Publications

neither a zinc supplement nor phytate-reduced maize nor their combination enhance growth of 6- to 12-month-old guatemalan infants.	after age 6 mo, the combination of breast-feeding and unfortified plant-based complementary feeding provides inadequate zinc (zn). additionally, high phytate intakes compromise the bioavailability of zinc. our principal objective in this randomized controlled, doubly masked trial was to determine the effect of substituting low-phytate maize, a daily 5-mg zinc supplement, or both, in infants between ages 6-12 mo on impaired linear growth velocity, a common feature of zinc deficiency. in the weste ...	2010	20335626
storage, preparation, and usage of fortified food aid among guatemalan, ugandan, and malawian beneficiaries: a field study report.	an important consideration in determining the ability of fortified food-aid commodities to meet the nutritional needs of beneficiaries is the manner in which commodities are utilized and prepared and the degree to which micronutrient losses occur during handling and cooking by the beneficiaries.	2008	18947034
estimated fumonisin exposure in guatemala is greatest in consumers of lowland maize.	fumonisin mycotoxins contaminate maize worldwide. analysis of maize samples (n = 396) collected from fields in guatemala from 2000 to 2003 found that lowland maize (<360 m) had significantly more fumonisin b1 than highland maize (>1200 m). for example, 78% of the lowland samples collected at harvest in 2002 contained >0.3 microg/g of fumonisin b1, whereas only 2% of the highland samples contained >0.3 microg/g. maize from the 2002 crop collected from storage in the highlands just before the 2003 ...	2007	18029490
identification of teosinte, maize, and tripsacum in mesoamerica by using pollen, starch grains, and phytoliths.	we examined pollen grains and starch granules from a large number of modern populations of teosinte (wild zea spp.), maize (zea mays l.), and closely related grasses in the genus tripsacum to assess their strengths and weaknesses in studying the origins and early dispersals of maize in its mesoamerican cradle of origin. we report new diagnostic criteria and question the accuracy of others used previously by investigators to identify ancient maize where its wild ancestor, teosinte, is native. pol ...	2007	17978176
intestinal excretion of endogenous zinc in guatemalan school children.	the intestine is the major route of excretion of endogenous zinc (zn) and has a key role in maintaining zn homeostasis. the principal objective of this paper is to provide an interpretative report of quantities of endogenous fecal zn (efz) excreted by rural guatemalan school children fed either normal or low phytate maize as their principal food staple. efz was measured by a zn stable isotope technique. efz did not differ between control and low phytate maize groups. the overall efz (n = 53) was ...	2007	17585025
understanding the potential impact of transgenic crops in traditional agriculture: maize farmers' perspectives in cuba, guatemala and mexico.	genetically engineered transgenic crop varieties (tgvs) have spread rapidly in the last 10 years, increasingly to traditionally-based agricultural systems (tbas) of the third world both as seed and food. proponents claim they are key to reducing hunger and negative environmental impacts of agriculture. opponents claim they will have the opposite effect. the risk management process (rmp) is the primary way in which tgvs are regulated in the us (and many other industrial countries), and proponents ...	2005	16634221
changes in farmers' knowledge of maize diversity in highland guatemala, 1927/37-2004.	small-scale studies on long-term change in agricultural knowledge might uncover insights with broader, regional implications. this article evaluates change in farmer knowledge about crop genetic resources in highland guatemala between 1927/37 and 2004. it concentrates on maize (zea mays ssp. mays l.) in one guatemalan township, jacaltenango, an area with much ecological and maize diversity. it relies on a particular type of baseline information: lists of farmer-defined cultivars drawn up by ethn ...	2006	16507113
zinc absorption in guatemalan schoolchildren fed normal or low-phytate maize.	poor bioavailability of zinc from high-phytate diets is an important contributory factor to zinc deficiency in low-income populations.	2006	16400050
total fumonisins are reduced in tortillas using the traditional nixtamalization method of mayan communities.	fumonisin b1 (fb1) is a maize mycotoxin. in tortilla preparation, maize is treated with lime (nixtamalization), producing hydrolyzed fb1 (hfb1) due to loss of the tricarballylic acid side chains. this study determined the following: 1) whether nixtamalization by mayan communities reduces total fumonisins, and 2) the steps in the process at which reduction occurs. tortillas prepared by the traditional process contained fb1, fb2 and fb3 and their hydrolyzed counterparts. there were equimolar amoun ...	2003	14519811
iron bioavailability from iron-fortified guatemalan meals based on corn tortillas and black bean paste.	corn masa flour is widely consumed in central america and is therefore a potentially useful vehicle for iron fortification.	2002	11864860
fumonisin b1 and hydrolyzed fumonisin b1 (ap1) in tortillas and nixtamalized corn (zea mays l.) from two different geographic locations in guatemala.	fumonisin b1 (fb1) is a common contaminant of corn worldwide and is responsible for several diseases of animals. in the preparation of tortillas, corn is treated with lime (producing nixtamal) that when heated hydrolyzes at least a portion of the fb1 to the aminopentol backbone (ap1), another known toxin. this study analyzed the amounts of fb1 and ap1 in tortillas and nixtamal from two communities in the central highlands of guatemala where corn is a major dietary staple (santa maria de jesus, s ...	1999	10528731
trace element intakes and dietary phytate/zn and ca x phytate/zn millimolar ratios of periurban guatemalan women during the third trimester of pregnancy.	repeated 24-h recalls (9-14/subject) were conducted on 52 periurban guatemalan pregnant women aged 25 +/- 5 y (means +/- sd). intakes of energy, protein, calcium, zinc, copper, manganese, nonstarch polysaccharide (nsp), phytate, and millimolar ratios of phytate to zinc and (calcium x phytate) to zinc were calculated from food-composition values on the basis of chemical analysis and the literature. mean (+/- sd) daily intakes were as follows: energy 8694 +/- 1674 kj, protein 63.0 +/- 13.3 g, calc ...	1993	8424388
preparation effects on tortilla mineral content in guatemala.	we have previously reported that in guatemala, the calcium, iron, and zinc contents of tortillas from rural areas are higher that that of tortillas from urban centers. this study examines variation in the calcium, iron, zinc and copper content of tortilla according to the implements used for making tortillas and inquires as to whether preparation effects mediate rural-urban variation in tortilla mineral content. tortilla samples and information on how the tortillas were prepared were collected f ...	1993	8002708
problems in the estimation of corn consumption in longitudinal studies in rural guatemala.		1980	7224776
[the protein quality of opaque-2 corn as an ingredient of diets of rural populations of guatemala].		1972	4664552
a protein concentrate from distillery yeast, and its application to supplement corn tortillas.	the purpose of this study was to increase the protein quality of tortillas supplementing them with a protein concentrate obtained from the yeast (saccharomyces cerevisiae) cream from an alcohol distillery. rupture of the yeast cell wall was studied, and a procedure for obtaining a high percentage of broken cells from the yeast was developed. a protein concentrate was obtained from the cell-wall free portion. techniques were developed to obtain the protein concentrate with a low level of nucleic ...	1989	2490894
nutrition in pregnancy in central america and panama.		1975	1130352
microflora of maize prepared as tortillas.	very little is known of the microflora in tortillas, the major component in the diet of many guatemalans and other central americans. based in a guatemalan highland indian village, this study examined the types and amounts of bacteria, yeasts, and molds in tortillas and in their maize precursors. coliforms, bacillus cereus, two species of staphylococcus, and many types of yeast were the main contaminants, but low concentrations of alpha-hemolytic streptococcus, facultative clostridium, and other ...	1975	808168
free amino acid, protein, and fat contents of breast milk from guatemalan mothers consuming a corn-based diet.	diet compositions and breast milk levels of free amino acids, protein, and lipid were compared in lactating american and guatemalan women. the protein in the american diet derived principally from animal sources, whereas that in the guatemalan diet was based most exclusively on cereal grains and legumes. corn, in the form of cornmeal, was the predominant food. because of these dietary differences, the guatemalan women consumed significantly smaller amounts of protein than the american women. the ...	1979	527522