Nut consumption, lipids, and risk of a coronary event

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

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

A comparison of fatty acid and sensory profiles of raw and roasted pecan cultivars

Five fatty acids comprise the bulk of the lipid content in pecans: palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid. Understanding the profiles of these fatty acids and how they relate to sensory characteristics may offer an explanation for flavor and flavor defects that may exist in certain cultivars of pecans. The objective of this study was to examine and compare fatty acid profiles of three cultivars of pecans (Major, Lakota, and Chetopa), over two crop years, under raw and roasted preparation methods, and understand the fatty acids association with sensory attributes. Percentages of palmitic, stearic, oleic, linoleic, and linolenic acids to total fatty acid content were determined using gas chromatography, and sensory profiles were generated using descriptive sensory analysis. Similar trends were seen across samples, with oleic acid comprising the majority of the total fatty acids and linolenic acid comprising the smallest percentage. There were significant differences in fatty acid content among cultivars and between pecans in the first and second crop year. Few associations were found between the fatty acids and sensory attributes, which suggest that combinations of the fatty acids contribute to certain pleasant or undesirable flavor attributes in the pecans. Subtle differences in fatty acid composition may lead to variation in flavor and flavor intensity or draw attention to or from certain attributes during consumption. Differences in crop year indicated that fatty acid content and therefore flavor are variable year to year. PRACTICAL APPLICATION: This study will help understand how fatty acid content of pecans varies from year to year. This should be taken into account when manufacturing products with pecans as the nutritional content of the product may change as the result.

Dietary Protocols to Maximize Disease Reversal and Long-Term Safety

This article covers some important concepts and controversies in modern nutritional science. It describes a diet style designed to maximize health, longevity, and disease reversal—foundationally structured on the quality and comprehensive adequacy of nutrients rather than the balance of macronutrients, as is more popular today. I call such a diet, which attempts to optimize micronutrients, a nutritarian diet. I will review a small case series demonstrating typical results in diabetics and some of my clinical observations over the last 25 years treating people with a nutritarian diet, which could be either vegan or flexitarian. I will also discuss health concerns observed from an unsupplemented vegan diet, specifically the risk of depression and later life dementia in individuals with enhanced need for long-chain omega-3 fatty acids.

Renal denervation decreases effective refractory period but not inducibility of ventricular fibrillation in a healthy porcine biomodel: a case control study

BACKGROUND

Ventricular arrhythmias play an important role in cardiovascular mortality especially in patients with impaired cardiac and autonomic function. The aim of this experimental study was to determine, if renal denervation (RDN) could decrease the inducibility of ventricular fibrillation (VF) in a healthy porcine biomodel.

METHODS

Controlled electrophysiological study was performed in 6 biomodels 40 days after RDN (RDN group) and in 6 healthy animals (control group). The inducibility of VF was tested by programmed ventricular stimulation from the apex of right ventricle (8 basal stimuli coupled with up to 4 extrastimuli) always three times in each biomodel using peripheral extracorporeal oxygenation for hemodynamic support. Further, basal heart rate (HR), PQ and QT intervals and effective refractory period of ventricles (ERP) were measured. Technical success of RDN was evaluated by histological examination.

RESULTS

According to histological findings, RDN procedure was successfully performed in all biomodels. Comparing the groups, basal HR was lower in RDN group: 79 (IQR 58; 88) vs. 93 (72; 95) beats per minute (p = 0.003); PQ interval was longer in RDN group: 145 (133; 153) vs. 115 (113; 120) ms (p < 0.0001) and QTc intervals were comparable: 402 (382; 422) ms in RDN vs. 386 (356; 437) ms in control group (p = 0.1). ERP was prolonged significantly in RDN group: 159 (150; 169) vs. 140 (133; 150) ms (p = 0.001), but VF inducibility was the same (18/18 vs. 18/18 attempts).

CONCLUSIONS

RDN decreased the influence of sympathetic nerve system on the heart conduction system in healthy porcine biomodel. However, the electrophysiological study was not associated with a decrease of VF inducibility after RDN.

DASH eating pattern is associated with favorable left ventricular function in the multi-ethnic study of atherosclerosis

OBJECTIVE

Potential associations between consistency with the Dietary Approaches to Stop Hypertension (DASH) diet and preclinical stages of heart failure (HF) in a large multiethnic cohort have not been evaluated. This study sought to determine the cross-sectional relationship between the DASH eating pattern and left ventricular (LV) function in the Multi-Ethnic Study of Atherosclerosis (MESA).

DESIGN

A total of 4506 men and women from four ethnic groups (40% white, 24% African American, 22% Hispanic American, and 14% Chinese American) aged 45-84 years and free of clinical cardiovascular disease (CVD) were studied. Diet was assessed using a validated food-frequency questionnaire. LV functional parameters including end-diastolic volume, stroke volume, and LV ejection fraction were measured by magnetic resonance imaging. Multivariate analyses were conducted to examine the association between LV function and DASH eating pattern (including high consumption of fruits, vegetables, whole grains, poultry, fish, nuts, and low-fat dairy products and low consumption of red meat, sweets, and sugar-sweetened beverages).

RESULTS

A 1-unit increase in DASH eating pattern score was associated with a 0.26 ml increase in end-diastolic volume and increases of 0.10 ml/m(2) in stroke volume, adjusted for key confounders. A 1-unit increase in DASH eating pattern score was also associated with a 0.04% increase in ejection fraction, but the relationship was marginally significant (p = 0.08).

CONCLUSIONS

In this population, greater DASH diet consistency is associated with favorable LV function. DASH dietary patterns could be protective against HF.

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.

Chemical composition of nuts and seeds sold in Korea

Eleven types of nuts and seeds were analyzed to determine their energy (326-733 mg), moisture (1.6-18.3 mg), carbohydrate (8.8-70.9 mg), protein (4.9-30.5 mg), lipid (2.5-69.8 mg), and ash (1.2-5.5 mg) contents per 100 g of sample. Energy content was highest in pine nuts (733 mg/100 g), carbohydrate level was highest in dried figs (70.9 mg/100 g) and protein was highest in peanuts (30.5 mg/100 g). The amino acid compositions of nuts and seeds were characterized by the dominance of hydrophobic (range = 1,348.6-10,284.6 mg), hydrophilic (range = 341.1-3,244.3 mg), acidic (range = 956.1-8,426.5 mg), and basic (range = 408.6-4,738.5 mg) amino acids. Monounsaturated fatty acids (MUFA) were highest in macadamia nuts (81.3%), whereas polyunsaturated fatty acids (PUFA) were highest in the walnuts (76.7%). Macadamia nuts did not contain any vitamin E, whereas sunflower seeds contained the highest level (60.3 mg/kg). Iron (Fe) content was highest in pumpkin seeds (95.85 ± 33.01 ppm), zinc (Zn) content was highest in pistachios (67.24 ± 30.25 ppm), copper (Cu) content was greatest in walnuts (25.45 ± 21.51 ppm), and lead (Pb) content was greatest in wheat nuts (25.49 ± 4.64 ppm), significantly (P < 0.05). In conclusion, current commercial nuts and seeds have no safety concerns, although further analysis of Pb contents is necessary to ensure safety.

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.

Is Almond Consumption More Effective Than Reduced Dietary Saturated Fat at Decreasing Plasma Total Cholesterol and LDL-c Levels? A Theoretical Approach

Hypercholesterolemia can be a consequence of excessive dietary saturated fatty acid (SFA), while almond-supplemented diets can improve lipid profiles. However, the differential and independent impacts of dietary SFA and almondsupplemented diets on plasma total cholesterol (pTC) and low-density lipoprotein (pLDL-c) concentrations have not been directly compared and are not well described. We reviewed the available data to construct multiple regression analyses to theoretically assess the impact of relative almond intake (RAI) and dietary SFA on reducing pTC and pLDL-c concentrations. Strong, negative correlations between RAI and percent change in mean pTC (R = 0.776; P = 0.005) and RAI and percent change in mean pLDL-c (R = 0.818; P = 0.002) were detected. The relationships between percent change in mean dietary SFA, and percent change in mean pTC and mean pLDL-c were weaker and only significant for pLDL-c. The multiple regression analyses demonstrated modest improvements in the strength of the correlations for both pTC (R = 0.804; P = 0.016) and pLDL-c (R = 0.855; P = 0.005). The models suggest that the increase in RAI contributes to the reduction in pTC and pLDL-c to a greater extent than a reduction in dietary SFA, but a simultaneous decrease in dietary SFA should further improve lipid profiles.

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 review of the rationale for additional therapeutic interventions to attain lower LDL-C when statin therapy is not enough

Statins alone are not always adequate therapy to achieve low-density lipoprotein (LDL) goals in many patients. Many options are available either alone or in combination with statins that makes it possible to reach recommended goals in a safe and tolerable fashion for most patients. Ezetimibe and bile acid sequestrants reduce cholesterol transport to the liver and can be used in combination. Niacin is very effective at lowering LDL, beyond its ability to raise high-density lipoprotein and shift LDL particle size to a less atherogenic type. When statins cannot be tolerated at all, red yeast rice can be used if proper formulations of the product are obtained. Nutrients can also be added to the diet, including plant stanols and sterols, soy protein, almonds, and fiber, either individually or all together as a portfolio diet. A clear understanding of how each of these strategies works is essential for effective results.

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.

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.

Pistachio nuts reduce triglycerides and body weight by comparison to refined carbohydrate snack in obese subjects on a 12-week weight loss program

OBJECTIVE

There is a widely held view that, due to high fat content, snacking on nuts will lead to weight gain, ultimately causing unhealthy changes in lipid profiles. This study is designed to study the effects of pistachio snack consumption on body weight and lipid levels in obese participants under real-world conditions.

METHODS

Participants were randomly assigned to consume 1 of 2 isocaloric weight reduction diets for 12 weeks, with each providing 500 cal per day less than resting metabolic rate. Each diet included an afternoon snack of either 53 g (240 cal) of salted pistachios (n  =  31) or 56 g of salted pretzels (220 cal; n  =  28).

RESULTS

Both groups lost weight during the 12-week study (time trend, p < 0.001), but there were significant differences in the changes in body mass index between the pretzel and pistachio groups (pistachio, 30.1 ± 0.4 to 28.8 ± 0.4 vs. pretzel, 30.9 ± 0.4 to 30.3 ± 0.5). At 6 and 12 weeks, triglycerides were significantly lower in the pistachio group compared with the pretzel group (88.04 ± 9.80 mg/dL vs. 144.56 ± 18.86 mg/dL, p  =  0.01 at 6 weeks and 88.10 ± 6.78 mg/dL vs. 132.15 ± 16.76 mg/dL, p  =  0.02 at 12 weeks), and there was a time trend difference between the 2 groups over the 12 weeks (p < 0.01). There were no significant differences in total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, insulin, or glucose between the 2 groups.

CONCLUSION

Pistachios can be consumed as a portion-controlled snack for individuals restricting calories to lose weight without concern that pistachios will cause weight gain. By comparison to refined carbohydrate snacks such as pretzels, pistachios may have beneficial effects on triglycerides as well.

Almond consumption and cardiovascular risk factors in adults with prediabetes

OBJECTIVE

The authors tested the hypothesis that in adults with prediabetes, an almond-enriched American Diabetes Association (ADA) diet improves measures of insulin sensitivity and other cardiovascular risk factors compared with an ADA nut-free diet.

METHODS

DESIGN

Randomized parallel-group trial.

SETTING

Outpatient dietary counseling and blood analysis.

SUBJECTS

Sixty-five adult participants with prediabetes.

INTERVENTION

Sixteen weeks of dietary modification featuring an ADA diet containing 20% of energy from almonds (approximately 2 oz per day).

MEASURES OF OUTCOME

Outcomes included fasting glucose, insulin, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides, TC:HDL-C, and HbA1c, which were measured at weeks 0, 8, and 16. Body weight, body mass index (BMI), waist circumference, blood pressure, and nutrient intake were measured at weeks 0, 4, 8, 12, and 16.

RESULTS

The almond-enriched intervention group exhibited greater reductions in insulin (-1.78 µU/ml vs. +1.47 µU/ml, p  =  0.002), homeostasis model analysis for insulin resistance (-0.48 vs. +0.30, p  =  0.007), and homeostasis model analysis for beta-cell function (-13.2 vs. +22.3, p  =  0.001) compared with the nut-free control group. Clinically significant declines in LDL-C were found in the almond-enriched intervention group (-12.4 mg/dl vs. -0.4 mg/dl) as compared with the nut-free control group. No changes were observed in BMI (-0.4 vs. -0.7 kg/m(2), p  =  0.191), systolic blood pressure (-4.4 mm Hg vs. -3.5 mm Hg, p  =  0.773), or for the other measured cardiovascular risk factors.

CONCLUSIONS

An ADA diet consisting of 20% of calories as almonds over a 16-week period is effective in improving markers of insulin sensitivity and yields clinically significant improvements in LDL-C in adults with prediabetes.

The phytochemical composition and antioxidant actions of tree nuts

In addition to being a rich source of several essential vitamins and minerals, mono- and polyunsaturated fatty acids, and fiber, most tree nuts provide an array of phytochemicals that may contribute to the health benefits attributed to this whole food. Although many of these constituents remain to be fully identified and characterized, broad classes include the carotenoids, hydrolyzable tannins, lignans, naphthoquinones, phenolic acids, phytosterols, polyphenols, and tocopherols. These phytochemicals have been shown to possess a range of bioactivity, including antioxidant, antiproliferative, anti-inflammatory, antiviral, and hypocholesterolemic properties. This review summarizes the current knowledge of the carotenoid, phenolic, and tocopherol content of tree nuts and associated studies of their antioxidant actions in vitro and in human studies. Tree nuts are a rich source of tocopherols and total phenols and contain a wide variety of flavonoids and proanthocyanidins. In contrast, most tree nuts are not good dietary sources of carotenoids and stilbenes. Phenolic acids are present in tree nuts but a systematic survey of the content and profile of these compounds is lacking. A limited number of human studies indicate these nut phytochemicals are bioaccessible and bioavailable and have antioxidant actions in vivo.

Functional Foods as Modifiers of Cardiovascular Disease

There is growing consensus that systemic inflammation is at the heart of cardiovascular disease (CVD). Inflammation is a key feature of the immune system, functioning to defend tissue integrity and function. However, chronic stimulation of inflammatory mediators leads to lasting vascular reactivity, insulin resistance, hyperlipidemia, and, subsequently, chronic disease. Dietary practices to minimize inflammatory stimuli and CVD risk include regular intakes of fatty fish rich in the eicosapentaenoic and docosahexaenoic acids that compete with the more pervasive membrane fatty acid, arachidonic acid, disrupting the metabolic cascades that stimulate inflammation. Another effective dietary strategy is to consume less arachidonic acid by reducing beef, poultry, fish, and eggs from the diet (e.g., adopting a vegetarian-like diet). Since oxidative stress plays a prominent role in immune system activation, regular ingestion of ample amounts of fruits and vegetables (8+ servings/d) rich in antioxidant compounds, the polyphenols, carotenoids, and vitamin C (e.g., citrus, tomatoes, berries, carrots, and greens), lowers inflammatory mediators and risk for chronic disease. Whole grains, legumes, and nuts have also been demonstrated in clinical trials to effectively reduce inflammatory mediators and risk for CVD. Hence, as proclaimed in antiquity, 'let food be thy medicine and medicine be thy food'.

Effect of almonds on insulin secretion and insulin resistance in nondiabetic hyperlipidemic subjects: a randomized controlled crossover trial

Nuts appear to have a marked effect in cohort studies in reducing the risk of coronary heart disease (CHD), but their demonstrated ability to lower cholesterol can only explain a proportion of the reduction in risk. Our aim was to assess whether improvement in carbohydrate metabolism provides a further explanation for the effect of nuts in reducing CHD. The effects of whole almonds, taken as snacks, were compared with the effects of low saturated fat (<5% energy) whole-wheat muffins (control) in the therapeutic diets of hyperlipidemic subjects. In a randomized crossover study, 27 hyperlipidemic men and women consumed 3 isoenergetic (mean, 423 kcal/d) supplements each for 1 month. Supplements provided 22.2% of energy and consisted of full-dose almonds (73 +/- 3 g/d), half-dose almonds plus half-dose muffins, and full-dose muffins. Subjects were assessed at weeks 0, 2, and 4 and fasting blood samples were obtained. Twenty-four-hour urinary output was collected at the end of week 4 on each treatment. Mean body weights differed by less than 300 g between treatments. No differences were seen in baseline or treatment values for fasting glucose, insulin, C-peptide, or insulin resistance as measured by homeostasis model assessment of insulin resistance. However, 24-hour urinary C-peptide output as a marker of 24-hour insulin secretion was significantly reduced on the half-and full-dose almonds by comparison to the control after adjustment for urinary creatinine output (P = .002 and P = .004, respectively). We conclude that reductions in 24-hour insulin secretion appear to be a further metabolic advantage of nuts that in the longer term may help to explain the association of nut consumption with reduced CHD risk.

Effect of Nut Paste Enrichment on Physical Characteristics and Consumer Acceptability of Bread

Four kinds of nut paste (almond, hazelnut, peanut, walnut) in three different percentages (5, 10, and 15%) were added to bread formula to study the morphogeometric and textural characteristics, and the consumer acceptability of enriched breads. The change of texture along time was also studied. Control bread presented the lowest volume, water loss and height, and the highest firmness and chewiness. The enrichment with 15% of nut paste caused a decrease in loaf volume, weight loss, cohesiveness, and resilience but an increase in height, firmness, and chewiness. Almond and walnut breads presented the lowest values in firmness and chewiness. The lowest cohesiveness and resilience corresponded to hazelnut bread. The increased firmness during storage was slower in enriched than in nonenriched breads. The adhesiveness, cohesiveness, and resilience decreases were more important in the first 2 days of storage. Breads added with 10 and 15% nut paste showed the highest intent for consumption, persistence, and texture values. Peanut-enriched bread was the least accepted bread. Only a third of the consumers were able to correctly identify the nuts added.

A macadamia nut-rich diet reduces total and LDL-cholesterol in mildly hypercholesterolemic men and women

Epidemiologic studies and clinical trials have demonstrated that the unique fatty acid profile of nuts beneficially affects serum lipids/lipoproteins, reducing cardiovascular disease (CVD) risk. Nuts are low in SFA and high in PUFA and monounsaturated fatty acids (MUFA). Macadamia nuts are a rich source of MUFA. A randomized, crossover, controlled feeding study (5-wk diet periods) compared a Macadamia nut-rich diet [42.5 g (1.5 ounces)/8.79 MJ (2100 kcal)] [MAC; 33% total fat (7% SFA, 18% MUFA, 5% PUFA)] vs. an average American diet [AAD; 33% total fat (13% SFA, 11% MUFA, 5% PUFA)] on the lipid/lipoprotein profile of mildly hypercholesterolemic (n = 25; 15 female, 10 male) subjects. Serum concentrations of total cholesterol (TC) and LDL cholesterol (LDL-C) following the MAC (4.94 +/- 0.17 mmol/L, 3.14 +/- 0.14 mmol/L) were lower than the AAD (5.45 +/- 0.17 mmol/L, 3.44 +/- 0.14 mmol/L; P < 0.05). The serum non-HDL cholesterol (HDL-C) concentration and the ratios of TC:HDL-C and LDL-C:HDL-C were reduced following consumption of the MAC diet (3.83 +/- 0.17, 4.60 +/- 0.24, and 2.91 +/- 0.17, respectively) compared with the AAD (4.26 +/- 0.17, 4.89 +/- 0.24, and 3.09 +/- 0.18, respectively; P < 0.05). There was no change in serum triglyceride concentration. Thus, macadamia nuts can be included in a heart-healthy dietary pattern that reduces lipid/lipoprotein CVD risk factors. Nuts as an isocaloric substitute for high SFA foods increase the proportion of unsaturated fatty acids and decrease SFA, thereby lowering CVD risk.

The evidence for dietary prevention and treatment of cardiovascular disease

During the past few decades numerous studies have reported the atherogenic potential of saturated fatty acids, trans-fatty acids, and cholesterol, and beneficial effects of fiber, phytostanols/phytosterols, n-3 fatty acids, a Mediterranean diet, and other plant-based approaches. The purpose of this article is to provide a comprehensive and systematic review of the evidence associated with key dietary factors and risk of cardiovascular disease-an umbrella term encompassing diseases that affect the heart and blood vessels, including coronary heart disease, coronary artery disease, dyslipidemia, and hypertension-in conjunction with the work of the American Dietetic Association Evidence Analysis Library review on diet and lipids, updated with new evidence from the past 2 years. The criteria used and results cited provide scientific rationale for food and nutrition professionals and other health professionals for counseling patients. Details of these searches are available within the American Dietetic Association Evidence Analysis Library online (http://adaevidencelibrary.com). Potential mechanisms and needs for future research are summarized for each relevant nutrient, food, or food component.

Peanuts improve blood glutathione, HDL-cholesterol level and change tissue factor activity in rats fed a high-cholesterol diet

BACKGROUND

The inverse association of peanut consumption and risk markers of CHD (lipids) has been reported however health professionals are still concerned whether hyperlipidemic subjects advised to eat peanuts will have increased serum lipid levels. Tissue factor (TF), the major regulator of normal haemostasis and thrombosis, plays a critical role in haemostasis in all tissues.

AIM OF THE STUDY

To investigate the effects of peanut consumption on lipid profile, blood Glutathione (GSH), thiobarbituric acid reactive substances (TBARS), haematologic parameters and TF activities in rats fed a high-cholesterol diet.

METHODS

32 Wistar Albino rats were divided into 4 groups of 8 rats each: 1-Control 2-Control+peanut 3-Hyperlipidemic and 4-Hyperlipidemic+peanut group. At the end of 12 weeks, blood samples were used to evaluate lipid profile, haemostatic parameters, GSH, TBARS and tissue samples were used for the determination of TF activities.

RESULTS

Peanut consumption increased blood GSH both in the control and hyperlipidemic groups; increased HDL-cholesterol and decreased TBARS in the hyperlipidemic group. The addition of peanut to the diet did not change blood lipids, prothrombin time, activated partial thromboplastin time or fibrinogen levels significantly both in the control and hyperlipidemic groups. It affected TF activities differently in both groups. It decreased brain and aorta TF activity but increased spleen and kidney TF activity in the control group. It led to significant increases in the TF activity of kidney, spleen and aorta and a significant decrease in the TF activity of brain in the hyperlipidemic group.

CONCLUSION

Peanut consumption improved GSH and HDL-C levels and decreased TBARS, without increasing other blood lipids in experimental hyperlipidemia. Nevertheless the mechanism of the effect of peanut consumption on the TF activity of tissues remains to be determined.

Antioxidant content and free radical scavenging ability of fresh red pummelo [Citrus grandis (L.) Osbeck] juice and freeze-dried products

The antioxidative phytochemicals in various fruits and vegetables are widely recognized for their role in scavenging free radicals, which are involved in the etiology of many chronic diseases. Colored fruits are especially considered a quality trait that correlates with their nutritional values and health benefits. The specific aim of this study was to investigate the antioxidants in the juice and freeze-dried flesh and peel of red pummelo and their ability to scavenge free radicals and compare them with those in white pummelo juice. The total phenolic content of red pummelo juice extracted by methanol (8.3 mg/mL) was found to be significantly higher than that of white pummelo juice (5.6 mg/mL). The carotenoid content of red pummelo juice was also significantly higher than that in white pummelo juice. The contents of vitamin C and delta-tocopherol in red pummelo juice were 472 and 0.35 mug/mL, respectively. The ability of the antioxidants found in red pummelo juice to scavenge radicals were found by methanol extraction to approximate that of BHA and vitamin C with a rapid rate in a kinetic model. The ability of methanol extracts of freeze-dried peel and flesh from red pummelo to scavenge these radicals was 20-40% that of BHA and vitamin C effects. Fresh red pummelo juice is an excellent source of antioxidant compounds and exhibited great efficiency in scavenging different forms of free radicals including DPPH, superoxide anion, and hydrogen peroxide radicals.

Pistachio Nut Consumption and Serum Lipid Levels

OBJECTIVE

Clinical and epidemiological studies have reported the beneficial effects of tree nuts and peanuts on serum lipid levels. We studied the effects of consuming 15% of the daily caloric intake in the form of pistachio nuts on the lipid profiles of free-living human subjects with primary, moderate hypercholesterolemia (serum cholesterol greater than 210 mg/dL).

METHODS

design: Randomized crossover trial. setting: Outpatient dietary counseling and blood analysis. subjects: 15 subjects with moderate hypercholesterolemia. intervention: Fours weeks of dietary modification with 15% caloric intake from pistachio nuts.

MEASURES OF OUTCOME

Endpoints were serum lipid levels of total cholesterol, HDL-C, LDL-C, VLDL-C, triglycerides and apolipoproteins A-1 and B-100. BMI, blood pressure, and nutrient intake (total energy, fat, protein, and fiber) were also measured at baseline, during, and after dietary intervention.

RESULTS

No statistically significant differences were observed for total energy or percent of energy from protein, carbohydrate or fat. On the pistachio nut diet, a statistically significant decrease was seen for percent energy from saturated fat (mean difference, -2.7%; 95% CI, -5.4% to -0.08%; p = 0.04). On the pistachio nut diet, statistically significant increases were seen for percent energy from polyunsaturated fat (mean difference, 6.5%; 95% CI, 4.2% to 8.9%; p<.0001) and fiber intake (mean difference, 15 g; 95% CI, 8.4 g to 22 g; p = 0.0003). On the pistachio diet, statistically significant reductions were seen in TC/HDL-C (mean difference, -0.38; 95% CI, -0.57 to -0.19; p = 0.001), LDL-C/HDL-C (mean difference, -0.40; 95% CI, -0.66 to -0.15; p = 0.004), B-100/A-1 (mean difference, -0.11; 95% CI, -0.19 to -0.03; p = 0.009) and a statistically significant increase was seen in HDL-C (mean difference, 2.3; 95% CI, 0.48 to 4.0; p = 0.02). No statistically significant differences were seen for total cholesterol, triglycerides, LDL-C, VLDL-C, apolipoprotein A-1 or apolipoprotein B-100. No changes were observed in BMI or blood pressure.

CONCLUSION

A diet consisting of 15% of calories as pistachio nuts (about 2-3 ounces per day) over a four week period can favorably improve some lipid profiles in subjects with moderate hypercholesterolemia and may reduce risk of coronary disease.

Comparison of extraction methods for the quantification of selected phytochemicals in peanuts (Arachis hypogaea)

Peanuts have been reported to contain bioactive phytochemicals, particularly isoflavones (genistein, daidzein, and biochanin A) and trans-resveratrol. Currently, limited data are available regarding the levels of these bioactive compounds in peanuts with variations in reported levels. The purpose of this study was to compare four methods of extraction [stirring, sonication, Soxtec, and microwave-assisted sonication (MAS)] for runner peanuts. Quantification of the selected compounds was conducted by reverse-phase high-performance liquid chromatography (RP-HPLC). The results showed that the MAS and Soxtec methods extracted significantly higher amounts of the phytochemicals. Also, the defatted peanuts gave significantly higher amounts of the phytochemicals compared to the nondefatted peanuts. The high levels of the isoflavones may be attributed to heat-induced conversion of conjugate glycosides to aglycons. The MAS and Soxtec methods may be used for total isoflavone content quantitation, while sonication or stirring may be the method of choice for quantitation of isoflavone composition (aglycons and glycoside conjugates) in peanuts.

Nut consumption and weight gain in a Mediterranean cohort: The SUN study

OBJECTIVE

To assess the association, in a Mediterranean population, between nut consumption and risk of weight gain (at least 5 kg) or the risk of becoming overweight/obese.

RESEARCH METHODS AND PROCEDURES

The Seguimiento Universidad de Navarra project is a prospective cohort of 8865 adult men and women who completed a follow-up questionnaire after a median of 28 months. Dietary habits were assessed with a previously validated semiquantitative food-frequency questionnaire.

RESULTS

Nine hundred thirty-seven participants reported a weight gain of > or =5 kg at follow-up. After adjusting for age, sex, smoking, leisure time physical activity, and other known risk factors for obesity, participants who ate nuts two or more times per week had a significantly lower risk of weight gain (odds ratio: 0.69; 95% confidence interval: 0.53 to 0.90, p for trend = 0.006) than those who never or almost never ate nuts. Participants with little nut consumption (never/almost never) gained an average of 424 grams (95% confidence interval: 102 to 746) more than frequent nut eaters. Nut consumption was not significantly associated with incident overweight/obesity in the cohort.

DISCUSSION

Frequent nut consumption was associated with a reduced risk of weight gain (5 kg or more). These results support the recommendation of nut consumption as an important component of a cardioprotective diet and also allay fears of possible weight gain.

Effects of pistachio nuts consumption on plasma lipid profile and oxidative status in healthy volunteers

BACKGROUND AND AIM

Effects of pistachio nuts consumption on plasma lipid profile and oxidative status were investigated in healthy volunteers with normal lipid levels.

METHODS AND RESULTS

The study was conducted in 24 healthy men and 20 healthy women. All subjects consumed their regular diets during a 1-week period. After this period, half of the subjects (12 men and 10 women, mean age 32.8 +/- 6.7 years) were randomized to a regular diet group and the other half (12 men and 10 women, mean age 33.4 +/- 7.2 years) were randomized to a pistachio group which involved substituting pistachio nuts for 20% of their daily caloric intake for 3 weeks. Plasma total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglyceride, malondialdehyde (MDA) and antioxidant potential (AOP) were measured before and after the dietary modification from all the subjects. After 3 weeks, with the pistachio diet, the mean plasma total cholesterol, MDA levels and, total cholesterol/HDL and LDL/HDL ratios were found to be significantly decreased (P < 0.05, P < 0.05, P < 0.001 and P < 0.01, respectively); on the contrary, HDL and AOP levels, and AOP/MDA ratios were significantly increased (P < 0.001, P < 0.05 and P < 0.01, respectively). Triglyceride and LDL levels also decreased but this was not statistically significant (P > 0.05).

CONCLUSION

These results indicated that consumption of pistachio nuts decreased oxidative stress, and improved total cholesterol and HDL levels in healthy volunteers.

Dietary approaches that delay age-related diseases

Reducing food intake in lower animals such as the rat decreases body weight, retards many aging processes, delays the onset of most diseases of old age, and prolongs life. A number of clinical trials of food restriction in healthy adult human subjects running over 2-15 years show significant reductions in body weight, blood cholesterol, blood glucose, and blood pressure, which are risk factors for the development of cardiovascular disease and diabetes. Lifestyle interventions that lower energy balance by reducing body weight such as physical exercise can also delay the development of diabetes and cardiovascular disease. In general, clinical trials are suggesting that diets high in calories or fat along with overweight are associated with increased risk for cardiovascular disease, type 2 diabetes, some cancers, and dementia. There is a growing literature indicating that specific dietary constituents are able to influence the development of age-related diseases, including certain fats (trans fatty acids, saturated, and polyunsaturated fats) and cholesterol for cardiovascular disease, glycemic index and fiber for diabetes, fruits and vegetables for cardiovascular disease, and calcium and vitamin D for osteoporosis and bone fracture. In addition, there are dietary compounds from different functional foods, herbs, and neutraceuticals such as ginseng, nuts, grains, and polyphenols that may affect the development of age-related diseases. Long-term prospective clinical trials will be needed to confirm these diet-disease relationships. On the basis of current research, the best diet to delay age-related disease onset is one low in calories and saturated fat and high in wholegrain cereals, legumes, fruits and vegetables, and which maintains a lean body weight. Such a diet should become a key component of healthy aging, delaying age-related diseases and perhaps intervening in the aging process itself. Furthermore, there are studies suggesting that nutrition in childhood and even in the fetus may influence the later development of aging diseases and lifespan.

Phytosterol composition of nuts and seeds commonly consumed in the United States

Phytosterols were quantified in nuts and seeds commonly consumed in the United States. Total lipid extracts were subjected to acid hydrolysis and then alkaline saponfication, and free sterols were analyzed as trimethylsilyl derivatives by capillary GC-FID and GC-MS. Delta5-Avenasterol was quantified after alkaline saponification plus direct analysis of the glucoside. Sesame seed and wheat germ had the highest total phytosterol content (400-413 mg/100 g) and Brazil nuts the lowest (95 mg/100 g). Of the products typically consumed as snack foods, pistachio and sunflower kernel were richest in phytosterols (270-289 mg/100 g). beta-Sitosterol, Delta5-avenasterol, and campesterol were predominant. Campestanol ranged from 1.0 to 12.7 mg/100 g. Only 13 mg/100 g beta-sitosterol was found in pumpkin seed kernel, although total sterol content was high (265 mg/100 g). Phytosterol concentrations were greater than reported in existing food composition databases, probably due to the inclusion of steryl glycosides, which represent a significant portion of total sterols in nuts and seeds.

Walnut consumption in hyperlipidemic patients

Walnut (Juglans regia L.) is described as an anticancer, tonic, blood purifier, and detoxifier agent. It is said that nuts have favorable fatty acids and nutrients. This study was performed to determine the lipid-lowering properties of walnut in a population in Shiraz, Southern Iran. In a randomized case-control study, 52 volunteers were divided into 2 groups: Group A consumed walnuts, 20 grams per day for 8 weeks and the control group (group B) consumed no walnuts. Triglycerides, total high-density lipoprotein (HDL), and low-density lipoprotein (LDL) levels were checked for each subject prior to, after 4 weeks, and at 8 weeks after the beginning of the study. In group A, the mean plasma TG level dropped by 17.1% from the baseline and HDL cholesterol also increased significantly by 9%. It was shown that frequent consumption of nuts in the daily diet was associated with a potentially decreased risk of coronary artery disease by decreasing the level of triglyceride and increasing the level of HDL.

Concept of a nutritious food: toward a nutrient density score

The American diet is said to be increasingly energy-rich but nutrient-poor. To help improve the nutrient-to-energy ratio, the 2005 Dietary Guidelines for Americans recommend that consumers replace some foods in their diets with more nutrient-dense options. Such dietary guidance presupposes the existence of a nutrient density standard. However, a review of the literature shows that the concept of a nutritious food is not based on any consistent standards or criteria. In many cases, healthful foods are defined by the absence of problematic ingredients-fat, sugar, and sodium-rather than by the presence of any beneficial nutrients they might contain. Past attempts to quantify the nutrient density of foods have been based on a variety of calories-to-nutrient scores, nutrients-per-calorie indexes, and nutrient-to-nutrient ratios. The naturally nutrient rich (NNR) score, which is based on mean percentage daily values (DVs) for 14 nutrients in 2000 kcal food, can be used to assign nutrient density values to foods within and across food groups. Use of the NNR score allows consumers to identify and select nutrient-dense foods while permitting some flexibility where the discretionary calories are concerned. This approach has implications for food labeling, nutritional policy making, and consumer education. The Food and Drug Administration has considered approving nutrient claims based on the ratio of a beneficial nutrient to the food's energy content, as opposed to a specified minimum amount of a nutrient per serving size. Given the current dietary trends, the nutrient density approach can be a valuable tool for nutrition education and dietary guidance.

Improved diet quality with peanut consumption

OBJECTIVE

To evaluate the diet quality of free-living men, women, and children choosing peanuts and peanut products.

DESIGN

Using data reported in the Continuing Survey of Food Intake by Individuals and Diet and Health Knowledge Survey (CSFII/DHKS) from 1994-1996, food codes were used to sort respondents by use or nonuse of peanuts.

SUBJECTS

A nationally representative sample of 4,751 men, 4,572 women, and 4,939 children (boys and girls, 2-19 yrs) who completed 2-day intake records.

MEASURES OF OUTCOME

The two-sample t test was used to analyze differences between peanut users and nonusers for energy, nutrient intakes, Health Eating Index (HEI) scores, and body mass index (BMI).

RESULTS

Peanut users (24% of CSFII/DHKS) had higher intakes (p < 0.001) of protein, total fat, polyunsaturated fat (PUFA), monounsaturated fat, (MUFA) (p < 0.01), fiber, vitamin A, vitamin E, folate, calcium, magnesium, zinc, and iron. Percent of energy from saturated fat was not significantly different for men, women or girls and was slightly lower (p < 0.01) for boys. Dietary cholesterol of peanut users was lower for all population groups; this decrease was significant for both men (p < 0.01) and children (p < 0.001). The HEI was calculated as a measure of overall nutrient profile of the diets and was significantly greater for peanut users (men 61.4, women, 65.1, children 66.8) compared to nonusers (men 59.9, women 64.1, children 64.7) for men (p = 0.0074) and children (p < 0.001). Energy intake was significantly higher in all population groups of peanut users (p < 0.001; boys: p < 0.01); however mean BMI for peanut users was lower for all gender/age categories (women: p < 0.05; children: p < 0.001).

CONCLUSIONS

These results demonstrate improved diet quality of peanut users, indicated by the higher intake of the micronutrients vitamin A, vitamin E, folate, calcium, magnesium, zinc, and iron and dietary fiber, and by the lower intake of saturated fat and cholesterol. Despite a higher energy intake over a two-day period, peanut consumption was not associated with a higher BMI.

Role of cell walls in the bioaccessibility of lipids in almond seeds

BACKGROUND

Certain nutrients and phytochemicals in almonds may confer protection against cardiovascular disease, but little is known about factors that influence their bioavailability. A crucial and relevant aspect is the amount of these dietary components available for absorption in the intestine, which is a concept referred to as bioaccessibility.

OBJECTIVE

We investigated the role played by cell walls in influencing the bioaccessibility of intracellular lipid from almond seeds.

DESIGN

Quantitative analyses of nonstarch polysaccharides (NSPs) and phenolic compounds of cell walls were performed by gas-liquid chromatography and HPLC, respectively. In a series of experiments, the effects of mechanical disruption, chewing, and digestion on almond seed microstructure and intracellular lipid release were determined. In the digestibility study, fecal samples were collected from healthy subjects who had consumed diets with or without almonds. Almond seeds and fecal samples were examined by microscopy to identify cell walls and intracellular lipid.

RESULTS

Cell walls were found to be rich in NSPs, particularly arabinose-rich polysaccharides, with a high concentration of phenolic compounds detected in the seed coat cell wall. During disruption of almond tissue by mechanical methods or chewing, only the first layer of cells at the fractured surface was ruptured and able to release lipid. In fecal samples collected from subjects consuming the almond diet, we observed intact cotyledonary cells, in which the cell walls encapsulated intracellular lipid. This lipid appeared susceptible to colonic fermentation once the cotyledonary cell walls were breached by bacterial degradation.

CONCLUSION

The cell walls of almond seeds reduce lipid bioaccessibility by hindering the release of lipid available for digestion.

Parvalbumin Corrects Slowed Relaxation in Adult Cardiac Myocytes Expressing Hypertrophic Cardiomyopathy-Linked α-Tropomyosin Mutations

Hypertrophic cardiomyopathy mutations A63V and E180G in α-tropomyosin (α-Tm) have been shown to cause slow cardiac muscle relaxation. In this study, we used two complementary genetic strategies, gene transfer in isolated rat myocytes and transgenesis in mice, to ascertain whether parvalbumin (Parv), a myoplasmic calcium buffer, could correct the diastolic dysfunction caused by these mutations. Sarcomere shortening measurements in rat cardiac myocytes expressing the α-Tm A63V mutant revealed a slower time to 50% relengthening (T50R: 44.2±1.4 ms in A63V, 36.8±1.0 ms in controls; n=96 to 108; P <0.001) when compared with controls. Dual gene transfer of α-Tm A63V and Parv caused a marked decrease in T50R (29.8±1.0 ms). However, this increase in relaxation rate was accompanied with a decrease in shortening amplitude (114.6±4.4 nm in A63+Parv, 137.8±5.3 nm in controls). Using an asynchronous gene transfer strategy, Parv expression was reduced (from ≈0.12 to ≈0.016 mmol/L), slow relaxation redressed, and shortening amplitude maintained (T50R=33.9±1.6 ms, sarcomere shortening amplitude=132.2±7.0 nm in A63V+PVdelayed; n=56). Transgenic mice expressing the E180G α-Tm mutation and mice expressing Parv in the heart were crossed. In isolated adult myocytes, the α-Tm mutation alone (E180G + /PV − ) had slower sarcomere relengthening kinetics than the controls (T90R: 199±7 ms in E180G + /PV − , 130±4 ms in E180G − /PV − ; n=71 to 72), but when coexpressed with Parv, cellular relaxation was faster (T90R: 36±4 ms in E180G + /PV + ). Collectively, these findings show that slow relaxation caused by α-Tm mutants can be corrected by modifying calcium handling with Parv.

Proposal for a dietary “phytochemical index”

There is ample reason to believe that diets rich in phytochemicals provide protection from vascular diseases and many cancers; direct antioxidant activity as well as modulation of enzyme expression or hormone activity contribute to this effect. Phytochemicals derived from diverse foods presumably can interact additively and (possibly) synergistically; thus, the total dietary load of phytochemicals may have important implications for health. As a means of very roughly quantifying this load, a "phytochemical index" (PI) is proposed, defined as the percent of dietary calories derived from foods rich in phytochemicals. Calories derived from fruits, vegetables (excluding potatoes), legumes, whole grains, nuts, seeds, fruit/vegetable juices, soy products, wine, beer, and cider - and foods compounded therefrom - would be counted in this index. Partial credit could be given for antioxidant-rich extra virgin olive oil. Other added oils, refined sugars, refined grains, potato products, hard liquors, and animal products - regrettably, the chief sources of calories in typical Western diets - would be excluded. Although the PI would provide only a very rough approximation of the quantity or quality of phytochemical nutrition, it nonetheless could aid epidemiologists in exploring the health consequences of diets high in phytochemical-rich plant foods, and could also help clinical nutritionists in their efforts to improve the phytochemical nutrition of their clients.

A search for truth in dietary epidemiology

Although results from epidemiologic studies of diet have taught us a great deal, much of the evidence remains mired in controversy because of the inconsistency of results among apparently good studies. I conclude that this can be largely explained by the combination of 2 problems: confounding and measurement error. This recognition allows some judgment as to which studies may be less prone to these difficulties and a search for new analytic methods that can produce less biased and more consistent results. The potential correlations between many nutrients, and to a lesser extent foods, make it difficult to know whether the nominated variable is actually the active principle or whether there is some other dietary risk factor that is closely associated. It is not generally recognized that all traditional analyses of this sort are based on a powerful but incorrect assumption: that there are no errors in dietary assessment. If the incorrect assumption is not satisfied, relative risk estimates become distorted-reduced by one-half or more in some cases. Regression calibration is a newer technique that uses a calibration substudy to provide information about errors and to correct results from the main study. There are a number of variants of this technique, all requiring assumptions about the data. Regression calibration methods that use carefully selected biological surrogates (correlates) of the dietary factor of interest in the calibration study seem to use more realistic assumptions.

Nut consumption and body weight

Frequent nut consumption is associated with lower rates of coronary artery disease (CAD). Also, nut-rich diets improve the serum lipid profile of participants in dietary intervention trials. However, nuts are fatty foods, and in theory their regular consumption may lead to body weight gain. Because obesity is a major public health problem and a risk factor for CAD, clinicians and policy makers ponder several questions. Will hypercholesterolemic patients advised to consume nuts gain weight? Is recommending increased nut consumption to the general population for CAD prevention sound public health advice? Epidemiologic studies indicate an inverse association between frequency of nut consumption and body mass index. In well-controlled nut-feeding trials, no changes in body weight were observed. Some studies on free-living subjects in which no constraints on body weight are imposed show a nonsignificant tendency to lower weight while subjects are on the nut diets. In another line of evidence, preliminary data indicate that subjects on nut-rich diets excrete more fat in stools. Further research is needed to study the effects of nut consumption on energy balance and body weight. In the meantime, the available cumulative data do not indicate that free-living people on self-selected diets including nuts frequently have a higher body mass index or a tendency to gain weight.

Effect on body weight of a free 76 Kilojoule (320 calorie) daily supplement of almonds for six months

OBJECTIVE

Regular nut consumption is associated with lower rates of heart attack. However, as nuts are fatty foods, they may in theory lead to weight gain, although preliminary evidence has suggested otherwise. We tested the hypothesis that a free daily supplement (averaging 76 kJ) of almonds for six months, with no dietary advice, would not change body weight.

METHODS

Eighty-one male and female subjects completed the randomized cross-over study. During two sequential six-month periods, diet, body weight and habitual exercise were evaluated repeatedly in each subject. Almonds were provided only during the second period. The design was balanced for seasonal and other calendar trends.

RESULTS

During the almond feeding period, average body weight increased only 0.40 (kg) (p approximately 0.09). The weight change depended on baseline BMI (p = 0.05), and only those initially in the lower BMI tertiles experienced small and mainly unimportant weight gains with the almonds. We estimated that 54% (recalls) or 78% (diaries) of the extra energy from almonds was displaced by reductions in other foods. The ratio unsaturated/saturated dietary fat increased by 40% to 50% when almonds were included in the diet.

CONCLUSION

Incorporating a modest quantity (76 kJ) of almonds in the diet each day for six months did not lead on average to statistically or biologically significant changes in body weight and did increase the consumption of unsaturated fats. Further studies are necessary to evaluate longer term effects, especially in men.

The scientific evidence for a beneficial health relationship between walnuts and coronary heart disease

The author and four independent experts evaluated the intent and quality of scientific evidence for a potential beneficial health relationship between the intake of walnuts and the reduction and prevention of coronary heart disease. The report also addresses the supporting evidence for the health benefit of other tree nuts and selected legumes. Compared to most other nuts, which contain monounsaturated fatty acids, walnuts are unique because they are rich in n-6 (linoleate) and n-3 (linolenate) polyunsaturated fatty acids. Walnuts contain multiple health-beneficial components, such as having a low lysine:arginine ratio and high levels of arginine, folate, fiber, tannins, and polyphenols. Though walnuts are energy rich, clinical dietary intervention studies show that walnut consumption does not cause a net gain in body weight when eaten as a replacement food. Five controlled, peer-reviewed, human clinical walnut intervention trials, involving approximately 200 subjects representative of the 51% of the adult population in the United States at risk of coronary heart disease were reviewed. The intervention trials consistently demonstrated walnuts as part of a heart-healthy diet, lower blood cholesterol concentrations. None of these studies were of extended duration that would be essential for evaluation of the sustainability of the observed outcomes. These results were supported by several large prospective observational studies in humans, all demonstrating a dose response-related inverse association of the relative risk of coronary heart disease with the frequent daily consumption of small amounts of nuts, including walnuts.

Almonds and almond oil have similar effects on plasma lipids and LDL oxidation in healthy men and women

Epidemiologic and clinical studies have shown that nut consumption is associated with favorable plasma lipid profiles and reduced cardiovascular risk. These effects may result from their high monounsaturated fat (MUFA) content but nuts contain constituents other than fatty acids that might be cardioprotective. We conducted a study to compare the effects of whole-almond vs. almond oil consumption on plasma lipids and LDL oxidation in healthy men and women. Using a randomized crossover trial design, 22 normolipemic men and women replaced half of their habitual fat (approximately 14% of approximately 29% energy) with either whole almonds (WA) or almond oil (AO) for 6-wk periods. Compliance was ascertained by monitoring dietary intake via biweekly 5-d food records, return of empty almond product packages and weekly meetings with a registered dietitian. Fat replacement with either WA and AO resulted in a 54% increase in percentage of energy as MUFA with declines in both saturated fat and cholesterol intake and no significant changes in total energy, total or polyunsaturated fat intake. The effects of WA and AO on plasma lipids did not differ compared with baseline; plasma triglyceride, total and LDL cholesterol significantly decreased, 14, 4 and 6% respectively, whereas HDL cholesterol increased 6%. Neither treatment affected in vitro LDL oxidizability. We conclude that WA and AO do not differ in their beneficial effects on the plasma lipid variables measured and that this suggests that the favorable effect of almonds is mediated by components in the oil fraction of these nuts.

Nutritional value of the marine invertebrates Anemonia viridis and Haliothis tuberculata and effects on serum cholesterol concentration in ratsopen star

The purpose of this study was to determine the nutritional value of diets with protein from two marine species (Haliotis tuberculata and Anemonia viridis) as compared to a high-quality protein reference based on casein or casein supplemented with olive oil. We also investigated the effects of these diets on serum lipid levels. Male rats were fed these diets for 23 days. Protein quality indicators (true digestibility, net protein utilization, biological value) were similar to those obtained for casein-based feeds except for lower true digestibility and net protein utilization values for the Anemonia viridis feed. HDL-cholesterol level was significantly higher (p < 0.05) in the groups fed marine species or casein supplemented with olive oil than in the casein group. Total-cholesterol level was higher in the group fed Haliotis tuberculata fed than in the other groups. These results suggest that these marine species are a good protein source, and that they may have positive effects on serum cholesterol level.

The beta blockers: are they as protective in hypertension as in other cardiovascular conditions?

Beta blockers are frequently used to treat hypertension because of their well established safety and efficacy. Large clinical trials yield a 12%--20% decline in cardiovascular end points in hypertensive patients treated with beta blockers. However, beta blockers account for only 11% of antihypertensive prescriptions, and their use appears to be declining as newer agents with fewer side effects become available. The metabolic side effects of beta blockers have recently been examined. While they may raise triglycerides, lower high-density lipoprotein cholesterol, induce glucose intolerance, and possibly unmask diabetes, these effects have not been shown to impact their clinical effectiveness. For hypertension, beta blockers are still recommended as first-line therapy in many patients, particularly those at high risk for cardiovascular disease. They are also indicated for other cardiovascular disorders, such as congestive heart failure and postmyocardial infarction, in which mortality reductions exceed that seen with hypertension treatment in patients without cardiovascular complications. (c)2001 Le Jacq Communications, Inc.