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Detection of trace amounts of hidden allergens: hazelnut and almond proteins in chocolate.

Scheibe, B., W. Weissa, F. Ruëff, B. Przybilla, A. Gőrg, 2001. Detection of trace amounts of hidden allergens: hazelnut and almond proteins in chocolate. J Chromatogr B, 756:229–237.

Many patients with immediate type allergy to tree pollen also suffer from intolerance to hazelnuts and almonds. Since rather low levels of hazelnut and almond proteins can provoke an allergic reaction in sensitized individuals, an immunoblot technique has been developed for the detection of potentially allergenic hazelnut and almond proteins in chocolate. Initially, IgE binding hazelnut and almond proteins were detected by immunoprobing with allergic patients’ sera. For routine analysis, patients’ sera were substituted with polyclonal rabbit antisera, and sensitivity was enhanced by the use of a chemiluminescent detection method. This technique allowed the detection of less than 0.5 mg of hazelnut or almond proteins per 100 g of chocolate (=5 ppm). It was applied for routine screening purposes in product quality control as well as for optimization of cleaning steps of filling facilities to minimize cross contamination during production.

Whole almonds and almond fractions reduce aberrant crypt foci in a rat model of colon carcinogenesis.

Davis, P.A., and C.K. Iwahashi, 2001. Whole almonds and almond fractions reduce aberrant crypt foci in a rat model of colon carcinogenesis. Cancer Letters. 165:27-33.

Almonds and other nuts appear to confer health benefits despite their high fat content. To assess the effect of almonds on colon cancer, whole almond-, almond meal- or almond oil-containing diet effects on aberrant crypt foci (ACF) in azoxymethane-treated F344 male rats were investigated. Six-week-old male F344 rats were fed the various almond and control diets and given subcutaneous injections of azoxymethane (15 mg/kg body weight) twice 1 week apart. After 26 weeks animals were injected with bromodeoxyuridine 1 h prior to sacrifice, after which colons were evaluated for ACF and cell turnover (labeling index, LI). Whole almond ACF and LI were both significantly lower than wheat bran and cellulose diet groups (-30 and -40%, respectively), while almond meal and almond oil ACF and almond meal LI declines were only significant vs. cellulose (P<0.05). These results suggest that almond consumption may reduce colon cancer risk and does so via at least one almond lipid-associated component.

A randomized controlled trial of a moderate fat, low energy diet compared with a low fat, low energy diet for weight loss in overweight adults.

McManus, K., L. Antinoro, F. Sacks, 2001.  A randomized controlled trial of a moderate fat, low energy diet compared with a low fat, low energy diet for weight loss in overweight adults. Int J Obesity.25:1503-11.

CONTEXT: Long-term success in weight loss with dietary treatment has been elusive. OBJECTIVE: To evaluate a diet moderate in fat based on the Mediterranean diet compared to a standard low-fat diet for weight loss when both were controlled for energy. DESIGN: A randomized, prospective 18 month trial in a free-living population. PATIENTS: A total of 101 overweight men and women (26.5 – 46 kg/m2). INTERVENTION: (1) Moderate-fat diet (35% of energy); (2) low-fat diet (20% of energy). MAIN OUTCOME MEASUREMENTS: Change in body weight. RESULTS: After 18 months, 31/50 subjects in the moderate-fat group, and 30/51 in the low fat group were available for measurements. In the moderate-fat group, there were mean decreases in body weight of 4.1 kg, body mass index of 1.6 kg/m2, and waist circumference of 6.9 cm, compared to increases in the low-fat group of 2.9 kg, 1.4 kg/m2 and 2.6 cm, respectively; P ≤ 0.001 between the groups. The difference in weight change between the groups was 7.0 kg. (95% CI 5.3, 8.7). Only 20% (10/51) of those in the low-fat group were actively participating in the weight loss program after 18 months compared to 54% (27/50) in the moderate-fat group, (P <0.002). The moderate-fat diet group was continued for an additional year. The mean weight loss after 30 months compared to baseline was 3.5 kg (n=19, P=0.03). CONCLUSIONS: A moderate-fat, Mediterranean-style diet, controlled in energy, offers an alternative to a low-fat diet with superior long-term participation and adherence, with consequent improvements in weight loss.

There are many Mediterranean diets.

Noah, A., A.S. Truswell, 2001.  There are many Mediterranean diets. Asia Pacific J Clin Nutr. 10(1):2-9.

Interest in Mediterranean diet began 30 years ago, when Ancel Keys published the results of the famous Seven Countries Study. Since 1945, almost 1.3 million people have come to Australia from Mediterranean countries as new settlers. There are 18 countries with coasts on the Mediterranean sea: Spain, southern France, Italy, Malta, Croatia, Bosnia, Albania, Greece, Cyprus, Turkey, Syria, Lebanon, Egypt, Libya, Malta, Tunisia, Algeria and Morocco. This study from which this report derives aims to investigate the influence of the food habits of immigrants from Mediterranean countries on Australian food intake. Here we look at the ‘traditional’ food habits of the above Mediterranean countries as told by 102 people we interviewed in Sydney, who came from 18 Mediterranean countries to Sydney. Most of the informants were women, their age ranged from 35 to 55 years. The interview was open-ended and held in the informant’s home. It usually lasted around 11/2 hours. The interview had three parts. Personal information was obtained, questions relating to the food habits of these people back in their original Mediterranean countries and how their food intake and habits have changed in Australia were also asked. From the interviews, we have obtained a broad picture of ‘traditional’ food habits in different Mediterranean countries. The interview data was checked with books of recipes for the different countries. While there were similarities between the countries, there are also important differences in the food habits of the Mediterranean countries. Neighboring countries’ food habits are closer than those on opposite sides of the Mediterranean Sea. We suggest that these food habits can be put into four groups. The data here refer to food habits in Mediterranean countries 20 or 30 years ago, as they were recovering from the Second World War. There is no single ideal Mediterranean diet. Nutritionists who use the concept should qualify the individual country and the time in history of their model Mediterranean diet.

U.S. consumption patterns of tree nuts.

Lin, B.H., E. Frazao, J. Allhouse, 2001.  U.S. consumption patterns of tree nuts. Food Review 24(2):54-8.

Americans are more than a little nutty when it comes to their diets. Recent USDA food consumption data show that about 1 in every 10 consumers eats tree nuts (almonds, walnuts, pecans, pistachios, cashews, and others) on any given day, and the amount eaten is fairly small. On average, slightly more than 1 gram of tree nuts are eaten per person per day. Tree nut consumption is higher among wealthier consumers and Whites in the United States. More adults age 40 and above eat tree nuts than younger consumers. A smaller proportion of consumers living in the South and in rural areas consume tree nuts than other consumers.

Electrophoretic and immunological analyses of almond (Prunus dulcis L.) genotypes and hybrids.

Sathe, S.K., S.S. Teuber, T.M. Gradziel, K.H. Roux, 2001. Electrophoretic and immunological analyses of almond (Prunus dulcis L.) genotypes and hybrids. J Agric Food Chem. 49(4): 2043-52.

Aqueous extracts from sixty almond samples representing various genotypes and interspecies hybrids of almond, including almond-peach, were analyzed for protein and peptide content using electrophoresis, Western immunoblotting, and enzyme-linked immunosorbent assay (ELISA). Nondenaturing nondissociating polyacrylamide gel electrophoresis (NDND-PAGE) of the aqueous extracts indicated that a single major storage protein (almond major protein — AMP or amandin) dominated the total soluble protein composition. Denaturing SDS–PAGE analyses of the aqueous extracts revealed that the AMP was mainly composed of two sets of polypeptides with estimated molecular masses in the ranges of 38–41 kDa and 20–22 kDa, regardless of the source; however, distinct variations in the intensity and electrophoretic mobility of some bands were noted between samples. In addition to AMP, several minor polypeptides were also present in all the genotypes, and variations were seen in these as well. Regardless of the genotype, AMP was recognized in Western blots by rabbit polyclonal anti-AMP antibodies, mouse monoclonal anti-AMP antibodies (mAbs), and serum IgE from patients displaying strong serum anti-almond IgE reactivity. As with protein staining results, antibody reactivity also revealed common patterns but displayed some variation between samples. An anti-AMP inhibition ELISA was used to quantify and compare aqueous extracts for various samples. All samples (n = 60) reacted in this assay with a mean +/- standard deviation (sigma n) = 0.82 +/- 0.18 when compared to reference aqueous extract from Nonpareil designated as 1.0.

Detection and stability of the major almond allergen in foods.

Roux, K.H., S.S. Teuber, J.M. Robotham, S.K. Sathe, 2001. Detection and stability of the major almond allergen in foods. J Agric Food Chem. 49:2131-6.

Almond major protein (AMP or amandin), the primary storage protein in almonds, is the major allergen recognized by almond-allergic patients. A rabbit antibody-based inhibition ELISA assay for detecting and quantifying AMP in commercial foods has been developed, and this assay, in conjunction with Western blotting analyses, has been applied to the investigation of the antigenic stability of AMP to harsh food-processing conditions. The ELISA assay detects purified AMP at levels as low as 87 +/-16 ng/mL and can detect almond at between 5 and 37 ppm in the tested foods. The assay was used to quantify AMP in aqueous extracts of various foods that were defatted and spiked with known amounts of purified AMP or almond flour. In addition, AMP was quantified in commercially prepared and processed almond-containing foods. Neither blanching, roasting, nor autoclaving of almonds markedly decreased the detectability of AMP in subsequent aqueous extracts of almonds. Western blots using both rabbit antisera and sera from human almond-allergic patients confirm a general stability of the various peptides that comprise this complex molecule and show that the rabbit antibody-based assay recognizes substantially the same set of peptides as does the IgE in sera from almond-allergic patients.

Chemical and histochemical characterization of cell wall polysaccharides in almond seeds in relation to lipid bioavailability.

Ren, Y, K.W. Waldron, J.F. Pacy, P.R. Ellis, 2001.  Chemical and histochemical characterization of cell wall polysaccharides in almond seeds in relation to lipid bioavailability. Biologically-active phytochemicals in food, (ed.) W. Pfannhauser, G.R. Fenwick & S. Khokhar, Royal Soc. of Chem., Cambridge, U.K. 448-452.

The research team reported that almond cell walls may prevent the body’s absorption of all the fat present in almonds.  Normal chewing of almonds breaks down only some of the cell walls, leaving others intact.  Thus, not all the fat was available for digestion.

Clinical cross-reactivity among foods of the Rosaceae family.

Rodriguez, J., J.F. Crespo, A. Lopez-Rubio, J. de la Cruz-Bertolo, P. Ferrando-Vivas, R. Vives,  P. Daroca, 2000. Clinical cross-reactivity among foods of the Rosaceae family. J Allergy Clin Immunol. 106:183-189.

Background: Foods from the Rosaceae botanical family have been increasingly reported as causes of allergic reaction. Patients frequently have positive skin tests or radioallergosorbent test results for multiple members of this botanical family. Objective: Our purpose was to investigate the clinical cross-reactivity assessed by double-blind, placebo-controlled food challenge (DBPCFC) of Rosaceae foods (apricot, almond, plum, strawberry, apple, peach, and pear). Methods: Thirty-four consecutive adult patients complaining of adverse reactions to Rosaceae were included in the study. Skin prick tests and CAP System (FEIA) were performed with Rosaceae foods in all patients. Clinical reactivity to Rosaceae was systematically evaluated by open food challenges (OFCs), unless there was a convincing history of a recent severe anaphylaxis. Positive reactions on OFCs were subsequently evaluated by DBPCFCs. Results: Twenty-six and 24 patients had positive skin prick tests and CAP FEIA with Rosaceae, respectively; from these 88% and 100% had positive tests with ≥2. No evidence of clinical reactivity was found in 66% percent of positive skin prick tests and 63% of positive specific IgE determinations to fruits. A total of 226 food challenges (including OFC and DBPCFC) were performed in the 28 patients with positive skin prick tests or CAP System FEIA. Of 182 initial OFCs carried out, 26 (14%) reactions were confirmed by DBPCFCs. Overall, 40 reactions were considered positive in 22 patients with positive skin tests or CAP FEIA. Thirty-eight reactions had been previously reported, the remaining two were detected by systematic challenges. Most reactions were caused by peach (22 patients), apple (6), and apricot (5). Ten patients (46%) were clinically allergic to peach and other Rosaceae. Conclusion: Positive skin test and CAP System FEIA should not be taken as the only guide for multi-species dietary restrictions. Nevertheless, the potential clinical allergy to other Rosaceae should not be neglected. If the reported reaction is confirmed, current tolerance to other Rosaceae should be precisely established unless there has been ingestion without symptoms after the reaction.

IgE binding to almond proteins in two CAP-FEIA-negative patients with allergic symptoms to almond as compared to three CAP-FEIA-false-positive subjects.

Pasini, G., B. Simonato, M. Giannattasio, C. Gemignani, A. Curioni, 2000. IgE binding to almond proteins in two CAP-FEIA-negative patients with allergic symptoms to almond as compared to three CAP-FEIA-false-positive subjects. Allergy. 55:955-958.

Background: Allergy to almonds has been frequently reported, but data on the identification of the almond allergens, as well as on the reliability of the methods for in vitro detection of specific IgE for these allergens, are scant. This study aimed to identify the almond allergens and to evaluate the reliability of the CAPFEIA as the standard system for detection of almond-specific IgE with clinical significance. Methods: Immunoblotting performed with an almond-protein extract was carried out on the sera of five patients who had previously been tested by the CAP-FEIA system; two of these patients had tested negative with the CAP-FEIA system but suffered life-threatening laryngeal edema after eating almonds, whereas the other three subjects, who had tested positive with CAP-FEIA, did not present any symptoms subsequent to almond ingestion. Results: The sera of the two symptomatic CAP-FEIA-negative patients had IgE that bound only to a 37-kDa protein in immunoblotting. On the contrary, the sera of the three asymptomatic subjects all showed IgE binding to two almond proteins of 62 and 50 kDa, corresponding to the glycosylated components of the extract. Conclusions: The results here presented suggest that, at least for the examined subjects, the positivity to almond, as measured with a standard laboratory method, is due to the presence of the 62/50-kDa glycoproteins with little or no immunologic significance, and not to the binding to the 37-kDa polypeptide, which appears to be a true almond allergen.