Tree nuts and the lipid profile: a review of clinical studies

Nut consumption and risk of mortality in the Physicians' Health Study

BACKGROUND

Previous studies have suggested that nut consumption is associated with beneficial cardiovascular outcomes. However, limited data are available on the association between nut intake and all-cause mortality.

OBJECTIVE

Our aim was to test the hypothesis that nut consumption is inversely associated with the risk of all-cause mortality.

DESIGN

In this prospective cohort study in 20,742 male physicians, we assessed nut intake between 1999 and 2002 via a food-frequency questionnaire and ascertained deaths through an endpoint committee. We used Cox regression to estimate multivariable-adjusted HRs for death according to nut consumption. In secondary analyses, we evaluated associations of nut consumption with cause-specific mortality.

RESULTS

During a mean follow-up of 9.6 y, there were 2732 deaths. The mean (±SD) age at baseline was 66.6 ± 9.3 y. Median nut consumption was 1 serving/wk. Multivariable-adjusted HRs (95% CIs) were 1.0 (reference), 0.92 (0.83, 1.01), 0.85 (0.76, 0.96), 0.86 (0.75, 0.98), and 0.74 (0.63, 0.87) for nut consumption of never or <1 serving/mo, 1-3 servings/mo, 1 serving/wk, 2-4 servings/wk, and ≥5 servings/wk, respectively (P-linear trend < 0.0001), after adjustment for age, body mass index, alcohol use, smoking, exercise, prevalent diabetes and hypertension, and intakes of energy, saturated fat, fruit and vegetables, and red meat. In a secondary analysis, results were consistent for cardiovascular disease mortality but only suggestive and non-statistically significant for coronary artery disease and cancer mortality.

CONCLUSION

Our data are consistent with an inverse association between nut consumption and the risk of all-cause and cardiovascular disease mortality in US male physicians.

Tree nut consumption is associated with better nutrient adequacy and diet quality in adults: National Health and Nutrition Examination Survey 2005-2010

Nutrient adequacy of tree nut consumers has not been examined. The National Health and Nutrition Examination Survey 2005–2010 data were used to assess the association of tree nut consumption by adults 19+ years (n = 14,386) with nutrient adequacy and diet quality. Covariate adjusted usual intake was determined using two 24-h dietary recalls and the National Cancer Institute method. Percentages of the consumption groups below the Estimated Average Requirement (EAR) or above the Adequate Intake (AI) were determined. Diet quality was determined using the Healthy Eating Index-2005 (HEI) score. Usual intake data showed consumers of tree nuts had a lower percentage (p < 0.0001) of the population below the EAR for vitamins A (22 ± 5 vs. 49 ± 1), E (38 ± 4 vs. 94 ± 0.4) and C (17 ± 4 vs. 44 ± 1); folate (2.5 ± 1.5 vs. 12 ± 0.6); calcium (26 ± 3 vs. 44 ± 1); iron (3 ± 0.6 vs. 9 ± 0.4); magnesium (8 ± 1 vs. 60 ± 1); and zinc (1.5 ± 1 vs. 13 ± 1). Tree nut consumers had a higher percentage (p < 0.0001) of the population above the AI for fiber (33 ± 3 vs. 4 ± 0.3) and potassium (12 ± 3 mg vs. 2 ± 0.2 mg). HEI-2005 total score was higher (p < 0.0001) in tree nut consumers (61 ± 0.7 vs. 52 ± 0.3) than non-consumers. Health professionals should encourage the use of tree nuts as part of a dietary approach to healthy eating.

Effects of daily almond consumption on cardiometabolic risk and abdominal adiposity in healthy adults with elevated LDL-cholesterol: a randomized controlled trial

BACKGROUND

Evidence consistently shows that almond consumption beneficially affects lipids and lipoproteins. Almonds, however, have not been evaluated in a controlled-feeding setting using a diet design with only a single, calorie-matched food substitution to assess their specific effects on cardiometabolic risk factors.

METHODS AND RESULTS

In a randomized, 2-period (6 week/period), crossover, controlled-feeding study of 48 individuals with elevated LDL-C (149±3 mg/dL), a cholesterol-lowering diet with almonds (1.5 oz. of almonds/day) was compared to an identical diet with an isocaloric muffin substitution (no almonds/day). Differences in the nutrient profiles of the control (58% CHO, 15% PRO, 26% total fat) and almond (51% CHO, 16% PRO, 32% total fat) diets were due to nutrients inherent to each snack; diets did not differ in saturated fat or cholesterol. The almond diet, compared with the control diet, decreased non-HDL-C (-6.9±2.4 mg/dL; P=0.01) and LDL-C (-5.3±1.9 mg/dL; P=0.01); furthermore, the control diet decreased HDL-C (-1.7±0.6 mg/dL; P<0.01). Almond consumption also reduced abdominal fat (-0.07±0.03 kg; P=0.02) and leg fat (-0.12±0.05 kg; P=0.02), despite no differences in total body weight.

CONCLUSIONS

Almonds reduced non-HDL-C, LDL-C, and central adiposity, important risk factors for cardiometabolic dysfunction, while maintaining HDL-C concentrations. Therefore, daily consumption of almonds (1.5 oz.), substituted for a high-carbohydrate snack, may be a simple dietary strategy to prevent the onset of cardiometabolic diseases in healthy individuals.

CLINICAL TRIAL REGISTRATION URL

www.clinicaltrials.gov; Unique Identifier: NCT01101230.

Influence of ultra-high-pressure homogenization treatment on the phytosterols, tocopherols, and polyamines of almond beverage

Ultra-high-pressure homogenization (UHPH) is an emerging technology based on the dynamic application of high pressure to obtain safe and high-quality liquid foods. The effect of six UHPH treatments at 200 and 300 MPa with different inlet temperatures (T(in)) (55, 65, and 75 °C) on the content of tocopherols, polyamines, and phytosterols of almond beverage was studied in comparison with the base product. Total tocopherol contents decreased about 80-90% as temperature and pressure increased, and whereas both parameters affected the tocopherol content, especially the effect of temperature was noticeable. α-Tocopherol was the most predominant type of tocopherol present and was also the most affected by UHPH treatments. Spermidine was the only polyamine found not to be affected by UHPH treatments. UHPH treatments resulted in an increase of 20-40% in the total phytosterol extractability. The highest extractability was obtained at the most severe conditions (300 MPa, 75 °C T(in)).

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.

Long-term intake of nuts in relation to cognitive function in older women

OBJECTIVE

Nuts contain nutrients that may benefit brain health; thus, we examined long-term intake of nuts in relation to cognition in older women.

DESIGN

Population-based prospective cohort study.

SETTING

Academic research using data from the Nurses' Health Study.

PARTICIPANTS

Nut intake was assessed in a food-frequency questionnaire beginning in1980, and approximately every four years thereafter. Between 1995-2001, 16,010 women age 70 or older (mean age = 74 years) without a history of stroke were administered 4 repeated telephone-based cognitive interviews over 6 years. Our final sample included 15,467 women who completed an initial cognitive interview and had complete information on nut intake.

MAIN OUTCOME MEASURES

The Telephone Interview for Cognitive Status (TICS), a global score averaging the results of all tests (TICS, immediate and delayed verbal recall, category fluency, and attention), and a verbal memory score averaging the results of tests of verbal recall.

RESULTS

In multivariable-adjusted linear regression models, higher long-term total nut intake was associated with better average cognitive status for all cognitive outcomes. For the global composite score combining all tests, women consuming at least 5 servings of nuts/week had higher scores than non-consumers (mean difference=0.08 standard units, 95% confidence interval 0.00-0.15; p-trend=0.003). This mean difference of 0.08 is equivalent to the mean difference we find between women 2 years apart in age. Long-term intake of nuts was not associated with rates of cognitive decline.

CONCLUSIONS

Higher nut intake may be related to better overall cognition at older ages, and could be an easily-modifiable public health intervention.

Walnuts decrease risk of cardiovascular disease: a summary of efficacy and biologic mechanisms

Given the pressing need to reduce cardiovascular disease (CVD) morbidity and mortality, there has been a focus on optimizing dietary patterns to reduce the many contributing risk factors. Over the past 2 decades, many studies have been conducted that have evaluated the effects of walnut consumption on CVD risk factors. Walnuts have been shown to decrease low density lipoprotein cholesterol (by ∼9-16%) and blood pressure (diastolic blood pressure by ∼2-3 mm Hg), 2 major risk factors for CVD. In addition, walnuts improve endothelial function, decrease both oxidative stress and some markers of inflammation, and increase cholesterol efflux. The effect of walnuts on multiple CVD targets over relatively short periods of time supports recommendations for their inclusion in a heart-healthy diet.

Effects of supplementing n-3 fatty acid enriched eggs and walnuts on cardiovascular disease risk markers in healthy free-living lacto-ovo-vegetarians: a randomized, crossover, free-living intervention study

Background

Plant and marine n-3 fatty acids (FA) may favorably modify select markers of cardiovascular disease risk. Whether supplementing the habitual diet of lacto-ovo-vegetarians (LOV) with walnuts (containing α-linolenic acid, ALA) and n-3 FA enriched eggs (containing primarily docosahexaenoic acid, DHA and ALA) would have equivalent effects on CVD risk factors is explored in this study.

Methods

In this study, 20 healthy free-living LOVs following their habitual diet were randomly assigned in a crossover design to receive one of three supplements: n-3 FA enriched egg (6/week), walnuts (28.4 g, 6/week) or a standard egg, 6/week (control) for 8 weeks each with 4-wk washout between treatments. Erythrocyte membrane fatty acids, serum lipids and inflammatory markers were measured at the end of each treatment.

Results

Dietary compliance was observed by an expected increase in erythrocyte membrane ALA following the walnut treatment and in DHA following the n-3 FA enriched egg treatment. Walnut treatment lowered serum triacylglycerol, total cholesterol and Apo B (p < 0.05) compared to the standard egg but not the n-3 FA enriched egg treatment. However, walnut treatment significantly reduced total: HDL cholesterol ratio compared to both egg treatments. There were no differences between treatments for any of the inflammatory markers.

Conclusions

For LOV, a direct source of DHA such as n-3 FA enriched eggs seems necessary to increase membrane levels of DHA. However for producing an overall favorable blood lipid profile, daily consumption of a handful of walnuts rich in ALA may be a preferred option for lacto-ovo vegetarian.

Acute effects of pistachio consumption on glucose and insulin, satiety hormones and endothelial function in the metabolic syndrome

BACKGROUND/OBJECTIVE

Nut consumption has been found to decrease risk of coronary heart disease and diabetes and to promote healthy body weights possibly related to their favorable macronutrient profile. We therefore assessed the effect of pistachios on postprandial glucose and insulin levels, gut hormones related to satiety and endothelial function.

SUBJECTS/METHODS

In this randomized crossover study, 20 subjects with metabolic syndrome consumed five study meals over 5-10 weeks. The meals differed in fat type and quantity, but were matched according to available carbohydrates (CHOs). Three meals had 50 g available CHO: white bread (WB50g), white bread, butter and cheese (WB+B+Ch) and white bread and pistachios (WB+P). Two meals had 12 g available CHO: white bread (WB12g) and pistachios (P).

RESULTS

Within each group of available CHO meals, postprandial glucose levels were the highest following the white bread-only meals, and glucose response was significantly attenuated when butter and cheese or pistachios were consumed (P<0.05). Postprandial insulin levels were highest after the WB+B+Ch meal (P<0.05), but did not differ between the white bread-only and pistachio meals. Both endothelial function (reactive hyperemia index) and arterial stiffness (augmentation index) significantly increased after the white bread-only meals compared with the WB+B+Ch meal (all P<0.05). Insulin secretagogue levels were higher when butter and cheese or pistachios were consumed than when white bread only was consumed (P<0.05).

CONCLUSIONS

Compared with white bread, pistachio consumption reduced postprandial glycemia, increased glucagon-like-peptide levels and may have insulin-sparing properties. These effects could be beneficial for individuals with diabetes and metabolic syndrome.

Online LC-GC-based analysis of minor lipids in various tree nuts and peanuts

As information on free sterols/stanols and steryl/stanyl esters in nuts is lacking, the compositions and contents of these lipid constituents in ten different nut types were analyzed. The applied approach was based on online liquid chromatography-gas chromatography and enabled the simultaneous analysis of free sterols/stanols and individual steryl/stanyl fatty acid esters, and additionally of tocopherols and squalene. Total contents of free sterols/stanols ranged from 0.62 mg/g nut in hazelnuts to 1.61 mg/g nut in pistachios, with sitosterol as the predominant compound. Total contents of steryl/stanyl fatty acid esters were in the range of 0.11-1.26 mg/g nut, being lowest in Brazil nuts and highest in pistachios. There were considerable differences between the various nut types not only regarding the contents, but also the compositions of both classes. The levels of tocopherols were highest in pine nuts (0.33 mg/g nut); those of squalene were remarkably high in Brazil nuts (1.11 mg/g nut).

A diet based on multiple functional concepts improves cognitive performance in healthy subjects

Background

Disorders such as the metabolic syndrome (MetS), impaired glucose tolerance and diabetes, are associated with increased risk of cognitive decline. Also several of the individual key features that define the MetS, e.g. hypertension, impaired glucose regulation, dyslipidemia, obesity, and inflammation, are related to an increased risk of cognitive decline. Consequently, a diet that prevents metabolic disorders might be expected to prevent cognitive decline. The purpose of the present study was to, in overweight but otherwise healthy subjects, investigate effects on cognitive functions of a dietary regime combining multiple functional concepts potentially beneficial to risk markers associated with MetS. The purpose was in addition to evaluate cognitive performance in relation to results on cardiometabolic risk variables (BMI, blood pressure, glucose, insulin, cholesterol, triglycerides, free fatty acids, lipoprotein A-1 and B, hs-CRP, HbA1c, interleukin-6, TNF-α, and PAI-1).

Methods

Fourty-four healthy women and men (50–73 years, BMI 25–33, fasting glycemia ≤ 6.1 mmol/L) participated in a randomized, controlled crossover intervention, comparing a multifunctional diet (active diet (AD)) including foods with a potential anti-inflammatory action, with a control diet (CD) devoid of the “active” components. Both diets were composed in close agreement with the Nordic dietary recommendations. Each diet was consumed during 4 wk, separated by a 4 wk washout period. Cognitive tests were performed at fasting and in the postprandial period after a standardized breakfast, after each diet period.

Results

In comparison with the CD, the AD improved performance in the Rey Auditory-Verbal Learning test (recognition test, p < 0.05, ANOVA, n = 42) and significantly improved performance in test of selective attention, which also included aspects of working memory (p < 0.05, n = 40). Performance in cognitive tests was inversely associated with plasma concentrations of cardiometabolic risk markers (fasting cholesterol, blood glucose, blood pressure) and cardiovascular risk scores (Framingham and Reynols), and positivly associated with apolipoprotein A1 (p < 0.05).

Conclusions

The results indicate that diet characteristics may modulate cognitive performance. A relationship seems to exist between cardiometabolic risk markers and cognitive performance in apparently healthy subjects. The results provide additional motives for diet based prevention of metabolic disturbances related to the MetS.

A single consumption of high amounts of the Brazil nuts improves lipid profile of healthy volunteers

Background. This study investigates the effects of Brazil nut ingestion on serum lipid profile in healthy volunteers. Methods. Ten healthy subjects were enrolled in the study. Each subject was tested 4 times in a randomized crossover in relation to the ingestion of different serving sizes of the Brazil nut: 0, 5, 20, or 50 g. At each treatment point, peripheral blood was drawn before and at 1, 3, 6, 9, 24, and 48 hours and 5 and 30 days. Blood samples were tested for total cholesterol, high- and low-density lipoprotein cholesterol (HDL-c and LDL-c, resp.), triglycerides, selenium, aspartate and alanine aminotransferases, albumin, total protein, alkaline phosphatase, gamma GT, urea, creatinine, and C-reactive protein. Results. A significant increase of the plasma selenium levels was observed at 6 hours within the groups receiving the nuts. Serum LDL-c was significantly lower, whereas HDL-c was significantly higher 9 hours after the ingestion of 20 or 50 g of nuts. The biochemical parameters of liver and kidney function were not modified by ingestion of nuts. Conclusions. This study shows that the ingestion of a single serving of Brazil nut can acutely improve the serum lipid profile of healthy volunteers.

Acute consumption of walnuts and walnut components differentially affect postprandial lipemia, endothelial function, oxidative stress, and cholesterol efflux in humans with mild hypercholesterolemia

Walnut consumption improves cardiovascular disease risk; however, to our knowledge, the contribution of individual walnut components has not been assessed. This study evaluated the acute consumption of whole walnuts (85 g), separated nut skins (5.6 g), de-fatted nutmeat (34 g), and nut oil (51 g) on postprandial lipemia, endothelial function, and oxidative stress. Cholesterol efflux (ex vivo) was assessed in the whole walnut treatment only. A randomized, 4-period, crossover trial was conducted in healthy overweight and obese adults (n = 15) with moderate hypercholesterolemia. There was a treatment × time point interaction for triglycerides (P < 0.01) and increased postprandial concentrations were observed for the oil and whole walnut treatments (P < 0.01). Walnut skins decreased the reactive hyperemia index (RHI) compared with baseline (P = 0.02) such that a difference persisted between the skin and oil treatments (P = 0.01). The Framingham RHI was maintained with the oil treatment compared with the skins and whole nut (P < 0.05). There was a treatment effect for the ferric reducing antioxidant potential (FRAP) (P < 0.01), and mean FRAP was greater with the oil and skin treatments compared with the nutmeat (P < 0.01). Cholesterol efflux increased by 3.3% following whole walnut consumption in J774 cells cultured with postprandial serum compared with fasting baseline (P = 0.02). Walnut oil favorably affected endothelial function and whole walnuts increased cholesterol efflux. These 2 novel mechanisms may explain in part the cardiovascular benefits of walnuts.

Nutritional evaluation and health promoting activities of nuts and seeds cultivated in Greece

Available data suggest that genetic as well as environmental factors may influence nuts and seeds nutrients content. In this context nuts and seeds cultivated in Greece were studied. Macronutrients content was in agreement with that from other areas. Total phenolics content was in the range of 43.0 ± 2.1-1512.7 ± 60.7 mg GAE/100 g for chestnut and walnut, respectively. Thirteen to 22 individual phenolics were identified in the studied species. Oleanolic acid was in the range of 0.10-9.03 mg/100 g. Pumpkin seeds contained the higher squalene content (71.6 mg/100 g). β-Sitosterol predominated in all samples except pumpkin seeds. Tocopherols ranged from 8.9 mg/100 g (chestnut) to 29.3 mg/100 g (almond). Nuts and seeds hydrophilic extracts at quantities corresponding to the estimated daily consumption by the Greeks succeeded in inhibiting LDL oxidation in vitro by increasing lag time 1.1-14.1 times. One serving of nuts or seeds may cover a significant fraction of health promoting microconstituents daily intake.

Walnut consumption is associated with lower risk of type 2 diabetes in women

Walnuts are rich in polyunsaturated fatty acids and have been shown to improve various cardiometabolic risk factors. We aimed to investigate the association between walnut intake and incident type 2 diabetes in 2 large cohort studies: the Nurses' Health Study (NHS) and NHS II. We prospectively followed 58,063 women aged 52-77 y in NHS (1998-2008) and 79,893 women aged 35-52 y in NHS II (1999-2009) without diabetes, cardiovascular disease, or cancer at baseline. Consumption of walnuts and other nuts was assessed every 4 y using validated food frequency questionnaires. Self-reported type 2 diabetes was confirmed by a validated supplemental questionnaire. We documented a total of 5930 incident type 2 diabetes cases during 10 y of follow-up. In the multivariable-adjusted Cox proportional hazards model without body mass index (BMI), walnut consumption was associated with a lower risk of type 2 diabetes, and the HRs (95% CIs) for participants consuming 1-3 servings/mo (1 serving = 28 g), 1 serving/wk, and ≥2 servings/wk of walnuts were 0.93 (0.88-0.99), 0.81 (0.70-0.94), and 0.67 (0.54-0.82) compared with women who never/rarely consumed walnuts (P-trend < 0.001). Further adjustment for updated BMI slightly attenuated the association and the HRs (95% CIs) were 0.96 (0.90-1.02), 0.87 (0.75-1.01), and 0.76 (0.62-0.94), respectively (P-trend = 0.002). The consumption of total nuts (P-trend < 0.001) and other tree nuts (P-trend = 0.03) was also inversely associated with risk of type 2 diabetes, and the associations were largely explained by BMI. Our results suggest that higher walnut consumption is associated with a significantly lower risk of type 2 diabetes in women.

Mechanistic examination of walnuts in prevention of breast cancer

Walnuts contain bioactive molecules that may contribute to their beneficial effects, including alpha-linolenic acid (ALA) and phytosterols. In these studies, extracts of walnut, purified compounds, or postprandial serum were examined for effects on breast cancer cell proliferation and gene expression. Extracts derived from walnut oil decreased proliferation of MCF-7 cells, as did ALA and β-sitosterol. The gene expression response of ALA in the mouse breast cancer cell line TM2H indicates this molecule has multiple cellular targets with peroxisome proliferator-activated receptor (PPAR) target genes, liver X receptor (LXR), and farnesoid X receptor (FXR) target genes being affected. In transactivation assays, walnut oil extracts increased activity of FXR to a greater extent than the other tested nuclear receptors. When examined separately, walnut components ALA and β-sitosterol were the most efficacious activators of FXR. When serum from individuals fed walnut components were applied to MCF-7 cells, there was a correlation between body mass index and breast cancer cell proliferation in vitro. Taken together, these data support an effect of walnut and its bioactive constituents on mammary epithelial cells and that multiple molecular targets may be involved.

Health benefits of nut consumption with special reference to body weight control

Nuts are an integral part of the Mediterranean food patterns, and their incorporation into the regular diets of human beings is believed to provide many health benefits. The recent recognition of nuts as "heart-healthy" foods by the U.S. Food and Drug Administration has given a major boost to the positive image of nuts. Nut consumption has been associated with several health benefits, such as antioxidant, hypocholesterolemic, cardioprotective, anticancer, anti-inflammatory, and antidiabetic benefits, among other functional properties. However, although nuts possess these many health benefits, their consumption has been hampered by a lack of adequate information regarding those benefits. In addition, because nuts are energy-dense foods with high-fat content, there is a misconception among consumers that increased consumption may lead to unwanted gain in body weight with the risk of developing overweight/obesity. Nonetheless, available epidemiologic studies and short-term controlled feeding trials have supported the theory that the inclusion of nuts in the typical diet does not induce weight gain, despite an expected increase in total caloric intake. To address the misperception about nuts and body weight gain, the present review focuses mainly on the relation between nut consumption and body weight gain, in the context of the many health benefits of nuts.

In comparison with palm oil, dietary nut supplementation delays the progression of atherosclerotic lesions in female apoE-deficient mice

Epidemiological studies have demonstrated the benefits of nut consumption on cardiovascular risk factors and CHD, attributed to their fatty acid profile, rich in unsaturated fatty acids, and also to other nutrients. The effect of nuts on atherosclerotic lesions was studied in female and male apoE-knockout mice fed a diet supplemented with 3 % (w/w) mixed nuts (mix: almonds, hazelnuts and walnuts in a proportion of 0.25:0·25:0.50, respectively), and compared with mice receiving an isoenergetic diet of similar fat content provided as palm oil. After 12 weeks, plasma lipid parameters and aortic lesions were measured. Males receiving nuts had lower plasma cholesterol than the palm oil group, and both sex groups had lower plasma non-HDL-cholesterol and lower content of reactive oxygen species in LDL than mice receiving the palm oil diet, the latter decrease being more pronounced in females than in males. Females consuming the nut diet showed a smaller aortic lesion area than those consuming palm oil, whereas no differences were observed in males. In females, hepatic paraoxonase 2 (Pon2) mRNA increased, and no change was observed in prenylcysteine oxidase 1 (Pcyox1) expression after the consumption of the nut-containing diet. In addition, aortic atherosclerotic lesions correlated directly with total plasma cholesterol and inversely with hepatic Pon2 expression. The results suggest that the beneficial effect of nut intake in female apoE-deficient mice may be attributed to reduced non-HDL-cholesterol levels and enhanced PON2 antioxidant activity.

A randomized trial of the effects of an almond-enriched, hypocaloric diet in the treatment of obesity

BACKGROUND

Increased consumption of nuts has been advocated because of their health benefits, but the role of nuts in the treatment of obesity is unclear given their high energy density.

OBJECTIVE

This study was designed to evaluate the effects of a hypocaloric, almond-enriched diet (AED) compared with a hypocaloric nut-free diet (NFD) on body weight and cardiovascular disease risk factors in the context of an 18-mo behavioral weight-management program.

DESIGN

Overweight and obese individuals [n = 123; age = 46.8 y, BMI (in kg/m(2)) = 34.0] were randomly assigned to consume an AED or NFD and instructed in traditional behavioral methods of weight control. Anthropometric and metabolic measurements were made at baseline, 6 mo, and 18 mo.

RESULTS

Those in the AED group lost slightly but significantly less weight than did those in the NFD group at 6 mo (-5.5 compared with -7.4 kg; P = 0.04), but there were no differences at 18 mo. No significant differences in body composition were found between the groups at 6 or 18 mo. The AED, compared with the NFD, was associated with greater reductions in total cholesterol (P = 0.03), total:HDL cholesterol (P = 0.02), and triglycerides (P = 0.048) at 6 mo, and no differences were observed between the groups at 18 mo.

CONCLUSIONS

The AED and NFD groups experienced clinically significant and comparable weight loss at 18 mo. Despite smaller weight loss in the AED group at 6 mo, the AED group experienced greater improvements in lipid profiles. This trial was registered at clinicaltrials.gov as NCT00194428.

A diet based on multiple functional concepts improves cardiometabolic risk parameters in healthy subjects

BACKGROUND

Different foods can modulate cardiometabolic risk factors in persons already affected by metabolic alterations. The objective of this study was to assess, in healthy overweight individuals, the impact of a diet combining multiple functional concepts on risk markers associated with cardiometabolic diseases (CMD).

METHODS

Fourty-four healthy women and men (50-73 y.o, BMI 25-33, fasting glycemia ≤ 6.1 mmol/L) participated in a randomized crossover intervention comparing a multifunctional (active) diet (AD) with a control diet (CD) devoid of the "active" components. Each diet was consumed during 4 wk with a 4 wk washout period. AD included the following functional concepts: low glycemic impact meals, antioxidant-rich foods, oily fish as source of long-chain omega-3 fatty acids, viscous dietary fibers, soybean and whole barley kernel products, almonds, stanols and a probiotic strain (Lactobacillus plantarum Heal19/DSM15313).

RESULTS

Although the aim was to improve metabolic markers without promoting body weight loss, minor weight reductions were observed with both diets (0.9-1.8 ± 0.2%; P < 0.05). CD did not modify the metabolic variables measured. AD promoted significant changes in total serum cholesterol (-26 ± 1% vs baseline; P < 0.0001), LDL-cholesterol (-34 ± 1%; P < 0.0001), triglycerides (-19 ± 3%; P = 0.0056), LDL/HDL (-27 ± 2%; P < 0.0001), apoB/apoA1 (-10 ± 2%; P < 0.0001), HbA1c (-2 ± 0.4%; P = 0.0013), hs-CRP (-29 ± 9%; P = 0.0497) and systolic blood pressure (-8 ± 1%¸ P = 0.0123). The differences remained significant after adjustment for weight change. After AD, the Framingham cardiovascular risk estimate was 30 ± 4% (P < 0.0001) lower and the Reynolds cardiovascular risk score, which considers CRP values, decreased by 35 ± 3% (P < 0.0001).

CONCLUSION

The improved biomarker levels recorded in healthy individuals following the multifunctional regime suggest preventive potential of this dietary approach against CMD.

Tree nut phytochemicals: composition, antioxidant capacity, bioactivity, impact factors. A systematic review of almonds, Brazils, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts

Tree nuts contain an array of phytochemicals including carotenoids, phenolic acids, phytosterols and polyphenolic compounds such as flavonoids, proanthocyanidins (PAC) and stilbenes, all of which are included in nutrient databases, as well as phytates, sphingolipids, alkylphenols and lignans, which are not. The phytochemical content of tree nuts can vary considerably by nut type, genotype, pre- and post-harvest conditions, as well as storage conditions. Genotype affects phenolic acids, flavonoids, stilbenes and phytosterols, but data are lacking for many other phytochemical classes. During the roasting process, tree nut isoflavones, flavanols and flavonols were found to be more resistant to heat than the anthocyanins, PAC and trans-resveratrol. The choice of solvents used for extracting polyphenols and phytosterols significantly affects their quantification, and studies validating these methods for tree nut phytochemicals are lacking. The phytochemicals found in tree nuts have been associated with antioxidant, anti-inflammatory, anti-proliferative, antiviral, chemopreventive and hypocholesterolaemic actions, all of which are known to affect the initiation and progression of several pathogenic processes. While tree nut phytochemicals are bioaccessible and bioavailable in humans, the number of intervention trials conducted to date is limited. The objectives of the present review are to summarise tree nut: (1) phytochemicals; (2) phytochemical content included in nutrient databases and current publications; (3) phytochemicals affected by pre- and post-harvest conditions and analytical methodology; and (4) bioactivity and health benefits in humans.

Update on the healthful lipid constituents of commercially important tree nuts

Uncharacteristic of most whole foods, the major component of tree nuts is lipid; surprisingly, information on the lipid constituents in tree nuts has been sporadic and, for the most part, not well reported. Most published papers focus on only one nut type, or those that report a cultivar lack a quality control program, thus making data comparisons difficult. The present study was designed to quantify the healthful lipid constituents of 10 different types of commercially important tree nuts (i.e., almonds, black walnuts, Brazil nuts, cashews, English walnuts, hazelnuts, macadamias, pecans, pine nuts, and pistachios) according to standardized, validated methods. The total lipid content of each nut type ranged from 44.4 ± 1.9% for cashews to 77.1 ± 1.7% for macadamias. As expected, the major fatty acids present in the tree nuts were unsaturated: oleic (18:1 ω9) and linoleic (18:2 ω6) acids. A majority of the lipid extracts contained <10% saturated fatty acids with the exceptions of Brazil nuts (24.5%), cashews (20.9%), macadamias (17.1%), and pistachios (13.3%). The total tocopherol (T) content ranged from 1.60 ± 1.27 mg/100 g nutmeat in macadamias to 32.99 ± 0.78 in black walnuts. The predominant T isomers in the nut types were α- and γ-T. Tocotrienols were also detected, but only in 6 of the 10 nut types (i.e., Brazil nut, cashews, English walnuts, macadamias, pine nuts, and pistachios). In most cases, total phytosterol contents were greater in the present study than reported in peer-reviewed journal papers and the USDA National Nutrient Database for Standard Reference, which is attributed to total lipid extraction and the inclusion of steryl glucosides in the analysis; the levels were highest for pistachios (301.8 ± 15.4 mg/100 g nutmeat) and pine nuts (271.7 ± 9.1 mg/100 g nutmeat). Minor sterols were also quantified and identified using GC-FID and GC-MS techniques.

Walnut oil increases cholesterol efflux through inhibition of stearoyl CoA desaturase 1 in THP-1 macrophage-derived foam cells

Background

Walnuts significantly decrease total and low-density lipoprotein cholesterol in normo- and hypercholesterolemic individuals. No study to date has evaluated the effects of walnuts on cholesterol efflux, the initial step in reverse cholesterol transport, in macrophage-derived foam cells (MDFC). The present study was conducted to investigate the mechanisms by which walnut oil affects cholesterol efflux.

Methods

The extract of English walnuts (walnut oil) was dissolved in DMSO and applied to cultured THP-1 MDFC cells (0.5 mg/mL). THP-1 MDFC also were treated with human sera (10%, v:v) taken from subjects in a walnut feeding study. Cholesterol efflux was examined by liquid scintillation counting. Changes in gene expression were quantified by real time PCR.

Results

Walnut oil treatment significantly increased cholesterol efflux through decreasing the expression of the lipogenic enzyme stearoyl CoA desaturase 1 (SCD1) in MDFC. Alpha-linolenic acid (ALA), the major n-3 polyunsaturated fatty acids found in walnuts, recaptured SCD1 reduction in MDFC, a mechanism mediated through activation of nuclear receptor farnesoid-X-receptor (FXR). Postprandial serum treatment also increased cholesterol efflux in MDFC. When categorized by baseline C-reactive protein (CRP; cut point of 2 mg/L), subjects in the lower CRP sub-group benefited more from dietary intervention, including a more increase in cholesterol efflux, a greater reduction in SCD1, and a blunted postprandial lipemia.

Conclusion

In conclusion, walnut oil contains bioactive molecules that significantly improve cholesterol efflux in MDFC. However, the beneficial effects of walnut intake may be reduced by the presence of a pro-inflammatory state.

Trial Registration

ClinicalTrials.gov: NCT00938340

Measured energy value of pistachios in the human diet

Previous studies have suggested that lipid from nuts is more poorly absorbed than that from other food sources. If lipid from nuts is poorly absorbed, then the metabolisable energy contained in the nuts is less than that predicted by the Atwater general factors. A crossover feeding study was conducted in which sixteen volunteers consumed pistachios for 3 weeks as part of a controlled diet. Pistachio doses were 0, 42 and 84 g/d. Urine and faecal samples were collected, and urine, faeces and diet were analysed for N, fat, total dietary fibre, ash and combustible energy. Blood was also collected after each treatment period and analysed for plasma lipids. Energy value of pistachio nuts was calculated from differences in energy excretion during the different dietary treatments. The measured energy density of pistachios was found to be 22·6 kJ/g, which is 5 % less than the currently accepted energy value of 23·7 kJ/g, as calculated using the Atwater general factors. The pistachio nut intervention lowered LDL-cholesterol by 6 %, but did not significantly change plasma total cholesterol, HDL-cholesterol or TAG. In conclusion, pistachio nuts contain less metabolisable energy than that calculated from the Atwater general factors. Accurate information about metabolisable energy content of foods is important for reliable food labelling.

Crossover study of diets enriched with virgin olive oil, walnuts or almonds. Effects on lipids and other cardiovascular risk markers

BACKGROUND AND AIMS

Virgin olive oil (VOO) and nuts are basic components of the Mediterranean diet, a heart-healthy dietary pattern. Nuts have well known cholesterol lowering effects, while evidence is unclear for VOO. We designed a study in hypercholesterolemic patients to assess the effects on serum lipids and other intermediate markers of cardiovascular risk of replacing 40% of the fat in the background diet with VOO, walnuts or almonds.

METHODS AND RESULTS

After a 4 week run-in period with a healthy diet, eligible candidates were randomized into three diet sequences in a crossover design, with a common background diet enriched with VOO, walnuts or almonds, lasting 4 weeks each. Outcomes were changes of serum lipids and oxidation and inflammation markers, measured by standard methods. Plasma fatty acids were determined by gas chromatography to assess compliance. In 18 participants completing the study (9 women, mean age 56 y, BMI 25.7 kg/m(2)), LDL-cholesterol was reduced from baseline by 7.3%, 10.8% and 13.4% after the VOO, walnut and almond diets, respectively (P = 0.001, Friedman test). Total cholesterol and LDL/HDL ratios decreased in parallel. LDL-cholesterol decreases were greater than predicted from dietary fatty acid and cholesterol exchanges among diets. No changes of other lipid fractions, oxidation analytes or inflammatory biomarkers were observed. Plasma fatty acid changes after each diet sequence supported good compliance.

CONCLUSION

The results confirm the cholesterol lowering properties of nut-enriched diets. They also suggest that phenolic-rich VOO has a cholesterol lowering effect independently of its fatty acid content, which clearly deserves further study.

The glycemic effect of nut-enriched meals in healthy and diabetic subjects

BACKGROUND AND AIMS

The intake of nuts has been linked to a reduced risk of cardiovascular disease (CVD) and diabetes in large cohort studies. One potential contributing mechanism may be the ability of nuts to improve post-meal glycemic response. We, therefore, examined the effect of nuts alone and in combination with white bread on postprandial glycemia.

METHODS AND RESULTS

30, 60 and 90 g (approximately 1, 2 and 3 ounces) of mixed nuts were consumed with and without 50 g available carbohydrate from white bread by 10-14 normoglycemic and 5-10 type 2 diabetic subjects. Glycemic response (GR) was assessed by calculating the incremental area under the 2 h blood glucose curve. All three doses of mixed nuts, when fed alone, significantly reduced the glycemic response in both normoglycemic and diabetic patients. Furthermore, in the normoglycemic subjects, adding nuts to white bread progressively reduced the GR of the meal by 11.2 ± 11.6%, 29.7 ± 12.2% and 53.5 ± 8.5% for the 30, 60, and 90 g doses (P = 0.354, P = 0.031 and P < 0.001, respectively), while in subjects with type 2 diabetes, the effect was half of that seen in the non-diabetic subjects (P = 0.474, P = 0.113 and P = 0.015, respectively).

CONCLUSION

Nuts alone have little effect on post-meal blood glucose response. Furthermore, when taken with bread, nuts progressively reduce the glycemic response in a dose-dependent manner. While these findings support a short-term benefit for nuts in postprandial glucose response, more studies are required to determine whether these acute benefits result in long-term improvements in glycemic control.

Influence of body mass index and serum lipids on the cholesterol-lowering effects of almonds in free-living individuals

BACKGROUND AND AIMS

Short-term (4-9 weeks) human feeding trials have shown nut consumption to reduce serum total cholesterol (TC) and LDL-cholesterol (LDL). We hypothesized that individual levels of BMI, LDL, TC and triglycerides modify the cholesterol-lowering effect of almonds in a 24-week almond supplementation trial in a free-living population.

METHODS AND RESULTS

We performed secondary analysis on data from a previously published study. Using a sequential study design, all participants followed their habitual diets during the first six months (control), and then consumed an almond-supplemented diet (habitual + almonds) for another six months. 100 adults enrolled; 19 were lost to attrition. Those who completed the study were men (n = 43) and women (n = 38) with mean (SD) age 49.4 (13.6) years. During almond supplementation, we found statistically significant changes in TC (-0.22 mmol/L), LDL (-0.22 mmol/L), TC:HDL (-0.35), and LDL:HDL (-0.28) in participants with baseline LDL levels ≥ 3.30 mmol/L, but not among normocholesterolemic individuals. Direction and magnitude of change were similar among individuals with TC ≥ 5.20 mmol/L but not in the lower strata. Tests of interaction (diet × TC and diet × LDL) were significant. Reductions in the ratios TC:HDL, and LDL:HDL were significant among those with BMI < 25 kg/m(2), but not in heavier individuals; however, formal tests of interaction did not reach significance.

CONCLUSIONS

We provide strong evidence that the cholesterol-lowering effect of almonds is responsive among hypercholesterolemic individuals, and weak evidence that BMI modifies the effect of almonds on serum lipids.

Effects of adiposity on plasma lipid response to reductions in dietary saturated fatty acids and cholesterol

Dietary SFA and cholesterol are major targets for reducing plasma total and LDL cholesterol as a strategy to decrease cardiovascular disease risk. However, many studies show that excess adiposity attenuates the expected lipid and lipoprotein response to a plasma cholesterol-lowering diet. Diets low in SFA and cholesterol are less effective in improving the lipid profile in obese individuals and in patients with metabolic syndrome. In contrast, lean persons are more responsive to reductions in dietary SFA and cholesterol. Multiple mechanisms likely contribute to the altered plasma lipid responses to dietary changes in individuals with excess adiposity. The greater rate of hepatic cholesterol synthesis in obese individuals suppresses the expression of hepatic LDL receptors (LDLR), thereby reducing hepatic LDL uptake. Insulin resistance develops as a result of adipose-tissue induced inflammation, causing significant changes in enzymes necessary for normal lipid metabolism. In addition, the LDLR-mediated uptake in obesity is attenuated by alterations in neuroendocrine regulation of hormonal secretions (e.g. growth hormone, thyroid hormone, and cortisol) as well as the unique gut microbiota, the latter of which appears to affect lipid absorption. Reducing adipose tissue mass, especially from the abdominal region, is an effective strategy to improve the lipid response to dietary interventions by reducing inflammation, enhancing insulin sensitivity, and improving LDLR binding. Thus, normalizing adipose tissue mass is an important goal for maximizing the diet response to a plasma cholesterol-lowering diet.

Almond consumption improved glycemic control and lipid profiles in patients with type 2 diabetes mellitus

Almond consumption is associated with ameliorations in obesity, hyperlipidemia, hypertension, and hyperglycemia. The hypothesis of this 12-week randomized crossover clinical trial was that almond consumption would improve glycemic control and decrease the risk for cardiovascular disease in 20 Chinese patients with type 2 diabetes mellitus (T2DM) (9 male, 11 female; 58 years old; body mass index, 26 kg/m²) with mild hyperlipidemia. After a 2-week run-in period, patients were assigned to either a control National Cholesterol Education Program step II diet (control diet) or an almond diet for 4 weeks, with a 2-week washout period between alternative diets. Almonds were added to the control diet to replace 20% of total daily calorie intake. Addition of approximately 60 g almonds per day increased dietary intakes of fiber, magnesium, polyunsaturated fatty acid, monounsaturated fatty acid, and vitamin E. Body fat determined with bioelectrical impedance analysis was significantly lower in patients consuming almonds (almonds vs control: 29.6% vs 30.4%). The almond diet enhanced plasma α-tocopherol level by a median 26.8% (95% confidence intervals, 15.1-36.6) compared with control diet. Furthermore, almond intake decreased total cholesterol, low-density lipoprotein cholesterol, and the ratio of low-density lipoprotein cholesterol to high-density lipoprotein cholesterol by 6.0% (1.6-9.4), 11.6% (2.8-19.1), and 9.7% (0.3-20.9), respectively. Plasma apolipoprotein (apo) B levels, apo B/apo A-1 ratio, and nonesterified fatty acid also decreased significantly by 15.6% (5.1-25.4), 17.4% (2.8-19.9), and 5.5% (3.0-14.4), respectively. Compared with subjects in the control diet, those in the almond diet had 4.1% (0.9-12.5), 0.8% (0.4-6.3), and 9.2% (4.4-13.2) lower levels of fasting insulin, fasting glucose, and homeostasis model assessment of insulin resistance index, respectively. Our results suggested that incorporation of almonds into a healthy diet has beneficial effects on adiposity, glycemic control, and the lipid profile, thereby potentially decreasing the risk for cardiovascular disease in patients with type 2 diabetes mellitus.

The impact of pistachio intake alone or in combination with high-carbohydrate foods on post-prandial glycemia

BACKGROUND/OBJECTIVES

Dietary strategies that reduce post-prandial glycemia are important in the prevention and treatment of diabetes and coronary heart disease (CHD). This may be achieved by addition of high-quality protein and fat contained in pistachio nuts, to carbohydrate-containing foods or meals.

SUBJECTS/METHODS

A total of 10 healthy volunteers (3 males, 7 females); aged 48.3±6.4 years; Body mass index (BMI) 28.0±4.8 kg/m(2) participated in two studies. Study 1 assessed the dose-response effect of 28, 56 and 84 g pistachios consumed alone or co-ingested with white bread (50 g available carbohydrate); Study 2 assessed the effective dose (56 g) of pistachios on post-prandial glycemia consumed with different commonly consumed carbohydrate foods (50 g available carbohydrate). Relative glycemic responses (RGRs) of study meals compared with white bread, were assessed over the 2 h post-prandial period.

RESULTS

The RGRs of pistachios consumed alone expressed as a percentage of white bread (100%) were: 28 g (5.7±1.8%); 56 g (3.8±1.8%); 84 g (9.3±3.2%), P<0.001. Adding pistachios to white bread resulted in a dose-dependent reduction in the RGR of the composite meal; 28 g (89.1±6.0, P=0.100); 56 g (67.3±9.8, P=0.009); 84 g (51.5±7.5, P<0.001). Addition of 56 g pistachios to carbohydrate foods significantly reduced the RGR: parboiled rice (72.5±6.0) versus rice and pistachios (58.7±5.1) (P=0.031); pasta (94.8±11.4) versus pasta and pistachios (56.4±5.0) (P=0.025); whereas for mashed potatoes (109.0±6.6) versus potatoes and pistachios, (87.4±8.0) (P=0.063) the results approached significance.

CONCLUSIONS

Pistachios consumed alone had a minimal effect on post-prandial glycemia and when taken with a carbohydrate meal attenuated the RGR. The beneficial effects of pistachios on post-prandial glycemia could, therefore, be part of the mechanism by which nuts reduce the risk of diabetes and CHD.

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

Nuts are known for their hypocholesterolaemic properties; however, to achieve optimal health benefits, nuts must be consumed regularly and in sufficient quantity. It is therefore important to assess the acceptability of regular consumption of nuts. The present study examined the long-term effects of hazelnut consumption in three different forms on ‘desire to consume’ and ‘overall liking’. A total of forty-eight participants took part in this randomised cross-over study with three dietary phases of 4 weeks: 30 g/d of whole, sliced and ground hazelnuts. ‘Overall liking’ was measured in a three-stage design: a pre- and post-exposure tasting session and daily evaluation over the exposure period. ‘Desire to consume’ hazelnuts was measured during the exposure period only. Ratings were measured on a 150 mm visual analogue scale. Mean ratings of ‘desire to consume’ were 92 (sd 35) mm for ground, 108 (sd 33) mm for sliced and 116 (sd 30) mm for whole hazelnuts. For ‘overall liking’, the mean ratings were 101 (sd 29) mm for ground, 110 (sd 32) mm for sliced and 118 (sd 30) mm for whole hazelnuts. Ground hazelnuts had significantly lower ratings than both sliced (P ≤ 0·034) and whole hazelnuts (P < 0·001), with no difference in ratings between sliced and whole hazelnuts (P ≥ 0·125). For each form of nut, ratings of ‘overall liking’ and ‘desire to consume’ were stable over the exposure period, indicating that not only did the participants like the nuts, but also they wished to continue eating them. Therefore, the guideline to consume nuts on a regular basis appears to be a sustainable behaviour to reduce CVD.

Development of a cell-based, high-throughput screening assay for cholesterol efflux using a fluorescent mimic of cholesterol

Reverse cholesterol transport is the process by which extrahepatic cells, including macrophage-derived foam cells in arterial atherosclerotic plaque, transport excessive cholesterol back to the liver for bile acid synthesis and excretion, thus lowering the peripheral lipid burden. Cholesterol efflux from peripheral cells is the first step in this process, and finding drugs and interventions that promote this event is an important endeavor. Radioisotope-labeled cholesterol traditionally has been employed in measuring efflux efficiency, but this reagent has limitations for high-throughput screening. We developed an alternative method to measure cholesterol efflux in macrophage-derived foam cells using a novel fluorescent cholesterol mimic comprising the Pennsylvania Green fluorophore, attached by a linker containing a glutamic acid residue, to a derivative of N-alkyl-3β-cholesterylamine. Compared with the traditional radioisotope-based assay, this fluorescence-based assay gave similar results in the presence of known modulators of cholesterol efflux, such as cyclic AMP, and different cholesterol acceptors. When the fluorescent probe was employed in a high-throughput screening format, a variety of chemicals and bioactive compounds with known and unknown effects on cholesterol efflux could be tested simultaneously by plate-reader in a short period of time. Treatment of THP-1-derived macrophages with inhibitors of the membrane transporter ATP-binding cassette A1, such as glyburide or a specific antibody, significantly reduced the export of this fluorescent compound, indicating that ATP-binding cassette A1 represents the primary mediator of its cellular efflux. This fluorescent mimic of cholesterol provides a safe, sensitive, and reproducible alternative to radioactive assays in efflux experiments and has great potential as a valuable tool when incorporated into a drug discovery program.

Nut consumption and risk of stroke in US male physicians

BACKGROUND & AIMS

While nut consumption has been shown to lower the risk of hypertension and coronary disease, it is not known whether nut consumption is associated with the risk of stroke. We sought to examine whether nut consumption is associated with total and subtypes of stroke.

METHODS

Prospective cohort of 21,078 participants from the Physicians' Health Study (1982-2008) who were free of stroke at baseline. Nut consumption was assessed using a simple 19-item food questionnaire and stroke cases were confirmed after reviewing medical records. We used Cox's proportional hazards regression to estimate relative risks of total, ischemic, and hemorrhagic stroke according to consumption of any nuts.

RESULTS

During a mean follow up of 21.1 years, 1424 incident cases of stroke occurred (219 hemorrhagic, 1189 ischemic, and 16 of undetermined cause). There was no statistically significant association between nut consumption and total or ischemic stroke. In contrast, there was a suggestive non-linear relation between nut intake and hemorrhagic stroke: compared to subjects who did not consume nuts, multivariable-adjusted hazard ratios (95% CI) for hemorrhagic stroke for subjects consuming nuts <1, 1, 2-4, 5-6, and ≥7 times/week were 1.13 (0.78-1.62), 1.05 (0.70-1.58), 0.49 (0.27-0.89), 1.50 (0.79-2.84), and 1.84 (0.95-3.57), respectively (p for quadratic trend 0.12).

CONCLUSIONS

Our data showed no association between nuts and ischemic stroke and suggested a J-shaped relation between nut consumption and hemorrhagic stroke. Replication of our findings in the general population is warranted.

Effect of pistachio oil on gene expression of IFN-induced protein with tetratricopeptide repeats 2: a biomarker of inflammatory response

When incorporated into the diet, pistachios have a beneficial effect on lipid and lipoprotein profiles. However, little is known about potential anti-inflammatory properties. This study was conducted to determine whether pistachio oil and an organic extract from pistachio oil extract (PE) regulated expression of inflammation-related genes. A mouse macrophage cell line (RAW 264.7 cells) was treated with pistachio oil and gene expression microarray analyses were performed. Pistachio oil significantly affected genes involved in immune response, defense response to bacteria, and gene silencing, of which INF-induced protein with tetratricopeptide repeats 2 (Ifit-2) was the most dramatically reduced. PE reduced the LPS-induced Ifit-2 by 78% and the bioactive molecules contained in PE, linoleic acid, and beta-sitosterol recapitulated this inhibition. Promoter analysis identified two adjacent IFN-stimulated response elements, which lie between -110 and -85bp of the 5'-flanking region of the Ifit-2 promoter, as being responsive to LPS activation and inhibition by PE. Our results indicate that pistachio oil and bioactive molecules present therein decrease Ifit-2 expressions, and due to the sensitivity of this effect, this gene is a potential biomarker for monitoring diet-induced changes in inflammation.

Herbals used for diabetes, obesity, and metabolic syndrome

Diabetes mellitus and particularly noninsulin-dependent diabetes (type 2 diabetes) is an increasingly prevalent condition worldwide with serious consequences of multiorgan involvement and in particular cardiovascular and renal disease. Obesity is a significant risk factor for type 2 diabetes, and its incidence has doubled in the past 2 decades among younger adults, adolescents, and children globally. Inflammation and insulin resistance are the underlying mechanisms for metabolic syndrome (MetS) and its increased risk of cardiovascular, renal, and pulmonary morbidity and mortality. MetS is affecting younger populations with adverse consequences seen in later years. Dietary supplements and herbals are often marketed for these conditions. This article review common herbals and supplements marketed or used by patients with diabetes, obesity, and MetS.

Health benefits of nut consumption

Nuts (tree nuts and peanuts) are nutrient dense foods with complex matrices rich in unsaturated fatty and other bioactive compounds: high-quality vegetable protein, fiber, minerals, tocopherols, phytosterols, and phenolic compounds. By virtue of their unique composition, nuts are likely to beneficially impact health outcomes. Epidemiologic studies have associated nut consumption with a reduced incidence of coronary heart disease and gallstones in both genders and diabetes in women. Limited evidence also suggests beneficial effects on hypertension, cancer, and inflammation. Interventional studies consistently show that nut intake has a cholesterol-lowering effect, even in the context of healthy diets, and there is emerging evidence of beneficial effects on oxidative stress, inflammation, and vascular reactivity. Blood pressure, visceral adiposity and the metabolic syndrome also appear to be positively influenced by nut consumption. Thus it is clear that nuts have a beneficial impact on many cardiovascular risk factors. Contrary to expectations, epidemiologic studies and clinical trials suggest that regular nut consumption is unlikely to contribute to obesity and may even help in weight loss. Safety concerns are limited to the infrequent occurrence of nut allergy in children. In conclusion, nuts are nutrient rich foods with wide-ranging cardiovascular and metabolic benefits, which can be readily incorporated into healthy diets.

Health benefits of nut consumption

We investigated the effect of a mixture of long-chain fructo-oligosaccharides, galacto-oligosaccharides and acidic oligosaccharides on the number and consistency of stools and on immune system biomarkers in 104 supplemented and non-supplemented subjects (aged 9-24 months) with acute diarrhea. Interleukin-1 (IL-1), IL-1RA, IL-6, IL-8, IL-10, TNF-α and sIL-2R cytokine levels were determined. The significant decrease in number of stools and increase in stool consistency in the supplemented group was of little clinical relevance. The only significant change in pro- and anti-inflammatory cytokines was decreased TNF-α levels in the supplemented group. Prebiotic supplementation during acute diarrhea episodes did not influence the clinical course.

Chronic and acute effects of walnuts on antioxidant capacity and nutritional status in humans: a randomized, cross-over pilot study

BACKGROUND

Compared with other common plant foods, walnuts (Juglans regia) are consistently ranked among the highest in antioxidant capacity. In vitro, walnut polyphenols inhibit plasma and LDL oxidation, while in animal models they lower biomarkers of oxidative stress and raise antioxidant capacity. A limited number of human feeding trials indicate that walnuts improve some measures of antioxidant status, but not others.

METHODS

A 19 wk, randomized crossover trial was conducted in 21 generally healthy men and postmenopausal women > or = 50 y to study the dose-response effects of walnut intake on biomarkers of antioxidant activity, oxidative stress, and nutrient status. Subjects were randomized to receive either 21 or 42 g raw walnuts/d during each 6 wk intervention phase with a 6 wk washout between phases. Subjects were instructed to consume their usual diet, but refrain from eating any other tree nuts, seeds, peanuts, or ellagitannin-rich foods during the entire study, and other polyphenol-rich foods for 2 d prior to each study visit.

RESULTS

Compared to baseline levels, red blood cell (RBC) linoleic acid and plasma pyridoxal phosphate (PLP) were significantly higher after 6 wk with 42 g/d walnuts (P < 0.05 for both). Overall, changes in plasma total thiols, and other antioxidant biomarkers, were not significant with either walnut dose. However, when compared to fasting levels, plasma total thiols were elevated within 1 h of walnut consumption with both doses during the baseline and end visits for each intervention phase (P < 0.05 for all). Despite the observed increase in RBC linoleic and linolenic acids associated with walnut consumption, this substrate for lipid peroxidation only minimally affected malondialdehyde (MDA) and antioxidant capacity. The proportional changes in MDA and Oxygen Radical Absorbance Capacity (ORAC) were consistent with a dose-response effect, although no significant within- or between-group differences were observed for these measures.

CONCLUSIONS

Walnut consumption did not significantly change the plasma antioxidant capacity of healthy, well-nourished older adults in this pilot study. However, improvements in linoleic acid and pyridoxal phosphate were observed with chronic consumption, while total plasma thiols were enhanced acutely. Future studies investigating the antioxidant effects of walnuts in humans are warranted, but should include either a larger sample size or a controlled feeding intervention.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00626691.

Effects of peanut processing on body weight and fasting plasma lipids

Peanuts and peanut butter are commonly consumed as a snack, meal component and ingredient in various commercial products. Their consumption is associated with reduced CVD risk and they pose little threat to positive energy balance. However, questions have arisen as to whether product form (e.g. whole nut v. butter) and processing properties (e.g. roasting and adding flavours) may compromise their positive health effects. The present study investigated the effects of peanut form and processing on two CVD risk factors: fasting plasma lipids and body weight. One hundred and eighteen adults (forty-seven males and seventy-one females; age 29.2 (sd 8.4) years; BMI 30.0 (sd 4.5) kg/m2) from Brazil, Ghana and the United States were randomised to consume 56 g of raw unsalted (n 23), roasted unsalted (n 24), roasted salted (n 23) or honey roasted (n 24) peanuts, or peanut butter (n 24) daily for 4 weeks. Peanut form and processing did not differentially affect body weight or fasting plasma lipid responses in the total sample. However, HDL-cholesterol increased significantly at the group level, and total cholesterol, LDL-cholesterol and TAG concentrations decreased significantly in individuals classified as having elevated fasting plasma lipids compared with those with normal fasting plasma lipids. These observations suggest that the processing attributes assessed in this trial do not compromise the lipid-lowering effects of peanuts, and do not negatively impact body weight. Further studies are warranted to determine the effects of form and processing on other health risk factors.