Nut consumption and incidence of metabolic syndrome after 6-year follow-up: the SUN (Seguimiento Universidad de Navarra, University of Navarra Follow-up) cohort

Consumption of Tree Nuts as Snacks Reduces Metabolic Syndrome Risk in Young Adults: A Randomized Trial

Metabolic syndrome (MetSx) and its chronic disease consequences are major public health concerns worldwide. Between-meal snacking may be a modifiable risk factor. We hypothesized that consuming tree nuts as snacks, versus typical carbohydrate snacks, would reduce risk for MetSx in young adults. A prospective, randomized, 16-week parallel-group diet intervention trial was conducted in 84 adults aged 22-36 with BMI 24.5 to 34.9 kg/m2 and ≥1 MetSx clinical risk factor. Tree nuts snacks (TNsnack) were matched to carbohydrate snacks (CHOsnack) for energy (kcal), protein, fiber, and sodium content as part of a 7-day eucaloric menu. Difference in change between groups was tested by analysis of covariance using general linear models. Multivariable linear regression modeling assessed main effects of TNsnack treatment and interactions between TNsnack and sex on MetSx score. Age, BMI, and year of study enrollment were included variables. There was a main effect of TNsnack on reducing waist circumference in females (mean difference: -2.20 ± 0.73 cm, p = 0.004) and a trend toward reduced visceral fat (-5.27 ± 13.05 cm2, p = 0.06). TNsnack decreased blood insulin levels in males (-1.14 ± 1.41 mIU/L, p = 0.05) and multivariable modeling showed a main effect of TNsnack on insulin. Main effects of TNsnack on triglycerides and TG/HDL ratio were observed (p = 0.04 for both) with TG/HDL ratio reduced ~11%. A main effect of TNsnack (p = 0.04) and an interaction effect between TNsnack and sex (p < 0.001) on total MetSx score yielded 67% reduced MetSx score in TNsnack females and 42% reduced MetSx score in TNsnack males. To our knowledge, this is the first randomized parallel-arm study to investigate cardiometabolic responses to TNsnacks versus typical CHOsnacks among young adults at risk of MetSx. Our study suggests daily tree nut consumption reduces MetSx risk by improving waist circumference, lipid biomarkers, and/or insulin sensitivity-without requiring caloric restriction.

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.

Walnut consumption and health outcomes with public health relevance-a systematic review of cohort studies and randomized controlled trials published from 2017 to present

CONTEXT

Considering the accumulation of recent studies investigating the health effects of walnut consumption, both including and beyond cardiovascular health effects, a systematic review of this literature to investigate the strength of the evidence is warranted.

OBJECTIVE

To investigate associations between walnut consumption and outcomes with public health relevance (specifically all-cause mortality, type 2 diabetes, CVD, metabolic syndrome, obesity, cancer, neurological and mental health, musculoskeletal, gastrointestinal, and maternal disorders) and the effect on associated disease risk markers, reported in studies published from 2017 to present.

DATA SOURCES

MEDLINE, FSTA, CENTRAL, and Scopus were searched from 1 January 2017 to 5 May 2021.

DATA EXTRACTION

Human studies (cohort studies and RCTs) ≥3 weeks in duration comparing consumption of walnuts (whole, pieces, or 100% butter) to a control and measuring associations with relevant public health outcomes and disease risk markers were assessed. Key study characteristics were extracted independently by 2 investigators using a standardized table. The quality of the studies was assessed using the Cochrane Risk-of-Bias tool 2.0 and the Newcastle-Ottawa Scale.

DATA ANALYSIS

Only 1 RCT was considered to be at low risk of bias for any of its outcomes. The cohort studies were considered to be of moderate or high quality. The results were synthesized using vote counting, based on the direction of effect. Thirty-three articles, 23 describing RCTs (walnut dose ∼10-99 g/day, 1,948 subjects) and 10 describing cohort studies (∼675,928 subjects), were included. Vote counting could be performed for the blood lipids, cardiovascular function, inflammation- and hemostatic-related factors, markers of glucose metabolism, and body weight and composition outcome groupings. The results are presented in effect direction plots. With respect to blood lipids, results from 8/8 RCTs favoured walnuts, in accordance with associations with a reduced risk of CVD suggested by cohort studies; results from 6/6 RCTs favoured control with respect to body weight and composition, although most of these effects were small. This was contrary to cohort study results suggesting small benefits of walnut consumption on body weight. There was no overall consistent direction of effect for cardiovascular function, markers of glucose metabolism, or inflammation- and hemostatic-related factors.

CONCLUSIONS

Evidence published since 2017 is consistent with previous research suggesting that walnut consumption improves lipid profiles and is associated with reduced CVD risk. Evidence is accumulating in other areas, such as cognitive health, although more research is needed to draw firm conclusions.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD4202122.

A review of harmonization methods for studying dietary patterns

Data harmonization is the process by which each of the variables from different research studies are standardized to similar units resulting in comparable datasets. These data may be integrated for more powerful and accurate examination and prediction of outcomes for use in the intelligent and smart electronic health software programs and systems. Prospective harmonization is performed when researchers create guidelines for gathering and managing the data before data collection begins. In contrast, retrospective harmonization is performed by pooling previously collected data from various studies using expert domain knowledge to identify and translate variables. In nutritional epidemiology, dietary data harmonization is often necessary to construct the nutrient and food databases necessary to answer complex research questions and develop effective public health policy. In this paper, we review methods for effective data harmonization, including developing a harmonization plan, which common standards already exist for harmonization, and defining variables needed to harmonize datasets. Currently, several large-scale studies maintain harmonized nutrient databases, especially in Europe, and steps have been proposed to inform the retrospective harmonization process. As an example, data harmonization methods are applied to several U.S longitudinal diet datasets. Based on our review, considerations for future dietary data harmonization include user agreements for sharing private data among participating studies, defining variables and data dictionaries that accurately map variables among studies, and the use of secure data storage servers to maintain privacy. These considerations establish necessary components of harmonized data for smart health applications which can promote healthier eating and provide greater insights into the effect of dietary patterns on health.

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.

Lack of association between nuts and legumes consumption and metabolic syndrome in young Iranian nurses

BACKGROUND

Most studies have investigated the association between dietary pattern and risk of metabolic syndrome. Limited studies have examined the association between nuts and legumes as a food group and metabolic syndrome. This study explored the association between nuts and legumes and components of metabolic syndrome in Iranian nurses.

METHODS

This cross-sectional study included a representative sample of 420 female nurses of Isfahan who were randomly selected. Nuts and legumes consumption was assessed using a validated dish-based semi quantitative food frequency questionnaire (FFQ). Metabolic syndrome was defined by the National Cholesterol Education Program's Adult Treatment Panel III (ATP III). Linear and logistic regression tests were used to study the association between nuts and legumes consumption and metabolic syndrome and its components.

RESULTS

Mean age of study participants was 35 years. The prevalence of the metabolic syndrome among study participants was 3.6%. Consumption of nuts and legumes was not associated with waist circumference either before (β = -0.01, P = 0.24) or after adjusting for potential confounders (β = -0.18, P = 0.41). The same findings were also observed for diastolic blood pressure (DBP) (β = 0.001, P = 0.42), serum triglyceride (TG) (β = 0.07, P = 0.32), high-density lipoprotein cholesterol (HDL-C) (β = 0.008, P = 0.65) and fasting blood sugar (FBS) (β = -0.001, P = 0.94). We failed to find a significant association between consumption of nuts and legumes and systolic blood pressure (SBP) after adjusting for confounders (β = 0.002, P = 0.38). Individuals in the highest category of nuts and legume consumption did not had elevated odds for metabolic syndrome after adjusting for potential confounders (OR = 0.89, 95% CI = 0.08-9.80, P = 0.93).

CONCLUSIONS

Nuts and legumes consumption was not associated with metabolic syndrome or its components. Prospective studies are needed to investigate further this association.

Are fatty nuts a weighty concern? A systematic review and meta-analysis and dose-response meta-regression of prospective cohorts and randomized controlled trials

Nuts are recommended for cardiovascular health, yet concerns remain that nuts may contribute to weight gain due to their high energy density. A systematic review and meta-analysis of prospective cohorts and randomized controlled trials (RCTs) was conducted to update the evidence, provide a dose-response analysis, and assess differences in nut type, comparator and more in subgroup analyses. MEDLINE, EMBASE, and Cochrane were searched, along with manual searches. Data from eligible studies were pooled using meta-analysis methods. Interstudy heterogeneity was assessed (Cochran Q statistic) and quantified (I2 statistic). Certainty of the evidence was assessed by Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Six prospective cohort studies (7 unique cohorts, n = 569,910) and 86 RCTs (114 comparisons, n = 5873) met eligibility criteria. Nuts were associated with lower incidence of overweight/obesity (RR 0.93 [95% CI 0.88 to 0.98] P < 0.001, "moderate" certainty of evidence) in prospective cohorts. RCTs presented no adverse effect of nuts on body weight (MD 0.09 kg, [95% CI -0.09 to 0.27 kg] P < 0.001, "high" certainty of evidence). Meta-regression showed that higher nut intake was associated with reductions in body weight and body fat. Current evidence demonstrates the concern that nut consumption contributes to increased adiposity appears unwarranted.

Nut Consumption Is Associated with Lower Risk of Metabolic Syndrome and Its Components in Type 1 Diabetes

Although nut consumption has been associated with several health benefits, it has not been investigated in individuals with type 1 diabetes. Therefore, our aim was to assess nut consumption and its association with metabolic syndrome in adult individuals with type 1 diabetes taking part in the Finnish Diabetic Nephropathy Study. The nut intake of the 1058 participants was assessed from 3-day food records that were completed twice, and the number of weekly servings, assuming a serving size of 28.4 g, was calculated. Metabolic syndrome was defined as the presence of ≥3 of the cardiovascular risk factors: central obesity, high blood pressure (≥130/85 mmHg or use of antihypertensive medication), high triglyceride concentration (≥1.70 mmol/L or use of lipid-lowering medication), low HDL-cholesterol concentration (<1.00 mmol/L in men and <1.30 mmol/L in women or use of lipid-lowering medication), and hyperglycaemia. Overweight/obesity was defined as a BMI ≥25 kg/m². HbA_1c > 59 mmol/mol (>7.5%) was used as a criterion for suboptimal glycaemic control. Of the 1058 (mean age 46 years, 41.6% men) participants, 689 (54.1%) reported no nut intake. In the remaining sample, the median weekly nut intake was 40.8 g. In the adjusted models, higher nut intake, as the continuous number of weekly servings and the comparison of those with <2 and ≥2 weekly servings, was associated with lower metabolic syndrome score, waist circumference, HbA_1c, and BMI. Nut consumption as a continuous variable was negatively associated with the presence of metabolic syndrome, its blood pressure, triglyceride, and HDL-cholesterol components, and suboptimal glycaemic control. Consumption of ≥2 weekly servings was associated with lower odds of suboptimal glycaemic control (by 51.5%), overweight/obesity (by 33.4%), and metabolic syndrome (by 51.8%) and meeting the waist (by 37.3%), blood pressure (by 44.5%), triglyceride (by 37.7%), and HDL-cholesterol (by 36.2%) components of the metabolic syndrome. In conclusion, a weekly nut intake of ≥2 servings was beneficially associated with all the components of the metabolic syndrome in type 1 diabetes. The causality of this association will need to be investigated.

Total Nut, Tree Nut, and Peanut Consumption and Metabolic Status in Southern Italian Adults

Background: Nut consumption has been associated with cardio-metabolic health benefits. However, studies conducted in the Southern Italian population, where adherence to the Mediterranean diet has been reported being relatively high, are rather scarce. The aim of this study was to test the association between consumption of total and specific types of nuts and metabolic status among adults living in Sicily, Southern Italy. Methods: Demographic and dietary characteristics of 2044 adults living in Southern Italy were analyzed. Multivariate logistic regression analyses were performed to calculate odds ratios (ORs) and 95% confidence intervals (CIs) of the association between nut consumption and metabolic status adjusting for potential confounding factors. Results: The energy-adjusted model revealed that higher nut intake was inversely associated with occurrence of hypertension, type-2 diabetes, and dyslipidemia. However, the association did not remain significant for the latter after adjusting for the main background characteristics, while an inverse association was stably confirmed for hypertension (OR = 0.61, 95% CI: 0.46–0.80 and OR = 0.44, 95% CI: 0.26–0.74, respectively) even after adjusting for adherence to the Mediterranean diet. Among individual nut types, most of the associations were null except for higher almond intake, which was inversely associated with occurrence of hypertension (OR = 0.70, 95% CI: 0.49–0.99). Conclusions: Higher nut consumption is associated with overall better metabolic status in individuals living in the Mediterranean area.

Effects of Supplementing the Usual Diet with a Daily Dose of Walnuts for Two Years on Metabolic Syndrome and Its Components in an Elderly Cohort

Accumulating evidence links nut consumption with an improved risk of metabolic syndrome (MetS); however, long-term trials are lacking. We examined the effects of a daily dose of walnuts for two years on MetS in a large elderly cohort. A total of 698 healthy elderly participants were randomly assigned to either a walnut supplemented or a control diet. The participants in the walnut group were provided with packaged walnuts (1, 1.5, or 2 oz. or ~15% of energy) and asked to incorporate them into their daily habitual diet. The participants in the control group were asked to continue with their habitual diet and abstain from eating walnuts and other tree nuts. Intake of n-3 fatty acid supplements was not permitted in either group. Fasting blood chemistries, blood pressure, and anthropometric measurements were obtained at baseline and at the end of intervention. A total of 625 participants (67% women, mean age 69.1 y) completed this two-year study (90% retention rate). Triglycerides decreased in both walnut (-0.94 mg/dl) and control (-0.96 mg/dl) groups, with no significant between-group differences. There was a non-significant decrease in systolic and diastolic blood pressure in the walnut group (-1.30 and -0.71 mm Hg, respectively) and no change in the control group. Fasting blood glucose decreased by ~1 point in both the walnut and control groups. There were no significant between-group differences in the development or reversion of MetS. In conclusion, supplementing the diet of older adults with a daily dose of walnuts had no effect on MetS status or any of its components, although the walnut group tended to have lower blood pressure.

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.

Long-term association of nut consumption and cardiometabolic risk factors

BACKGROUND AND AIMS

Long-term associations between nut consumption and cardiometabolic risk factors are not well known. We investigated the relationship between nut consumption and cardiometabolic risk factors including dyslipidemia, hypertension, diabetes mellitus (DM), and obesity in a cohort of Iranian adults.

METHODS AND RESULTS

The study was conducted within the framework of the Isfahan Cohort Study on 1387 healthy participants. The participants were followed up for 12 years. A validated food frequency questionnaire was completed, and anthropometric measurements, blood pressure, and fasting serum lipids and blood sugar were evaluated in three phases. Mixed-effects binary logistic regression was applied to examine the associations between nut consumption and cardiometabolic risk factors. The participants were classified according to the tertiles of nut consumption as cut-points, and associations were evaluated between the thirds of nut intake. Subjects in the last third were less likely to have hypercholesterolemia [OR (95% CI): 0.76 (0.60-0.97)], hypertriglyceridemia [OR (95% CI): 0.74 (0.58-0.93)], and obesity [OR (95% CI): 0.79 (0.50-0.98)] but more likely to have DM [OR (95% CI): 1.85 (1.27-2.68)] than those in the first third. However, after adjustment for various potential confounders, the associations remained significant only for obesity [OR (95% CI): 0.67 (0.48-0.94)] and DM [OR (95% CI): 2.23 (1.37-3.64)].

CONCLUSION

After adjustment for potential confounders, we observed an inverse association for nut consumption and obesity but positive association for DM and nut intake. On the basis of our findings, it is suggested that incorporation of nuts into people's usual diet may have beneficial effects for individuals with lower risk such as subjects without DM.

Inverse association of long-term nut consumption with weight gain and risk of overweight/obesity: a systematic review

Nuts contain a variety of nutrients and bioactive compounds that are capable of promoting metabolic health. However, due to their high energy density, concerns have been raised that nut consumption in the long term may contribute to weight gain. This systematic review summarizes the findings of prospective studies regarding the relationship between long-term nut consumption and obesity. Searches were conducted up through February 2018, using the PUBMED, EMBASE, and SCOPUS databases with the relevant MeSH terms and phrases. This systematic review included prospective cohort studies investigating the relationship between consumption of total nut and/or nut subtypes with changes in weight, body mass index (BMI), and waist circumference (WC), as well as the risk of overweight/obesity, with follow-up duration ≥1-year. Out of a total of 1580 papers that were initially examined, 6 met the inclusion criteria. Four out of the 6 studies showed an inverse association between nut consumption (typically at the dosages of ≥1 to 2 servings per week) and weight gain and risk of overweight/obesity. The remaining 2 studies evaluated the association between nut intake and changes in WC. From these 2 studies, only one study reported a significant inverse association. Overall, evidence from limited cohort studies demonstrated that long-term nut intake was associated with less weight gain and reduced risk of overweight/obesity. Whether such findings are generalizable to racially diverse ethnic groups, individuals of low socioeconomic status, and populations in developing countries should be addressed in future studies.

Food Groups and Risk of Overweight, Obesity, and Weight Gain: A Systematic Review and Dose-Response Meta-Analysis of Prospective Studies

This meta-analysis summarizes the evidence of a prospective association between the intake of foods [whole grains, refined grains, vegetables, fruit, nuts, legumes, eggs, dairy, fish, red meat, processed meat, and sugar-sweetened beverages (SSBs)] and risk of general overweight/obesity, abdominal obesity, and weight gain. PubMed and Web of Science were searched for prospective observational studies until August 2018. Summary RRs and 95% CIs were estimated from 43 reports for the highest compared with the lowest intake categories, as well as for linear and nonlinear relations focusing on each outcome separately: overweight/obesity, abdominal obesity, and weight gain. The quality of evidence was evaluated with use of the NutriGrade tool. In the dose-response meta-analysis, inverse associations were found for whole-grain (RRoverweight/obesity: 0.93; 95% CI: 0.89, 0.96), fruit (RRoverweight/obesity: 0.93; 95% CI: 0.86, 1.00; RRweight gain: 0.91; 95% CI: 0.86, 0.97), nut (RRabdominal obesity: 0.42; 95% CI: 0.31, 0.57), legume (RRoverweight/obesity: 0.88; 95% CI: 0.84, 0.93), and fish (RRabdominal obesity: 0.83; 95% CI: 0.71, 0.97) consumption and positive associations were found for refined grains (RRoverweight/obesity: 1.05; 95% CI: 1.00, 1.10), red meat (RRabdominal obesity: 1.10; 95% CI: 1.04, 1.16; RRweight gain: 1.14; 95% CI: 1.03, 1.26), and SSBs (RRoverweight/obesity: 1.05; 95% CI: 1.00, 1.11; RRabdominal obesity: 1.12; 95% CI: 1.04, 1.20). The dose-response meta-analytical findings provided very low to low quality of evidence that certain food groups have an impact on different measurements of adiposity risk. To improve the quality of evidence, better-designed observational studies, inclusion of intervention trials, and use of novel statistical methods (e.g., substitution analyses or network meta-analyses) are needed.

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.

Nut Oils and their Dietetic and Cosmetic Significance: a Review

Vegetable oils, which are a rich source of unsaturated fatty acids, phytosterols, vitamins and antioxidants, have a significant effect on the functioning and development of the body and contribute to health maintenance. They can be obtained from seeds, fruit stones, fruit, nuts or sprouts. This study discusses various species of plants that are sources of nut oils consumed in the daily diet and also used in the pharmaceutical and cosmetics industries.

Healthy Lifestyle and Incidence of Metabolic Syndrome in the SUN Cohort

We assessed the relationship between a healthy lifestyle and the subsequent risk of developing metabolic syndrome. The “Seguimiento Universidad de Navarra” (SUN) Project is a prospective cohort study, focused on nutrition, lifestyle, and chronic diseases. Participants (n = 10,807, mean age 37 years, 67% women) initially free of metabolic syndrome were followed prospectively for a minimum of 6 years. To evaluate healthy lifestyle, nine habits were used to derive a Healthy Lifestyle Score (HLS): Never smoking, moderate to high physical activity (>20 MET-h/week), Mediterranean diet (≥4/8 adherence points), moderate alcohol consumption (women, 0.1–5.0 g/day; men, 0.1–10.0 g/day), low television exposure (<2 h/day), no binge drinking (≤5 alcoholic drinks at any time), taking a short afternoon nap (<30 min/day), meeting up with friends >1 h/day, and working at least 40 h/week. Metabolic syndrome was defined according to the harmonizing definition. The association between the baseline HLS and metabolic syndrome at follow-up was assessed with multivariable-adjusted logistic regressions. During follow-up, we observed 458 (4.24%) new cases of metabolic syndrome. Participants in the highest category of HLS adherence (7–9 points) enjoyed a significantly reduced risk of developing metabolic syndrome compared to those in the lowest category (0–3 points) (adjusted odds ratio (OR) = 0.66, 95% confidence interval (CI) = 0.47–0.93). Higher adherence to the Healthy Lifestyle Score was associated with a lower risk of developing metabolic syndrome. The HLS may be a simple metabolic health promotion tool.

Nuts and Cardio-Metabolic Disease: A Review of Meta-Analyses

OBJECTIVES

Accumulating epidemiological and intervention evidence suggest that nut consumption is associated with reduced incidence of some cardiometabolic diseases. However, to date no review of meta-analyses of epidemiological and intervention studies has evaluated the effects of nut consumption on cardiometabolic disease. Design/Results: Electronic searches for meta-analyses of epidemiological and intervention studies were undertaken in PubMed®/MEDLINE®. Meta-analyses of prospective studies show that nut consumption appears to be associated with reduced all-cause mortality by 19⁻20% (n = 6), cardiovascular disease (CVD) incidence (19%; n = 3) and mortality (25%; n = 3), coronary heart disease (CHD) incidence (20⁻34%; n = 2) and mortality (27⁻30%; n = 2) and stroke incidence (10⁻11%; n = 7) and mortality (18%; n = 2). No association between nut consumption and the risk of type 2 diabetes mellitus (T2DM) was observed in meta-analyses of prospective studies, whereas a decrease in fasting blood glucose ranging from 0.08 to 0.15 mmol/L was observed in 3 meta-analyses of intervention studies. In the interventions, nut consumption also had favorable effects on total cholesterol (0.021 to 0.28 mmol/L reduction from 8 meta-analyses of interventions) and low-density lipoprotein cholesterol (0.017 to 0.26 mmol/L reduction from 8 meta-analyses of interventions) and endothelial function (0.79 to 1.03% increase in flow-mediated dilation from 4 meta-analyses of interventions). Nut consumption did not significantly affect body weight. Nut consumption had no effect on inflammatory markers in intervention studies. The effect on blood pressure was inconsistent. A higher nut consumption was associated with a lower incidence of hypertension in prospective studies, while nut consumption did not improve blood pressure in intervention studies.

CONCLUSIONS

Nut consumption appeared to be associated with lower all-cause mortality and CVD and CHD mortality. There was no association between nut consumption and the incidence of T2DM although fasting blood glucose is decreased in intervention studies. In intervention studies nuts lower total cholesterol and low-density lipoprotein cholesterol (LDL-C).

Nut consumption and risk of metabolic syndrome and overweight/obesity: a meta-analysis of prospective cohort studies and randomized trials

Background

Nut consumption has been shown to reduce the risk of cardiovascular disease. However, its role in the prevention of metabolic disorders, such as metabolic syndrome (Mets) and overweight/obesity, remains controversial. We therefore conducted a meta-analysis to determine the association of nut consumption with Mets and overweight/obesity.

Methods

Eligible studies were identified by searching the PubMed and Embase databases and by reviewing the references of relevant literatures. We used random effect models to pool the studies-specific risk ratio (RR) and weighted mean difference (WMD).

Results

This meta-analysis included six prospective cohort studies with 420,890 subjects and 62 randomized feeding trials with 7184 participants. Among the cohort studies, the summary RR for every 1-serving/week increase in nut intake was 0.96 (95% confidence interval [CI]: 0.92 to 0.99; n = 3) for Mets, 0.97 (95% CI: 0.95 to 0.98; n = 2) for overweight/obesity, and 0.95 (95% CI: 0.89 to 1.02; n = 2) for obesity. Pooling of randomized trials indicated that nut consumption was related to a significant reduction in body weight (WMD: - 0.22 Kg, 95% CI: -0.40 to - 0.04), body mass index (WMD: - 0.16 Kg/m², 95% CI: -0.31 to - 0.01), and waist circumference (WMD: - 0.51 cm, 95% CI: -0.95 to - 0.07). These findings remained stable in the sensitivity analysis, and no publication bias was detected.

Conclusion

Nut consumption may be beneficial in the prevention of Mets and overweight/obesity. Additional prospective studies are needed to enhance these findings and to explore the metabolic benefits for specific subclasses of nut.

Nut consumption in relation to all-cause and cause-specific mortality: a meta-analysis 18 prospective studies

Several previous meta-analyses show a consistent inverse association between nut consumption and all-cause mortality, but the associations with cause-specific mortality remain uncertain. A recent meta-analysis on nut consumption and multiple health outcomes combined incidence and mortality outcomes across most of the analyses, which may have introduced heterogeneity across studies. We conducted an updated meta-analysis to evaluate the nut-mortality association. We searched PubMed and EMBASE and we contacted authors for additional data. The final analyses included 18 prospective studies. The random-effects summary RRs for high compared with low nut consumption were 0.81 (95% CI: 0.78-0.84) for all-cause mortality (18 studies with 81 034 deaths), 0.75 (95% CI: 0.71-0.79) for CVD mortality (17 studies with 20 381 deaths), 0.73 (95% CI: 0.67-0.80) for CHD mortality (14 studies with 10 438 deaths), 0.82 (95% CI: 0.73-0.91) for stroke mortality (13 studies with 4850 deaths) and 0.87 (95% CI: 0.80-0.93) for cancer mortality (11 studies 21 353 deaths). These results were broadly consistent within subgroups according to various study and population characteristics and within sensitivity analyses that took into account potential confounders. Peanut (5 studies) and tree nut (3 studies) consumption were similarly associated with mortality risks. Dose-response analyses suggested evidence for nonlinear associations between nut consumption and mortality (P-nonlinearity <0.001 for all outcomes except cancer mortality), with mortality risk levelling off at the consumption of about 3 servings per week (12 g d^-1). Our findings suggest that nut consumption is associated with reduced all-cause and cause-specific mortality, with the strongest reduction for CHD mortality. Both tree nuts and peanuts may lower mortality and most of the survival benefits may be achieved at a relative low level of nut consumption.

Nut consumption and total and cause-specific mortality: results from the Golestan Cohort Study

Background

A number of prospective studies have observed inverse associations between nut consumption and chronic diseases. However, these studies have predominantly been conducted in Western countries, where nut consumption tends to be more common among individuals with healthier lifestyles. It is important to examine the association in other parts of the world, and particularly among populations with different patterns of disease, socioeconomic status, lifestyles and disease risk factors. Our objective was to examine the association between nut consumption and mortality in a population whose nut consumption does not track with a healthy lifestyle.

Methods

We examined the association between nut consumption and all-cause and cause-specific mortality in the 50 045 participants of the Golestan Cohort Study. Participants were aged 40 and older at baseline in 2004, and have been actively followed since that time. Dietary data were collected using a validated semi-quantitative food frequency questionnaire that was administered at baseline.

Results

During 349 677 person-years of follow-up, 3981 cohort participants died, including 1732 women and 2249 men. Nut consumption was associated inversely with all-cause mortality. The pooled multivariate adjusted hazard ratios for death among participants who ate nuts, as compared with those who did not, were 0.89 [95% confidence interval (CI), 0.82-0.95] for the consumption of less than one serving of nuts per week, 0.75 (95% CI, 0.67-0.85) for one to less than three servings per week and 0.71 (95% CI, 0.58-0.86) for three or more servings per week ( P < 0.001 for trend). Among specific causes, significant inverse associations were observed between nut consumption and deaths due to cardiovascular disease, all cancers and gastrointestinal cancers.

Conclusions

This study provides evidence for an inverse association between nut consumption and mortality in a developing country, where nut consumption does not track with a healthy lifestyle. Further work is needed to establish the underlying mechanisms responsible for this association.

The relationship between nut intake and risk of colorectal cancer: a case control study

BACKGROUND

Nut consumption is known to reduce the risk of obesity, diabetes mellitus, and cardiovascular disease. However, in previous studies, portion sizes and categories of nut consumption have varied, and few studies have assessed the association between colorectal cancer risk and nut consumption. In this study, we investigated the relationship between nut consumption and colorectal cancer risk.

METHODS

A case-control study was conducted among 923 colorectal cancer patients and 1846 controls recruited from the National Cancer Center in Korea. Information on dietary intake was collected using a semi-quantitative food frequency questionnaire with 106 items, including peanuts, pine nuts, and almonds (as 1 food item). Nut consumption was categorized as none, < 1 serving per week, 1-3 servings per week, and ≥3 servings per week. A binary logistic regression model was used to estimate odds ratios (OR) and their 95% confidence intervals (CI) for the association between nut consumption and colorectal cancer risk, and a polytomous logistic regression model was used for sub-site analyses.

RESULTS

High nut consumption was strongly associated with reduced risk of colorectal cancer among women (adjusted ORs: 0.30, 95%CI: 0.15-0.60 for the ≥3 servings per week group vs. none). A similar inverse association was observed for men (adjusted ORs: 0.28, 95% CI: 0.17-0.47). In sub-site analyses, adjusted ORs (95% CIs) comparing the ≥3 servings per week group vs none were 0.25 (0.09-0.70) for proximal colon cancer, 0.39 (0.19-0.80) for distal colon cancer, and 0.23 (0.12-0.46) for rectal cancer among men. An inverse association was also found among women for distal colon cancer (OR: 0.13, 95% CI: 0.04-0.48) and rectal cancer (OR: 0.40, 95% CI: 0.17-0.95).

CONCLUSIONS

We found a statistically significant association between high frequency of nut consumption and reduced risk of colorectal cancer. This association was observed for all sub-sites of the colon and rectum among both men and women, with the exception of proximal colon cancer for women.

Nut Consumption and Survival in Patients With Stage III Colon Cancer: Results From CALGB 89803 (Alliance)

Purpose

Observational studies have reported increased colon cancer recurrence and mortality in patients with states of hyperinsulinemia, including type 2 diabetes, obesity, sedentary lifestyle, and high glycemic load diet. Nut intake has been associated with a lower risk of type 2 diabetes, metabolic syndrome, and insulin resistance. However, the effect of nut intake on colon cancer recurrence and survival is not known.

Patients and Methods

We conducted a prospective, observational study of 826 eligible patients with stage III colon cancer who reported dietary intake on food frequency questionnaires while enrolled onto a randomized adjuvant chemotherapy trial. Using Cox proportional hazards regression, we assessed associations of nut intake with cancer recurrence and mortality.

Results

After a median follow-up of 6.5 years, compared with patients who abstained from nuts, individuals who consumed two or more servings of nuts per week experienced an adjusted hazard ratio (HR) for disease-free survival of 0.58 (95% CI, 0.37 to 0.92; P_trend = .03) and an HR for overall survival of 0.43 (95% CI, 0.25 to 0.74; P_trend = .01). In subgroup analysis, the apparent benefit was confined to tree nut intake (HR for disease-free survival, 0.54; 95% CI, 0.34 to 0.85; P_trend = .04; and HR for overall survival, 0.47; 95% CI, 0.27 to 0.82; P_trend = .04). The association of total nut intake with improved outcomes was maintained across other known or suspected risk factors for cancer recurrence and mortality.

Conclusion

Diets with a higher consumption of nuts may be associated with a significantly reduced incidence of cancer recurrence and death in patients with stage III colon cancer.

Lifestyle recommendations for the prevention and management of metabolic syndrome: an international panel recommendation

The importance of metabolic syndrome (MetS) lies in its associated risk of cardiovascular disease and type 2 diabetes, as well as other harmful conditions such as nonalcoholic fatty liver disease. In this report, the available scientific evidence on the associations between lifestyle changes and MetS and its components is reviewed to derive recommendations for MetS prevention and management. Weight loss through an energy-restricted diet together with increased energy expenditure through physical activity contribute to the prevention and treatment of MetS. A Mediterranean-type diet, with or without energy restriction, is an effective treatment component. This dietary pattern should be built upon an increased intake of unsaturated fat, primarily from olive oil, and emphasize the consumption of legumes, cereals (whole grains), fruits, vegetables, nuts, fish, and low-fat dairy products, as well as moderate consumption of alcohol. Other dietary patterns (Dietary Approaches to Stop Hypertension, new Nordic, and vegetarian diets) have also been proposed as alternatives for preventing MetS. Quitting smoking and reducing intake of sugar-sweetened beverages and meat and meat products are mandatory. Nevertheless, there are inconsistencies and gaps in the evidence, and additional research is needed to define the most appropriate therapies for MetS. In conclusion, a healthy lifestyle is critical to prevent or delay the onset of MetS in susceptible individuals and to prevent cardiovascular disease and type 2 diabetes in those with existing MetS. The recommendations provided in this article should help patients and clinicians understand and implement the most effective approaches for lifestyle change to prevent MetS and improve cardiometabolic health.

Prospective Study of Nut Consumption and Incidence of Metabolic Syndrome: Tehran Lipid and Glucose Study

This study aimed to assess the association of various types of nut per se, and total nut consumption with the incidence of metabolic syndrome (MetS). A 6.2 ± 0.7-year population-based prospective study was conducted among 1265 adults, aged 19–74 years, participants of the Tehran Lipid and Glucose Study. A 168-item semi-quantitative food frequency questionnaire was used to collect information on nut consumption. MetS was defined according to the Joint Interim Statement guidelines and 276 new cases of MetS were identified. Median ± interquartile range of nut consumption was 2.08 (0.88–5.68) servings/week. After adjusting for family history of diabetes, age, gender, smoking, physical activity, fasting serum glucose at baseline, serum high density lipoprotein cholesterol (HDL-C) at baseline, energy intake, fiber, macronutrients, cholesterol intake, fruit, vegetables, dairy products and body mass index (BMI), a statistically significant decrease was observed in MetS in the third (≥5 servings/week) tertile of nuts (odds ratio: 0.68, 95% CI: 0.44–0.91, p trend: 0.03) compared with the lowest (≤1 serving/week). Walnut consumption showed a significant, inverse association with MetS risk; associations for other nut varieties were not significant. For each additional serving/week of walnuts consumed, incidence of MetS decreased by 3% (ORs: 0.97 CI: 0.93–0.99), after adjusting for confounding factors. Total nut consumption, especially walnuts, reduces the risk of MetS.

Metabolic syndrome and dietary patterns: a systematic review and meta-analysis of observational studies

PURPOSE

Lifestyle is linked to the risk of developing metabolic syndrome (MetS); however, its relationship with dietary patterns remains unclear. This systematic review and meta-analysis aims to analyse the association of a posteriori dietary patterns with the metabolic syndrome.

METHODS

The PubMed, CINAHL and Scopus databases were searched for epidemiological studies of dietary patterns and MetS. The association between dietary patterns and MetS was estimated using a random-effects meta-analysis with 95 % confidence intervals (CIs).

RESULTS

A total of 28 cross-sectional studies and three cohort studies were included in the meta-analysis. In a comparison of the highest to the lowest category of prudent/healthy dietary patterns, the pooled odds ratio (OR) for MetS was 0.83 (95 % CI 0.76, 0.90; P for heterogeneity =0.0; and I ² = 72.1 %) in cross-sectional studies, and the pooled relative risk (RR) for MetS in cohort studies was 0.91 (95 % CI 0.68, 1.21; P for heterogeneity =0.005; I ² = 81.1 %). The pooled OR for MetS in a comparison of the highest to the lowest category of Western dietary patterns was 1.28 (95 % CI 1.17, 1.40; P for heterogeneity =0.0; and I ² = 72.0 %) in cross-sectional studies, and the RR was 0.96 (95 % CI 0.53, 1.73; P for heterogeneity =0.102; I ² = 62.6 %) in cohort studies.

CONCLUSIONS

The results from cross-sectional studies showed that a prudent/healthy pattern is associated with a lower prevalence of MetS, whereas a Western/unhealthy is associated with an increased risk for MetS. Additional prospective studies are needed to confirm the association between dietary patterns and MetS.

Nut consumption and risk of colorectal cancer in women

BACKGROUND/OBJECTIVES

Increasing nut consumption has been associated with reduced risk of obesity and type II diabetes, the risk factors for colorectal cancer. However, the association between nut consumption and colorectal cancer risk is unclear. We aimed to examine the association of long-term nut consumption with risk of colorectal cancer.

SUBJECTS/METHODS

We prospectively followed 75,680 women who were free of cancer at baseline in the Nurses' Health Study, and examined the association between nut consumption and colorectal cancer risk. Nut consumption was assessed at baseline and updated every 2-4 years. Relative risks (RRs) and 95% confidence intervals (95% CIs) were estimated using Cox proportional hazards models.

RESULTS

During 2,103,037 person-years of follow-up, we identified 1503 colorectal cancer cases. After adjustment for other known or suspected risk factors, women who consumed nuts 2 or more times per week (that is, ⩾ 56 g per week) had a 13% lower risk of colorectal cancer compared with those who rarely consumed nuts, but the association was not statistically significant (RR: 0.87; 95% CI: 0.72-1.05; P-trend: 0.06). No association was observed for peanut butter.

CONCLUSIONS

In this large prospective cohort of women, frequent nut consumption was not significantly associated with colorectal cancer risk after adjusting for other risk factors.

Nutritional composition of raw fresh cashew (Anacardium occidentale L.) kernels from different origin

The total dietary fiber, sugar, protein, lipid profile, sodium, and energy contents of 11 raw cashew kernel (Anacardium occidentale L.) samples from India, Brazil, Ivory Coast, Kenya, Mozambique, and Vietnam were determined. Total fat was the major component accounting for 48.3% of the total weight, of which 79.7% were unsaturated FA (fatty acids), 20.1% saturated FA, and 0.2% trans FA. Proteins, with 21.3 g/100 g, were ranked second followed by carbohydrates (20.5 g/100 g). The average sodium content was 144 mg/kg. Fourteen FA were identified among which oleic acid was the most abundant with a contribution of 60.7% to the total fat, followed by linoleic (17.77%), palmitic (10.2%), and stearic (8.93%) acids. The mean energy content was 2525 kJ/100g. Furthermore, the sterol profile and content, amino acids, vitamins, and minerals of four raw cashew kernel samples from Brazil, India, Ivory Coast, and Vietnam were determined. β-Sitosterol with 2380 ± 4 mg/kg fat was the most occurring sterol. Glutamic acid, with 4.60 g/100 g, was the amino acid with highest presence, whereas tryptophan with 0.32 g/100 g was the one with lower presence. Vitamin E with an average contribution of 5.80 mg/100 g was the most abundant vitamin. Potassium with a mean value of 6225 mg/kg was the mineral with highest amount in cashew samples.

Consumption of nuts and risk of total and cause-specific mortality over 15 years

BACKGROUND AND AIMS

The published literature shows that nut consumption has a favorable impact on health. We aimed to assess the association between nut consumption and risk of 15-year total mortality, and mortality from cardiovascular disease (CVD) (including ischemic heart disease, IHD, and stroke), and cancer.

METHODS AND RESULTS

Prospective analyses involved 2893 participants aged ≥49 years at baseline. Dietary data were collected by using a semi-quantitative food-frequency questionnaire, and nut intakes were calculated. Deaths and cause of death were confirmed by data linkage with the Australian National Death Index. Over 15 years, 1044 participants had died, of these 430 had died from stroke and another 430 had died from IHD. Participants in the second tertile of nut consumption versus those in the first tertile of intake had reduced risk of total mortality: multivariable-adjusted HR 0.76 (95% CI 0.65-0.89). Participants in the second tertile compared to those in the first tertile had 24% and 23% reduced risk of 15-year CVD and IHD mortality, respectively. Associations were more marked in women compared to men. Women in the second versus first tertile of nut consumption had 27%, 39%, 34% and 49% reduced risk of death from all causes (n = 489), CVD (n = 258), IHD (n = 188) and stroke mortality (n = 101), respectively.

CONCLUSIONS

Nut consumption was independently associated with a decreased risk of overall and vascular-disease mortality, particularly in women.

Nuts and CVD

Nuts are nutrient-dense foods with complex matrices rich in unsaturated fatty acids and other bioactive compounds, such as l-arginine, fibre, healthful minerals, vitamin E, phytosterols and polyphenols. By virtue of their unique composition, nuts are likely to beneficially affect cardiovascular health. Epidemiological studies have associated nut consumption with a reduced incidence of CHD in both sexes and of diabetes in women, but not in men. Feeding trials have clearly demonstrated that consumption of all kinds of nuts has a cholesterol-lowering effect, even in the context of healthy diets. There is increasing evidence that nut consumption has a beneficial effect on oxidative stress, inflammation and vascular reactivity. Blood pressure, visceral adiposity and the metabolic syndrome also appear to be positively influenced by nut consumption. Contrary to expectations, epidemiological studies and clinical trials suggest that regular nut consumption is not associated with undue weight gain. Recently, the PREvención con DIeta MEDiterránea randomised clinical trial of long-term nutrition intervention in subjects at high cardiovascular risk provided first-class evidence that regular nut consumption is associated with a 50 % reduction in incident diabetes and, more importantly, a 30 % reduction in CVD. Of note, incident stroke was reduced by nearly 50 % in participants allocated to a Mediterranean diet enriched with a daily serving of mixed nuts (15 g walnuts, 7·5 g almonds and 7·5 g hazelnuts). Thus, it is clear that frequent nut consumption has a beneficial effect on CVD risk that is likely to be mediated by salutary effects on intermediate risk factors.

Nuts in the prevention and treatment of metabolic syndrome

Nuts are rich in many bioactive compounds that can exert beneficial effects on cardiovascular health. We reviewed the evidence relating nut consumption and the metabolic syndrome (MetS) and its components. Nuts reduce the postprandial glycemic response; however, long-term trials of nuts on insulin resistance and glycemic control in diabetic individuals are inconsistent. Epidemiologic studies have shown that nuts may lower the risk of diabetes incidence in women. Few studies have assessed the association between nuts and abdominal obesity, although an inverse association with body mass index and general obesity has been observed. Limited evidence suggests that nuts have a protective effect on blood pressure and endothelial function. Nuts have a cholesterol-lowering effect, but the relation between nuts and hypertriglyceridemia and high-density lipoprotein cholesterol is not well established. A recent pooled analysis of clinical trials showed that nuts are inversely related to triglyceride concentrations only in subjects with hypertriglyceridemia. An inverse association was found between the frequency of nut consumption and the prevalence and the incidence of MetS. Several trials evaluated the effect of nuts on subjects with MetS and found that they may have benefits in some components. Compared with a low-fat diet, a Mediterranean diet enriched with nuts could be beneficial for MetS management. The protective effects on metabolism could be explained by the modulation of inflammation and oxidation. Further trials are needed to clarify the role of nuts in MetS prevention and treatment.

Association of nut consumption with total and cause-specific mortality

BACKGROUND

Increased nut consumption has been associated with a reduced risk of major chronic diseases, including cardiovascular disease and type 2 diabetes mellitus. However, the association between nut consumption and mortality remains unclear.

METHODS

We examined the association between nut consumption and subsequent total and cause-specific mortality among 76,464 women in the Nurses' Health Study (1980-2010) and 42,498 men in the Health Professionals Follow-up Study (1986-2010). Participants with a history of cancer, heart disease, or stroke were excluded. Nut consumption was assessed at baseline and updated every 2 to 4 years.

RESULTS

During 3,038,853 person-years of follow-up, 16,200 women and 11,229 men died. Nut consumption was inversely associated with total mortality among both women and men, after adjustment for other known or suspected risk factors. The pooled multivariate hazard ratios for death among participants who ate nuts, as compared with those who did not, were 0.93 (95% confidence interval [CI], 0.90 to 0.96) for the consumption of nuts less than once per week, 0.89 (95% CI, 0.86 to 0.93) for once per week, 0.87 (95% CI, 0.83 to 0.90) for two to four times per week, 0.85 (95% CI, 0.79 to 0.91) for five or six times per week, and 0.80 (95% CI, 0.73 to 0.86) for seven or more times per week (P<0.001 for trend). Significant inverse associations were also observed between nut consumption and deaths due to cancer, heart disease, and respiratory disease.

CONCLUSIONS

In two large, independent cohorts of nurses and other health professionals, the frequency of nut consumption was inversely associated with total and cause-specific mortality, independently of other predictors of death. (Funded by the National Institutes of Health and the International Tree Nut Council Nutrition Research and Education Foundation.).

Nut consumption and risk of pancreatic cancer in women

Background:

Increasing nut intake has been associated with reduced risk of diabetes mellitus, which is a risk factor for pancreatic cancer.

Methods:

We prospectively followed 75 680 women in the Nurses' Health Study, and examined the association between nut consumption and pancreatic cancer risk. Participants with a previous history of cancer were excluded. Nut consumption was assessed at baseline and updated every 2 to 4 years. Relative risks (RRs) and 95% confidence intervals (95% CIs) were estimated using Cox proportional hazards models.

Results:

We documented 466 incident cases of pancreatic cancer. After adjusting for age, height, smoking, physical activity, and total energy intake, women who consumed a 28-g (1 oz) serving size of nuts ⩾2 times per week experienced a significantly lower risk of pancreatic cancer (RR, 0.65; 95% CI, 0.47–0.92; P for trend=0.007) when compared with those who largely abstained from nuts. The results did not appreciably change after further adjustment for body mass index (BMI) and history of diabetes mellitus (RR, 0.68; 95% CI, 0.48–0.95; P for trend=0.01). The inverse association persisted within strata defined by BMI, physical activity, smoking, and intakes of red meat, fruits, and vegetables.

Conclusion:

Frequent nut consumption is inversely associated with risk of pancreatic cancer in this large prospective cohort of women, independent of other potential risk factors for pancreatic cancer.

Cross-sectional assessment of nut consumption and obesity, metabolic syndrome and other cardiometabolic risk factors: the PREDIMED study

Introduction

Prospective studies have consistently suggested that nut consumption is inversely related to fatal and non-fatal coronary heart disease. Limited data are available on the epidemiological associations between nut intake and cardiometabolic risk factors.

Objective

To evaluate associations between frequency of nut consumption and prevalence of cardiometabolic risk factors [obesity, metabolic syndrome (MetS), type-2 diabetes, hypertension, and dyslipidemia] in a Mediterranean population at high cardiovascular risk.

Materials and Methods

Cross-sectional study of 7,210 men and women (mean age, 67 y) recruited into the PREDIMED study. MetS was defined by the harmonized ATPIII and IDF criteria. Diabetes and hypertension were assessed by clinical diagnosis and dyslipidemia (high triglycerides, low HDL-cholesterol, and hypercholesterolemia) by lipid analyses. Nut consumption was assessed using a validated food frequency questionnaire and categorized as <1, 1–3, and >3 servings/wk. Control of confounding was done with multivariate logistic regression.

Results

Compared to participants consuming <1 serving/wk of nuts, those consuming >3 servings/wk had lower adjusted odds ratios (OR) for obesity (0.61, 95% confidence interval 0.54 to 0.68; P-trend <0.001), MetS (0.74, 0.65 to 0.85; P-trend<0.001), and diabetes (0.87, 0.78 to 0.99; P-trend = 0.043). Higher nut consumption was also associated with lower risk of the abdominal obesity MetS criterion (OR 0.68, 0.60 to 0.79; P-trend<0.001). No significant associations were observed for the MetS components high blood pressure, dyslipidemia, or elevated fasting glucose.

Conclusions

Nut consumption was inversely associated with the prevalence of general obesity, central obesity, MetS, and diabetes in subjects at high cardiovascular risk.