Consuming Almonds vs. Isoenergetic Baked Food Does Not Differentially Influence Postprandial Appetite or Neural Reward Responses to Visual Food Stimuli

Neuroimaging Investigations of Obesity: a Review of the Treatment of Sex from 2010

PURPOSE OF REVIEW

To summarize the results of adult obesity neuroimaging studies (structural, resting-state, task-based, diffusion tensor imaging) published from 2010, with a focus on the treatment of sex as an important biological variable in the analysis, and identify gaps in sex difference research.

RECENT FINDINGS

Neuroimaging studies have shown obesity-related changes in brain structure, function, and connectivity. However, relevant factors such as sex are often not considered. We conducted a systematic review and keyword co-occurrence analysis. Literature searches identified 6281 articles, of which 199 met inclusion criteria. Among these, only 26 (13%) considered sex as an important variable in the analysis, directly comparing the sexes (n = 10; 5%) or providing single-sex/disaggregated data (n = 16, 8%); the remaining studies controlled for sex (n = 120, 60%) or did not consider sex in the analysis (n = 53, 27%). Synthesizing sex-based results, obesity-related parameters (e.g., body mass index, waist circumference, obese status) may be generally associated with more robust morphological alterations in men and more robust structural connectivity alterations in women. Additionally, women with obesity generally expressed increased reactivity in affect-related regions, while men with obesity generally expressed increased reactivity in motor-related regions; this was especially true under a fed state. The keyword co-occurrence analysis indicated that sex difference research was especially lacking in intervention studies. Thus, although sex differences in the brain associated with obesity are known to exist, a large proportion of the literature informing the research and treatment strategies of today has not specifically examined sex effects, which is needed to optimize treatment.

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.

Mixed Tree Nut Snacks Compared to Refined Carbohydrate Snacks Resulted in Weight Loss and Increased Satiety during Both Weight Loss and Weight Maintenance: A 24-Week Randomized Controlled Trial

Mixed tree nuts (MTNs) are an excellent source of protein and healthy fat contributing to satiety. However, their relatively high caloric content might not be beneficial in a weight loss diet. The present study was designed to test whether including MTNs in a weight loss and maintenance program interferes with weight management compared to a refined carbohydrate pretzel snack (PS). We performed a randomized, controlled, two-arm study in 95 overweight individuals consuming 1.5 oz of MTNs or PS daily as part of a hypocaloric weight loss diet (−500 kcal) over 12 weeks followed by an isocaloric weight maintenance program for 12 weeks. Participants in both groups experienced significant weight loss (12 weeks: −1.6 and −1.9 and 24 weeks: −1.5 and −1.4 kg) compared to baseline in the MTN and PS groups, respectively. However, there was no difference in weight loss and other outcome parameters between the MTN and PS groups. The MTN group showed a significant increase in satiety at 24 weeks. Both groups had a decrease in diastolic blood pressure at 12 weeks. Participants in the MTN group showed significant decreases in heart rate at 4, 12, and 24 weeks. Plasma oleic acid was significantly increased at 12 and 24 weeks in the MTN group but only at 12 weeks in the PS group. Plasma MCP-1 was decreased significantly in the MTN group at 4 weeks. In summary, participants in both groups lost weight, but only the MTN intervention increased satiety at 24 weeks, enhanced retention, decreased heart rate, and increased serum oleic acid at 24 weeks.

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.

Daily consumption of pistachios over 12 weeks improves dietary profile without increasing body weight in healthy women: A randomized controlled intervention

Dietary guidelines around the world recommend the regular intake of nuts because of their nutrient contribution to the diet and reported health benefits. However, consumers are often reluctant to include nuts in their diet due to the high caloric density of nuts. In a 12-week randomized, controlled intervention, we investigated how adding a pistachio portion to the daily diet affects body weight and composition, satiety, energy and nutrient intake. Sixty healthy pre-menopausal women who did not typically consume nuts were randomly assigned to a control or an experimental groups. Experimental participants (n = 30) consumed 44 g (250 kcal) pistachios mid-morning while controls (n = 30) maintained their current eating habits for 12 weeks. Ad libitum food intake and appetite sensations following the pistachio portion were assessed in all participants before and after the intervention in four 2-consecutive-day test sessions (under laboratory and then free-living conditions). Body weight and composition (DXA) were unchanged in both groups after 12 weeks. Pre- and post-intervention tests showed that ad libitum intake adjusted to the pistachio portion, mostly via reduced intakes of carbohydrates and starch, in parallel with decreased hunger and increased satiety following the morning snack. Intakes of MUFA, PUFA, linoleic acid, thiamin, pyridoxine, copper, manganese, and zinc were significantly higher among women consuming the pistachio snack, in spite of compensatory adjustments in intake. In conclusion, daily intake of 44 g pistachios improved nutrient intake without affecting body weight or composition in healthy women. The additional calories provided by the pistachios induced satiety and sufficient adjustment of intake to prevent body weight changes. CLINICAL TRIAL REGISTRY NUMBER: NCT03526120https://clinicaltrials.gov/ct2/show/NCT03526120.

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.

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

Despite high energy content, nut consumption has not been associated with weight gain in epidemiological and clinical investigations. Since a satiety effect a decreased sense of hunger in the following meals has been proposed as the mechanism of nuts against obesity, the present meta-analysis was performed to examine how nut consumption affects "energy intake", "hunger", and "fullness". "Weight" was not included among the search terms but weight data were extracted from the collected articles in order to help interpreting the results. A total of 1048 trials were found, of which 31 passed the eligibility process. Daily energy intake was mostly assessed by 3-day food records, and hunger and fullness were estimated by visual analog scale (VAS). Nut consumption was associated with increased energy intake (mean difference (MD) (nuts - control) = 76.3 kcal; 95% CI: 22.7, 130 kcal; P = 0.005). In contrast, hunger suppressed following nut consumption (MD = -6.54 mm VAS; 95% CI: -12.7, -0.42 mm VAS; P = 0.03). Nuts did not affect sense of fullness and weight in the overall estimate. Subgroup analysis based on participants' BMI revealed that energy intake of overweight/obese individuals was increased following nut consumption while such effect was not observed in normal weight participants. In conclusion, pooled estimates of available clinical trials showed increased energy intake following nut consumption in overweight/obese individuals but not in persons with normal weight. Nut consumption was associated with decreased hunger but no effect was observed on fullness and weight.

Tree Nut Consumption and Adipose Tissue Mass: Mechanisms of Action

There is concern that tree nuts may cause weight gain due to their energy density, yet evidence shows that tree nuts do not adversely affect weight status. Epidemiologic and experimental studies have shown a reduced risk of chronic diseases with tree nut consumption without an increased risk of weight gain. In fact, tree nuts may protect against weight gain and benefit weight-loss interventions. However, the relation between tree nut consumption and adiposity is not well understood at the mechanistic level. This review summarizes the proposed underlying mechanisms that might account for this relation. Evidence suggests that tree nuts may affect adiposity through appetite control, displacement of unfavorable nutrients, increased diet-induced thermogenesis, availability of metabolizable energy, antiobesity action of bioactive compounds, and improved functionality of the gut microbiome. The gut microbiome is a common factor among these mechanisms and may mediate, in part, the relation between tree nut consumption and reduced adiposity. Further research is needed to understand the impact of tree nuts on the gut microbiome and how the gut microbial environment affects the nutrient absorption and metabolism of tree nuts. The evidence to date suggests that tree nut consumption favorably affects body composition through different mechanisms that involve the gut microbiome. A better understanding of these mechanisms will contribute to the evolving science base that addresses the causes and treatments for overweight and obesity.

Nut Consumption and Cardiovascular Risk Factors: A Cross-Sectional Study in a Mediterranean Population

Nuts are often considered beneficial for health, yet few studies have examined determinants of their intake and the associations between nut consumption and various cardiovascular disease risk factors. The aim of this study was to identify factors associated with nut intake in a Mediterranean population, in Croatia, and to investigate the association of nut intake and various cardiovascular risk factors.

METHODS

Subjects from the Island of Vis, Island of Korčula and the City of Split were included in this cross-sectional study (n = 4416 in total; 4011 without known cardiovascular disease). Survey responses, medical records and clinically relevant measurements were utilized. Multivariate ordinal and logistic regression models were used in the analysis, adjusting for known confounding factors.

RESULTS

As low as 5% of all subjects reported daily, and 11% reported weekly, nut consumption. The characteristics associated with more frequent nut intake were female gender (Odds ratio (OR) = 1.39; 95% confidence interval (CI) 1.19-1.62), highest level of education (1.42; 1.15-1.76) and material status (1.58; 1.29-1.93), smoking abstinence (1.21; 1.04-1.42 in never-smokers and 1.22; 1.02-1.46 in ex-smokers), Mediterranean diet adherence (1.87; 1.62-2.15), and absence of central obesity (1.29; 1.09-1.53), absence of diabetes (1.30; 1.02-1.66) and metabolic syndrome (1.17; 1.01-1.36). Subjects who consumed nuts had more favorable waist-to-height (overall p = 0.036) and waist-to-hip ratios (0.033), lesser odds of elevated fibrinogen (p < 0.001 in both weekly and monthly nut consumers) and reduced high-density lipoprotein (HDL) cholesterol (p = 0.026), compared to non-consumers.

CONCLUSIONS

It appears that frequent nut consumption is an integral part of a healthy lifestyle and better socioeconomic status. A beneficial association of nut intake with cardiovascular risk factors was confirmed in this study.