Food oxalate: Factors affecting measurement, biological variation, and bioavailability

Department of Food Science and Human Nutrition, Washington State University, Spokane, WA 99210-1495, USA.
Journal of the American Dietetic Association (Impact Factor: 3.92). 08/2007; 107(7):1191-4; quiz 1195-6. DOI: 10.1016/j.jada.2007.04.007
Source: PubMed

ABSTRACT Food and nutrition professionals provide medical nutrition therapy for patients with kidney stones. If the stones contain oxalate or the patient has been diagnosed with hyperoxaluria, reduction of dietary oxalate may be appropriate. Differences in oxalate values for a single food may be due to analytical methods, and/or biological variation from several sources, including cultivar, time of harvest, and growing conditions. Bioavailability of food oxalate and, thus, urine oxalate, will also be affected by salt forms of oxalate, food processing and cooking methods, meal composition, and the presence of Oxalabacter formigenes in the patient's gut. Dietary advice for reducing urinary oxalate should include both reduction of dietary oxalate and simultaneous consumption of calcium-rich food or supplement to reduce oxalate absorption.

1 Follower
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cassava is mainly grown for its roots whereas leaves are mostly considered as a byproduct. Cassava leaves are a rich source of protein, minerals, and vitamins. However, the presence of antinutrients and cyanogenic glucosides are the major drawbacks in cassava leaves which limit its human consumption. These antinutrients and toxic compounds of cassava leaves cause various diseases depending on the consumption level. Hence these antinutriens and toxic potential of cassava leaves should be addressed during cassava leaf processing (CLP) before human consumption. Several CLP methods have been developed but every method has its own limitations. Some CLP methods successfully detoxify cassava leaves but simultaneously destroy the nutrients. Efforts have also been made for cassava leaf protein extraction in the form of cassava leaf protein concentrate (CLPC) but protein recovery was very low. This review summarizes the nutrient, antinutrient and toxic composition of cassava leaves, CLPC, different CLP methods, human consumption and diseases caused by cassava leaves. Furthermore, recommendations have been made in order to encourage cassava leaves consumption as an important source of protein and micronutrients.
    Trends in Food Science & Technology 04/2015; 44(2). DOI:10.1016/j.tifs.2015.04.006 · 4.65 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cocoa and dark chocolate have been promoted as health foods due to the high levels of antioxidants found in cocoa beans (Theobroma cacao L.) and their products but they also contain moderate to high levels of oxalates which can cause some health concerns. Fifteen samples of commercially available cocoa powder were collected from four different countries and the total and soluble oxalate content was analysed by HPLC chromatography. The total oxalate contents ranged from 650 to 783mg/100g dry matter (DM), mean 729±8.4mg/100g DM, while the soluble oxalate contents ranged from 360 to 567mg/100g DM, mean 469±15mg/100g DM. The total oxalate contents of 34 samples of dark chocolate collected from 13 different countries ranged from 155 to 485mg/100g DM, mean 254±12mg/100g DM while the soluble oxalate contents ranged from 157 to 351mg/100g DM, mean 216±10mg/100g DM. Oxalate bioavailability was determined by feeding 68.0±0.7g of dark chocolate containing 232.0±2.3mg total oxalate as a test meal to 14 volunteers. The mean availability of total oxalate in the chocolate measured from the increase in urinary oxalate output over the following 6h was 1.82±0.27%.
    Journal of Food Composition and Analysis 11/2011; 24(7):916-922. DOI:10.1016/j.jfca.2011.03.008 · 2.26 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The Role of Organic Acids in the Domestication of Oxalis tuberosa: A New Model for Studying Domestication Resulting in Opposing Crop Phenotypes. Though few crops display directly opposing domesticated phenotypes, these crops may be the key to understanding domestication processes that address conflicting selective pressures in the agricultural ecosystem. Two relatively well-known examples are cassava (Manihot esculenta Crantz), which has high-cyanide and low-cyanide varieties, and potato (Solanum section Petota). Among the potatoes are several species, including the common potato (Solanum tuberosum L.), that have low levels of glycoalkaloids and there are other species of “bitter potato” with elevated levels of glycoalkaloids. We propose that Oxalis tuberosa Molina, “oca,” may represent a third example of such a crop system, with opposing high organic acid and low organic acid cultivars. Each cultivar set has different cultural food preparation practices (“use-categories”), similar to the “use-categories” that have been described for potatoes in the Andes (Brush et al. Economic Botany 35;70–88, 1981; Zimmerer Journal of Biogeography 18;165–178, 1991). Our initial analyses suggest that organic acids in tubers may be an important biochemical difference between use-categories, based on both oxalic acid and pH data. Here, we review our understanding of organic acids in oca tubers, while highlighting areas that merit further investigation. Los ácidos orgánicos y la domesticación de Oxalis tuberosa: un nuevo modelo para el estudio de la domesticación que resulta en los fenotipos domésticos opuestos. Aunque pocos cultivos presentan fenotipos domésticos directamente opuestos , estos cultivos pueden ser la clave para entender los procesos de domesticación que muestran conflicto en la presión selectiva en el ecosistema agrícola. Dos ejemplos relativamente bien conocidos son la yuca (Manihot esculenta Crantz), que tiene variedades de alto y bajo contenido de cianuro, y la papa (Solanum sección Petota). Entre las papas hay varias especies, incluyendo la papa común (Solanum tuberosum L.), que tienen bajos niveles de glicoalcaloides mientras otras especies como las "papas amargas", tienen elevados niveles de glicoalcaloides. Nosotros proponemos que Oxalis tuberosa Molina, oca, puede representar un tercer ejemplo de este sistema de cultivo, con niveles altos y bajos de ácidos orgánicos. Cada grupo de variedades de oca tiene diferentes practicas culturales respecto a su preparación como alimentos (categorías de uso), similar a las categorías de uso que se han descrito para las papas en los Andes (Brush et al. Economic Botany 35;70–88, 1981; Zimmerer Journal of Biogeography 18;165–178, 1991). Los análisis iniciales sugieren que los ácidos orgánicos en los tubérculos pueden deberse a una diferencia bioquímica importante entre el uso de categorías basadas en el ácido oxálico y los datos de pH. En este artículo examinamos nuestra interpretación de los ácidos orgánicos en los tubérculos de oca, además de destacar las áreas que merecen mayor investigación. Key Words Oxalis tuberosa–domestication–artificial selection–oxalic acid–organic acids–folk classification–Manihot esculenta–Solanum section Petota–Peru
    Economic Botany 01/2011; 65(1):76-84. DOI:10.1007/s12231-010-9141-0 · 0.77 Impact Factor