Dismore, M.L., D.B. Haytowitz, S.E. Gebhardt, J.W. Peterson, S.L. Booth, 2003. Vitamin K content of nuts and fruits in the US diet. J Am Diet Assoc. 103:1650-1652.
Assessment of vitamin K dietary intakes has been limited by incomplete vitamin K food composition data for the US food supply. The phylloquinone (vitamin K1) concentrations of nuts (n=76) and fruits (n=215) were determined by high-performance liquid chromatography. Each sample represented a composite of units obtained from 12 to 24 outlets, which provided geographic representation of the US food supply. With the exception of pine nuts and cashews, which contain 53.9 and 34.8 µg of phylloquinone per 100 g of nut, respectively, nuts are not important dietary sources of vitamin K. Similarly, most fruits are not important sources of vitamin K, with the exception of some berries, green fruits, and prunes. Menu planning for patients on warfarin can include a healthy diet including fruits and nuts without compromising the stability of their oral anticoagulation therapy.
Wood, R.A., 2003. The natural history of food allergy. Pediatrics. 111:1631–1637.
The natural history of food allergy refers to the development of food sensitivities as well as the possible loss of the same food sensitivities over time. Most food allergy is acquired in the first 1 to 2 years of life, whereas the loss of food allergy is a far more variable process, depending on both the individual child and the specific food allergy. For example, whereas most milk allergy is outgrown over time, most allergies to peanuts and tree nuts are never lost. In addition, whereas some children may lose their milk allergy in a matter of months, the process may take as long as 8 or 10 years in other children. This review provides an overview of the natural history of food allergy and provides specific information on the natural course of the most common childhood food allergies.
Roux, K.H., S.S. Teuber, S.K. Sathe, 2003. Tree nut allergens. Int Arch Allergy Immunol. 131:234–244.
Allergic reactions to tree nuts can be serious and life threatening. Considerable research has been conducted in recent years in an attempt to characterize those allergens that are most responsible for allergy sensitization and triggering. Both native and recombinant nut allergens have been identified and characterized and, for some, the IgE-reactive epitopes described. Some allergens, such as lipid transfer proteins, profilins, and members of the Bet v 1-related family, represent minor constituents in tree nuts. These allergens are frequently cross-reactive with other food and pollen homologues, and are considered panallergens. Others, such as legumins, vicilins, and 2S albumins, represent major seed storage protein constituents of the nuts. The allergenic tree nuts discussed in this review include those most commonly responsible for allergic reactions such as hazelnut, walnut, cashew, and almond as well as those less frequently associated with allergies including pecan, chestnut, Brazil nut, pine nut, macadamia nut, pistachio, coconut, Nangai nut, and acorn.
Teuber, S.S., S.S. Comstock, S.K. Sathe, K.H. Roux, 2003. Tree nut allergy. Current Allergy and Asthma Reports. 3:54–61.
Tree nuts are clinically associated with severe immunoglobulin E–mediated systemic allergic reactions independent of pollen allergy and with reactions that are usually confined to the oral mucosa in patients with immunoglobulin E directed toward cross-reacting pollen allergens. The latter reactions can progress to severe and life-threatening episodes in some patients. Many patients with severe tree nut allergy are co-sensitized to peanut. Clinical studies on cross-reactivity between the tree nuts are few in number, but based on reports to date, avoidance of the other tree nuts once sensitivity is diagnosed appears prudent unless specific challenges are performed to ensure clinical tolerance. Even then, great care must be taken to avoid cross-contamination. As with other severe food allergies, a recurrent problem in clinical management is the failure of physicians to prescribe self-injectable epinephrine to patients who are at risk of anaphylaxis.
Akkerdaas, J.H., M. Wensing, A.C. Knulst, M. Krebitz, H. Breiteneder, S. de Vries, A.H. Penninks, R.C. Aalberse, S.L. Hefle, R. van Ree, 2003. How accurate and safe is the diagnosis of hazelnut allergy by means of commercial skin prick test reagents? Int Arch Allergy Immunol. 132:132–140.
Background: Allergy to tree nuts, like hazelnuts, ranks among the most frequently observed food allergies. These allergies can start at early childhood and are, in contrast to other food allergies, not always outgrown by the patient. Tree nut allergy is frequently associated with severe reactions. Diagnosis partially relies on in vivo testing by means of a skin prick test (SPT) using commercially available SPT reagents. Methods: Protein and allergen composition of nine commercial SPT solutions was evaluated using standard protein detection methods and specific immunoassays for measurement of five individual allergens. Diagnostic performance was assessed by SPT in 30 hazelnut-allergic subjects, of which 15 were provocation proven. Results: Protein concentrations ranged from 0.2–14 mg/ml. SDS-PAGE/silver staining revealed clear differences in protein composition. The major allergen Cor a 1 was present in all extracts but concentrations differed up to a factor 50. An allergen associated with severe symptoms, Cor a 8 (lipid transfer protein), was not detected on immunoblot in three products, and concentrations varied by more than a factor 100 as was shown by RAST inhibition. Similar observations were made for profilin, thaumatin-like protein and a not fully characterized 38-kD allergen. Ratios of individual allergens were variable among the nine extracts. SPT showed significant difference, and 6/30 patients displayed false-negative results using 3/9 products. Conclusion: Variability in the composition of products for the diagnosis of hazelnut allergy is extreme. Sometimes, allergens implicated in severe anaphylaxis are not detected by immunoblotting. These shortcomings in standardisation and quality control can potentially cause a false-negative diagnosis in subjects at risk of severe reactions to hazelnuts.
Hansen, K.S., B.K. Ballmer-Weber, D. Lüttkopf, P.S. Skov, B. Wüthrich, C. Bindslev-Jensen, S. Vieths, L.K. Poulsen, 2003. Roasted hazelnuts – allergenic activity evaluated by double-blind, placebo-controlled food challenge. Allergy. 58:132–138.
Background: Allergy to hazelnuts is a common example of birch pollen related food allergy. Symptoms upon ingestion are often confined to the mouth and throat, but severe systemic reactions have been described in some patients. The aim of the study was to evaluate the reduction in allergenicity by roasting of the nuts. Methods: Double-blind, placebo-controlled food challenges (DBPCFC) with roasted hazelnuts (140°C, 40 min) were performed in 17 birch pollen allergic patients with DBPCFC-confirmed food allergy to raw hazelnuts. The effect of roasting was further evaluated by skin prick test (SPT), histamine release (HR), measurement of specific IgE, and IgE-inhibition experiments. Results: In 5/17 patients the DBPCFC with the roasted nuts were positive. The symptoms were generally mild and included OAS (oral allergy syndrome) in all patients. Roasting of the nuts significantly reduced the allergenic activity evaluated by SPT, HR, specific IgE, and IgE-inhibition. Immunoblotting experiments with recombinant hazelnut allergens showed sensitization against Cor a 1.04 in 16/17 patients and against Cor a 2 in 7/17 patients. None of the patients were sensitized to Cor a 8. Challenge-positive patients did not differ from the rest in IgE-binding pattern. Conclusions: All the applied methods indicated that roasting of hazelnuts reduces the allergenicity, but since 5/17 birch pollen allergic patients were DBPCFC-positive to the roasted nuts, ingestion of roasted hazelnuts or products containing roasted hazelnuts can not be considered safe for a number of hazelnut allergic consumers. For patients with a history of severe allergic symptoms upon ingestion of hazelnuts, thorough and conscientious food labelling of hazelnuts and hazelnut residues is essential.
Akkerdaas, J.H., M. Wensing, A.C. Knulst, M. Krebitz, H. Breiteneder, S. de Vries, A.H. Penninks, R.C. Aalberse, S.L. Hefle, R. van Ree, 2003. How accurate and safe is the diagnosis of hazelnut allergy by means of commercial skin prick test reagents? Int Arch Allergy Immunol. 132:132–140.
Background: Allergy to tree nuts, like hazelnuts, ranks among the most frequently observed food allergies. These allergies can start at early childhood and are, in contrast to other food allergies, not always outgrown by the patient. Tree nut allergy is frequently associated with severe reactions. Diagnosis partially relies on in vivo testing by means of a skin prick test (SPT) using commercially available SPT reagents. Methods: Protein and allergen composition of nine commercial SPT solutions was evaluated using standard protein detection methods and specific immunoassays for measurement of five individual allergens. Diagnostic performance was assessed by SPT in 30 hazelnut-allergic subjects, of which 15 were provocation proven. Results: Protein concentrations ranged from 0.2–14 mg/ml. SDS-PAGE/silver staining revealed clear differences in protein composition. The major allergen Cor a 1 was present in all extracts but concentrations differed up to a factor 50. An allergen associated with severe symptoms, Cor a 8 (lipid transfer protein), was not detected on immunoblot in three products, and concentrations varied by more than a factor 100 as was shown by RAST inhibition. Similar observations were made for profilin, thaumatin-like protein and a not fully characterized 38-kD allergen. Ratios of individual allergens were variable among the nine extracts. SPT showed significant difference, and 6/30 patients displayed false-negative results using 3/9 products. Conclusion: Variability in the composition of products for the diagnosis of hazelnut allergy is extreme. Sometimes, allergens implicated in severe anaphylaxis are not detected by immunoblotting. These shortcomings in standardization and quality control can potentially cause a false-negative diagnosis in subjects at risk of severe reactions to hazelnuts.
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.
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.
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.
