Fleischer, D.M., 2007. The natural history of peanut and tree nut allergy. Current Allergy and Asthma Reports. 7:175–181.
Peanut and tree nut allergies were once thought to be permanent. Recent studies have shown that about 20% and 10%, respectively, of young patients may outgrow peanut and tree nut allergies. For the majority of patients, however, the natural history is not favorable. In addition, approximately 8% of patients who outgrow peanut allergy may suffer a recurrence. The rising prevalence of these allergies, coupled with the knowledge that allergic reactions to these foods have the potential to be severe or fatal and that accidental exposures are common, makes developing effective treatments to alter the natural history of peanut and tree nut allergies even more crucial for those who will not outgrow them. At this time, avoidance of the offending foods and being prepared to treat a potential reaction after accidental ingestion is the only treatment, but many promising therapeutic interventions are being investigated.
Jebb, S.A., 2007. Dietary determinants of obesity. Obesity Reviews.8 (Suppl. 1)93-97
One of the few incontrovertible facts about obesity is that weight is only gained when energy intake exceeds energy needs for a prolonged period. This is clear from studies of basic physiology under standardized conditions and controlled intervention studies involving manipulations of the components of energy balance. However, energy intake must be considered in the context of an individual’s energy needs. Obesity results not from a high absolute energy intake but from intake which exceeds energy needs, even as a small fraction of energy flux. It is thus the coupling between intake and expenditure that lies at the heart of the problem. The search for specific dietary factors that increase the risk of obesity is therefore a quest for factors that undermine the innate regulatory control of body weight. There are multiple mechanisms by which this can occur which are explored elsewhere in this series of reviews, including satiety, palatability, food availability or low-energy needs as a consequence of physical inactivity. This review will focus on the evidence for specific dietary determinants of obesity largely from observational and intervention studies.
Ritter, M.M.C., G.P. Savage, 2007. Soluble and insoluble oxalate content of nuts. Journal of Food Composition and Analysis. 20:169-174.
This study was conducted to determine the oxalate contents in common nuts either locally grown or imported into New Zealand. Samples of imported nuts were purchased from supermarkets in Christchurch while locally grown nuts were obtained directly from the growers. In this experiment gastric soluble and intestinal soluble oxalates were extracted from the nuts using an in vitro assay, which involved incubations of the food samples for 2 h at 37 1C in gastric and intestinal juice. The extracted oxalates were then determined by HPLC chromatography. Roasted pistachio nuts and chestnuts contained very low levels (<85 mg/100 g fresh weight (FW)) of gastric soluble oxalate. Peanuts, Spanish peanuts, peanut butter, ginkgo, cashew nuts and pecan nuts all contained relatively low levels of gastric soluble oxalate (147–250 mg gastric soluble oxalate/100 g FW). Almonds, Brazil, pine and candle nuts contained high levels of gastric soluble oxalate (492.0–556.8 mg/100 g FW). The intestinal soluble oxalate is the fraction that will be absorbed in the small intestine. Peanuts, Spanish peanuts, peanut butter, ginkgo and pecan nuts all contained relatively low levels of intestinal soluble oxalate (129–173 mg intestinal soluble oxalate/100 g FW). Almonds, Brazil, cashew and candle nuts contained higher levels of intestinal soluble oxalate (216–305 mg/100 g FW). Pine nuts contained the highest levels of intestinal soluble oxalate (581 mg/100 g FW), while chestnuts and roasted pistachio nuts were low (72 and 77 mg /100 g FW). Overall the mean soluble oxalate content of nuts was 78% of the gastric soluble oxalate content (41–100%). The results obtained in this study confirm that the intestinal soluble oxalate contents of nuts range widely and people who have a tendency to form kidney stones would be wise to moderate their consumption of certain nuts.
Lunn, J., J.L. Buttriss, 2007. Carbohydrates and dietary fiber. Nutrition Bulletin. 32: 21-64
The health benefits of including sufficient dietary fiber in the diet have been well described and have formed the basis of dietary recommendations around the world. However, dietary fiber is a complex dietary entity, consisting of many non-digestible components of food. Debate surrounding the definition and measurement of dietary fiber has resulted in inconsistencies in labeling, description and recommendations set across the world. In the UK, dietary recommendations are made using the fraction of non-digestible material described as non-starch polysaccharide that is measured by the Englyst method. However, the Association of Official Analytical Chemists (AOAC) methods, used widely by the food industry, capture a much greater range of non-digestible material, that some suggest should be included in any definition of dietary fiber. An attempt to resolve such discrepancies, possibly by taking an approach that considers the health effects of fractions not captured in the Englyst method, is probably overdue. Additionally, it is clear that the effects of these various non-digestible components of dietary fiber are not interchangeable, and it is important that fiber comes from a range of sources to ensure maximum health benefits from the fiber in the diet. Traditional ‘insoluble’ fibers are required to add bulk as well as rapidly fermentable, viscous fibers to bring about cholesterol lowering. There is also a convincing argument for including slowly fermented components, such as resistant starches, that are well tolerated in the digestive system and can bring about improvements in gut function. Currently there is insufficient data from well designed human intervention trials to make specific recommendations on the amounts of these fiber components in the diet, but it may be useful for health professionals to talk in terms of the different food sources of these types of fiber, as well as total fiber amounts.
Larsson, S.C., A. Wolk, 2007. Magnesium intake and risk of type 2 diabetes: a meta-analysis. J Intern Med. 262(2):208 – 214.
Objective. To assess the association between magnesium intake and risk of type 2 diabetes. Design. Meta-analysis of prospective cohort studies. Data Sources. We retrieved studies published in any language by systematically searching MEDLINE from 1966 to February 2007 and by manually examining the references of the original articles. Study Selection. We included prospective cohort studies reporting relative risks with 95% confidence intervals for the association between magnesium intake and incidence of type 2 diabetes. Results. The seven identified cohort studies of magnesium intake [from foods only (n = 4) or from foods and supplements combined (n = 3)] and incidence of type 2 diabetes included 286 668 participants and 10 912 cases. All but one study found an inverse relation between magnesium intake and risk of type 2 diabetes, and in four studies the association was statistically significant. The overall relative risk for a 100 mg day-1 increase in magnesium intake was 0.85 (95% CI, 0.79-0.92). Results were similar for intake of dietary magnesium (RR, 0.86; 95% CI, 0.77-0.95) and total magnesium (RR, 0.83; 95% CI, 0.77-0.89). There was no evidence of publication bias (P = 0.99). Conclusions. Magnesium intake was inversely associated with incidence of type 2 diabetes. This finding suggests that increased consumption of magnesium rich foods such as whole grains, beans, nuts, and green leafy vegetables may reduce the risk of type 2 diabetes.
Rona, R.J., T. Keil, C. Summers, D. Gislason, L. Zuidmeer, E. Sogergren, S.T. Sigurdardottir, T. Lindner, K. Goldhahn, J. Dahlstrom, D. McBride, C. Madsen, 2007. The prevalence of food allergy: a meta-analysis. Allergy Clin Immunol. 120:638-646.
Background: There is uncertainty about the prevalence of food allergy in communities. Objective: To assess the prevalence of food allergy by performing a meta-analysis according to the method of assessment used. Methods: The foods assessed were cow’s milk, hen’s egg, peanut, fish, shellfish, and an overall estimate of food allergy. We summarized the information in 5 categories: self-reported symptoms, specific IgE positive, specific skin prick test positive, symptoms combined with sensitization, and food challenge studies. We systematically searched MEDLINE and EMBASE for publications since 1990. The meta-analysis included only original studies. They were stratified by age groups: infant/preschool, school children, and adults. Results: A total of 934 articles were identified, but only 51 were considered appropriate for inclusion. The prevalence of self-reported food allergy was very high compared with objective measures. There was marked heterogeneity between studies regardless of type of assessment or food item considered, and in most analyses this persisted after age stratification. Self-reported prevalence of food allergy varied from 1.2% to 17% for milk, 0.2% to 7% for egg, 0% to 2% for peanuts and fish, 0% to 10% for shellfish, and 3% to 35% for any food. Conclusion: There is a marked heterogeneity in the prevalence of food allergy that could be a result of differences in study design or methodology, or differences between populations. Clinical implications: We recommend that measurements be made by using standardized methods, if possible food challenge. We need to be cautious in estimates of prevalence based only on self-reported food allergy.
Fitó, M., M. Guxens, D. Corella, G. Sáez, R. Estruch, R. de la Torre, F. Francés, C. Cabezas, M. del C. López-Sabaterl, J. Marrugat, A. García-Arellano, F. Arós, V. Ruiz-Gutierrez, E. Ros, J. Salas-Salvadó, M. Fiol, R. Solá, M.I. Covas; for the PREDIMED Study, 2007. Effect of a traditional Mediterranean diet on lipoprotein oxidation: a randomized controlled trial. Arch Intern Med. 167:1195-203.
Background: Despite the richness in antioxidants of the Mediterranean diet, to our knowledge, no randomized controlled trials have assessed its effect on in vivo lipoprotein oxidation. Methods: A total of 372 subjects at high cardiovascular risk (210 women and 162 men; age range, 55-80 years), who were recruited into a large, multicenter, randomized, controlled, parallel-group clinical trial (the Prevencio’n con Dieta Mediterra’nea [PREDIMED] Study) directed at testing the efficacy of the traditional Mediterranean diet (TMD) on the primary prevention of coronary heart disease, were assigned to a low-fat diet (n=121) or one of 2 TMDs (TMD + virgin olive oil or TMD + nuts). The TMD participants received nutritional education and either free virgin olive oil for all the family (1 L/wk) or free nuts (30 g/d). Diets were ad libitum. Changes in oxidative stress markers were evaluated at 3 months. Results: After the 3-month interventions, mean (95% confidence intervals) oxidized low-density lipoprotein (LDL) levels decreased in the TMD + virgin olive oil (−10.6 U/L [−14.2 to −6.1]) and TMD + nuts (−7.3 U/L [−11.2 to −3.3]) groups, without changes in the low-fat diet group (−2.9 U/L [−7.3 to 1.5]). Change in oxidized LDL levels in the TMD + virgin olive oil group reached significance vs that of the low-fat group (P=.02). Malondialdehyde changes in mononuclear cells paralleled those of oxidized LDL. No changes in serum glutathione peroxidase activity were observed. Conclusions: Individuals at high cardiovascular risk who improved their diet toward a TMD pattern showed significant reductions in cellular lipid levels and LDL oxidation. Results provide further evidence to recommend the TMD as a useful tool against risk factors for CHD.
Ryan, E., K. Galvin, T.P. O’Connor, A.R. Maguire, N.M. O’Brien, 2006. Fatty acid profile, tocopherol, squalene and phytosterol content of brazil, pecan, pine, pistachio and cashew nuts. International Journal of Food Sciences and Nutrition. 57(3/4):219-228.
Nuts contain bioactive constituents that elicit cardio-protective effects including phytosterols, tocopherols and squalene. The objective of the present study was to determine the total oil content, peroxide value, fatty acid composition and levels of tocopherols, squalene and phytosterols in oil extracted from freshly ground brazil, pecan, pine, pistachio and cashew nuts. The total oil content of the nuts ranged from 40.4 to 60.8% (w/w) while the peroxide values ranged from 0.14 to 0.22 mEq O2/kg oil. The most abundant monounsaturated fatty acid was oleic acid (C18:1), while linoleic acid (C18:2) was the most prevalent polyunsaturated fatty acid. The levels of total tocopherols ranged from 60.8 to 291.0 mg/g. Squalene ranged from 39.5 mg/g oil in the pine nut to 1377.8 mg/g oil in the brazil nut. β-Sitosterol was the most prevalent phytosterol, ranging in concentration from 1325.4 to 4685.9 mg/g oil. In conclusion, the present data indicate that nuts are a good dietary source of unsaturated fatty acids, tocopherols, squalene and phytosterols.
Vlieg-Boerstra, B.J., S. van der Heide, C.M.A. Bijleveld, J. Kukler, E.J. Duiverman, S.A.A. Wolt-Plompen, A.E.J. Dubois, 2006. Dietary assessment in children adhering to a food allergen avoidance diet for allergy prevention. European Journal of Clinical Nutrition. 60:1384–1390.
Objective: The purpose of this investigation was to verify if avoidance of allergenic foods in children adhering to a food allergen avoidance diet from birth was complete and feasible, and whether dietary assessment can be used as a tool in predicting the outcome of double-blind, placebo-controlled food challenges (DBPCFCs). Design: Children adhering to an allergen avoidance diet from birth underwent DBPCFCs. The investigator-dietician verified whether the elimination was complete, using food frequency questionnaires for common allergenic foods. Setting: University Medical Centre Groningen, the Netherlands. Subjects: Thirty-eight children aged 1–13 years, who were consecutively referred to the University Medical Centre Groningen for DBPCFC between January 2002 and February 2004. Results: Among the 38 children undergoing DBPCFCs, there were 15 challenges with egg, 15 with peanut, five with hazelnut and three with soy. Fifteen food challenges (39%) were positive. Small quantities of allergenic foods were inadvertently present in the diets of 13 patients (34%), were possibly present in the diets of 14 patients (37%) and could not be identified in the diets of 11 patients (29%). Seven patients (54%) who had inadvertently ingested small quantities of allergenic foods without sequelae had a positive DBPCFC. Conclusion: Dietary avoidance was incomplete and not feasible in most cases. Tolerance of small amounts of allergenic foods does not preclude positive challenge reactions. Dietary assessment does not seem a useful tool in predicting the outcome of DBPCFC in children adhering to an elimination diet. Sponsorship: The Stichting Astma Bestrijding (Foundation for the Prevention of Asthma), The Netherlands.
Sicherer, S.H., D.Y.M. Leung, 2006. Advances in allergic skin disease, anaphylaxis, and hypersensitivity reactions to foods, drugs, and insects. J Allergy Clin Immunol. 118:170-177.
This review highlights some of the research advances in anaphylaxis; hypersensitivity reactions to foods, drugs, and insects; and allergic skin disease that were reported primarily in the Journal in 2005. Although studies documented deficiencies in community management of anaphylaxis, guidelines and National Institutes of Health summary reports provide direction toward improved research and education. At least 9% of young children ‘‘outgrow’’ a tree nut allergy. Advances in food allergy diagnosis include reports of probability of reactions to peanut at various peanut-specific IgE concentrations and skin test response size and the utility of evaluating IgE binding to specific epitopes. Future food allergy treatments might include selection of ‘‘less allergenic’’ fruit cultivars, genetic silencing of major allergens, and treatment of allergic patients with Chinese herbal remedies. Osteopontin might be a useful biomarker for success of venom immunotherapy. Progress in our understanding of the immunology of atopic dermatitis and autoimmune urticaria has also been made. These observations will likely contribute toward optimizing management of these common allergic disorders.
