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Research Nut: Mixed Nuts

Effects of protein, monounsaturated fat, and carbohydrate intake on blood pressure and serum lipids: results of the OmniHeart randomized trial

Appel, L.J., F.M. Sacks, V.J. Carey, E. Obarzanek, J.F. Swain, E.R. Miller III, P.R. Conlin, T.P. Erlinger, B.A. Rosner, N.M. Laranjo, J. Charleston, P. McCarron, L.M. Bishop for the OmniHeart Collaborative Research Group, 2005. Effects of Protein, Monounsaturated Fat, and Carbohydrate Intake on Blood Pressure and Serum Lipids: Results of the OmniHeart Randomized Trial. JAMA. 294:2455-2464.

Context Reduced intake of saturated fat is widely recommended for prevention of cardiovascular disease. The type of macronutrient that should replace saturated fat remains uncertain. Objective To compare the effects of 3 healthful diets, each with reduced saturated fat intake, on blood pressure and serum lipids. Design, Setting, and Participants Randomized, 3-period, crossover feeding study (April 2003 to June 2005) conducted in Baltimore, Md, and Boston, Mass. Participants were 164 adults with pre-hypertension or stage 1 hypertension. Each feeding period lasted 6 weeks and body weight was kept constant. Interventions A diet rich in carbohydrates; a diet rich in protein, about half from plant sources; and a diet rich in unsaturated fat, predominantly monounsaturated fat. Main Outcome Measures Systolic blood pressure and low-density  lipoprotein cholesterol. Results Blood pressure, low-density lipoprotein cholesterol, and estimated coronary heart disease risk were lower on each diet compared with baseline. Compared with the carbohydrate diet, the protein diet further decreased mean systolic blood pressure by 1.4 mm Hg (P = .002) and by 3.5 mm Hg (P=.006) among those with hypertension and decreased low-density lipoprotein cholesterol by 3.3 mg/dL (0.09 mmol/L; P=.01), high density lipoprotein cholesterol by 1.3 mg/dL (0.03 mmol/L; P=.02), and triglycerides by 15.7 mg/dL (0.18 mmol/L; P<.001). Compared with the carbohydrate diet, the unsaturated fat diet decreased systolic blood pressure by 1.3 mm Hg (P = .005) and by 2.9 mm Hg among those with hypertension (P=.02), had no significant effect on low-density lipoprotein cholesterol, increased high-density lipoprotein cholesterol by 1.1 mg/dL (0.03 mmol/L; P=.03), and lowered triglycerides by 9.6 mg/dL (0.11 mmol/L; P=.02). Compared with the carbohydrate diet, estimated 10-year coronary heart disease risk was lower and similar on the protein and unsaturated fat diets. Conclusion In the setting of a healthful diet, partial substitution of carbohydrate with either protein or monounsaturated fat can further lower blood pressure, improve lipid levels, and reduce estimated cardiovascular risk.

Advances in seed protein research: A perspective on seed allergens.

Sathe, S.K., H.H. Kshirsagar, K.H. Roux, 2005. Advances in seed protein research: A perspective on seed allergens. J Food Sci. 70(6):r93–r120.

For various reasons, a considerable majority of the global population must rely on plant proteins obtained from cereals, legumes (including oilseeds), fruits, vegetables, and nuts to satisfy dietary protein needs and requirements. Edible seeds are a significant source of proteins in livestock production and in the manufacture of pet foods. In addition, edible seeds are important sources of carbohydrates (including dietary fiber), minerals, and certain vitamins in human and animal food supply. For various reasons, edible seeds are underutilized as human food. To fully exploit this renewable natural resource to its full potential, focused research efforts are warranted. With increased number of seed proteins being identified as food allergens, renewed interest in seed proteins is evident. In this article, a brief overview of seed proteins with special reference to their allergenicity is provided. An attempt is made to identify areas needing further research.

Prevalence of sensitization to food allergens, reported adverse reaction to foods, food avoidance, and food hypersensitivity among teenagers.

Pereira, B., C. Venter, J. Grundy, C.B. Clayton, S.H. Arshad, T. Dean, 2005. Prevalence of sensitization to food allergens, reported adverse reaction to foods, food avoidance, and food hypersensitivity among teenagers. J Allergy Clin Immunol. 116:884-892.

Background: There is a paucity of information on food hypersensitivity (FHS) among teenagers. Objectives: We sought to investigate the sensitization rates, perception of FHS, food avoidance, and FHS assessed by means of food challenges among teenagers. Methods: This cohort study recruited 757 eleven-year-olds and 775 fifteen-year-olds in the United Kingdom. Sensitization rates, reported rates of FHS, and rates of food avoidance were measured. The prevalence of FHS was established by using food challenges. Results: The prevalence of reported FHS among the 11- and 15-year-old cohorts was 11.6% (90/775) and 12.4% (94/757), respectively. One hundred twenty-two (15.7%) and 142 (18.7%) of the 11- and 15-year-olds reported they were avoiding some food. The rates of sensitization to the food allergens were 5.1% (36/699) and 4.9% (32/649) for the 11- and 15-year-olds, respectively. FHS was confirmed in 8 (1.0%) 11-year-old children and 8 (1.0%) 15-year-old children by means of open food challenge and in 1 (0.1%) 11-year-old and 4 (0.5%) 15-year-olds by means of double-blind, placebo-controlled food challenge. The prevalence of FHS, as confirmed by using open food challenges and positive skin prick test responses  plus a history of adverse reactions, was 18 (2.3%) of 775 in the 11-year-old cohort and 17 (2.3%) of 757 in the 15-year-old cohort. Conclusions: The rate of reported FHS was significantly more than sensitization to the predetermined allergens (odds ratio, 2.17; 95% CI, 1.47-3.18; P <.001 in the 11-year-olds; odds ratio, 2.73; 95% CI, 1.81-4.13; P < .001 in the 15-year-olds). By means of objective assessment, 2.3% of both 11- and 15-year-old children had FHS, with the majority showing immediate reactions.

 

A framework for measuring costs to society of IgE-mediated food allergy.

Miles, S., R. Fordham, C. Mills, E. Valovirta, M. Mugford, 2005. A framework for measuring costs to society of IgE-mediated food allergy. Allergy. 60:996–1003.

Both immunoglobulin E (IgE)-mediated food allergy and food intolerance can lead to many changes in personal behaviour and health care resource use which have important economic consequences. These costs will impact directly, indirectly and intangibly on both individuals and society in general. It is important to measure the cost of illness (COI) of food allergy as a first step in developing and evaluating measures to reduce and control the burden of illness. This paper outlines a framework for assessing COI of food allergy from different viewpoints. It offers a structure for identifying the different cost impacts on allergic and nonallergic consumers, food producers and society as a whole, and for scoping, measurement and valuation of relevant costs. Within this structure, the existing literature is reviewed. This review illustrates the lack of information and clear methodology for assessing costs of food allergy. The paper concludes that there is a need for a more structured research programme to generate data essential for future evaluations of procedures and technologies for the diagnosis, treatment and management of food allergy.

The natural history of tree nut allergy.

Fleischer, D.M., M.K. Conover-Walker, E.C. Matsui, R.A. Wood, 2005. The natural history of tree nut allergy. J Allergy Clin Immunol. 116:1087-1093.

Background: Although 20% of children outgrow peanut allergy, the natural history of tree nut (TN) allergy has not been well studied. Objective: The goals of the study were to estimate the proportion of children who outgrow TN allergy and examine predictors of outgrowing it. Methods: Patients with TN allergy, defined as a history of reaction on ingestion and evidence of TN-specific IgE (TN-IgE) or positive TN-specific IgE level but no history of ingestion, were evaluated. If all current TN-IgE levels were less than 10 kilounits of antibody (kUA)/L, double-blind, placebo-controlled food challenges were offered. Patients who had undergone open TN challenges as part of routine clinical care were also included. Results: Two hundred seventy-eight patients with TN allergy were identified. One hundred one (36%) had a history of acute reactions, 12 (12%) of whom had reactions to multiple TNs and 73 (63%) of whom had a history of moderate-to-severe reactions. Nine of 20 patients who had previously reacted to a TN passed challenges, so that 9 (8.9%; 95% CI, 4% to 16%) of 101 patients with a history of prior TN reactions outgrew TN allergy. Fourteen of 19 who had never ingested TNs but had detectable TN-specific IgE levels passed challenges. One hundred sixty-one did not meet the challenge criteria, and 78 met the criteria but declined challenges. Looking at specific TN-IgE cutoffs, 58% with TN-IgE levels of 5 kUA/L or less and 63% with TN-IgE levels of 2 kUA/L or less passed challenges. Conclusions: Approximately 9% of patients outgrow TN allergy, including some who had prior severe reactions. Although ideal cutoffs for challenge cannot be firmly recommended on the basis of these data, patients aged 4 years or older with all TN-IgE levels of 5 kUA/L or less should be considered for challenge.

Plant food allergies: a suggested approach to allergen-resolved diagnosis in the clinical practice by identifying easily available sensitization markers.

Riccardo Asero, 2005. Plant food allergies: a suggested approach to allergen-resolved diagnosis in the clinical practice by identifying easily available sensitization markers. Int Arch Allergy Immunol. 138:1–11.

Background: Molecular biology techniques have led to the identification of a number of allergens in vegetable foods, but due to the lack of purified food proteins for routine diagnostic use, the detection of sensitizing allergens remains a nearly impossible task in most clinical settings. The allergen-resolved diagnosis of food allergy is essential because each plant-derived food may contain a number of different allergens showing different physical/chemical characteristics that strongly influence the clinical expression of allergy; moreover, many allergens may cross-react with homologue proteins present in botanically unrelated vegetable foods. Objective: Through a review of the available literature, this study aimed to detect ‘markers’ of sensitization to specific plant food allergens that are easily accessible in the clinical practice. Results: There are several ‘markers’ of sensitization to different allergenic proteins in vegetable foods that can be helpful in the clinical practice. Specific algorithms for patients allergic to Rosaceae and to tree nuts were built. Conclusion: Clinical allergologists lacking the assistance of an advanced molecular biology lab may take advantage of some specific clinical data as well as of some ‘markers’ in the difficult task of correctly diagnosing patients with plant food allergy and to provide them the best preventive advice.

Food allergy—accurately identifying clinical reactivity

Sampson H.A., 2005. Food allergy—accurately identifying clinical reactivity. Allergy. 60 (Suppl.79):19-24.

Up to 25% of adults believe that they or their children are afflicted with a food allergy. However, the actual prevalence of food allergy is much lower: approximately 6-8% of children suffer from food allergy during their first 3 years of life, and many children then develop clinical tolerance. Food allergy encompasses a whole spectrum of disorders, with symptoms that may be cutaneous, gastrointestinal or respiratory in nature. Food disorders also differ according to the extent that they are immunoglobulin E (IgE)-mediated. Skin-prick testing is often used to identify food sensitization, although double-blind, placebo-controlled food challenge (DBPCFC) tests remain the gold standard for diagnosis. Recent evidence suggests that quantitative IgE measurements can predict the outcome of DBPCFC tests and can replace about half of all oral food challenges. When an extensive medical history is obtained in combination with IgE quantification, even fewer patients may require formal food challenges. It has also become possible to map the IgE-binding regions of many major food allergens. This may help to identify children with persistent food allergy, as opposed to those who may develop clinical tolerance. In future, microarray technology may enable physicians to screen patients for a large number of food proteins and epitopes, using just a few drops of blood.

Dietary fats, teas, dairy, and nuts: potential functional foods for weight control?

St-Onge, M.P., 2005.  Dietary fats, teas, dairy, and nuts: potential functional foods for weight control? Am J Clin Nutr. 81:7-15.

Functional foods are similar to conventional foods in appearance, but they have benefits that extend beyond their basic nutritional properties. For example, functional foods have been studied for the prevention of osteoporosis, cancer, and cardiovascular disease. They have yet to be related to the prevention of obesity, although obesity is one of the major health problems today. The inclusion of foods or the replacement of habitual foods with others that may enhance energy expenditure (EE) or improve satiety may be a practical way to maintain a stable body weight or assist in achieving weight loss; such foods may act as functional foods in body weight control. Some foods that might be classified as functional foods for weight control because of their effects on EE and appetite—including medium chain triacylglycerols, diacylglycerols, tea, milk, and nuts—are reviewed here. Only human studies reporting EE, appetite, or body weight are discussed. When studies of whole food items are unavailable, studies of nutraceuticals, the capsular equivalents of functional foods, are reviewed. To date, dietary fats seem to be most promising and have been the most extensively studied for their effects on body weight control. However, the weight loss observed is small and should be considered mostly as a measure to prevent weight gain. Carefully conducted clinical studies are needed to firmly ascertain the effect of tea, milk, and nuts on body weight maintenance, to assess their potential to assist in weight-loss efforts, and to ascertain dose-response relations and mechanisms of action for the 4 food types examined.

Identification and characterization of anthocyanins by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry in common foods in the United States: vegetables, nuts, and grain

Wu, X., R.L. Prior, 2005. Identification and characterization of anthocyanins by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry in common foods in the United States: vegetables, nuts, and grains. J. Agric. Food Chem. 53, 3101-3113

Anthocyanins in common foods in the United States, other than fruits and berries, were identified and characterized by high-performance liquid chromatography (HPLC)-electrospray ionization tandem mass spectrometry coupled with diode array detection. Of all of the 40+ vegetables, nuts, and grains screened, seven vegetables, one nut, and one grain were found to contain anthocyanins; the number of anthocyanins detected varied from two in pistachio nuts to 34 in red radishes. The individual anthocyanins were identified by comparing their mass spectrometric data and retention times with those of standards, published data, and reference food samples. In all of the samples analyzed, except for sorghum, only six common anthocyanidins (delphinidin, cyanidin, pelargonidin, petunidin, peonidin, and malvidin) were found as their glycosides. Anthocyanins in certain vegetables such as red cabbage and red radish were highly conjugated with sugars and acylated groups, and thus, their structures were very complicated. Eight different either aliphatic or aromatic acylated groups (acetoyl, coumaroyl, malonoyl, p-hydroxybenzoyl, feruoyl, caffeoyl, sinapoyl, and oxaloyl) were identified in the anthocyanins. In addition to glucose, six other sugar moieties (galactose, xylose, rhamnose, rutinose, sambubiose, and laminaribiose) were observed. Three varieties of sorghum were found to contain 3-deoxyanthocyanidins and their derivatives as major anthocyanins. A number of new anthocyanins were identified in the foods studied. This paper presents complete HPLC profiles and MS spectrometric data, obtained under the same experimental conditions, for common vegetables, pistachio nuts, and sorghum that contain anthocyanins.

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

Phillips, K.M., D.M. Ruggio, M. Ashraf-Khorassani, 2005. Phytosterol composition of nuts and seeds commonly consumed in the United States. J. Agric. Food Chem. 53, 9436-9445.

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. Δ5-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 kernels were richest in phytosterols (270-289 mg/100 g). β-Sitosterol, Δ5-avenasterol, and campesterol were predominant. Campestanol ranged from 1.0 to 12.7 mg/100 g. Only 13 mg/100 g β-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.