Hunger in young children of Mexican immigrant families

OBJECTIVE: To measure rates of hunger and food insecurity among young US-born Latino children with Mexican immigrant parents (Latinos) compared with a non-immigrant non-Latino population (non-Latinos) in a low-income clinic population. DESIGN, SETTING AND SUBJECTS: A repeated cross-sectional survey of 4278 caregivers of children < 3 years of age in the paediatric clinic of an urban county hospital for a 5-year period from 1998 to 2003. A total of 1310 respondents had a US-born child with at least one parent born in Mexico. They were compared with a reference group comprised of non-Latino US-born participants (n = 1805). Child hunger and household food insecurity were determined with the US Household Food Security Scale. RESULTS: Young Latino children had much higher rates of child hunger than non-Latinos, 6.8 versus 0.5%. Latino families also had higher rates of household food insecurity than non-Latinos, 53.1 versus 15.6%. Latino children remained much more likely to be hungry (odds ratio (OR) = 13.0, 95% confidence interval (CI) = 5.9-28.7, P < 0.01) and in household food-insecure households (OR = 6.6, 95% CI = 5.2-8.3, P < 0.01) than non-Latinos after controlling for the following variables in multivariate analysis: child's age, sex, maternal education level, single-headed household status, family size, young maternal age ( < 21 years), food stamp programme participation, TANF (Temporary Assistance to Needy Families, or 'welfare') programme participation and WIC (Women, Infants, and Children) usage, and reason for clinic visit (sick visit versus well-child). CONCLUSION: Young children in Mexican immigrant families are at especially high risk for hunger and household food insecurity compared with non-immigrant, non-Latino patients in a low-income paediatric clinic.     

Beyond-brand effect of television food advertisements on food choice in children: the effects of weight status

OBJECTIVE: To investigate the effect of television food advertising on children's food intake, specifically whether childhood obesity is related to a greater susceptibility to food promotion. DESIGN: The study was a within-subject, counterbalanced design. The children were tested on two occasions separated by two weeks. One condition involved the children viewing food advertisements followed by a cartoon, in the other condition the children viewed non-food adverts followed by the same cartoon. Following the cartoon, their food intake and choice was assessed in a standard paradigm. SETTING: The study was conducted in Liverpool, UK. SUBJECTS: Fifty-nine children (32 male, 27 female) aged 9-11 years were recruited from a UK school to participate in the study. Thirty-three children were normal-weight (NW), 15 overweight (OW) and 11 obese (OB). RESULTS: Exposure to food adverts produced substantial and significant increases in energy intake in all children (P < 0.001). The increase in intake was largest in the obese children (P = 0.04). All children increased their consumption of high-fat and/or sweet energy-dense snacks in response to the adverts (P < 0.001). In the food advert condition, total intake and the intake of these specific snack items correlated with the children's modified age- and gender-specific body mass index score. CONCLUSIONS: These data suggest that obese and overweight children are indeed more responsive to food promotion, which specifically stimulates the intake of energy-dense snacks.     

Television food advertising to children: the extent and nature of exposure

OBJECTIVE: To describe the pattern and prevalence of food and drink advertisements to children on commercial television in Sydney, Australia, and compare these with advertising regulations set out in the Children's Television Standards and results from a similar study in 2002. DESIGN: Data were collected by recording television from 06.00 hours until 23.00 hours on all three commercial channels from Sunday 14 May 2006 to Saturday 20 May 2006 (357 h). The study analysed advertisements in two children's viewing periods, one as defined in the 2002 study and the other according to current standards. Food advertisements were coded using 18 food categories and were analysed by time period and popular children's programmes. RESULTS: Food advertisements occurred in similar proportions during children's viewing hours and adult's viewing hours (25.5 vs. 26.9% of all advertisements, respectively), although there was a higher rate of high-fat/high-sugar food advertisements during children's viewing hours (49 vs. 39% of all food advertisements, P < 0.001). There were even more advertisements for high-fat/high-sugar foods during popular children's programmes, contributing to 65.9% of all food advertisements. Estimates of exposure indicate that children aged 5-12 years were exposed to 96 food advertisements, including 63 high-fat/high-sugar advertisements per week. Since 2002, there has been a reduction in overall food and high-fat/high-sugar food advertisements.CONCLUSION: Despite reductions in overall levels of food advertising, children continue to experience high levels of exposure to food advertisements, which remain skewed towards unhealthy foods. Further food advertising regulation should be required to curtail the current levels of advertising of high-fat/high-sugar foods to children, to make them commensurate with recommended levels of consumption.     

Organophosphorus pesticide residues in Mexican commercial pasteurized milk

A study was conducted to measure residues of 13 organophosphorus (OP) pesticides, widely used as dairy cattle ectoparasiticides or in crops used for animal feed, in homogenized and pasteurized Mexican milk samples. Four different milk brands with high distribution were collected biweekly during a 12 month period (n = 96) in supermarkets. OP pesticide residues were measured by gas chromatography with a flame photometric detector. Approximately 39.6% of the samples contained detectable levels of OP pesticide residues. Eight samples contained residues exceeding established maximum residue limits (MRL), and the OP pesticides present in these samples were dichlorvos (five samples), phorate, chlorpyrifos, and chlorfenvinphos (one sample, respectively). Average residues of 13 OP pesticides measured were below established MRLs ranging between 0.0051 and 0.0203 ppm.     

Captive breeding promotes aggression in an endangered Mexican fish

We compared the behaviour of wild and captive-bred butterfly splitfins (Ameca splendens), an endangered freshwater fish, to investigate whether captive breeding results in the behavioural divergence of wild and captive individuals. In a first experiment, we examined whether the captive environment allows for the similar expression of behaviours observed in wild fish. The foraging, courtship and aggressive behaviour of fish in their natural habitat (in Mexico) was compared with that of their counterparts that have been bred at London Zoo, UK, for 40 years. These in situ observations revealed that wild fish were preoccupied with searching for food whereas captive fish engaged more in aggressive interactions. In a subsequent laboratory experiment we compared the behaviour of wild-caught and captive-bred fish under standard conditions in two novel habitats: structured (enriched) and unstructured (bare) aquaria. Overall, captive-bred butterfly splitfins displayed higher levels of aggression than wild-caught fish. The relationship between aggression and habitat structure was influenced by density; captive-bred males were more aggressive when observed in structured habitats than unstructured ones, but only when they were stocked at a high density. We also found an effect of tank structure on foraging behaviour, with individuals spending more time foraging in unstructured tanks than structured tanks. There was no effect of captive breeding or habitat structure on courtship behaviour.Our findings suggest that captive environments can promote the development of aggressive behaviour which may affect the suitability of captive-bred fishes for reintroduction into the wild.     

Biological and mineralogical features of Andisols in the Mexican volcanic higlands

In the montane grasslands of Mexico, perennial grass and black Andisols are linked in a complex mechanism of soil formation in which both biogenic and mineral products interact. In this ecosystem, typical of the volcanic highlands, a sequence of profiles has been studied by macro- and micro-morphology, scanning and transmission electron microscopy (TEM), infra-red spectroscopy of soil samples and humic acid (HA) extracts, radiocarbon dating and pollen record, soil moisture and available water determinations and soil water analyses. The grass Muhlennberrgia macroura is important in the soil-forming process as it is the host of micro- and meso-fauna which produce abundant organic micro-aggregates. Soil formation began 7550 years ago and continued through several climatic and vegetation changes. The soil thickens as its age increases. Mineral neoformation is oriented towards allophane and halloysite, rather than Al-rich minerals such as imogolite and gibbsite, and high Si contents are observed in the soil water. The black Andisols have high water and carbon storage capacities and play a prominent role in regulating drainage. Presentday destruction of the grassland for potato cultivation will decrease the waterer reserve of these volcanic highlands.     

Morphological Changes in Leaves of Mexican Lime Affected by Iron Chlorosis

Iron (Fe) chlorosis reduces the concentration of photosynthetic pigments, photosynthates, and crop yield. The effect of Fe chlorosis on leaf composition and cell structure was evaluated in Mexican lime (Citrus aurantifolia) with different degrees of Fe chlorosis. Iron chlorosis significantly reduced concentrations of chlorophylls a, b, and a + b, and caused thickening of leaves, due to the increase in palisade and spongy parenchyma cells. The chloroplasts of the chlorotic and albino leaves showed a disorganized ultrastructure; they had an elongated shape with disarrayed thylakoids, underdeveloped grana, scarce starch granules, and hole-like folds in the thylakoid membranes. The accumulation of calcium oxalate crystals in the upper and lower sides of the epidermis, crystal length, and total crystal content increased with Fe chlorosis severity. The green leaves, in contrast, had chloroplasts with typical ultrastructure. The degree of Fe chlorosis in the leaves significantly affected the concentrations of potassium (K); Fe, manganese (Mn), Fe²⁺, and the phosphorus (P)/Fe and K/calcium (Ca) ratios.     

Deforestation and extant distributions of Mexican endemic mammals

Deforestation threatens biodiversity conservation worldwide, but little quantitative information is available on how it affects individual species’ distributions. We modeled potential distributions of 85 continental endemic Mexican mammal species using ecological niche modeling, and produced testable predictions of species’ extant distributions by limiting ecological niches to remnant untransformed habitat based on the Inventario Nacional Forestal 2000. We included point occurrence data for all endemics only from collecting localities prior to 1970, before wide areas of habitat transformation occurred nationwide. Most endemics (61 of 85, 72%) showed a high proportion of transformed habitat (34.5%) at the national level. More than one-fourth of the endemics (23 out of 85, 27%) lost more than 50% of untransformed habitat within their potential distributions; two showed drastic areal loss of more than 90%; another two showed a loss of more than 80%. Only 34 of the endemics are listed as endangered or threatened in the Mexican Norma Oficial Mexicana (NOM). No significant association existed between proportional loss and conservation status as assigned in the NOM, nor are correlations significant between original distributional area and area of remnant untransformed habitat. Both findings suggest that geographic location determines extinction risks rather than area per se. Endemics in the state of Veracruz and in the Transvolcanic Belt suffered the most drastic niche reductions and thus appear to be at high extinction risk from further deforestation.