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Prevalence of peanut and tree nut allergy in the United States determined by means of a random digit dial telephone survey: A 5 year follow-up

Sicherer, S.H., A. Munoz-Furlong, H.A. Sampson, 2003. Prevalence of peanut and tree nut allergy in the United States determined by means of a random digit dial telephone survey: A 5 year follow-up. J Allergy Clin Immunol. 112:1203-1207.

Background: Allergy to peanuts and tree nuts (TNs) is the leading cause of fatal and near-fatal food allergic reactions. Peanut allergy appears to be increasing in prevalence. Objectives: We sought to determine the prevalence of self-reported peanut and TN allergy among the general population of the United States in 2002 by sex and age and to compare the results with prevalence estimates obtained 5 years earlier. Methods: We performed a nationwide, cross-sectional, random telephone survey by using a standardized questionnaire. Results: A total of 4855 households participated (53% participation rate), representing a census of 13,493 individuals. Peanut allergy, TN allergy, or both was self-reported in 166(1.2%; 95% CI, 1.0%-1.4%) individuals in 155 (3.2%; 95% CI, 2.7%-3.7%) households, overall prevalence rates similar to those reported in 1997. Also similar to the 1997 survey, the severity level was high, with 79% reporting respiratory or multiple organ system reactions and 66% experiencing more than 5 lifetime reactions. Despite the severity and reaction frequency, only 74% of the children and 44% of the adults sought evaluation for the allergy, and fewer than half who did were prescribed self-injectable epinephrine. Applying conservative rules to adjust for persons with unconvincing reactions and a false-positive rate of the survey instrument (7%), a final prevalence estimate of 1.04% (95% CI, 0.9%-1.24%) was obtained. A male predominance of peanut-TN allergy was reported in children younger than 18 years (1.7% vs 0.7%, = .02), and a female predominance was reported among adults (1.7% vs 0.9%, = .0008). Although the rate of peanut allergy, TN allergy, or both was not significantly different from 1997 to 2002 among adults, the rate increased from 0.6% to 1.2% among children, primarily as a result of an increase in reported allergy to peanut (0.4% in 1997 to 0.8% in 2002, = .05). Conclusions: Self-reported peanut allergy has doubled among children from 1997 to 2002, and peanut allergies, TN allergies, or both continue to be reported by more than 3 million Americans. Considering that reactions are severe and the allergy is persistent, these allergies represent an increasing health concern.

Nut consumption and body weight

Sabaté, J., 2003.  Nut consumption and body weight. Am J Clin Nutr. 78(suppl):647S-50S.

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 weightý Is recommending increased nut consumption to the general population for CAD prevention sound public health adviceý 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 non-significant 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.

Substitution of saturated with monounsaturated fat in a 4-week diet affects body weight and composition of overweight and obese men

Piers, L.S., K.Z. Walker, R.M. Stoney, M.J. Soares, K. O’Dea, 2003.  Substitution of saturated with monounsaturated fat in a 4-week diet affects body weight and composition of overweight and obese men. British Journal of Obesity. 90:717-27.

This randomized crossover study looked at whether or not substituting saturated fat (SF) with monounsaturated fat (MUFA) effects body weight and composition.  Eight overweight or obese men followed two diets for four weeks each.  The MUFA diet included nuts, olive oil and avocado, while the SFA diet was rich in milk, butter, cream, cheese and fatty meat.  At the end of the study the men had lost more weight and fat mass on the MUFA diet than on the SFA diet.  The researchers concluded that substituting SFA with unsaturated fats, particularly MUFA, can result in a small but significant loss of body weight and fat mass without a significant change in fat intake or total calories.

Nut consumption, body weight and insulin resistance

García-Lorda, P. I. M. Rangil, J. Salas-Salvadó, 2003.  Nut consumption, body weight and insulin resistance. Eur J Clin Nutr. 57(suppl 1):S8-S11.

The beneficial effects of nuts on cardiovascular health are well known. However, since nuts provide a high caloric and fat content, some concern exists regarding a potential detrimental effect on body weight and insulin resistance. The current data available did not support such a negative effect of nut consumption on the short term or when nuts are included on diets that meet energy needs. Furthermore, there is some intriguing evidence that nuts can help to regulate body weight and protect against type II diabetes. This, however, still has to be proved and more research is needed to address the specific effects of nuts on satiety, energy balance, body weight and insulin resistance.

Plant-based foods and prevention of cardiovascular disease: an overview

Hu, F.B., 2003.  Plant-based foods and prevention of cardiovascular disease: an overview. Am J Clin Nutr. 78:544S-51S.

Evidence from prospective cohort studies indicates that a high consumption of plant-based foods such as fruit and vegetables, nuts, and whole grains is associated with a significantly lower risk of coronary artery disease and stroke. The protective effects of these foods are probably mediated through multiple beneficial nutrients contained in these foods, including mono- and polyunsaturated fatty acids, n-3 fatty acids, antioxidant vitamins, minerals, phytochemicals, fiber, and plant protein. In dietary practice, healthy plant-based diets do not necessarily have to be low in fat. Instead, these diets should include unsaturated fats as the predominant form of dietary fat (e.g., fats from natural liquid vegetable oils and nuts), whole grains as the main form of carbohydrate, an abundance of fruit and vegetables, and adequate n-3 fatty acids. Such diets, which also have many other health benefits, deserve more emphasis in dietary recommendations to prevent chronic diseases.

Can we determine a threshold level for allergenic foods by statistical analysis of published data in the literature?

Bindslev-Jensen, C., D. Briggs, M. Osterballe, 2002. Can we determine a threshold level for allergenic foods by statistical analysis of published data in the literature? Allergy. 57: 741–746.

Background: The aim of this paper was to investigate whether a statistical model could be developed to estimate a ‘‘threshold’’ dose for foods eliciting allergic reactions in susceptible patients. The threshold dose is defined to be one that elicits allergic reactions in a given (small) proportion of susceptible patients, using data from published studies. Methods: Based on data available from the literature, we developed a statistical model using the actual allergen content in the four foods, where data for allergen content are available (peanut, soy, egg, milk). Results: The model demonstrated that the threshold doses giving a reaction of one in a million in susceptible patients were within the same order of magnitude for egg, milk and soy, but were an order of magnitude lower for peanut flour: 0.005 mg of cow’s milk, 0.002 mg of fresh hen’s egg, 0.0007 mg of peanut, or 0.0013 mg of soy flour. Conclusions: Although several assumptions were made in creating this statistical model, we demonstrated that the previously published differences in threshold doses for various foods can be largely eliminated by comparing actual allergen content; this may therefore serve as a model for further studies.

Dietary patterns and risk for type 2 diabetes mellitus in U.S. men.

van Dam, R.M., E.B. Rimm, W.C. Willett, M.J. Stampfer, F.B. Hu, 2002. Dietary patterns and risk for type 2 diabetes mellitus in U.S. men. Ann Intern Med. 136:201-209.

Background: The role of diet in the development of type 2 diabetes mellitus remains unsettled. Objective: To examine the association between major dietary patterns and risk for type 2 diabetes mellitus. Design: Prospective cohort study. Setting: United States. Participants: 42 504 male health professionals, 40 to 75 years of age, without diagnosed diabetes, cardiovascular disease, or cancer at baseline. Measurements: Using factor analysis based on data from food frequency questionnaires, we identified and validated two major dietary patterns that we labeled “prudent” (characterized by higher consumption of vegetables, fruit, fish, poultry and whole grains) and “western” (characterized by higher consumption of red meat, processed meat, French fries, high-fat dairy products, refined grains, and sweets and desserts). Relative risks and 95% CIs were adjusted for potential confounders, including body mass index (BMI), physical activity, and cigarette smoking. Results: During 12 years of follow-up (466 508 person-years), we documented 1321 cases of type 2 diabetes. The prudent dietary pattern score was associated with a modestly lower risk for type 2 diabetes (relative risk for extreme quintiles, 0.84 [CI, 0.70 to 1.00]). In contrast, the western dietary pattern score was associated with an increased risk for type 2 diabetes (relative risk, 1.59 [CI, 1.32 to 1.93]; P < 0.001 for trend). A high score for the western dietary pattern combined with low physical activity (relative risk comparing extreme quintiles of dietary pattern score and physical activity, 1.96 [CI, 1.35 to 2.84]) or obesity (relative risk for BMI ≥30 kg/m2 vs. <25 kg/m2, 11.2 [CI, 8.07 to 15.6]) was associated with a particularly high risk for type 2 diabetes. Conclusion: Our findings suggest that a western dietary pattern is associated with a substantially increased risk for type 2 diabetes in men.

Effect of an Indo-Mediterranean diet on progression of coronary artery disease in high-risk patients (Indo-Mediterranean Diet Heart Study): a randomized single-blind trial.

Singh, R.B., G. Dubnov, M.A. Niaz, S. Ghosh, R. Singh, S.S. Rastogi, O. Manor, D. Pella, E.M. Berry, 2002.  Effect of an Indo-Mediterranean diet on progression of coronary artery disease in high-risk patients (Indo-Mediterranean Diet Heart Study): a randomized single-blind trial. Lancet. 360:1455-61.

BACKGROUND: The rapid emergence of coronary artery disease (CAD) in south Asian people is not explained by conventional risk factors. In view of cardioprotective effects of a Mediterranean style diet rich in alpha-linolenic acid, we assessed the benefits of this diet for patients at high risk of CAD. METHODS: We did a randomized, single-blind trial in 1000 patients with angina pectoris, myocardial infarction, or surrogate risk factors for CAD. 499 patients were allocated to a diet rich in whole grains, fruits, vegetables, walnuts, and almonds. 501 controls consumed a local diet similar to the step I National Cholesterol Education Program (NCEP) prudent diet. FINDINGS: The intervention group consumed more fruits, vegetables, legumes, walnuts, and almonds than did controls (573 g [SD 127] vs 231 g [19] per day p<0.001). The intervention group had an increased intake of whole grains and mustard or soy bean oil. The mean intake of alpha-linolenic acid was two-fold greater in the intervention group (1.8 g [SD 0.4] vs 0.8 g [0.2] per day, p<0.001). Total cardiac end points were significantly fewer in the intervention group than the controls (39 vs 76 events, p<0.001). Sudden cardiac deaths were also reduced (6 vs 16, p=0.015), as were non-fatal myocardial infarctions (21 vs 43, p<0.001). We noted a significant reduction in serum cholesterol concentration and other risk factors in both groups, but especially in the intervention diet group. In the treatment group, patients with pre-existing CAD had significantly greater benefits compared with such patients in the control group. INTERPRETATION: An Indo-Mediterranean diet that is rich in alpha-linolenic acid might be more effective in primary and secondary prevention of CAD than the conventional step I NCEP prudent diet.

Nut consumption and decreased risk of sudden cardiac death in the Physicians’ Health Study.

Albert, C.M., M. Gaziano, W.C. Willett, J.E. Manson,  2002.  Nut consumption and decreased risk of sudden cardiac death in the Physicians’ Health Study. Arch. Intern. Med. 162:1382.

Background: Dietary nut intake has been associated with a reduced risk of coronary heart disease mortality; however, the mechanism is unclear. Since components of nuts may have antiarrhythmic properties, part of the benefit may be due to a reduction in sudden cardiac death. – Methods: We prospectively assessed whether increasing frequency of nut consumption, as ascertained by an abbreviated food frequency questionnaire at 12 months of follow-up, was associated with a lower risk of sudden cardiac death and other coronary heart disease end points among 21454 male participants enrolled in the US Physicians’ Health Study. Participants were followed up for an average of 17 years. Results: Dietary nut intake was associated with a significantly reduced risk of sudden cardiac death after controlling for known cardiac risk factors and other dietary habits (for trend, .01). Compared with men who rarely or never consumed nuts, those who consumed nuts 2 or more times per week had reduced risks of sudden cardiac death (relative risk, 0.53; 95% confidence interval, 0.30-0.92) and total coronary heart disease death (relative risk, 0.70; 95% confidence interval, 0.50-0.98). In contrast, nut intake was not associated with significantly reduced risks of non-sudden coronary heart disease death or nonfatal myocardial infarction. Conclusion: These prospective data in US male physicians suggest that the inverse association between nut consumption and total coronary heart disease death is primarily due to a reduction in the risk of sudden cardiac death.

A voluntary registry for peanut and tree nut allergy: Characteristics of the first 5149 registrants.

Background: A voluntary registry of individuals with peanut and/or tree nut allergy was established in 1997 to learn more about these food allergies. Objective: The purpose of this study was to elucidate a variety of features of peanut and tree nut allergy among the first 5149 registry participants. Methods: The registry was established through use of a structured questionnaire distributed to all members of the Food Allergy and Anaphylaxis Network and to patients by allergists. Parental surrogates completed the forms for children under the age of 18 years. Results: Registrants were primarily children (89% of registrants were younger than 18 years of age; the median age was 5 years), reflecting the membership of the Network. Isolated peanut allergy was reported by 3482 registrants (68%), isolated tree nut allergy by 464 (9%), and allergy to both foods by 1203 (23%). Registrants were more likely to have been born in October, November, or December (odds ratio, 1.2; 95% CI, 1.18-1.23; P < .0001). The median age of reaction to peanut was 14 months, and the median age of reaction to tree nuts was 36 months; these represented the first known exposure for 74% and 68% of registrants, respectively. One half of the reactions involved more than 1 organ system, and more than 75% required treatment, frequently from medical personnel. Registrants with asthma were more likely than those without asthma to have severe reactions (33% vs 21%; P < .0001). In comparison with initial reactions, subsequent reactions due to accidental ingestion were more severe, more common outside the home, and more likely to be treated with epinephrine. Conclusions: Allergic reactions to peanut and tree nut are frequently severe, often occur on the first known exposure, and can become more severe over time.