Current guidelines for nut consumption are achievable and sustainable: a hazelnut intervention

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.

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.

Can Nuts Mitigate Malnutrition in Older Adults? A Conceptual Framework

The proportion of adults aged over 60 years in the world is expected to reach 20% by the year 2050. Ageing is associated with several physiological changes that increase the risk of malnutrition among this population. Malnutrition is characterized by deficiencies or insufficiencies of macro- and micronutrients. Malnutrition has detrimental effects on the health, wellbeing, and quality of life in older adults. Nuts are rich in energy, unsaturated fats, and protein, as well as other nutrients that provide a range of health benefits. While the effects of nuts on overnutrition have been studied extensively, very few studies have been specifically designed to understand the role of nuts in mitigating undernutrition in the elderly. Therefore, this review explores the potential role of nuts in improving the nutritional status of older adults who are at risk of undernutrition. Several properties of whole nuts, some of which appear important for addressing overnutrition, (e.g., hardness, lower-than-expected nutrient availability, satiety-enhancing effects) may limit their effectiveness as a food to combat undernutrition. However, we propose that modifications such as transforming the physical form of nuts, addressing the timing of nut ingestion, and introducing variety may overcome these barriers. This review also discusses the feasibility of using nuts to prevent and reverse undernutrition among older adults. We conclude with a recommendation to conduct clinical studies in the future to test this conceptual framework.

Current nut recommendation practices differ between health professionals in New Zealand

OBJECTIVE

Despite evidence linking regular nut consumption with reduced chronic disease risk, population-level intakes remain low. Research suggests nut-promoting advice from doctors facilitates regular nut consumption. However, there is no information on current nut recommendation practices of health professionals. The aim of the present study was to examine the advice provided by health professionals regarding nut consumption.

DESIGN

In this cross-sectional study, participants were invited to complete a survey including questions about their nut recommendation practices.

SETTING

New Zealand (NZ).

SUBJECTS

The NZ Electoral Roll was used to identify dietitians, general practitioners and practice nurses.

RESULTS

In total 318 dietitians, 292 general practitioners and 149 practice nurses responded. Dietitians were more likely (82·7 %) to recommend patients increase consumption of nuts than general practitioners (55·5 %) and practice nurses (63·1 %; both P<0·001). The most popular nuts recommended were almonds, Brazil nuts and walnuts, with most health professionals recommending raw nuts. The most common recommendation for frequency of consumption by dietitians and practice nurses was to eat nuts every day, while general practitioners most frequently recommended 2-4 times weekly, although not statistically significantly different between professions. Dietitians recommended a significantly greater amount of nuts (median 30 g/d) than both general practitioners and practice nurses (20 g/d; both P<0·001).

CONCLUSIONS

Dietitians were most likely to recommend consumption of nuts in accordance with current guidelines, but there are opportunities to improve the adoption of nut consumption recommendations for all professions. This may be a viable strategy for increasing population-level nut intakes to reduce chronic disease.

Almond Consumption during Energy Restriction Lowers Truncal Fat and Blood Pressure in Compliant Overweight or Obese Adults

BACKGROUND

The inclusion of almonds in an energy-restricted diet has been reported both to enhance or to have no effect on weight loss. Their effects specifically on visceral body fat stores during energy restriction have not been widely examined. In addition, almond consumption has been associated with reduced blood pressure (BP), but whether this is linked to or independent of changes in body composition has to our knowledge not been examined.

OBJECTIVE

We evaluated the effects of consuming almonds as part of an energy-restricted diet on body composition, specifically visceral adipose tissue (VAT) and BP, compared to a nut-free energy-restricted diet.

METHODS

A randomized controlled 12-wk clinical trial of 86 healthy adults [body mass index (in kg/m²): 25-40] was conducted. Participants were randomly assigned to 1 of 2 energy-restricted (500-kcal deficit/d) diets: an almond-enriched diet (AED) (15% energy from almonds) or a nut-free diet (NFD). A linear mixed-model analysis on primary outcomes such as body weight, body fat, VAT, and BP was performed on all participants [intention-to-treat (ITT) analysis] and compliant participants (complier analysis).

RESULTS

Body weight, truncal and total fat percentage, VAT, and systolic BP decreased after 12 wk of energy restriction in both the ITT and complier analyses (P < 0.05). The complier analysis (but not the ITT analysis) indicated a greater mean ± SEM reduction in truncal fat (AED: -1.21% ± 0.26%; NFD: -0.48% ± 0.24%; P = 0.025), total fat (AED: -1.79% ± 0.36%; NFD: -0.74% ± 0.33%; P = 0.035), and diastolic BP (AED: -2.71 ± 1.2 mm Hg; NFD: 0.815 ± 1.1 mm Hg; P = 0.029), and a greater tendency for VAT loss (AED: -8.19 ± 1.8 cm²; NFD: -3.99 ± 1.7 cm²; P = 0.09) over time in the AED group than the NFD group.

CONCLUSIONS

Moderate almond consumption by compliant overweight and obese individuals during energy restriction results in greater proportional reductions of truncal and total body fat as well as diastolic BP and hence may help to reduce metabolic disease risk in obesity. This trial was registered at clinicaltrials.gov as NCT02360787.

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 regular consumption of different forms of almonds and hazelnuts on acceptance and blood lipids

PURPOSE

Regular nut consumption is inversely associated with cardiovascular disease risk. No study has compared the effects of regular consumption of different types and forms of nuts on acceptance, which is a crucial determinant of long-term compliance to consume nuts regularly.

METHODS

This study examined the effects of different types and forms of raw, unpeeled nuts on acceptance and the effects of nut consumption on blood lipids through a randomised crossover study with six dietary phases: 30 g/day of ground, sliced, or whole almonds or hazelnuts for 5 days each (n = 74). Acceptance ('desire' and 'liking') for nuts was measured daily using visual analogue scales. Blood lipids were measured at baseline and week 6.

RESULTS

Acceptance was stable over all conditions, but there were differences between nut forms (ground < sliced < whole, P < 0.001 for both 'desire' and 'liking') with some nut type-nut form interactions. Compared with baseline, week 6 HDL-C was higher (0.06 mmol/L, 95% CI 0.02-0.10, P = 0.002) while LDL-C and total-C:HDL-C ratio were lower (0.15 mmol/L, 95% CI 0.06-0.25, P = 0.002 and 0.25, 95% CI 0.07-0.43, P = 0.006).

CONCLUSIONS

In conclusion, acceptance was stable for all combinations but was highest for whole nuts. Six weeks of nut consumption improved blood lipids.

The dose of hazelnuts influences acceptance and diet quality but not inflammatory markers and body composition in overweight and obese individuals

Regular nut consumption may improve markers of inflammation and endothelial dysfunction. The quantity of nuts required to achieve these health benefits without compromising body weight and acceptance is unknown. This study compared the effects of incorporating hazelnuts at 2 different doses with a diet without nuts on inflammatory markers, cell adhesion molecules, and body composition in 107 overweight and obese individuals. This was a randomized, controlled, parallel 12-wk intervention including 3 treatment arms: no nuts (control group), 30 g/d of hazelnuts, or 60 g/d of hazelnuts. Blood pressure, body composition, plasma high-sensitivity C-reactive protein (hs-CRP), interleukin 6 (IL-6), intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), lipid, and apolipoprotein (apo) profiles were assessed at baseline and at 6 and 12 wk. "Desire" and "liking" for nuts were assessed during the intervention. Results showed no significant differences in follow-up clinical outcomes between groups after adjusting for baseline values, age, sex, and BMI (all P ≥ 0.10), except for a tendency toward improvement in VCAM-1 concentration in the 60-g/d nut group (P = 0.07). Hazelnut consumption significantly improved diet quality in a dose-response manner. Desire and liking for nuts remained stable in the 30-g/d group, whereas these ratings decreased significantly over time in the 60-g/d group (both P < 0.001). In conclusion, 12 wk of hazelnut consumption appears to have minimal effect on inflammatory markers and cell adhesion molecules in this group of healthy, normocholesterolemic overweight and obese individuals. Nut consumption improves diet quality without adversely affecting body composition. Consuming 30 g/d of nuts regularly is achievable, whereas 60 g/d appears to compromise desire and liking.

Markers of cardiovascular risk in postmenopausal women with type 2 diabetes are improved by the daily consumption of almonds or sunflower kernels: a feeding study

Dietary guidelines for the treatment of type 2 diabetes advocate the regular consumption of nuts and seeds. Key lipid abnormalities associated with diabetes include raised LDL-C, VLDL-C, and TAG concentrations and decreased concentrations of HDL-C. The fatty acid profiles of nuts and seeds differ and may potentially influence lipid outcomes in people with diabetes differently. To examine the effects of nut or seed consumption on lipid and lipoprotein markers of cardiovascular disease (CVD), we added almonds (AD) or sunflower kernels (SKD) to a recommended diet in a randomised crossover feeding study. Twenty-two postmenopausal women with type 2 diabetes consumed personalised diets, with the addition of 30 g/d of either almonds or sunflower kernels. All food was supplied for two periods of three weeks, separated by a four-week washout. There was a significant reduction in high-density lipoprotein cholesterol (HDL-C), triacylglycerol (TAG), and apolipoprotein (apo) A1 and B100 on the SKD compared to the AD. Total (TC) and low density lipoprotein cholesterol (LDL-C) decreased significantly on both diets from baseline, with no difference between diets. A diet with the addition of either almonds or sunflower kernels has clinically beneficial effects on lipid- and lipoprotein-mediated CVD risk.

Effects of autoclaving and high pressure on allergenicity of hazelnut proteins

Background

Hazelnut is reported as a causative agent of allergic reactions. However it is also an edible nut with health benefits. The allergenic characteristics of hazelnut-samples after autoclaving (AC) and high-pressure (HHP) processing have been studied and are also presented here. Previous studies demonstrated that AC treatments were responsible for structural transformation of protein structure motifs. Thus, structural analyses of allergen proteins from hazelnut were carried out to observe what is occurring in relation to the specific-IgE recognition of the related allergenic proteins. The aims of this work are to evaluate the effect of AC and HHP processing on hazelnut in vitro allergenicity using human-sera and to analyse the complexity of hazelnut allergen-protein structures.

Methods

Hazelnut-samples were subjected to AC and HHP processing. The specific IgE- reactivity was studied in 15 allergic clinic-patients via western blotting analyses. A series of homology-based-bioinformatics 3D-models (Cora 1, Cora 8, Cora 9 and Cora 11) were generated for the antigens included in the study to analyse the co mplexity of their protein structure. This study is supported by the Declaration of Helsinki and subsequent ethical guidelines.

Results

A severe reduction in vitro in allergenicity to hazelnut after AC processing was observed in the allergic clinic-patients studied. The specific-IgE binding of some of the described immunoreactive hazelnut protein-bands: Cora 1 ~18KDa, Cora 8 ~9KDa, Cora 9 ~35-40KDa and Cora 11 ~47-48 KDa decreases. Furthermore a relevant glycosylation was assigned and visualized via structural analysis of proteins (3D-modelling) for the first time in the protein-allergen Cora 11 showing a new role which could open a new door for allergenicity-unravellings.

Conclusion

Hazelnut allergenicity-studies in vivo via Prick-Prick and other means using AC processing are crucial to verify the data we observed via in vitro analyses. Glycosylation studies provided us with clues to elucidate, in the near future, mechanisms of the structures that contribute to hazelnut allergenicity, which thus, in turn, help alleviate food allergens.

Long-term consumption of high energy-dense snack foods on sensory-specific satiety and intake

BACKGROUND

The sensory attributes of foods may have an important influence on intake because of sensory-specific satiety (SSS). Foods with high SSS may aid in body weight maintenance as a result of termination of consumption before metabolic satiety. No studies have investigated whether long-term exposure to a food might change SSS or how this affects food intake.

OBJECTIVE

The objective was to compare the effects of daily consumption of 3 energy-dense snack foods (hazelnuts, chocolate, and potato chips) for 12 wk on SSS and ad libitum intake during a tasting session.

DESIGN

One hundred eighteen participants took part in this randomized, controlled, parallel study with 4 arms: control group (no additional food) or ∼1100 kJ/d for each snack. SSS, food intake, and body composition were measured at baseline and at week 12.

RESULTS

Daily consumption of snacks for 12 wk resulted in a statistically significant reduction in SSS in all 3 snack groups (P = 0.015). However, no such changes were seen in the control group (P = 0.608). Ad libitum energy intake increased over the study during the tasting sessions for the snack food across all groups, including the control group (P = 0.039). Inverse associations were found between baseline SSS and BMI (P = 0.039), percentage body fat (P = 0.013), and fat mass (P = 0.004).

CONCLUSION

Habitual consumption of a high energy-dense snack food results in a decrease in SSS, which could lead to a higher energy intake of the snack. This trial was registered at www.anzctr.org.au as ACTRN12609000265279.