed in tree nuts, not in peanuts. More well-designed studies with detailed specifications of nut varieties are needed to further elaborate the issues examined in this study.