Effect of nuts on energy intake, hunger, and fullness, a systematic review and meta-analysis of randomized clinical trials

Effect of Nuts on Anthropometric and Glycemic Indexes and Blood Pressure in Secondary Cardiovascular Prevention: A Systematic Review and Meta-analysis of Randomized Controlled Trials

CONTEXT

Nut-enriched diets have a positive impact on cardiovascular risk factors, such as body mass, blood pressure, and fasting blood glucose. However, studies in individuals undergoing secondary cardiovascular prevention show controversial results.

OBJECTIVE

This systematic review with meta-analysis assessed the effect of nut supplementation on anthropometric, glycemic, and blood pressure indices in patients with atherosclerotic cardiovascular disease, as well as the frequency of adverse events.

DATA SOURCES

Six databases were used for the search-PubMed, Cochrane Library, EMBASE, BVS (Biblioteca Virtual da Saude), Web of Science, and ClinicalTrials.gov-until February 2023, with no language restrictions.

DATA EXTRACTION

The Cochrane Handbook for Systematic Reviews of Interventions methodology and the PICOS (Population, Intervention, Comparison, Outcome, Setting/design) strategy were used. Seven independent reviewers were involved in data extraction and resolution of disagreements. Certainty of the evidence was evaluated using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system.

DATA ANALYSIS

From 5187 records identified, 6 publications containing data referring to 5 randomized clinical trials (n = 436) were included in the final analyses. The nuts evaluated were almonds, pecans, Brazil nuts, and mixed nuts, with portions that varied between 5 g and 85 g (median: 30 g/day). The intervention period varied between 6 and 12 weeks. The nuts had no effect on fasting glucose and anthropometric indices, although the certainty of the evidence for most of these outcomes was low or very low. They also had no effect on systolic (mean difference [MD]: -1.16 mmHg [95% CI, -5.68 to 3.35], I2 = 0%-moderate certainty of evidence) or diastolic (MD: 0.10 mmHg [95% CI, -2.30 to 2.51], I2 = 0%-high certainty of evidence) blood pressure. It was not possible to aggregate data on adverse events.

CONCLUSION

Nut supplementation had no effect on blood pressure, fasting glucose, or anthropometric profile in the context of atherosclerotic cardiovascular disease.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42020163456.

Metabolisable energy from nuts and patterns of nut consumption in the Australian population: a secondary analysis of the 2011-12 National Nutrition and Physical Activity Survey

BACKGROUND

Nut intake is not associated with increased body weight, which may be explained by their metabolisable energy, among other factors. Therefore, total energy intake may be overestimated among nut consumers. This study aimed to describe the metabolisable energy from nuts and nut consumption patterns in the Australian population.

METHODS

A nut-specific database was expanded to include metabolisable energy of nuts (based on nut type and form) and applied to the 2011-12 National Nutrition and Physical Activity Survey (NNPAS). Participants were Australians aged 2 years and older from the 2011-12 NNPAS (n = 12,153, with n = 4,765 nut consumers). Mean metabolisable energy intake was compared with mean energy intake using Atwater factors in nut consumers. Additionally, nut consumption patterns were explored, including the proportion of nuts consumed at meals and snacks.

RESULTS

Among nut consumers, mean metabolisable energy from nuts based only on nut type was 241.2 (95% confidence interval [CI]: 232.0, 250.5) kJ/day and mean metabolisable energy considering both nut type and form was 260.7 (95% CI: 250.2, 271.2) kJ/day. Energy intake from nuts using Atwater factors was 317.6 (95% CI: 304.8, 330.3) kJ/day. Nuts were more likely to be consumed at snack occasions, with approximately 63% of nut intake occurring as a snack.

CONCLUSION

Application of metabolisable energy to the 2011-12 NNPAS has a significant impact on calculation of energy intake from nuts. Nut consumption patterns identified a majority of nut consumption occurring as snacks. These findings may inform strategies to support nut consumption in Australia.

Nuts and seeds - a scoping review for Nordic Nutrition Recommendations 2023

Background

Nuts and seeds have been part of diets in most of the world for millenniums, and they have also been consumed in the Nordic and Baltic countries for centuries. Consumption of nuts and seeds is linked with various health outcomes. Therefore, when updating the Nordic Nutrition Recommendations (NNR), summarizing the best evidence on key health outcomes from the consumption of nuts and seeds is essential.

Objectives

This study aims to evaluate the updated evidence on the consumption of nuts and seeds and health outcomes regarded relevant for the Nordic and Baltic countries, as well as their dose-response relationship presented in updated systematic reviews and meta-analyses.

Method

The scoping review is built on a de novo systematic review and an umbrella review published in 2022 on the consumption of nuts and seeds and its various health outcomes, including cardiovascular disease and diabetes.

Results

Intake of nuts and seeds is associated with a lower risk of cardiovascular diseases, with evidence assessed as probable. This conclusion is mirrored by evidence from trials on biomarkers for chronic diseases. An intake of a serving of nuts of 28-30 g/day compared to not eating nuts is estimated to translate into approximately 20% relative reduction in the risks of cardiovascular disease and premature deaths. For cancers, consumption of a serving of nuts is inversely associated with cancer mortality. However, for type 2 diabetes, there are mixed and inconclusive results. Additionally, there are inverse associations between nut consumption and respiratory and infectious disease mortality. Allergies for nuts are seen among 1-2% of the population.

Conclusion

Overall, the current evidence supports dietary recommendations to increase nut consumption to a serving of nuts and seeds per day for people without allergies to these foods.

Almonds vs. carbohydrate snacks in an energy-restricted diet: Weight and cardiometabolic outcomes from a randomized trial

OBJECTIVE

This study evaluated weight and cardiometabolic outcomes after a 3-month energy-restricted diet (-30%) containing almonds (almond-enriched diet [AED]) or containing carbohydrate-rich snacks (nut-free control diet [NFD]) (Phase 1), followed by 6 months of weight maintenance (Phase 2).

METHODS

Participants (25-65 years old) with overweight or obesity (BMI 27.5-34.9 kg/m2 ) were randomly allocated to AED (n = 68) or NFD (n = 72).

RESULTS

Both groups lost weight during Phase 1 (p < 0.001) (mean [SE], -7.0 [0.5] kg AED vs. -7.0 [0.5] kg NFD, p = 0.858) and Phase 2 (p = 0.009) (-1.1 [0.5] kg AED vs. -1.3 [0.6] NFD, p = 0.756), with improvements in percentage lean mass after Phase 2 (4.8% [0.3%], p < 0.001). Reductions occurred in fasting glucose (-0.2 [0.07] mmol/L, p = 0.003), insulin (-8.1 [4.0] pmol/L, p = 0.036), blood pressure (-4.9 [0.8] mm Hg systolic, -5.0 [0.5] mm Hg diastolic, p < 0.001), total cholesterol (-0.3 [0.1] mmol/L), low-density lipoprotein (LDL) (-0.2 [0.1] mmol/L), very low-density lipoprotein (-0.1 [0.03] mmol/L), and triglycerides (-0.3 [0.06] mmol/L) (all p < 0.001), and high-density lipoprotein increased (0.1 [0.02] mmol/L, p = 0.011) by the end of Phase 2 in both groups. There were group by time interactions for lipoprotein particle concentrations: very small triglyceride-rich (-31.0 [7.7] nmol/L AED vs. -4.8 [7.9] nmol/L NFD, p = 0.007), small LDL (-109.3 [40.5] nmol/L AED vs. -20.7 [41.6] nmol/L NFD, p = 0.017), and medium LDL (-24.4 [43.4] nmol/L AED vs. -130.5 [44.4] nmol/L NFD, p = 0.045).

CONCLUSIONS

An energy-restricted AED resulted in weight loss and weight loss maintenance comparable to an energy-restricted NFD, and both diets supported cardiometabolic health. The AED resulted in greater improvements in some lipoprotein subfractions, which may enhance reductions in cardiovascular risk.

The effects of macro-algae supplementation on serum lipid, glycaemic control and anthropometric indices: A systematic review and meta-analysis of clinical trials

INTRODUCTION

Macro-algae products have been shown to ameliorate the metabolic disorders state. Thus, highlighting their function as supplementary therapeutic agents can be a novel strategy for clinical therapies. This systematic review and meta-analysis of clinical trials aimed to summarize the effect of macro-algae consumption on serum lipid profile, glycaemic control and anthropometric factors.

METHODS

In this systematic review and meta-analysis, a comprehensive search was performed for relevant studies published up to May 2023. The Cochran's Q test and I-square (I2 ) tests were used to evaluate heterogeneity across the included studies. The meta-analysis was conducted using random-effects model (DerSimonian and Laird), and weighted mean difference (WMD) was considered as the pooled effect size.

RESULTS

Out of 8602 papers in the initial screening, eight clinical trials with a total of 438 participants were included into this meta-analysis. The results indicated that macro-algae supplementation significantly decreased serum levels of total cholesterol (TC) (WMD = -6.7 mg/dL; 95% CI: -12.59, -0.80; item = 0.026) and low-density lipoprotein cholesterol (LDL-c) (WMD = -8.25 mg/dL; 95% CI: -15.38, -1.12; p-value = .023). There was an increase in level of high-density lipoprotein cholesterol (HDL-c) (WMD = 0.48 mg/dL; 95% CI: -2.05, 3.01; p-value = .71) which was not statistically significant. Macro-algae supplementation reduced body mass index (BMI) (WMD = -0.28 kg/m2 ; 95% CI: -0.96, 0.41; p-value = .426), weight (WMD = -0.39 kg; 95% CI: -3.6, 2.83; p-value = .81), waist circumference (WC) (WMD = -0.52 cm; 95% CI: -2.71, 1.66; p-value = .64), fasting blood sugar (FBS) (WMD = -1.95 mg/dL; 95% CI: -5.19, 1.28; p-value = .24) and HbA1c (WMD = -0.02%; 95% CI: -0.14, 0.09; p-value = .66) in intervention group.

CONCLUSIONS

This meta-analysis indicated that macro-algae supplementation significantly decreased TC and LDL-c level. It can also increase HDL-c level and reduce anthropometric indices and glycaemic control factors.

The Metabolizable Energy and Lipid Bioaccessibility of Tree Nuts and Peanuts: A Systematic Review with Narrative Synthesis of Human and In Vitro Studies

Nuts are an energy-dense food, yet regular consumption is not associated with weight gain. A proportion of the fats found within nuts remains encapsulated within cell walls and cannot be digested. Metabolizable energy (ME) can be explored by measuring fecal fat excretion in human studies and fat release among in vitro studies. This systematic review with narrative synthesis aimed to examine the ME of tree nuts and peanuts (PROSPERO CRD42021252287). PubMed, MEDLINE, CINAHL, Cochrane, and Embase databases were searched to June 2021. Both in vitro and human studies (adults ≥18 y) were included. Data was synthesized via narrative synthesis with results reported in summary tables and compared between form, processing, and dose of nuts, where available. Twenty-one studies were included. The ME of nuts was consistently lower than that predicted by Atwater factors for investigated nut types (almonds, cashews, hazelnuts, pistachios, walnuts, and peanuts). The mechanisms may relate to a lower fat release from nuts, hence higher fecal fat excretion; however, this review did not consider the digestibility of carbohydrates and protein, which should be considered when interpreting the outcomes. ME was influenced by nut type (ME = 22.6 kJ/g for pistachios; ME = 18.5 kJ/g for raw almonds), physical form (flour > chopped > whole nuts), heat processing (butter > roasted > raw) and dose of consumption. The lower-than-expected ME may explain a lack of association between nut intake and body weight observed in the literature and has implications for the development of food composition databases, food labeling, and informing dietary guidelines. However, the strength of the evidence base was reduced by the variation in methods used between studies, suggesting that further clinical trials are needed to determine the impact of the findings of this review for clinical dietetics.

Determination of the level of evidence for the association between different food groups/items and dietary fiber intake and the risk of cardiovascular diseases and hypertension: An umbrella review

Evidence has suggested that nutrition is a preventive factor against cardiovascular disease (CVD) risk. Because of a sharp growth in published meta-analyses and pooled analyses in recent years, a reassessment of old evidence is needed. We aimed to determine the level of evidence for the association between the consumption of different food groups/items and dietary fiber and the incidence risk of CVDs, hypertension, and atrial fibrillation from meta-analyses and pooled analyses of observational studies. Databases Scopus, PubMed/Medline, and Web of Science were searched for related studies. Fifty-eight articles met the inclusion criteria for evidence grading. In summary, grading the level of evidence showed a suggestive inverse association between the higher consumption of fruits, whole grains, fish, legumes, nuts, and dietary fibers with the incidence risk of hypertension and different types of CVD. Also, there was a probable inverse association between the higher consumption of total and low-fat dairy products and the risk of hypertension. Higher red meat consumption had a probable association with the increased risk of ischemic stroke. Higher consumption of processed meat and poultry also had a suggestive direct association with the incidence risk of stroke and hypertension. We have tried to present a comprehensive and useful overview of the level of evidence based on the most updated findings. The summary of results in the current umbrella review can be a helpful tool for nutritionists, dietitians, and researchers to establish new studies and identify research gaps in related issues.

Nuts, Energy Balance and Body Weight

Over several decades, the health benefits of consuming nuts have been investigated, resulting in a large body of evidence that nuts can reduce the risk of chronic diseases. The consumption of nuts, being a higher-fat plant food, is restricted by some in order to minimize weight gain. In this review, we discuss several factors related to energy intake from nuts, including food matrix and its impact on digestibility, and the role of nuts in regulating appetite. We review the data from randomized controlled trials and observational studies conducted to examine the relationship between nut intake and body weight or body mass index. Consistently, the evidence from RCTs and observational cohorts indicates that higher nut consumption does not cause greater weight gain; rather, nuts may be beneficial for weight control and prevention of long-term weight gain. Multiple mechanisms likely contribute to these findings, including aspects of nut composition which affect nutrient and energy availability as well as satiety signaling.

The Effects of Tree Nut and Peanut Consumption on Energy Compensation and Energy Expenditure: A Systematic Review and Meta-Analysis

Nut consumption is not associated with a higher body weight, and potential energy-regulating mechanisms may include a reduced subsequent energy intake and increased EE. The aim of this study was to examine the effect of tree nut and peanut consumption on energy intake, compensation, and expenditure. PubMed, MEDLINE, CINAHL, Cochrane, and Embase databases were searched from inception to June 2, 2021. Human studies with adults aged ≥18 y older were included. Energy intake and compensation studies were restricted to acute effects (intervention duration of ≤24 h), whereas intervention duration was not limited for EE studies. Random effects meta-analyses were conducted to explore weighted mean differences in REE. Twenty-eight articles from 27 studies (16 energy intake studies, 10 EE studies, and 1 study investigating both) with 1121 participants were included in this review, with a variety of nut types addressed (almonds, Brazil nuts, cashews, chestnuts, hazelnuts, peanuts, pistachios, walnuts, and mixed nuts). Energy compensation occurred after nut-containing loads (range: -280.5% to +176.4%) and the degree of compensation varied depending on the form (whole and chopped) and how they were consumed (alone and within a meal). The meta-analyses identified a nonsignificant increase in REE associated with nut consumption (weighted mean difference: 28.6 kcal/d; 95% CI: -10.7, 67.8 kcal/d). This study provided support for energy compensation as a potential mechanism for a lack of association between nut consumption and body weight, whereas no evidence was found for EE as an energy-regulating mechanism of nuts. This review was registered at PROSPERO as CRD42021252292.

Acute feeding with almonds compared to a carbohydrate-based snack improves appetite-regulating hormones with no effect on self-reported appetite sensations: a randomised controlled trial

PURPOSE

Early satiety has been identified as one of the mechanisms that may explain the beneficial effects of nuts for reducing obesity. This study compared postprandial changes in appetite-regulating hormones and self-reported appetite ratings after consuming almonds (AL, 15% of energy requirement) or an isocaloric carbohydrate-rich snack bar (SB).

METHODS

This is a sub-analysis of baseline assessments of a larger parallel-arm randomised controlled trial in overweight and obese (Body Mass Index 27.5-34.9 kg/m²) adults (25-65 years). After an overnight fast, 140 participants consumed a randomly allocated snack (AL [n = 68] or SB [n = 72]). Appetite-regulating hormones and self-reported appetite sensations, measured using visual analogue scales, were assessed immediately before snack food consumption, and at 30, 60, 90 and 120 min following snack consumption. A sub-set of participants (AL, n = 49; SB, n = 48) then consumed a meal challenge buffet ad libitum to assess subsequent energy intake. An additional appetite rating assessment was administered post buffet at 150 min.

RESULTS

Postprandial C-peptide area under the curve (AUC) response was 47% smaller with AL compared to SB (p < 0.001). Glucose-dependent insulinotropic polypeptide, glucagon and pancreatic polypeptide AUC responses were larger with AL compared to SB (18%, p = 0.005; 39% p < 0.001; 45% p < 0.001 respectively). Cholecystokinin, ghrelin, glucagon-like peptide-1, leptin and polypeptide YY AUCs were not different between groups. Self-reported appetite ratings and energy intake following the buffet did not differ between groups.

CONCLUSION

More favourable appetite-regulating hormone responses to AL did not translate into better self-reported appetite or reduced short-term energy consumption. Future studies should investigate implications for longer term appetite regulation.

ANZCTR REFERENCE NUMBER

ACTRN12618001861246 2018.

Nut-enriched energy restricted diet has potential to decrease hunger in women at cardiometabolic risk: a randomized controlled trial (Brazilian Nuts Study)

Successful weight management represents a challenge to obesity control. Evidence suggests that nut consumption promotes a prolonged satiety response. Therefore, we hypothesize that nuts could be associated with greater weight loss in comparison to a control group, and we evaluate the acute and long-term effects of Brazilian nuts (BN: 15 g of Brazil nuts + 30 g of cashew nuts) included in an energy-restricted intervention on food intake, appetite, and peptide hormones. We conducted an 8-week, randomized, open-label, controlled, parallel-arm clinical trial with 28 women at cardiometabolic risk who received an energy-restricted diet containing BN or an energy-restricted nut-free diet (control). At baseline and after 8 weeks of intervention, subjective postprandial appetite ratings were assessed using a visual analog scale (VAS) before and after consumption (0, 10, 60, 120, 180, and 240 minutes) of a 437-kcal nut-enriched (BN group) or nut-free (control) breakfast meal. Subsequently, an ad libitum lunch was served, and the participants completed another VAS at 280 minutes. Plasma concentrations of ghrelin, glucose-dependent insulinotropic polypeptide, glucagon-like peptide 1, and leptin were measured at fasting and postprandially at 60, 120, and 240 minutes. Last, subsequent reported 24-hour energy intake was assessed in a free-living setting. BN consumption did not have acute effects on food intake, appetite, or peptide hormones. However, after an 8-week intervention, postprandial ghrelin (difference between post- and preintervention area under the curve) decreased in the BN group in comparison to the control (mean difference, 1978 pg/mL/min, 95% CI, 27-3929 pg/mL/min; P = .047) and therefore, an energy-restricted diet containing demonstrated potential to decrease hunger in cardiometabolic risk women.

The role of dietary fibers in regulating appetite, an overview of mechanisms and weight consequences

Dietary fibers prevent obesity through reduction of hunger and prolongation of satiety. A number of mechanical and endocrine signals from gastrointestinal tract are stimulated by fibers and their fermentation products, reach regions of brain involved in the regulation of appetite, and ultimately reduce food intake. Gastric distention, delayed gastric emptying, prevention of hypoglycemic, increased amounts of unabsorbed nutrients reaching to the ileum, and stimulation of enteroendocrine cells for secretion of cholecystokinin, glucagon-like peptide-1 (GLP-1), and peptide YY are among mechanisms of fibers in decreasing hunger and prolongation of satiety. Fermentation of fibers produces short-chain fatty acids that also stimulates enteroendocrine cells to secrete GLP-1 and PYY. Randomized controlled trials have shown reductions in energy intake and body weight along with increased satiation and reduced hunger following consumption of fibers. Prospective cohort studies have confirmed these results but the extent of weight loss in some studies has been small. Controversies exist between studies particularly for the effect of fibers on the gastrointestinal hormones, subsequent food intake, and the resultant weight loss. More studies are needed before a clear conclusion can be drawn especially for the effect of fibers on appetite-related hormones and weight loss.

Nuts and Metabolic Syndrome: Reducing the Burden of Metabolic Syndrome in Menopause

Menopause imposes a dramatic fall in estrogens, which is followed by an increase in the proportion of fat. The rising androgen/estrogen ratio along the menopause transition favors the accumulation of central fat, which contributes to insulin resistance and a series of concatenated effects, leading to a higher incidence of metabolic syndrome. The modulatory effect of diet on the metabolic syndrome phenotype has been shown for the Mediterranean diet, and nuts are key determinants of these health benefits. This review of the impact of nuts on the risk factors of the metabolic syndrome cluster examined studies—prioritizing meta-analyses and systemic reviews—to summarize the potential benefits of nut ingestion on the risk of metabolic syndrome associated with menopause. Nuts have a general composition profile that includes macronutrients, with a high proportion of unsaturated fat, bioactive compounds, and fiber. The mechanisms set in motion by nuts have shown different levels of efficacy against the disturbances associated with metabolic syndrome, but a beneficial impact on lipids and carbohydrate metabolism, and a potential, but minimal reduction in blood pressure and fat accumulation have been found.

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

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

The Negative Effects of Long Time Physical Activity Calorie Equivalent Labeling on Purchase Intention for Unhealthy Food

(1) Background: Obesity has become a global epidemic that arouse much attention from governments, companies and scholar. Physical activity calorie equivalent (PACE) labels are introduced as a more effective nudge invention on less-calorie ordering. However, the effects of PACE labels are controversial in previous literature, thus, the research objective is to explore the effects of different PACE labels and furtherly to explore the underlying psychological mechanism; (2) Methods: Across four scenario-based experiments, involving potato chips, chocolate and cookies, this study manipulated the three calorie-information labeling (standard calorie label, long time PACE and short time PACE labels). Meanwhile, the mediating mechanism of the effects involving anticipatory guilt and the moderation effects between consumers’ future self-continuity and PACE labels are also measured; (3) Results: Results show that compared with the short time PACE and calorie labels, the longtime PACE labels have more negative influence on consumers’ purchase intention for unhealthy food. What’s more, the anticipatory guilt has negative effect of PACE labels as consumers are often prone to feeling guilty in the process of unhealthy food consumption. In addition, individuals with high future self-continuity have higher self-control and take more consideration of future outcomes, they are reluctant to choose unhealthy food than others; (4) Conclusions: Unhealthy food with a long time PACE label has more negative effect on consumers’ purchase intention rather than a short time PACE label. At the same time, companies that produce healthy foods should actively participate in the movement to label calories through the PACE labels.

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.

Snacking on Almonds Lowers Glycaemia and Energy Intake Compared to a Popular High-Carbohydrate Snack Food: An Acute Randomised Crossover Study

Consuming nuts may have advantages over other snack foods for health and body-weight regulation. Suggested mechanisms include increased satiety and lower glycaemia. We used an acute randomised crossover trial to assess glycaemic and appetite responses to consuming two isocaloric snacks (providing 10% of participants’ total energy requirements or 1030 kJ (equivalent to 42.5 g almonds), whichever provided greater energy): raw almonds and sweet biscuits among 100 participants with available data (25 males and 75 females) following 106 being randomised. Two hours after consuming a standardised breakfast, participants consumed the snack food. Finger-prick blood samples measuring blood glucose and subjective appetite ratings using visual analogue scales were taken at baseline and at 15 or 30 min intervals after consumption. Two hours after snack consumption, an ad libitum lunch was offered to participants and consumption was recorded. Participants also recorded food intake for the remainder of the day. The mean area under the blood glucose response curve was statistically and practically significantly lower for almonds than biscuits (mean (95% CI) difference: 53 mmol/L.min (45, 61), p < 0.001). Only the composite appetite score at 90 min was higher in the almond treatment compared to the biscuit treatment (45.7 mm vs. 42.4 mm, p = 0.035 without adjustment for multiple comparisons). There was no evidence of differences between the snacks for all other appetite ratings or for energy intake at the ad libitum lunch. However, mean energy intakes following snack consumption were significantly lower, both statistically and in practical terms, for the almond treatment compared to the biscuit (mean (95% CI) diff: 638 kJ (44, 1233), p = 0.035). Replacing popular snacks with almonds may have advantages in terms of glycaemia and energy balance.

Effects of acute and chronic nuts consumption on energy metabolism: a systematic review of randomised clinical trials

Nuts are high-energy density foods and are associated with beneficial effects on health, including weight control. Effects on resting energy expenditure, respiratory quotient, and diet-induced thermogenesis are suggested mechanisms behind the effects of nuts consumption on weight control. Thus, we revised the randomised clinical trials that assessed acute and chronic nuts consumption effects on energy metabolism. Walnuts (22.1 g to 56 g) consumption appears to modulate energy metabolism markers differently depending on the dose and profile of the evaluated subject. In its turn, 56 g of high-oleic peanuts increased postprandial energy expenditure and thermic effect of food after three hours postprandial compared to consumption of conventional peanuts. Almonds, hazelnuts, peanuts, and a mix of nuts were the nuts studies in the chronic studies, which does not seem to influence energy metabolism markers. Further studies are needed to elucidate the effects of other types of nuts consumption on energy metabolism.

Is a Handful an Effective Way to Guide Nut Recommendations?

Dietary guidelines recommend consuming 30 g of nuts per day to reduce the risk of chronic disease. A 'handful' is commonly used to guide consumers. Research is lacking on how this translates into actual gram amounts. This study quantified the grams of nuts represented by different portion size measures, including a 'handful' and '30 g serving' among 120 participants. Each participant was randomised to a sequence where they received three of six different nut types (from almonds, cashews, hazelnuts, macadamias, peanuts, and walnuts) and were instructed to take a: 'usual serving', 'handful', 'small handful', 'large handful', and '30 g serving' of each. Combining all nut types, the median 'handful' was 36.3 g, compared to 28.7 g for the estimated '30 g serving' and 24.8 for the 'usual serving'. The 'large handful' was approximately double the 'handful' (61.3 g), whereas the 'small handful' was about half (16.7 g). Eighty-three percent of portions chosen were at least 80% of the recommended 30 g intake when participants were asked to take a 'handful', compared to 63% for the '30 g serving'. It appears a 'handful' can be used as a practical tool to guide recommended nut intakes, and increases the amount selected compared to instructions to take a '30 g serving'.

The Role of Physical Fitness in the Relationship between Nut Consumption and Body Composition in Young Adults

The main objective of this study was to estimate the association between nut consumption and body composition-related measures and to examine whether this relationship is mediated by cardiorespiratory fitness (CRF) and the muscle strength index (MSI) in young adults. A cross-sectional study involving college students (n = 354) aged 18-30 years from a Spanish public university was conducted. Body composition and fitness components were assessed using standard methods. Nut consumption was evaluated using a Food-Frequency Questionnaire. ANCOVA models were used to assess the mean differences in physical fitness and body composition by nut consumption categories. Hayes's PROCESS macro was applied for mediation and interaction analyses adjusted for the main confounders. Young adults with high nut consumption (≥5 portions of 30 g/week) showed significantly higher values of physical fitness components and fat-free mass and lower values of adiposity-related measures than their peers in the lowest categories of nut consumption (˂1 portion/week) (p < 0.05). No significant interaction between CRF and nut consumption on body composition was found. In the mediation analysis, CRF and MSI acted as full mediators of the relationship of nut consumption with fat-free mass and waist circumference/height index. Otherwise, CRF and MSI partially mediated the relationship between nut consumption and body mass index and percent of fat mass. Finally, nut consumption, per se, does not appear to have a significant impact on body composition indicators because these associations have been shown to be partially (for BMI and %BF) or entirely (for ratio WC/height and fat-free mass) explained by CRF and MSI.

Almond oil: A comprehensive review of chemical composition, extraction methods, preservation conditions, potential health benefits, and safety

Almond oil, a rich source of macronutrients and micronutrients, is extracted for food flavorings and the cosmetics industry. In recent years, the need for high-quality and high-quantity production of almond oil for human consumption has been increased. The present review examines the chemical composition of almond oil, storage conditions, and clinical evidence supporting the health benefits of almond oil. From the reviewed studies, it appears that almond oil contains a significant proportion of poly and monounsaturated fatty acids, with oleic acid as the main compound, and an important amount of tocopherol and phytosterol content. Some variations in almond oil composition can be found depending on the kernel's origin and the extraction system used. Some new technologies such as ultrasonic-assisted extraction, supercritical fluid extraction, subcritical fluid extraction, and salt-assisted aqueous extraction have emerged as the most promising extraction techniques that allow eco-friendly and effective recovery of almond oil. This safe oil was reported by several clinical studies to have potential roles in cardiovascular risk management, glucose homeostasis, oxidative stress reduction, neuroprotection, and many dermatologic and cosmetic applications. However, the anticarcinogenic and fertility benefits of almond oil have yet to be experimentally verified.

Acute consumption of a shake containing cashew and Brazil nuts did not affect appetite in overweight subjects: a randomized, cross-over study

PURPOSE

Evidence from epidemiological and clinical studies suggests that nut consumption provides satiety and may contribute to the management of obesity. However, the effect of acute intake of nuts on appetite responses remains unclear. The objective of this study was to evaluate the acute effect of a shake containing 30 g of cashew nuts (Anacardium occidentale L.) and 15 g of Brazil nuts (Bertholletia excelsa H.B.K) on appetite responses in overweight subjects.

METHODS

This was a clinical, randomized, controlled, single-blind, cross-over, pilot study. On two non-consecutive test days, 15 subjects received a shake containing nuts, and a shake absent of nuts matched for energy and macronutrient content. Subjective appetite sensation was evaluated by visual analogue scales (VAS). Food intake was measured by weighing the lunch served at the end of each morning-test, which subjects ate ad libitum. Total energy intake was estimated by food records. This study is registered on the Brazilian Registers of Clinical Trials-ReBEC (protocol: U1111-1203-9891).

RESULTS

We observed no significant difference in subjective appetite sensations between the groups. Food intake at lunch, as well as energy intake throughout the day also did not differ between the treatments.

CONCLUSION

Our results suggest that the acute intake of a shake containing nuts was not able to enhance satiety, compared to a shake matched for energy and macronutrient content. Further studies are warranted to elucidate the satiety mechanisms of nuts intake.

Nut consumption and type 2 diabetes risk: a systematic review and meta-analysis of observational studies

BACKGROUND

Previous meta-analyses, with some methodological controversies, have assessed the relation between nut consumption and type 2 diabetes (T2D) risk and pointed to contradictory results, making desirable the performance of an updated meta-analysis.

OBJECTIVES

We aimed to systematically review and meta-analyze all the published studies investigating the relations of total nuts and different types of nuts-i.e., walnuts, peanuts, peanut butter, and total tree nuts-with the prevalence and incidence of T2D.

METHODS

A systematic search was conducted in the PubMed and Cochrane databases through 12 August, 2020. The inverse variance method with fixed-effect models was used to pool data across studies, expressed as risk ratios (RRs) or ORs and 95% CIs for prospective cohort and cross-sectional studies, respectively. The Cochran Q test and I2 statistics were used to test and quantify heterogeneity, respectively. Dose-response meta-analysis was also conducted.

RESULTS

Eight studies (5 prospective and 3 cross-sectional) were included in the quantitative synthesis. Meta-analyses of cross-sectional studies and prospective cohort studies, comparing the highest with the lowest categories, revealed a nonsignificant association between total nut consumption and T2D. Meta-analyses of prospective cohort studies showed an inverse association between peanut butter consumption and T2D incidence (RR: 0.87; 95% CI: 0.77, 0.98; I2 = 50.6%; Pheterogeneity = 0.16), whereas no association was observed between peanuts or tree nuts and T2D. There was no evidence of a linear dose-response or nonlinear dose-response gradient for total nut and peanut consumption in prospective cohort studies. The certainty of the evidence using NutriGrade was very low for all the exposures.

CONCLUSIONS

Current results do not demonstrate an association of total nut, peanut, or tree nut consumption with T2D. Peanut butter consumption may be inversely associated with this disease.This review protocol was registered at www.crd.york.ac.uk/prospero/ as CRD42020149756.

The Differential Effects of Physical Activity Calorie Equivalent Labeling on Consumer Preferences for Healthy and Unhealthy Food Products: Evidence from a Choice Experiment

Background: Since numerical calorie labels have limited effects on less-calorie food ordering, an alternative called physical activity calorie equivalent (PACE) labels, which exhibit calories using visible symbols and the minutes of exercise to burn off the calories, may be more effective in reducing calories ordered. Methods: By using a choice experiment (CE) approach, the aims of this study were to estimate the effects of PACE labels on consumer preferences for healthy and unhealth food. Red date walnuts and potato chips were used as the representatives of healthy and unhealthy foods respectively in this study. Moreover, future time perspective (FTP) is an individual trait variable of consumers, which has been recognized as a significant driver of healthy behaviors. We also included FTP into the interaction with PACE labels. Results: Firstly, the results were opposite between the healthy and unhealthy food groups. Respondents showed significantly more positive attitudes toward red date walnuts (i.e., healthy food) with PACE labels, while they showed significantly more negative preferences for chips (i.e., unhealthy food) with PACE labels. Secondly, people with higher FTP are preferred red date walnuts with PACE labels, while PACE labels on chips could undermine the preferences of respondents with higher FTP. Thirdly, we found that women (vs. men) were less inclined to choose healthy food with standard calorie labels and labels showing the minutes of running to burn off the calories, as well as that the elderly (vs. younger) people in the healthy food group preferred the labels showing the minutes of running to burn off the calories. People with a higher body mass index (BMI) were reluctant to purchase walnuts with the information about the minutes of walking. Conclusions: Results from this study showed that PACE labels have significant effects on consumers’ preferences for food products.

Nuts and Older Adults' Health: A Narrative Review

Although the beneficial effects of nuts on cardiometabolic diseases have been well established, little is known about the effects of nuts on age-related diseases. Given that age-related diseases share many biological pathways with cardiometabolic diseases, it is plausible that diets rich in nuts might be beneficial in ameliorating age-related conditions. The objective of this review was to summarise the findings from studies that have examined the associations or effects of nut consumption, either alone or as part of the dietary pattern, on three major age-related factors—telomere length, sarcopenia, and cognitive function—in older adults. Overall, the currently available evidence suggests that nut consumption, particularly when consumed as part of a healthy diet or over a prolonged period, is associated with positive outcomes such as longer telomere length, reduced risk of sarcopenia, and better cognition in older adults. Future studies that are interventional, long-term, and adequately powered are required to draw definitive conclusions on the effects of nut consumption on age-related diseases, in order to inform dietary recommendations to incorporate nuts into the habitual diet of older adults.

Dietary interventions for obesity: clinical and mechanistic findings

Dietary modification is central to obesity treatment. Weight loss diets are available that include various permutations of energy restriction, macronutrients, foods, and dietary intake patterns. Caloric restriction is the common pathway for weight reduction, but different diets may induce weight loss by varied additional mechanisms, including by facilitating dietary adherence. This narrative Review of meta-analyses and select clinical trials found that lower-calorie diets, compared with higher-calorie regimens, reliably induced larger short-term (<6 months) weight losses, with deterioration of this benefit over the long term (>12 months). Few significant long-term differences in weight loss were observed for diets of varying macronutrient composition, although some regimens were found to have short-term advantages (e.g., low carbohydrate versus low fat). Progress in improving dietary adherence, which is critical to both short- and long-term weight loss, could result from greater efforts to identify behavioral and metabolic phenotypes among dieters.

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.

Evaluation of the Influence of Raw Almonds on Appetite Control: Satiation, Satiety, Hedonics and Consumer Perceptions

Snack foods can be substantial contributors to daily energy intake, with different types of snacks exerting potentially different effects on satiety per calorie consumed. The present research compared the effect of consuming almonds as a mid-morning snack compared to an energy and weight-matched comparator snack (savoury crackers) or the equivalent weight of water (zero energy control). In a crossover design, 42 female participants (age: 26.0 ± 7.9, BMI: 22.0 ± 2.0) consumed a fixed breakfast then a mid-morning snack. Appetite, 24-h energy intake, food hedonics, and consumer perceptions of the snack foods were assessed under laboratory conditions. AUC analyses revealed a lower overall hunger drive after consuming almonds compared to crackers or water. There was no difference in 24-h energy intake in the almond compared to the cracker or the zero-energy control condition, however participants consumed more energy in the cracker condition compared to the zero-energy control condition. In addition, almonds suppressed hedonic preference (implicit wanting) for consuming high-fat foods and demonstrated a higher satiety quotient (SQ) than crackers. Almonds were perceived to have a more favourable consumer profile aligned with successful weight management. In conclusion, these findings demonstrate that in the context of a 24-h period of objectively measured energy intake, raw almonds are effective for controlling appetite compared to an energy matched alternative snack. This trial was registered at clinicaltrials.gov [NCT02480582].

A Randomized Controlled Pilot Study to Assess Effects of a Daily Pistachio (Pistacia Vera) Afternoon Snack on Next-Meal Energy Intake, Satiety, and Anthropometry in French Women

Including nuts in the diet improves appetite control and does not lead to weight gain. However, for pistachios, evidence from randomized intervention studies is limited and there are no data on the effect of pistachios on satiety. The objective of this study was to assess the effect of daily consumption of pistachios as an afternoon snack on satiety, self-reported energy, self-reported nutrient intake, body weight, and body composition. This randomized controlled pilot study included two parallel groups of 30 healthy French women, in a free-living setting. For four weeks, groups were instructed to consume either 56 g (1318 kJ) of pistachios or 56 g of isoenergetic/equiprotein savory biscuits as an afternoon snack. Evening energy intake, changes in anthropometric measures, and daily intake of energy and selected nutrients were assessed. Visual analogue scales (VAS) were used to rate hunger, fullness, desire to eat, and prospective consumption. Satiety effects were not different between groups, as assessed by evening energy intake or VAS scores. Consuming pistachios or biscuits had no impact on body weight. Thiamin, vitamin B6, copper, and potassium intakes were significantly higher in the pistachio group. Consuming pistachios or biscuits as an afternoon snack resulted in similar post-snack food intake and subjective feelings of satiety. A daily pistachio snack for a month did not affect body weight or composition but it did improve micronutrient intake.

Mixed Nuts May Promote Satiety While Maintaining Stable Blood Glucose and Insulin in Healthy, Obese, and Overweight Adults in a Two-Arm Randomized Controlled Trial

Multiple studies have examined the impacts of various nuts on appetitive and metabolic effects; however, fewer studies have addressed the impacts of mixed nuts. The objective was to examine the acute effects of consumption of an isocaloric (253 kcal) snack of mixed nuts or pretzels on appetite hormones, glucose and insulin responses, and subjective appetite ratings in overweight and obese adults. In a two-arm randomized controlled trial, overweight and obese adults consumed either mixed nuts (n = 27) or pretzels (n = 27) with 16 men and 11 women per group. After an overnight fast, blood glucose, insulin, and appetite hormone were measured at baseline and 60 min post snack consumption. Appetite/satiety questionnaires were completed at baseline and 20, 40, 60, 90, 120 min after snack consumption. Both snacks increased satiety and reduced hunger over time. The pretzels group exhibited higher subjective satiety and lower hunger (P < .001) following consumption than the mixed nuts group. Pretzel consumption increased glucose and insulin (P < .001), while no elevation was detected in the mixed nuts at 60 min post snack consumption. Leptin and ghrelin concentrations were significantly lower for the mixed nuts group at 60 min compared with baseline (P < .05). Mixed nuts promote satiety in overweight and obese adults while maintaining stable blood glucose and insulin levels. These results suggest that mixed nuts snack may be beneficial for those who are overweight or obese. Future mixed nuts studies are warranted to examine long-term effects.