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Biomedical subjects

L A Mejía

Publications and source records attributed to L A Mejía.

At least 19 recordsLinked to original sources
PubMed1995

Fortification of sugar with iron sodium ethylenediaminotetraacetate (FeNaEDTA) improves iron status in semirural Guatemalan populations.

A 32-mo-long, double-blind field study involving one highland control community receiving only vitamin A-fortified sugar and three vitamin A- and FeNaEDTA-sugar-fortified communities, two in the lowlands and one in the highlands of Guatemala, was undertaken to test the effectiveness of this approach in controlling iron deficiency. The communities' population ranged between 1200 and 17000. Sugar fortified with 1 g FeNaEDTA and 15 mg retinol as retinyl palmitate/kg was stable, did not segregate, and was well accepted by the communities. The impact of fortification on iron nutrition was estimated at 8, 20, and 32 mo of intervention. All pregnant women and subjects with severe anemia received supplements or treatment and were excluded from the analysis. Iron stores in the fortified communities increased significantly except for women 18-48 y of age in one lowland community and > 49 y in the highland community. Iron stores in the control community remained unchanged except for a rise among adult males.

Adolescent↗
PubMed1994

[Effect of ripening and drying on pro-vitamin A carotenoid content in pepper (Capsicum annuum var. Anaheim)].

The content of the principal carotenes with biological activity (alpha-, beta, gamma-carotene and beta-criptoxantine) in green pepper (Capsicum annuum var. Anaheim) was determined in order to investigate the vitamin A content during the traditional process of ripening and drying. The analytical technique used was high pressure liquid chromatography (HPLC) with a Novapack C18 column and acetonitrile/methanol/tetrahydrofuran (58V:35V:7V) as a mobile phase. The results showed differences in vitamin A activity of 7.2 +/- 0.8, 51.1 +/- 2.4 and 55.3 +/- 1.2 micrograms of RE/g dry matter for immature, mature and dry pepper fruit respectively (p < 0.05). Approximately 95% of total activity was due to beta-carotene being synthesized faster than the other carotenes under study during the ripening process. Total vitamin A activity reached its highest value at 14 days after harvest (2738.8 +/- 128.6 micrograms RE/100 g of edible portion), with a decrease in activity with time.

Carotenoids↗
PubMed1992

Infant feeding practices among low-income Mexican urban women: a four month follow-up.

We studied the infant feeding practices of 61 healthy women who delivered vaginally and without complications in two public hospitals in the city of Hermosillo, Sonora, Mexico. During the hospital stay, 51% of the women were planning full breastfeeding (full-BF), 43% partial breastfeeding (partial-BF) and 6% exclusive formula feeding (FF). At 2 weeks and 4 months post-partum (pp) the predominant feeding modes were partial-BF (59%) and FF (61%) respectively. The parameters that were positively associated with any breastfeeding at 4 months pp were: social support, previous breastfeeding experience and neonatal feeding mode. The infant feeding policies in both hospitals were not conducive for breastfeeding. The majority of infants were already receiving solid foods and juices by 3 months pp.

Adult↗
PubMed1990

[Psychological, nutritional, socioeconomic aspects and family relations of Mexican children with low school performance].

Two groups of children (aged 4-6 years) living in poor urban areas of Hermosillo (Sonora) and having "low" and "adequate" school achievements, were studied with the objective of determining their psychological, social, economic and nutritional characteristics. They were evaluated by means of standardized psychological tests. Their nutritional condition was assessed by dietary anthropometric and biochemical indicators. The socioeconomic characteristics of their micro-environment were also determined including the degree of home stimulation. It was found that school performance does not depend solely from their execution in psychological tests (Intelligence Quotient and visuomotor and linguistic performance) but also from other micro-environmental factors. The children with "low"school performance were characterized by sub-optimal energy intakes, mild-to-moderate undernutrition, belonged to large families, lived under more crowded conditions, and had a low level of home stimulation. It is concluded that poor nutrition and a disadvantageous micro-environment particularly home stimulation) are important factors related to the poor school performance of the children studied.

Achievement↗
PubMed1988

Hematological effect of supplementing anemic children with vitamin A alone and in combination with iron.

Ninety-nine anemic children aged 1-8 y were divided into four groups. Each group was supplemented for 2 mo with vitamin A, iron, vitamin A plus Fe, or a placebo. Clinical, hematological, and Fe biochemical evaluations were performed at the beginning and end of the study. Vitamin A supplementation produced significant elevations in the serum levels of retinol, blood hemoglobin, hematocrit, erythrocytes, serum Fe, and percent transferrin saturation (%TS) and had no effect on total Fe binding capacity (TIBC) or serum ferritin. Fe supplementation did not affect serum retinol. However, it improved hematological and Fe nutrition indicators, including TIBC and serum ferritin. The simultaneous administration of vitamin A and Fe resulted in a better response of serum Fe and %TS than when the supplement consisted only of vitamin A or Fe alone. Vitamin A benefits hematological condition and Fe metabolism.

Anemia, Hypochromic↗
PubMed1987

Development and evaluation of a simplified method to collect blood samples to determine hemoglobin and hematocrit using chromatographic paper discs.

A simplified method for the simultaneous determination of hemoglobin and hematocrit using dried capillary blood collected on chromatographic paper discs was developed and evaluated under laboratory and field conditions. The paper disc method (PDM) was compared with traditional laboratory methods (TM) in blood samples collected from human subjects with a wide range of hemoglobin and hematocrit values. Associations between PDM and TM were highly significant (p less than 0.001). Correlation coefficients were 0.90454 for hemoglobin and 0.9266 for hematocrit and there were no significant differences between mean values obtained by both procedures. Hemoglobin levels in discs remained unchanged during a storage for 1 mo. Hematocrit values, however, were constant throughout a 6-mo evaluation. On average, the percent coefficients of variation were 3.4 and 8.3% for determinations of hemoglobin and hematocrit, respectively. It is concluded that PDM represents a practical alternative approach for assessing hematological status in the field.

Adult↗
PubMed1986

[Replacement of peanut oil used for the fortification of sugar with vitamin A for other vegetable oils available in Central America].

The objective of this study was to determine the technical feasibility of replacing the peanut oil used in the preparation of the premix to fortify sugar with vitamin A, for other vegetable oils available in Central America. For this purpose, cottonseed, soybean, corn and African Palm oils were tested. Premixes were prepared using each one of the oils and stored for evaluation during a six-month period. A premix prepared with peanut oil was used as a control. It was found that the stability of vitamin A was similar in all premixes; less than 10% of the original activity was lost through the duration of the study. The physical characteristics of the premixes were also acceptable, with the exception of the one containing soybean oil which became caked and rancid. The peroxide content of the oils contained in the premixes increased throughout the study period. The lowest level of oxidation occurred in the premix made with African Palm oil. Its peroxide content changed only from 1.4 to 8.8 mEq/kg of oil. In contrast, that containing soybean oil showed the greatest change in peroxide from 2.8 to 130.0 mEq/kg of oil. It was concluded that it is indeed technically feasible to substitute the peanut oil by another vegetable oil, which should be low in peroxides and of high stability. Furthermore, it should not alter significantly the stability of the vitamin A contained in the premix during storage. On this basis, the African Palm oil was the most suitable one.

Arachis↗
PubMed1985

[Formulation and evaluation of the protein quality of a flour mixture of shark fillet by-products and shrimp heads].

A flour proposed as a protein source for chick feeding was evaluated. The flour consisted in a 1.00:1.15 dry mixture of by-products from shark filleting (dt) and shrimp by products (cc). It had a crude protein content of 55.66%, a Ca:P ratio of 5.76 and an essential amino acid pattern similar to that of fish meal and/or shark meat. Methionine proved to be the first limiting essential amino acid. The shark meat and the by-products from shark filleting had adequate levels of available lysine (from 337 to 383 mg/g N). The flour had a fineness modulus (F.M.) of 3.95, an average particle diameter of 0.0175 inches (0.444 mm) and a uniformity index of 1:5:4 (coarse:medium:fine parts). The flour was considered suitable for chick feeding. The protein quality of the flour mixture (dt-cc) was evaluated in rats using diets which contained 3, 6, 9 and 12% protein from the product, and determining the PER, NPR and NGI values. Diets containing similar protein levels prepared from dried shark meat flour, mixed with casein, were used as standards. The flour mixture (dt-cc) had a PER of 1.60, an NGIo of 2.46, an NGI of 2.49 and an apparent digestibility of 88.80%. These values proved to be significantly (p less than 0.05) lower than those found for the corresponding shark meat flour-casein standard diets. The above results are partially explained by the high mineral content, high Ca:P ratio and high Na and K of the dt-cc mixture, factors which could interfere with the utilization of the most limiting essential amino acids and other nutrients, as some vitamins, in these diets. The Kruskal-Wallis test of the feed efficiency (EA) data obtained in growing chicks revealed that there was a significant (p less than 0.05) difference between the EA values obtained with the dried shark meat-containing diets and the standard commercial diets (Purina and a diet based on a 1.6:1.0 soybean meal:cottonseed meal mixture). No significant differences were found between the dt-cc mixture-containing diets and the commercial ones used as standard. The diet containing 6% shark meat flour was found to be the best based on the EA data. The diet with 12% of the dt-cc mixture gave similar EA values than all those containing shark meat flour; however, the greater nutritional-economic impact based on the EA data was found for the diets containing 3 and 6% of the dt-cc flour mixture.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acids, Essential↗
PubMed1984

Significance of postprandial blood concentrations of retinol, retinol-binding protein, and carotenoids when assessing the vitamin A status of children.

The effect of ingesting a breakfast rich in vitamin A on postprandial blood serum concentration of retinol, retinol-binding protein, and carotenoids has been investigated in children between 5 and 8 yr of age. They were divided by age in two groups (5 to 6 and 7 to 8 yr) and then randomly assigned in three groups to be studied cross-sectionally immediately before and at 2 and 4 h after the ingestion of a meal containing 337 micrograms of retinol equivalents (48% as retinol and 52% as carotenoids). The ingestion of breakfast did not alter significantly (p greater than 0.05) the postprandial serum concentrations of retinol, retinol-binding protein; or carotenoids in any of the age groups. These results indicate that up to 4 h the postprandial blood serum concentrations of these parameters are representative of their corresponding basal concentrations. Therefore, in practice and particularly under field survey conditions, the blood samples required to assess the vitamin A status of children can be obtained either fasting or within 4 h after breakfast without altering the results.

Administration, Oral↗
PubMed1984

Body iron reserves of rural and urban Guatemalan women of reproductive age.

Body iron reserves (using serum ferritin as an index), hematological status, and other indicators of iron nutrition were evaluated in three groups of non-pregnant nulliparous women with ages comprised between 14 and 29 years (mean = 19 years). The first group (n = 33) included residents of the rural coastal area (less than 750 m above sea level) (group RCG); the second (n = 32) from the rural highlands (751-1,500 m) (group RHG); and the third group (n = 104) from urban Guatemala City (1,500 m) (group UG). The women in the UG group belonged to the middle or high socioeconomic stratum. Median values in serum ferritin levels (ng/ml) for each group were: RCG = 11.5 (undetectable 50.6); RHG = 17.2 (1.9-83.1) and UG = 20.2 (3.9-56.7). The difference between RCG and UG was statistically significant (P less than 0.05). The percentage of women with serum ferritin levels less than or equal to 9 ng/ml (iron deficiency) was 45 in the RCG, 25 in the RHG and 12 in the UG group. In addition, the prevalence of subnormal hemoglobin levels (below mean - 1 SD) was 46% in the RCG, 12% in the RHG and 8% in the UG. There were no cases of subnormal blood folate levels. As results indicate, the women studied had low iron reserves, the rural coastal group being the most affected. They also evidenced the high prevalence of iron deficiency in the region and the need for public health actions to overcome this nutrition problem.

Adolescent↗
PubMed1983

Determination of vitamin A in blood. Some practical considerations on the time of collection of the specimens and the stability of the vitamin.

The stability of vitamin A and retinol-binding protein (RBP) in serum separated from the clot at different times after blood extraction and the effect of ingesting a vitamin A-rich breakfast on postprandial serum levels of retinol, carotenoids, and RBP were investigated. In the stability trials, venous blood was drawn from 12 well-nourished young adult subjects and sample aliquots were maintained, respectively, at 4 degree C or at room temperature (26 to 28 degrees C). The serum was separated from the clot either immediately after blood clotting or at 2, 4, 6, 12, and 24 h after blood extraction. Serum retinol and RBP were stable either at 4 degrees C or at room temperature, even if the serum was separated from the clot 24 h after blood extraction. In the breakfast experiment, seven young adult subjects ingested a meal containing 291 microgram of retinol equivalents. The serum levels of retinol, carotenoids, and RBP were measured pre- and postprandially up to a period of 4 h. The ingestion of the breakfast meal did not alter significantly the postprandial serum levels of retinol, carotenoids, or RBP. These results are of practical importance for the performance of vitamin A nutrition surveys involving field work, when as is common, blood specimens cannot be collected under fasting and, in addition, they have to be transported from far away localities to the laboratory.

Adult↗
PubMed1983

Ferritin concentrations in plasma from capillary (finger prick) blood and venous blood compared.

Investigating the feasibility and validity of determining plasma ferritin concentration in blood obtained by finger prick, we studied 29 adults (ages 21-49 years) and 35 children (ages 14-66 months). Blood was sampled simultaneously in the same subject from both the antecubital vein (venous blood) and by finger pricking (capillary blood). The plasma was obtained by centrifugation. Ferritin concentration was determined by immunoradiometric analysis. Ferritin concentration in plasma from capillary blood was significantly higher than in venous plasma (p less than 0.01). This difference was more marked in children. The correlation between ferritin from the two blood sources was highly significant (r2 = 0.945 and 0.994 for samples from adults and children, respectively), and the slopes of the respective regression lines in both children and adults were significantly different from 1 (p less than 0.0001). We conclude that, despite the close association between the two procedures, the determination of ferritin concentration in capillary blood plasma overestimates the concentration of ferritin in venous blood plasma.

Blood Specimen Collection↗
PubMed1982

The effect of vitamin A fortification of sugar on iron metabolism in preschool children in Guatemala.

The effect of improvement in vitamin A nutriture on biochemical indicators of iron nutrition during national vitamin A fortification of sugar was investigated longitudinally. Four "paired-comparison-subgroups" of preschoolers were studied before fortification (survey I) and, respectively, at 6 months (survey I versus II), at 1 yr (survey I versus III), at 1 1/2 yr (survey I versus IV), and at 2 yr (survey I versus V) after fortification began. Comparing I versus II gave a positive correlation (p less than 0.001) between changes in serum retinol or retinol-binding protein and changes in iron, total iron binding capacity, and percentage transferrin saturation. In contrast, changes in serum ferritin correlated negatively (p less than 0.05). Comparing V with I, retinol, retinol-binding protein, iron, and percentage transferritin saturation increased, but ferritin also increased (p less than 0.05). Consequently, the distribution of serum iron and ferritin values of the children improved (p less than 0.05). Because dietary iron did not change through the study period, the results suggest that vitamin A fortification had a favorable effect on iron metabolism and nutritional status.

Child, Preschool↗
PubMed1981

The effect of vitamin A fortification of sugar on the serum vitamin A levels of preschool Guatemalan children: a longitudinal evaluation.

Based on the Guatemalan program of vitamin A fortification of sugar, a longitudinal evaluation on serum retinol levels of preschool-aged children was performed. Five consecutive surveys executed every 6 months were examined, considering only children who were surveyed more than once. Thus, the changes in their serum retinol after the intervention were evaluated. Natural dietary vitamin A remained unchanged throughout. Addition of retinyl palmitate to sugar increased significantly the intake (p < 0.001). After 1 yr of fortification 76% of the children experienced an elevation of retinol. All those with initial values < 20 microgram/dl showed an increase. Mean values increased significantly, particularly for children below 20 microgram/dl whose levels changed from 16.2 +/- 2.9 to 30.2 +/- 9.7 (P < 0.00001). Those between 20 to 29 microgram/dl increased from 24.9 +/- 3.2 to 30.1 +/- 8.1 (p < 0.0003). Similar results were obtained after 2 yr. The results indicated the effectiveness of the program in raising serum retinol levels.

Child, Preschool↗