Effects of hazelnut-enriched diet on plasma cholesterol and lipoprotein profiles in hypercholesterolemic adult men

The Cardioprotective Properties of Selected Nuts: Their Functional Ingredients and Molecular Mechanisms

Nuts have been known as a nutritious food since ancient times and can be considered part of our original diet: they are one of the few foods that have been eaten in the same form for thousands of years. They consist of various dry fruits and seeds, with the most common species being almonds (Prunus dulcis), hazelnuts (Corylus avellana), cashews (cashew nuts, Anacardium occidentale), pistachios (Pistacia vera), walnuts (Italian nuts, Juglans regia), peanuts (Arachia hypogaca), Brazil nuts (Bartholletia excels), pecans (Corya illinoinensis), macadamia nuts (Macademia ternifolia) and pine nuts. Both in vitro and in vivo studies have found nuts to possess a range of bioactive compounds with cardioprotective properties, and hence, their consumption may play a role in preventing and treating cardiovascular diseases (CVDs). The present work reviews the current state of knowledge regarding the functional ingredients of various nuts (almonds, Brazil nuts, cashew nuts, hazelnuts, macadamia nuts, peanuts, pecan nuts, pine nuts, pistachios, and walnuts) and the molecular mechanisms of their cardioprotective action. The data indicate that almonds, walnuts and pistachios are the best nut sources of bioactive ingredients with cardioprotective properties.

Sex-dependent colonic microbiota modulation by hazelnut (Corylus avellana L.) dietary fiber

Although many efforts have been made to characterize the functional properties of hazelnut constituents (mainly its oil, protein, and phenolics), those of its dietary fiber (DF) have not been elucidated yet. Here, we aimed to investigate the impact of DF of natural and roasted hazelnuts, and hazelnut skin on the colonic microbiota in vivo (C57BL/6J mouse models) by determining their composition through 16S rRNA sequencing and microbial short-chain fatty acids (SCFAs) using gas chromatography. Our results revealed that hazelnut DF generally showed an acetogenic effect in male mice, whereas the same trend was not observed in the female counterparts. The 16S rRNA sequencing results showed that hazelnut DF, especially that of natural hazelnuts, increased the relative abundances of Lactobacillus-related OTUs that have probiotic potential. LEfSe analysis indicated that, for female mice, Lachnospiraceae, Prevotella, Ruminococcaceae, and Lactobacillus were found to be discriminators for DF of natural hazelnuts, roasted hazelnuts, hazelnut skin, and control, respectively, whereas Bacteroides, Lactobacillus, Prevotella, and Lactococcus were the discriminators for the male counterparts, respectively. This study clearly indicates that, although the roasting process slightly alters the functionalities, hazelnut DF favors beneficial microbes and stimulates beneficial microbial metabolites in the colon in a sex-dependent way, which could be a contributing factor to the health-promoting effects of hazelnuts. Furthermore, hazelnut skin, a byproduct of the hazelnut industry, was found to have potential to be utilized to produce functional DF targeting colonic health.

The Effect of MUFA-Rich Food on Lipid Profile: A Meta-Analysis of Randomized and Controlled-Feeding Trials

Since the effects of mono-unsaturated fatty acids (MUFA) on lipid profile are still controversial, a meta-analysis of randomized controlled trials was conducted in the present study to assess the effect of MUFA-rich food on lipid profiles. The study was designed, conducted, and reported according to the guidelines of the 2020 preferred reporting items for systematic reviews and meta-analysis (PRISMA) statement. A systematic and comprehensive search was performed in several databases from inception up to 30 January 2022. The results showed that the intake of edible oil-derived MUFA (EDM) could increase the blood HDL-C level (mean difference = 0.08; 95%CI: -0.01, 0.17, p = 0.03), but did not affect the level of TC, TG, or LDL-C. Moreover, the consumption of other food-derived MUFA (ODM) significantly decreased TG concentration (mean difference = -0.35; 95%CI: -0.61, -0.09, p = 0.01)), but did not affect the level of TC, LDL-C, or HDL-C. Findings from this study suggest that MUFA-rich food might be beneficial to modulate the blood lipid profile.

Effects of Hazelnut Consumption on Cardiometabolic Risk Factors and Acceptance: A Systematic Review

Despite being rich sources of monounsaturated fat and a number of vitamins, minerals, and phytonutrients, hazelnuts have received less attention than some other nut types. A qualitative systematic review was carried out to determine the effects of hazelnut consumption on acceptance and markers of cardiometabolic health, including blood lipids and lipoproteins, apolipoproteins A1 and B100, body weight and composition, blood pressure, glycemia, antioxidant status, oxidative stress, inflammation, and endothelial function. In total, 22 intervention studies (25 publications) met our inclusion criteria. The findings indicate some improvements in cardiometabolic risk factors; however, limitations in study design mean interpretation is problematic. The inclusion of hazelnuts in the diet did not adversely affect body weight and composition. Acceptance of hazelnuts remained stable over time confirming nut consumption guidelines are feasible and sustainable. Future studies using more robust study designs in a variety of populations are required to draw more definitive conclusions on the health benefits of hazelnut consumption.

Effects of nut consumption on blood lipid profile: A meta-analysis of randomized controlled trials

BACKGROUND & AIMS

Several randomized controlled trials (RCTs) have assessed the effects of nut consumption on blood lipid profile. The aim of this study was to conduct a meta-analysis to quantitatively estimate the effects of nut consumption on blood lipid profile.

METHODS AND RESULTS

The PubMed, EMBASE, Cochrane Library, and Google Scholar databases were systematically searched to identify RCTs examining the effects of nut intake on blood total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TGs) from inception until March 2021. A random-effects model was used to pool standardized mean differences (SMDs) and 95% confidence intervals (CIs). Potential publication bias was assessed using Begg's test and Egger's test. Sensitivity analysis was performed to assess the impact of each individual study on the pooled results. The meta-analysis showed that nut consumption had no significant effect on the blood lipid profile. However, there was a significant reduction in TC (SMD: -2.89, 95% CI: -4.80, -0.98, I² = 97.4) for pistachio consumption, and cashew consumption significantly increased HDL-C (SMD: 0.24, 95% CI: 0.04, 0.43, I² = 0.0) compared with that in controls. There was no significant publication bias in the meta-analysis. The sensitivity analysis showed that removing one study at a time did not change the significance of the results.

CONCLUSION

There was no overall effect of nut consumption on lipid profile, and the results may vary depending on nut type. We found that pistachio consumption may reduce TC levels, while cashew consumption increases HDL-C.

REGISTRY NUMBER

PROSPERO CRD42021249147.

Monitoring of Hazelnut oil quality during thermal processing in comparison with extra virgin olive oil by using ATR-FTIR spectroscopy combined with chemometrics

Hazelnut oil (HO), which is not widely used because its healthy properties are not fully known yet, is an excellent nutrient due to its high content of monounsaturated fatty acids and antioxidants. In this study, the effects of thermal processing on the quality of HO in comparison to extra virgin olive oil (EVOO), which is one of the healthiest and heat-resistant oils, were investigated using Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy. Oil samples were heated at a frying temperature (180 °C) for 24 h in periods of 8 h per day and alterations in the spectra of these oils sampled every 2 h were evaluated. The heating process caused decreases in the areas of the bands at 3007 and 722 cm^-1 and the area ratios of 3007/2854 and 722/2854 cm^-1 and increases in the areas of the bands at 987 and 965 cm^-1 and the area ratio of 965/2854 cm^-1 in both oils suggesting the conjugation and cis-trans isomerization of unsaturated fatty acids. In addition, heating caused increases in the areas of the bands at 3475 and 1744 cm^-1 and the ratios of 3475/2854 cm^-1 and 1744/2854 cm^-1, a shift to a lower value in the wavenumber and a broadening of the 1744 cm^-1 band indicating the formation of primary and secondary oxidation products in the heated oils, which were also supported by chemical studies. Most of these changes began earlier in EVOO and all occurred to a higher extent, revealing that HO has a higher thermal stability than EVOO. Principal component analysis and hierarchical cluster analysis confirmed that HO is more resistant to heat than EVOO. These results showed that HO is superior to EVOO and it could be used for frying as a healthier and cheaper oil alternative. This study also indicated that oil oxidation could be monitored easily and rapidly via ATR-FTIR spectroscopy.

The Relationship of Tree Nuts and Peanuts with Adiposity Parameters: A Systematic Review and Network Meta-Analysis

The network meta-analysis and systematic review conducted aim to comparatively assess the effects of tree nuts and peanuts on body weight (BW), body mass index (BMI), waist circumference (WC), and body fat percentage (BF%). A systematic search up to 31 December 2020 was performed. A random-effects network meta-analysis was conducted following the PRISMA-NMA statement. A total of 105 randomized controlled trials (RCTs) with measures of BW (n = 6768 participants), BMI (n = 2918), WC (n = 5045), and BF% (n = 1226) were included. The transitivity assumption was met based on baseline characteristics. In the comparisons of nut consumption versus a control diet, there was no significant increase observed in any of the adiposity-related measures examined except for hazelnut-enriched diets, which raised WC. Moreover, almond-enriched diets significantly reduced WC compared to the control diet and to the pistachio-, mixed nuts-, and hazelnut-enriched diets. In subgroup analyses with only RCTs, designed to assess whether nut consumption affected weight loss, almonds were associated with reduced BMI and walnuts with reduced %BF. The evidence supports that: (1) tree nut and peanut consumption do not influence adiposity, and (2) compared to a control diet, the consumption of almond-enriched diets was associated with a reduced waist circumference.

The Effects of Medicinal Plants and Bioactive Natural Compounds on Homocysteine

Background: Among non-communicable diseases, cardiovascular diseases (CVDs) are the leading cause of mortality and morbidity in global communities. By 2030, CVD-related deaths are projected to reach a global rise of 25 million. Obesity, smoking, alcohol, hyperlipidemia, hypertension, and hyperhomocysteinemia are several known risk factors for CVDs. Elevated homocysteine is tightly related to CVDs through multiple mechanisms, including inflammation of the vascular endothelium. The strategies for appropriate management of CVDs are constantly evolving; medicinal plants have received remarkable attention in recent researches, since these natural products have promising effects on the prevention and treatment of various chronic diseases. The effects of nutraceuticals and herbal products on CVD/dyslipidemia have been previously studied. However, to our knowledge, the association between herbal bioactive compounds and homocysteine has not been reviewed in details. Thus, the main objective of this study is to review the efficacy of bioactive natural compounds on homocysteine levels according to clinical trials and animal studies. Results: Based on animal studies, black and green tea, cinnamon, resveratrol, curcumin, garlic extract, ginger, and soy significantly reduced the homocysteine levels. According to the clinical trials, curcumin and resveratrol showed favorable effects on serum homocysteine. In conclusion, this review highlighted the beneficial effects of medicinal plants as natural, inexpensive, and accessible agents on homocysteine levels based on animal studies. Nevertheless, the results of the clinical trials were not uniform, suggesting that more well-designed trials are warranted.

Intake of Nuts or Nut Products Does Not Lead to Weight Gain, Independent of Dietary Substitution Instructions: A Systematic Review and Meta-Analysis of Randomized Trials

Several clinical interventions report that consuming nuts will not cause weight gain. However, it is unclear if the type of instructions provided for how to incorporate nuts into the diet impacts weight outcomes. We performed a systematic review and meta-analysis of published nut-feeding trials with and without dietary substitution instructions to determine if there are changes in body weight (BW) or composition. PubMed and Web of Science were searched through 31 December 2019 for clinical trials involving the daily consumption of nuts or nut-based snacks/meals by adults (≥18 y) for >3 wk that reported BW, BMI, waist circumference (WC), or total body fat percentage (BF%). Each study was categorized by whether or not it contained dietary substitution instructions. Within these 2 categories, an aggregated mean effect size and 95% CI was produced using a fixed-effects model. Quality of studies was assessed through the Cochrane risk-of-bias tool. Fifty-five studies were included in the meta-analysis. In studies without dietary substitution instructions, there was no change in BW [standardized mean difference (SMD): 0.01 kg; 95% CI: -0.07, 0.08; I2 = 0%] or BF% (SMD: -0.05%; 95% CI: -0.19, 0.09; I2 = 0%). In studies with dietary substitution instructions, there was no change in BW (SMD: -0.01 kg; 95% CI: -0.11, 0.09; I2 = 0%); however, there was a significant decrease in BF% (SMD: -0.32%; 95% CI: -0.61%, -0.03%; I2 = 35.4%; P < 0.05). There was no change in BMI or WC for either category of studies. Nut-enriched diet interventions did not result in changes in BW, BMI, or WC in studies either with or without substitution instructions. Slight decreases in BF% may occur if substitution instructions are used, but more research is needed. Limitations included varying methodologies between included studies and the frequency of unreported outcome variables in excluded studies.

Effect of Tree Nuts Consumption on Serum Lipid Profile in Hyperlipidemic Individuals: A Systematic Review

Many epidemiological studies have regularly connected nuts intake with decreased risk for coronary heart disease. The primary mechanism by which nuts protect against cardiovascular disease is through the improvement of lipid and apolipoprotein profile. Therefore, numerous dietary intervention studies investigated the impact of nut consumption on blood lipid levels. Many studies have shown that nut intake can enhance the lipid profile in a dose-response way among individuals with increased serum lipids. This systematic review examines the effectiveness of nuts on the lipid profile among patients with dyslipidemia from different age groups. A total of 29 interventional studies from 5 databases met the inclusion criteria. In all, 20 studies were randomized controlled clinical trials, whereas 9 were crossover-controlled clinical trials. Participants included in the studies were different in terms of age, sex and, serum lipid profile. The studies were inconsistent in the type of tree nuts, duration, dose, and the nut forms. All studies indicated changes in the lipid profile after the intervention particularly on the total cholesterol, high-density lipoprotein, low-density lipoprotein, triglycerides, total cholesterol/high-density lipoprotein. Interventional periods ranged from 3 weeks up to 12 months with doses ranged from 15 to 126 gm. In conclusion, this review provides an evidence of favorable effect of nuts consumption of serum lipid profile.

Risk of coronary heart disease in the rural population in Xinjiang: A nested case-control study in China

Background and aim

Coronary heart disease (CHD) is a chronic complex disease caused by a combination of factors such as lifestyle behaviors and environmental and genetic factors. We conducted this study to evaluate the risk factors affecting the development of CHD in Xinjiang, and to obtain valuable information for formulating appropriate local public health policies.

Method

We conducted a nested case-control study with 277 confirmed CHD cases and 554 matched controls. The association of the risk factors with the risk of CHD was assessed using the multivariate Cox proportional hazard model. Multiplicative interactions were evaluated by entering interaction terms in the Cox proportional hazard model. The additive interactions among the risk factors were assessed by the index of additive interaction.

Results

The risk of CHD increased with frequent high-fat food consumption, dyslipidemia, obesity, and family history of CHD after adjustment for drinking, smoking status, hypertension, diabetes, family history of hypertension, and family history of diabetes. We noted consistent interactions between family history of CHD and frequent high-fat food consumption, family history of CHD and obesity, frequent high-fat food consumption and obesity, frequent high-fat food consumption and dyslipidemia, and obesity and dyslipidemia. The risk of CHD events increased with the presence of the aforementioned interactions.

Conclusions

Frequent high-fat food consumption, family history of CHD, dyslipidemia and obesity were independent risk factors for CHD, and their interactions are important for public health interventions in patients with CHD in Xinjiang.

Tree nut snack consumption is associated with better diet quality and CVD risk in the UK adult population: National Diet and Nutrition Survey (NDNS) 2008–2014

Objectives:

To examine associations of tree nut snack (TNS) consumption with diet quality and cardiovascular disease (CVD) risk in UK adults from National Diet and Nutrition Survey (NDNS) 2008–2014.

Design:

Cross-sectional analysis using data from 4-d food diaries, blood samples and physical measurements for CVD risk markers. To estimate diet quality, modified Mediterranean Diet Score (MDS) and modified Healthy Diet Score (HDS) were applied. Associations of TNS consumption with diet quality and markers of CVD risk were investigated using survey-adjusted multivariable linear regression adjusted for sex, age, ethnicity, socio-economic and smoking status, region of residency and total energy and alcohol intake.

Setting:

UK free-living population.

Subjects:

4738 adults (≥19 years).

Results:

TNS consumers had higher modified MDS and HDS relative to non-consumers. TNS consumers also had lower BMI, WC, SBP and DBP and higher HDL compared to non-consumers, although a dose-related fully adjusted significant association between increasing nut intake (g per 4184 kJ/1000 kcal energy intake) and lower marker of CVD risk was only observed for SBP. TNS consumption was also associated with higher intake of total fat, mono-, n-3 and n-6 polyunsaturated fatty acids, fibre, vitamin A, thiamin, folate, vitamin C, vitamin E, potassium, magnesium, phosphorus, selenium and iron; and lower intake of saturated fatty acids, trans fatty acids, total carbohydrate, starch, free sugar, sodium and chloride.

Conclusions:

TNS consumers report better dietary quality and consumption was associated with lower CVD risk factors. Encouraging replacement of less healthy snacks with TNS should be encouraged as part of general dietary guidelines.

Nuts

Nuts are fruits composed of two parts: an inedible hard shell and an edible seed. Nuts are known as an energy-dense and nutrient-rich food source. In general, nuts are recognized as a good source of fat, fiber, and protein. Nuts are extremely beneficial parts of any diet since their consumption may lower risk for some diseases, such as cardiovascular diseases and cancer. They are acknowledged for their low glycemic index owning to high unsaturated fat and protein content and relatively low carbohydrate content. They have been shown to increase cognitive function as well.

Mediterranean products as promising source of multi-target agents in the treatment of metabolic syndrome

Alteration of nutritional habits play an essential role on the risk of developing Metabolic Syndrome (MetS). Several epidemiological studies have shown that assuming diets rich of foods included in the Mediterranean diet (MetDiet) pattern like, such as olive oil, nuts, fruit, fiber, vegetables, wine and grain cereals has protective effects on the different risk factors characterizing the MetS. The beneficial effects of the MetDiet in the MetS are mainly due to the antioxidant and anti-inflammatory properties of the most abundant phytochemical components of such foods as polyphenols like resveratrol and oleuropein, allyl sulfides, ellagic acid, mono- and poly-unsaturated fatty acids (MUFA and PUFA), tocopherols and flavonoids like quercetin, which have shown positive results in the prevention of cardiovascular diseases (CVDs), with related risk factors, like hypertension, hypercholesterolemia and obesity. In this review, we highlighted the multi-target activities of the bioactive components contained in some foods typical of the Mediterranean area like olive oil, onion, liquorice, rosemary, oregano, hazelnut, pistachio, "Melannurca" apple, red wine, hot pepper, Citrus sp. fruits, saffron and garlic, with particular focus on their impact on health outcomes in relation to MetS main key factors, such as insulin resistance (IR) and type 2 diabetes mellitus (T2DM), endothelial dysfunctions, inflammatory response, oxidative stress and dyslipidaemic and hypercholesterolemic effects.

Biochemistry of blood platelet activation and the beneficial role of plant oils in cardiovascular diseases

The main function of blood platelets is to form hemostatic plugs and enable thrombosis. These properties, however, can be greatly influenced by dietary components which may inhibit certain steps of platelet activation, including platelet aggregation. Such inhibition can play a role in the prophylaxis and treatment of cardiovascular diseases associated with blood platelet hyperactivation. In fact, plant and fish oils have been identified and specifically used for this purpose. Numerous in vivo and in vitro experiments have explored the potential use of these oils to inhibit platelet activation as well as their role in reducing oxidative stress and blood pressure, and lowering triglyceride and cholesterol. This chapter presents and compares the anti-platelet effects of fish and plant oils and their constituents, especially fatty acids. Studies on healthy subjects and patients with various cardiovascular diseases are also examined. Findings indicate that both fish and plant oils contain protective components with anti-platelet activity having clearly defined mechanisms of action. Although both are excellent sources of omega fatty acids and vitamins, plant oils contain components with cardioprotective benefit in hypercholesterolemics, i.e., phytosterols. Plant oils may hence play a key role in strategies for preventing and treating cardiovascular diseases associated with platelet hyperactivation. Further studies are clearly needed to determine the precise dose of these components needed for effective prophylaxis and treatment.

Dietary Supplementation with Hazelnut Oil Reduces Serum Hyperlipidemia and Ameliorates the Progression of Nonalcoholic Fatty Liver Disease in Hamsters Fed a High-Cholesterol Diet

Objective: Hazelnut oil (HO) is rich in monounsaturated fatty acids and polyunsaturated fatty acids. This study intended to analyze the effects of hazelnut oil supplementation on the serum lipid profile and nonalcoholic fatty liver disease in hamsters fed a high-cholesterol (HC) diet. Methods: Hamsters were fed a basic diet (control group) and an HC diet (HC group) for 16 weeks (n = 10 in each group). Hamsters were fed an HC diet for four weeks to induce hyperlipidemia and were then fed an HC diet enriched with 5% (low-dose HC + HO group; n = 10) and 10% HO (high-dose HC + HO group; n = 10) for 12 weeks. Serum lipid levels, hepatic changes (including steatosis, inflammation, and fibrosis), and hepatic prooxidant-antioxidant status (malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione S-transferase (GST)) were evaluated after the treatment period. Results: Hamsters in the control group showed normal serum lipid profiles, normal liver function, and moderate glycogen storage without hepatic steatosis. Hamsters in the HC group showed severe hyperlipidemia, severe hepatic steatosis, and moderate steatohepatitis (mononuclear cell and neutrophil infiltration, oval cell hyperplasia, and fibrosis). Compared to the HC group, both the low-dose and the high-dose HC + HO groups showed a significant reduction of hyperlipidemia (serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and very-low-density lipoprotein cholesterol (VLDL-C levels)) and improved liver function (serum glutamic-oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT)). Additionally, compared to the HC group, intrahepatic triglyceride accumulation (IHTC) was significantly higher in the HC + HO group, while the incidence of steatohepatitis was significantly lower. The intake of the HC diet was associated with a higher level of lipid peroxidation (malondialdehyde, MDA) and a lower concentration of hepatic antioxidant enzymes (SOD, GPx, and GST), and all these factors were partially improved in the low-dose and high-dose HC + HO groups. Conclusions: Our findings indicate that the intake of HO reduced serum hyperlipidemia and oxidative stress and ameliorated the progression of nonalcoholic fatty liver disease in hamsters fed a high-cholesterol diet.

The Mediterranean Diet as source of bioactive compounds with multi-targeting anti-cancer profile

Many bioactive agents have been extracted from plants or belong to functional foods and have been considered in the treatment of serious and multifactorial diseases, such as cancer. In particular, this review is focused on the anti-cancer properties owned by several natural products typically from the Mediterranean area. In some regions of the South of Italy, a lower cancer incidence has been observed. There is increasing evidence that adherence to a Mediterranean dietary pattern correlates with reduced risk of several cancer types. This could be mainly attributed to the typical lifestyle aspects of the Mediterranean diet, such as high consumption of fruit and vegetables. In this review, the main natural products of the Mediterranean area are discussed, with particular attention on their anti-cancer properties endowed with multi-target profiles.

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.

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).

Daily Consumption of Oregon Hazelnuts Affects α-Tocopherol Status in Healthy Older Adults: A Pre-Post Intervention Study

Background

Inadequate vitamin E and magnesium intakes are of concern for older adults owing to the associated incidence of age-related diseases.

Objective

This study was designed to determine the extent to which a 16-wk intervention with hazelnuts alters vitamin E and magnesium status in a group of older men and women, and used a pre-post intervention design without a control group to adjust for temporal changes.

Methods

Participants (n = 32 including 22 women; mean ± SD age: 63 ± 6 y) consumed hazelnuts (∼57 g/d) for 16 wk. Blood and urine samples and anthropomorphic measures were taken at the start and end of the intervention to determine plasma concentrations of α-tocopherol and serum concentrations of magnesium, lipids, glucose, insulin, and high-sensitivity C-reactive protein along with urinary vitamin E metabolites; several other micronutrients were measured by a lymphocyte proliferation assay. There were 3 primary endpoints, calculated as the mean changes in measurements between baseline and the end of the 16-wk intervention for 1) plasma α-tocopherol, 2) urinary α-carboxyethyl hydroxychromanol (α-CEHC; an α-tocopherol metabolite), and 3) serum magnesium.

Results

Hazelnut consumption increased concentrations of the urinary α-tocopherol metabolite α-CEHC (mean ± SD: 0.84 ± 0.45 to 1.14 ± 0.50 µmol/g creatinine; P = 0.0006). In addition, hazelnut consumption increased serum concentrations of magnesium (+2.1%, P = 0.05), decreased concentrations of fasting glucose (-3.4%, P = 0.03) and LDL cholesterol (-6.0%, P = 0.02), and decreased total:HDL cholesterol ratios (-4.5%, P = 0.009). No significant changes were observed in blood pressure, lymphocyte proliferation assays, and serum concentrations of insulin, high-sensitivity C-reactive protein, triglyceride, α-tocopherol, or HDL cholesterol.

Conclusions

Consuming hazelnuts improves a biomarker of vitamin E status in older adults. Vitamin E is a shortfall micronutrient, as identified by the Dietary Guidelines for Americans 2015-2020, which frequently is consumed at levels less than the Estimated Average Requirement of 12 mg/d; thus, hazelnuts should be considered as part of a healthy dietary pattern. This trial was registered at clinicaltrials.gov as NCT03485989.

Authentication of an Italian PDO hazelnut ("Nocciola Romana") by NIR spectroscopy

Common hazelnuts are widely present in human diet all over the world, and their beneficial effects on the health have been extensively investigated and demonstrated. Different in-depth researches have highlighted that the harvesting area can define small variations in the chemical composition of the fruits, affecting their quality. As a consequence, it has become relevant to develop methodologies which would allow authenticating and tracing hazelnuts. In the light of this, the present work aims to develop a non-destructive method for the authentication of a specific high-quality Italian hazelnut, "Nocciola Romana," registered with a protected designation of origin (PDO). Thus, different samples of this fruit have been analyzed by near-infrared (NIR) spectroscopy and then classification models have been built, in order to distinguish between the PDO fruits and the hazelnuts not coming from the designated region. In particular, two different classification approaches have been tested, a discriminant one, partial least squares-discriminant analysis, and a class-modeling one, soft independent modeling of class analogies. Both methods led to very high prediction capability in external validation on a test set (classification accuracy in one case, and sensitivity and specificity in the other, all higher than 92%), suggesting that the proposed methodologies are suitable for a rapid and non-destructive authentication of the product.

Nut consumption and metabolic syndrome in US adolescents

OBJECTIVE

To determine whether nut intake is associated with the prevalence of metabolic syndrome in US adolescents.

DESIGN

A cross-sectional analysis of data from the National Health and Nutrition Examination Survey (NHANES) years 2003-2012. Anthropometric measurements, blood tests, 24 h diet recalls and demographic data were retrieved for participating adolescents. Metabolic syndrome was defined according to paediatric-modified Adult Treatment Panel III criteria. The exposure was defined as a nut intake ≥5 g/d.

SETTING

USA.

SUBJECTS

Individuals aged 12-19 years (n 2805).

RESULTS

Nut consumption was associated with lower odds for metabolic syndrome (crude OR=0·25; 95 % CI 0·11, 0·55; P≤0·001). This effect was independent of age, sex, race/ethnicity and family income:poverty ratio (adjusted OR=0·27; 95 % CI 0·12, 0·61; P=0·002), and was stable after controlling for nutritional covariates including intake of sugar and total energy consumption (OR=0·36; 95 % CI 0·16, 0·81; P=0·014).

CONCLUSION

Nut consumption of ≥5 g/d is independently associated with lower odds for metabolic syndrome in US adolescents.

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.

Optimizing Non-Pharmacologic Management of Hypertriglyceridemia

The cornerstone of initial management for hypertriglyceridemia (HTG) is lifestyle modification. The combination of weight loss through caloric restriction, alteration in macronutrient composition and increased energy expenditure reduces TG levels by approximately 50%. The addition of cinnamon, cacao products and isocaloric substitution of 1 serving of nuts may contribute another 5-15% lowering of TG. This can be particularly beneficial in patients with HTG who are at increased risk of cardiovascular disease.

Dietary Strategies and Novel Pharmaceutical Approaches Targeting Serum ApoA-I Metabolism: A Systematic Overview

The incidence of CHD is still increasing, which underscores the need for new preventive and therapeutic approaches to decrease CHD risk. In this respect, increasing apoA-I concentrations may be a promising approach, especially through increasing apoA-I synthesis. This review first provides insight into current knowledge on apoA-I production, clearance, and degradation, followed by a systematic review of dietary and novel pharmacological approaches to target apoA-I metabolism. For this, a systematic search was performed to identify randomized controlled intervention studies that examined effects of whole foods and (non)nutrients on apoA-I metabolism. In addition, novel pharmacological approaches were searched for, which were specifically developed to target apoA-I metabolism. We conclude that both dietary components and pharmacological approaches can be used to increase apoA-I concentrations or functionality. For the dietary components in particular, more knowledge about the underlying mechanisms is necessary, as increasing apoA-I per se does not necessarily translate into a reduced CHD risk.

Effects of Hazelnut Consumption on Blood Lipids and Body Weight: A Systematic Review and Bayesian Meta-Analysis

Hazelnuts are rich in monounsaturated fatty acids and antioxidant bioactive substances: their consumption has been associated with a decreased risk of cardiovascular disease events. A systematic review and a meta-analysis was performed to combine the results from several trials and to estimate the pooled (overall) effect of hazelnuts on blood lipids and body weight outcomes. Specifically, a Bayesian random effect meta-analysis of mean differences of Δ-changes from baseline across treatment (MDΔ) (i.e., hazelnut-enriched diet vs. control diet) has been conducted. Nine studies representing 425 participants were included in the analysis. The intervention diet lasted 28–84 days with a dosage of hazelnuts ranging from 29 to 69 g/day. Out of nine studies, three randomized studies have been meta-analyzed showing a significant reduction in low-density lipoprotein (LDL) cholesterol (pooled MDΔ = −0.150 mmol/L; 95% highest posterior density interval (95%HPD) = −0.308; −0.003) in favor of a hazelnut-enriched diet. Total cholesterol showed a marked trend toward a decrease (pooled MDΔ = −0.127 mmol/L; 95%HPD = −0.284; 0.014) and high-density lipoprotein (HDL) cholesterol remained substantially stable (pooled MDΔ = 0.002 mmol/L; 95%HPD = −0.140; 0.147). No effects on triglycerides (pooled MDΔ = 0.045 mmol/L; 95%HPD = −0.195; 0.269) and body mass index (BMI) (pooled MDΔ = 0.062 kg/m²; 95%HPD = −0.293; 0.469) were found. Hazelnut-enriched diet is associated with a decrease of LDL and total cholesterol, while HDL cholesterol, triglycerides and BMI remain substantially unchanged.

Nutritional management of hyperapoB

Plasma apoB is a more accurate marker of the risk of CVD and type 2 diabetes (T2D) than LDL-cholesterol; however, nutritional reviews targeting apoB are scarce. Here we reviewed eighty-seven nutritional studies and present conclusions in order of strength of evidence. Plasma apoB was reduced in all studies that induced weight loss of 6–12 % using hypoenergetic diets (seven studies; 5440–7110 kJ/d; 1300–1700 kcal/d; 34–50 % carbohydrates; 27–39 % fat; 18–24 % protein). When macronutrients were compared in isoenergetic diets (eleven studies including eight randomised controlled trials (RCT); n 1189), the diets that reduced plasma apoB were composed of 26–51 % carbohydrates, 26–46 % fat, 11–32 % protein, 10–27 % MUFA, 5–14 % PUFA and 7–13 % SFA. Replacement of carbohydrate by MUFA, not SFA, decreased plasma apoB. Moreover, dietary enriching with n-3 fatty acids (FA) (from fish: 1·1–1·7 g/d or supplementation: 3·2–3·4 g/d EPA/DHA or 4 g/d EPA), psyllium (about 8–20 g/d), phytosterols (about 2–4 g/d) or nuts (30–75 g/d) also decreased plasma apoB, mostly in hyperlipidaemic subjects. While high intake of trans-FA (4·3–9·1 %) increased plasma apoB, it is unlikely that these amounts represent usual consumption. Inconsistent data existed on the effect of soya proteins (25–30 g/d), while the positive association of alcohol consumption with low plasma apoB was reported in cross-sectional studies only. Five isoenergetic studies using Mediterranean diets (including two RCT; 823 subjects) reported a decrease of plasma apoB, while weaker evidence existed for Dietary Approaches to Stop Hypertension (DASH), vegetarian, Nordic and Palaeolithic diets. We recommend using a Mediterranean dietary pattern, which also encompasses the dietary components reported to reduce plasma apoB, to target hyperapoB and reduce the risks of CVD and T2D.

Nutrigenomics and its Impact on Life Style Associated Metabolic Diseases

Post-human genome revelation observes the emergence of 'Nutigenomics' as one of the exciting scientific advancement influencing mankind around the world. Food or more precisely 'nutrition' has the major impact in defining the cause-response interaction between nutrient (diet) and human health. In addition to substantial understanding of nutrition-human-health interaction, bases of 'nutrigenomic' development foster on advent in transcriptomics, genomics, proteomics and metabolomics as well as insight into food as health supplement. Interaction of selected nutrient with associated genes in specific organ or tissue necessary to comprehend that how individual's genetic makeup (DNA transcribed into mRNA and then to proteins) respond to particular nutrient. It provided new opportunities to incorporate natural bioactive compounds into food for specific group of people with similar genotype. As inception of diabetes associated with change in gene expression of, not limited to, protein kinase B, insulin receptor, duodenal homeobox and glucokinase, thus, targeting such proteins by modifying or improving the nutritional availability or uptake may help to devise novel food, supplements, or nutraceuticals. In this article, various aspects of R&D in nutrigenomics are reviewed to ascertain its impact on human health, especially with life-style associated diseases.

Do dry roasting, lightly salting nuts affect their cardioprotective properties and acceptability?

PURPOSE

Previous studies have reported improvements in cardiovascular disease (CVD) risk factors with the consumption of raw nuts. However, around one-third of nuts consumed are roasted and salted. Thus, it is important to determine whether roasting and salting nuts affect the health benefits observed with raw nuts. This study aimed to compare the effects of consuming two different forms of hazelnuts on cardiovascular risk factors and acceptance.

METHODS

Using a randomised crossover design, 72 participants were asked to consume 30 g/day of either raw or dry roasted, lightly salted hazelnuts for 28 days each. CVD risk factors were measured at the beginning and end of each treatment period. "Desire to consume" and "overall liking" for both forms of hazelnuts were assessed daily using a 150-mm visual analogue scale.

RESULTS

Body composition, blood pressure, plasma total and low-density lipoprotein-cholesterol, apolipoprotein A1 and B100, glucose and α-tocopherol concentrations did not differ between forms of hazelnuts (all P ≥ 0.054). High-density lipoprotein (HDL)-cholesterol (P = 0.037) and triacylglycerol (P < 0.001) concentrations were significantly lower following the consumption of dry roasted, lightly salted hazelnuts when compared to the raw hazelnuts. Compared with baseline, consuming both forms of hazelnuts significantly improved HDL-cholesterol and apolipoprotein A1 concentrations, total-C/HDL-C ratio, and systolic blood pressure without significantly changing body composition. Acceptance ratings did not differ between forms of hazelnuts and remained high throughout the study.

CONCLUSION

Dry roasting and lightly salting nuts do not appear to negate the cardioprotective effects observed with raw nut consumption, and both forms of nuts are resistant to monotony. Public health messages could be extended to include dry roasted and lightly salted nuts as part of a heart healthy diet.

Effects of tree nuts on blood lipids, apolipoproteins, and blood pressure: systematic review, meta-analysis, and dose-response of 61 controlled intervention trials

BACKGROUND

The effects of nuts on major cardiovascular disease (CVD) risk factors, including dose-responses and potential heterogeneity by nut type or phytosterol content, are not well established.

OBJECTIVES

We examined the effects of tree nuts (walnuts, pistachios, macadamia nuts, pecans, cashews, almonds, hazelnuts, and Brazil nuts) on blood lipids [total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein, and triglycerides], lipoproteins [apolipoprotein A1, apolipoprotein B (ApoB), and apolipoprotein B100], blood pressure, and inflammation (C-reactive protein) in adults aged ≥18 y without prevalent CVD.

DESIGN

We conducted a systematic review and meta-analysis following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Two investigators screened 1301 potentially eligible PubMed articles in duplicate. We calculated mean differences between nut intervention and control arms, dose-standardized to one 1-oz (28.4 g) serving/d, by using inverse-variance fixed-effects meta-analysis. Dose-response for nut intake was examined by using linear regression and fractional polynomial modeling. Heterogeneity by age, sex, background diet, baseline risk factors, nut type, disease condition, duration, and quality score was assessed with meta-regression. Publication bias was evaluated by using funnel plots and Egger's and Begg's tests.

RESULTS

Sixty-one trials met eligibility criteria (n = 2582). Interventions ranged from 3 to 26 wk. Nut intake (per serving/d) lowered total cholesterol (-4.7 mg/dL; 95% CI: -5.3, -4.0 mg/dL), LDL cholesterol (-4.8 mg/dL; 95% CI: -5.5, -4.2 mg/dL), ApoB (-3.7 mg/dL; 95% CI: -5.2, -2.3 mg/dL), and triglycerides (-2.2 mg/dL; 95% CI: -3.8, -0.5 mg/dL) with no statistically significant effects on other outcomes. The dose-response between nut intake and total cholesterol and LDL cholesterol was nonlinear (P-nonlinearity < 0.001 each); stronger effects were observed for ≥60 g nuts/d. Significant heterogeneity was not observed by nut type or other factors. For ApoB, stronger effects were observed in populations with type 2 diabetes (-11.5 mg/dL; 95% CI: -16.2, -6.8 mg/dL) than in healthy populations (-2.5 mg/dL; 95% CI: -4.7, -0.3 mg/dL) (P-heterogeneity = 0.015). Little evidence of publication bias was found.

CONCLUSIONS

Tree nut intake lowers total cholesterol, LDL cholesterol, ApoB, and triglycerides. The major determinant of cholesterol lowering appears to be nut dose rather than nut type. Our findings also highlight the need for investigation of possible stronger effects at high nut doses and among diabetic populations.

Nut consumption for the primary prevention of cardiovascular disease

BACKGROUND

Nuts contain a number of nutritional attributes which may be cardioprotective. A number of epidemiological studies have shown that nut consumption may have a beneficial effect on people who have cardiovascular disease (CVD) risk factors. However, results from randomised controlled trials (RCTs) are less consistent.

OBJECTIVES

To determine the effectiveness of nut consumption for the primary prevention of CVD.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Web of Science Core Collection, CINAHL, Database of Abstracts of Reviews of Effects (DARE), Health Technology Assessment Database (HTA) and Health Economics Evaluations Database (HEED) up to 30 July 2015. We searched trial registers and reference lists of reviews for further studies. We did not apply any language restrictions.

SELECTION CRITERIA

We included RCTs of dietary advice to increase nut consumption or provision of nuts to increase consumption lasting at least three months and including healthy adults or adults at moderate and high risk of CVD. The comparison group was no intervention or minimal intervention. The outcomes of interest were CVD clinical events and CVD risk factors.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, abstracted the data and assessed the risk of bias in included trials.

MAIN RESULTS

We included five trials (435 participants randomised) and one ongoing trial. One study is awaiting classification. All trials examined the provision of nuts to increase consumption rather than dietary advice. None of the included trials reported on the primary outcomes, CVD clinical events, but trials were small and short term. All five trials reported on CVD risk factors. Four of these trials provided data in a useable format for meta-analyses, but heterogeneity precluded meta-analysis for most of the analyses. Overall trials were judged to be at unclear risk of bias.There were variable and inconsistent effects of nut consumption on CVD risk factors (lipid levels and blood pressure). Three trials monitored adverse events. One trial reported an allergic reaction to nuts and three trials reported no significant weight gain with increased nut consumption. None of the included trials reported on other secondary outcomes, occurrence of type 2 diabetes as a major risk factor for CVD, health-related quality of life and costs.

AUTHORS' CONCLUSIONS

Currently there is a lack of evidence for the effects of nut consumption on CVD clinical events in primary prevention and very limited evidence for the effects on CVD risk factors. No conclusions can be drawn and further high quality longer term and adequately powered trials are needed to answer the review question.

Effect of 12 Weeks High Oleic Peanut Consumption on Cardio-Metabolic Risk Factors and Body Composition

Epidemiological evidence indicates an inverse association between nut consumption and obesity, inflammation, hyperlipidaemia and glucose intolerance. We investigated effects of high oleic peanut consumption vs. a nut free diet on adiposity and cardio-metabolic risk markers. In a randomised cross-over design, 61 healthy subjects (65 ± 7 years, body mass index (BMI) 31 ± 4 kg/m²) alternated either high oleic peanuts (15%-20% of energy) or a nut free diet for 12 weeks. Body composition and mass, waist circumference, C-reactive protein (CRP), lipids, glucose and insulin were assessed at baseline and after each phase. Repeated measures analysis of variance (ANOVA) compared the two diets. Consistent with other nut studies, there were no differences in lipids, CRP, glucose and insulin with peanut consumption. In contrast, some reports have demonstrated benefits, likely due to differences in the study cohort. Energy intake was 10% higher (853 kJ, p < 0.05), following peanut consumption vs. control, attributed to a 30% increase in fat intake (p < 0.001), predominantly monounsaturated (increase 22 g, p < 0.05). Despite greater energy intake during the peanut phase, there were no differences in body composition, and less than predicted increase (0.5 kg) in body weight for this additional energy intake, possibly due to incomplete nutrient absorption and energy utilisation.

Olive Oil Polyphenols Decrease LDL Concentrations and LDL Atherogenicity in Men in a Randomized Controlled Trial

BACKGROUND

Olive oil polyphenols have shown protective effects on cardiovascular risk factors. Their consumption decreased oxidative stress biomarkers and improved some features of the lipid profile. However, their effects on LDL concentrations in plasma and LDL atherogenicity have not yet been elucidated.

OBJECTIVE

Our objective was to assess whether the consumption of olive oil polyphenols could decrease LDL concentrations [measured as apolipoprotein B-100 (apo B-100) concentrations and the total number of LDL particles] and atherogenicity (the number of small LDL particles and LDL oxidizability) in humans.

METHODS

The study was a randomized, cross-over controlled trial in 25 healthy European men, aged 20-59 y, in the context of the EUROLIVE (Effect of Olive Oil Consumption on Oxidative Damage in European Populations) study. Volunteers ingested 25 mL/d raw low-polyphenol-content olive oil (LPCOO; 366 mg/kg) or high-polyphenol-content olive oil (HPCOO; 2.7 mg/kg) for 3 wk. Interventions were preceded by 2-wk washout periods. Effects of olive oil polyphenols on plasma LDL concentrations and atherogenicity were determined in the sample of 25 men. Effects on lipoprotein lipase (LPL) gene expression were assessed in another sample of 18 men from the EUROLIVE study.

RESULTS

Plasma apo B-100 concentrations and the number of total and small LDL particles decreased (mean ± SD: by 5.94% ± 16.6%, 11.9% ± 12.0%, and 15.3% ± 35.1%, respectively) from baseline after the HPCOO intervention. These changes differed significantly from those after the LPCOO intervention, which resulted in significant increases of 6.39% ± 16.6%, 4.73% ± 22.0%, and 13.6% ± 36.4% from baseline (P < 0.03). LDL oxidation lag time increased by 5.0% ± 10.3% from baseline after the HPCOO intervention, which was significantly different only relative to preintervention values (P = 0.038). LPL gene expression tended to increase by 26% from baseline after the HPCOO intervention (P = 0.08) and did not change after the LPCOO intervention.

CONCLUSION

The consumption of olive oil polyphenols decreased plasma LDL concentrations and LDL atherogenicity in healthy young men. This trial was registered at www.controlled-trials.com as ISRCTN09220811.

Analysis of different European hazelnut (Corylus avellana L.) cultivars: authentication, phenotypic features, and phenolic profiles

Hazelnuts exhibit functional properties due to their content in fatty acids and phenolic compounds that could positively affect human health. The food industry requires precise traits for morphological, chemical, and physical kernel features so that some cultivars could be more suitable for specific industrial processing. In this study, agronomical and morphological features of 29 hazelnut cultivars were evaluated and a detailed structural characterization of kernel polyphenols was performed, confirming the presence of protocatechuic acid, flavan-3-ols such as catechin, procyanidin B2, six procyanidin oligomers, flavonols, and one dihydrochalcone in all the analyzed cultivars. In addition, an innovative methodology based on the MALDI-TOF mass spectrometric analysis of peptide/protein components extracted from kernels was developed for the authentication of the most valuable cultivars. The proposed method is rapid, simple, and reliable and holds the potential to be applied in quality control processes. These results could be useful in hazelnut cultivar evaluation and choice for growers, breeders, and food industry.

A review of the effects of nuts on appetite, food intake, metabolism, and body weight

Tree nuts and peanuts are good sources of many nutrients and antioxidants, but they are also energy dense. The latter often limits intake because of concerns about their possible contribution to positive energy balance. However, evidence to date suggests that nuts are not associated with predicted weight gain. This is largely due to their high satiety value, leading to strong compensatory dietary responses, inefficiency in absorption of the energy they contain, a possible increment in resting energy expenditure, and an augmentation of fat oxidation. Preliminary evidence suggests that these properties are especially evident when they are consumed as snacks.

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.

Nut consumption for vascular health and cognitive function

Nuts are rich in many nutrients that can benefit multiple cardiometabolic functions, including arterial compliance, blood pressure, inflammation, glucoregulation and endothelial vasodilatation. Impaired vasodilatation may contribute to impaired cognitive performance due to poor cerebral perfusion. The present narrative review examines associations between nut consumption, vascular health and cognitive function. It includes a systematic search which identified seventy-one epidemiological or intervention studies in which effects of chronic nut consumption on blood pressure, glucoregulation, endothelial vasodilator function, arterial compliance, inflammatory biomarkers and cognitive performance were evaluated. Weighted mean changes were estimated where data were available; they indicate that nut consumption reduces blood pressure and improves glucoregulation, endothelial vasodilator function and inflammation, whilst a limited number of studies suggest that nut consumption may also improve cognitive performance. Further clinical trials are warranted to explore relationships between nut consumption, endothelial function and cognitive function.

Nut intake and adiposity: meta-analysis of clinical trials

BACKGROUND

Epidemiologic studies have shown an inverse association between the frequency of nut consumption and body mass index (BMI) and risk of obesity. However, clinical trials that evaluated nut consumption on adiposity have been scarce and inconclusive.

OBJECTIVE

We performed a systematic review and meta-analysis of published, randomized nut-feeding trials to estimate the effect of nut consumption on adiposity measures.

DESIGN

MEDLINE and the Cochrane Central Register of Controlled Trials databases were searched for relevant clinical trials of nut intake that provided outcomes of body weight, BMI (in kg/m(2)), or waist-circumference measures and were published before December 2012. There were no language restrictions. Two investigators independently selected and reviewed eligible studies. The weighted mean difference (WMD) between nut or control diets was estimated by using a random-effects meta-analysis with 95% CIs.

RESULTS

Thirty-three clinical trials met our inclusion criteria. Pooled results indicated a nonsignificant effect on body weight (WMD: -0.47 kg; 95% CI: -1.17, 0.22 kg; I(2) = 7%), BMI (WMD: -0.40 kg/m(2); 95% CI: -0.97, 0.17 kg/m(2); I(2) = 49%), or waist circumference (WMD: -1.25 cm; 95% CI: -2.82, 0.31 cm; I(2) = 28%) of diets including nuts compared with control diets. These findings were remarkably robust in the sensitivity analysis. No publication bias was shown.

CONCLUSION

Compared with control diets, diets enriched with nuts did not increase body weight, body mass index, or waist circumference in controlled clinical trials.

Dietary (poly)phenolics in human health: structures, bioavailability, and evidence of protective effects against chronic diseases

Human intervention trials have provided evidence for protective effects of various (poly)phenol-rich foods against chronic disease, including cardiovascular disease, neurodegeneration, and cancer. While there are considerable data suggesting benefits of (poly)phenol intake, conclusions regarding their preventive potential remain unresolved due to several limitations in existing studies. Bioactivity investigations using cell lines have made an extensive use of both (poly)phenolic aglycones and sugar conjugates, these being the typical forms that exist in planta, at concentrations in the low-μM-to-mM range. However, after ingestion, dietary (poly)phenolics appear in the circulatory system not as the parent compounds, but as phase II metabolites, and their presence in plasma after dietary intake rarely exceeds nM concentrations. Substantial quantities of both the parent compounds and their metabolites pass to the colon where they are degraded by the action of the local microbiota, giving rise principally to small phenolic acid and aromatic catabolites that are absorbed into the circulatory system. This comprehensive review describes the different groups of compounds that have been reported to be involved in human nutrition, their fate in the body as they pass through the gastrointestinal tract and are absorbed into the circulatory system, the evidence of their impact on human chronic diseases, and the possible mechanisms of action through which (poly)phenol metabolites and catabolites may exert these protective actions. It is concluded that better performed in vivo intervention and in vitro mechanistic studies are needed to fully understand how these molecules interact with human physiological and pathological processes.

The relationship between nut consumption and lipid profile among the Iranian adult population; Isfahan Healthy Heart Program

BACKGROUND/OBJECTIVE

The study was carried out to assess the relationship between nut consumption and lipid profile among Iranian adults.

SUBJECT/METHODS

The study was based on data from the Isfahan Healthy Heart Program across three counties in central Iran in 2007. A cross-sectional survey of 9660 randomly selected adults aged ≥ 19 years were chosen based on sex, age and settlement distributions in each community. Nutritional behaviors were assessed by validated qualitative 48-item food frequency questionnaires, which covered regular intakes of four types of nuts: walnuts, almonds, pistachios and hazelnuts. Analysis of covariance and logistic regression tests were utilized to determine odds ratio (OR) 95% confidence interval of hyperlipidemia according to nut consumption patterns in unadjusted and three-adjusted models.

RESULTS

The results showed a significant link between high nut consumption and lower total cholesterol, triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) levels and apo B/apo A ratio (P<0.05) in female subjects and lower TG, LDL-C and apoB/apoA ratio in male subjects (P<0.05). The frequency of nut consumption was inversely associated with dyslipidemia, especially for those who had consumed nuts ≥ 4 times weekly (0.67 (0.57-0.79)). After adjusting for sex, age and other potential confounders, ORs increased enormously. Except for low apo A and high LDL-C, more frequent nut consumption (4 ≤ times per week) had a significant inverse effect on other dyslipidemia risk factors in all four models.

CONCLUSIONS

We concluded that frequent consumption of nuts, particularly ≥ 4 times a week, may result in lower dyslipidemia occurrences and may exert cardioprotective effects.

Nut consumption is associated with decreased health risk factors for cardiovascular disease and metabolic syndrome in U.S. adults: NHANES 1999-2004

BACKGROUND

Few recent epidemiologic studies have assessed the effect that nut consumption (including tree nuts and peanuts) has on health risks, including metabolic syndrome (MetS).

OBJECTIVE

This study compared the health risk for cardiovascular disease, type 2 diabetes, and MetS of nut consumers with that of nonconsumers.

DESIGN

Adults 19+ years (n = 13,292) participating in the 1999-2004 National Health and Nutrition Examination Survey were used. Intake from 24-hour recalls was used to determine intake. Nut/tree nut consumers consumed ≥¼; ounce per day. Covariate-adjusted means, standard errors, and prevalence rates were determined for the nut consumption groups.

RESULTS

The prevalence of nut consumers was 18.6% ± 0.7% and 21.0% ± 0.9% in those 19-50 years and 51 years and older, respectively. Nut consumption was associated with a decreased body mass index (27.7 kg/m(2) ± 0.2 vs 28.1 ± 0.1 kg/m(2), p < 0.05), waist circumference (95.6 ± 0.4 cm vs 96.4 ± 0.3 cm, p < 0.05), and systolic blood pressure (121.9 ± 0.4 mmHg vs 123.20 ± 0.3 mmHg, p < 0.01) compared with nonconsumers. Tree nut consumers also had a lower weight (78.8 ± 0.7 kg vs 80.7 ± 0.3 kg, p < 0.05). Nut consumers had a lower percentage of two risk factors for MetS: hypertension (31.5% ± 1.0% vs 34.2% ± 0.8%, p < 0.05) and low high density lipoprotein-cholesterol (HDL-C) (29.6% ± 1.0% vs 34.8% ± 0.8%, p < 0.01). Tree nut consumers had a lower prevalence of four risk factors for MetS: abdominal obesity (43.6% ± 1.6% vs 49.5% ± 0.8%, p < 0.05), hypertension (31.4% ± 1.2% vs 33.9% ± 0.8%, p < 0.05), low HDL-C (27.9% ± 1.7% vs 34.5% ± 0.8%, p < 0.01), high fasting glucose (11.4% ± 1.4% vs 15.0% ± 0.7%, p < 0.05), and a lower prevalence of MetS (21.2% ± 2.1% vs 26.6% ± 0.7%, p < 0.05).

CONCLUSION

Nut/tree nut consumption was associated with a decreased prevalence of selected risk factors for cardiovascular disease, type 2 diabetes, and MetS.