Conjunctival impression cytology (CIC) to detect subclinical vitamin A deficiency: comparison of CIC with biochemical assessments.

By use of sensitivity and specificity analysis, conjunctival impression cytology (CIC) was compared with fasting serum vitamin A levels and relative dose response (RDR) of Guatemalan children. One impression was taken from the temporal bulbar aspect of each eye, fasting serum vitamin A levels were then drawn, 480 RE of oil-based retinyl palmitate was given, and a 5-h postdosing vitamin A level was drawn (RDR procedure). For a 20% RDR cutoff, the sensitivity of CIC was 23% with a specificity of 80% and a positive predictive value of 9% (n = 213 children). Compared with fasting vitamin A levels alone (with 0.70 mumol/L as abnormal), the sensitivity of CIC was 26%, specificity was 81%, and positive predictive value was 22% (n = 221 children). There was no significant difference in the mean serum retinol level between those with abnormal and normal CIC. In this study population CIC does not identify the same group of children with marginal vitamin A as identified biochemically.

Retinol concentrations in capillary dried blood spots from healthy volunteers: method validation.

BACKGROUND: Vitamin A deficiency (VAD) is a major public health problem in the developing world, leading to >3 million eye-related problems in preschool children. Nearly 250 million children have subclinical VAD, resulting in a 23% increase in childhood mortality. Difficulties in obtaining samples to assess VAD have hampered the detection, intervention, and surveillance of VAD. The use of dried blood spots (DBS) could ameliorate many problems of vitamin A assessment. OBJECTIVE: The objective of this study was to validate the use of retinol in DBS for vitamin A assessment by comparing it with venous and capillary serum retinol. DESIGN: Venous and capillary blood specimens were obtained simultaneously from 20 healthy adult volunteers. From each blood specimen, both DBS and liquid serum were prepared (a total of 80 samples). All specimens were maintained at -70 degrees C until HPLC analysis. RESULTS: The mean retinol concentrations in the 4 sample types were as follows: venous serum (2.02 +/- 0.42 micromol/L, or 58 +/- 12 microg/dL), capillary serum (2.06 +/- 0.42 micromol/L, or 59 +/- 12 microg/dL), venous DBS (2.06 +/- 0.49 micromol/L, or 59 +/- 14 microg/dL), and capillary DBS (2.09 +/- 0.45 micromol/L, or 60 +/- 13 microg/dL). Of the 6 possible 2-way combinations, the R(2) values ranged from 0.77 for capillary DBS versus venous DBS to 0.95 for venous serum versus capillary serum. CONCLUSIONS: DBS retinol measured by HPLC is comparable with serum retinol. Thus, it is possible to compare and combine blood retinol concentration data obtained from DBS with current and historic measurements in serum.

Effects of discontinuing coffee intake on iron status of iron-deficient Guatemalan toddlers: a randomized intervention study.

Coffee is one of the first liquids given to infants in Guatemala. To evaluate whether this practice has an adverse effect on iron status, 160 children 12-24 mo of age who had received coffee for > or = 2 mo and had at least one indicator of iron deficiency were stratified by initial hemoglobin concentration (anemic, or nonanemic, ie, hemoglobin > or = 105 g/L) and randomly assigned to a control (continuation of coffee; coffee) or intervention (provided with a substitute consisting of sugar and coloring; substitute) group for 5 mo. Anemic children were provided with iron supplements for 2-3 mo. Hematologic and anthropometric measurements were made before and after the intervention and dietary and morbidity data were collected every 2 wk. A total of 139 children completed the study: 45 coffee, nonanemic; 56 substitute, nonanemic; 19 coffee, anemic; and 19 substitute, anemic. Compliance with the procedures was good: median coffee intake was 891 mL/wk in the coffee group compared with 18 mL/wk in the substitute group (P = 0.0001). There was no significant effect of discontinuing coffee consumption on changes in hemoglobin, hematocrit, ratio of zinc protoporphyrin to heme or plasma iron, zinc or copper in either nonanemic or anemic children, or plasma ferritin in children who did not take iron supplements. In children who took iron supplements, change in plasma ferritin was significantly greater in the substitute group than in the coffee group (106% compared with 1%, P < 0.05). This implies that coffee interferes with the utilization of supplemental iron. It is likely that the amount and strength of coffee consumed by Guatemalan toddlers are too low to significantly affect the other indexes of iron status.

Studies on the application of the relative-dose-response test for assessing vitamin A status in older adults.

We investigated the time course and the reproducibility of the relative-dose-response (RDR) test for assessing vitamin A status in older adults. The maximum plasma retinol response to 480 retinol equivalents (RE) of retinyl palmitate in abnormal responses was at 6 or 7 h after dosing compared with the 5-h sampling interval recommended by others for younger adults and children. With respect to reproducibility, the diagnostic concordance of two RDR tests at 7-d intervals in 14 elders was 71%. In 29% of tests, one test was abnormal and the other normal. Linear regression of the two RDR values in these 14 subjects gave a correlation coefficient of -0.08. We conclude that the procedure for the RDR should be modified when applied to persons greater than 60 y of age, and that multiple repetitions of the test are needed to provide a stable indication of vitamin A stores in an elderly individual.

Plasma response of children to short-term chronic beta-carotene supplementation.

Plasma concentrations of beta-carotene and retinol after supplementation of children with beta-carotene in supplements and in foods were compared in Guatemalan children. The children received 6 mg/d beta-carotene [1000 retinol equivalents (RE)] as purified supplements or as carrots for 20 d and the effects on plasma beta-carotene and retinol concentrations were assessed. Plasma concentrations of beta-carotene were increased by 0.59 +/- 0.65 and 0.60 +/- 0.67 mumol/L after supplementation with beta-carotene capsules for 10 and 20 d, respectively. Addition of cooked carrots to the diet resulted in no significant change in plasma beta-carotene. Fasting plasma retinol concentrations were 1.23 +/- 0.35 mumol/L and were not significantly changed in response to supplementation with either of the carotene treatments with retinyl palmitate (1000 RE/d) for 20 d. Possible explanations for the differences in effects of plasma concentrations between the two methods of supplementation are discussed.

Determination of discretionary salt intake in rural Guatemala and Benin to determine the iodine fortification of salt required to control iodine deficiency disorders: studies using lithium-labeled salt.

The use of discretionary salt, which is salt added during cooking and at the table, as a suitable vehicle for iodine intake was assessed by measuring salt consumption using the lithium-marker technique in rural areas of Guatemala and Benin. In both countries, we studied boys aged 6-12 y and their mothers. Subjects used lithium-labeled salt after all unlabeled salt was removed from their households. In Guatemala, 24-h urine samples for 9 mother-son pairs were collected at baseline and on days 7, 8, and 9 during the use of lithium-labeled salt. Total maternal salt intake averaged 5.2 +/- 1.7 g/d (mean +/- SD), of which 77 +/- 24% came from discretionary sources, whereas Guatemalan boys consumed 1.8 +/- 0.6 g salt/d, of which 72 +/- 12% came from discretionary sources. In Benin, urine collection from 13 mother-son pairs took place at baseline and on days 5 and 7. Beninese mothers had a total salt intake of 9.0 +/- 2.9 g/d and their sons had an intake of 5.7 +/- 2.8 g/d; discretionary salt contributed 52 +/- 14% and 50 +/- 13%, respectively, of total salt consumed. Therefore, fortification of household salt appears to be an appropriate method of controlling iodine deficiency in both countries, although fortification of other salt sources could be considered in Benin.

Conjunctival impression cytology: feasibility of a field trial to detect subclinical vitamin A deficiency.

Two hundred and thirty-six Guatemalan children aged 2-14 y were examined for subclinical vitamin A deficiency by use of conjunctival impression cytology (CIC). The feasibility of the technique and quality of a modified touch procedure were assessed. Neither lid speculum nor physical restraint in the form of a papoose board was used. The CIC technique was easily performed on children aged greater than 3 y but was more difficult among those less than or equal to 3 y. Laboratory processing of specimens is uncomplicated but interpretation may be problematic and requires clearly defined criteria of normal and abnormal cytology as well as careful standardization of readers.

Plasma response to oral beta-carotene in Guatemalan schoolchildren.

The response to oral doses of beta-carotene (0 mg, n = 10; 15 mg, n = 20; and 30 mg, n = 21) was studied in 51 Guatemalan children aged 8-15 y, with mean fasting plasma retinol concentrations of 1.72 +/- 0.38 mumol/L. Beta-carotene was delivered with a chocolate drink containing 8.4 g fat. Serial blood sampling was performed at intervals up to 48 h. Circulating retinol concentrations remained relatively constant. The maximum increases in plasma beta-carotene after the 30- and 15-mg doses for all subjects occurred at 24 h and were 0.29 and 0.23 mumol/L, respectively. Time of maximum increase for individuals varied and average maxima over the 48-h period for individuals were 0.13 and 0.26 mumol/L for the 15- and 30-mg-treatment groups, respectively. Increased plasma beta-carotene concentrations were not predicted by recent intake of dietary vitamin A, fasting plasma concentrations, or anthropometric measurements.

Plant sources of vitamin A and human nutrition revisited: recent evidence from developing countries.

Although certain green edible plants and fruits are natural sources of beta-carotene, their inclusion in the diets of children in third world countries as a practical source of vitamin A may be unrealistic due to cultural bias. Further examination of cultural perceptions and beliefs should be undertaken before proposing or endorsing dietary recommendations.

Plant sources of provitamin A and human nutriture.

Hypovitaminosis A is a problem in many parts of the developing world. Beyond the stop-gap measures of capsule distribution and food fortification, increased consumption of accessible sources of vitamin A, specifically of the carotenoid provitamin A in yellow, orange, and green plants, has been promoted as the sustainable, long-term solution. However, a search of the available literature reveals few examples of human studies to support the effectiveness of this solution. Evidence from feeding studies shows an almost universally poorer uptake of intact carotenoids from plant sources as opposed to pure, chemical sources. With notable exceptions, the bioconversion of plant carotenoids to preformed vitamin A also seems to be inefficient. Epidemiologic observations in poor Third World populations and in vegetarians in an industrialized nation indicate a relatively greater potency for animal sources of vitamin A. In developing countries, low fat intakes, intestinal roundworms, recurrent diarrhea, and tropical enteropathy all may contribute to reduced utilization of plant provitamin A. The accepted 6:1 equivalency of beta-carotene to preformed vitamin A must be challenged and reexamined in the context of dietary plants. The consequences of operating on a miscalculation could be serious indeed for public health programs designed to alleviate and eradicate hypovitaminosis A.

Weanling diarrhea: a case report.

This case report describes a 14-month-old Guatemalan boy suffering from diarrhea and malnutrition. He had been healthy and experienced normal growth until weaning, which began at six months of age. Introduction of semisolid foods at this time was accompanied by bouts of diarrhea and a reduced growth rate. After admission to hospital at 14 months of age, he was found to have protein-energy malnutrition of the edematous type (kwashiorkor) and to be infected with Giardia lamblia. Therapy with metronidazole and a high-protein diet resulted in satisfactory weight gain and cessation of the diarrhea.

Identification and production of local carotene-rich foods to combat vitamin A malnutrition.

OBJECTIVES: To address, with respect to improvement of human vitamin A status by dietary approaches, the three theoretical postulates that: 1) the most practical and economical manner to increase the amount of dietary vitamin A available to low-income persons in low-income nations is through plant sources of provitamin A carotenoids; 2) there will be constraints and limitation to the efficiency of a given intervention approach related to behavioural, cultural, biological and botanical considerations; and 3) the nature of these constraints and limitations must be understood, and then overcome where possible, to maximize the impact of such interventions on the vitamin A status of developing country populations. CONCLUSIONS: We review how local plant sources of provitamin A that would be acceptable for the at-risk populations and outline six settings and scenarios for the processing of carotene-rich foods: 1) cooking for hygiene; 2) long-term preservation; 3) compacting to reduce volume; 4) formulation for specific consumers; 5) improving bioavailability and bioconversion; and 6) to increase 'value added' in commerce. We describe our experiences in Guatemala (with sweet potato flakes), and those of others in the Caribbean, the African Sahel, and East Africa (with solar-drying for preservation of a variety of plants), and in Sri Lanka (with leaf concentrates) in promoting increased carotene-rich food intake, and the lessons learned from their evaluations. This overall approach to combatting endemic hypovitaminosis A in developing countries is evaluated within the constraints of: 1) the volumes of plant-based foods required to satisfy vitamin A requirements; and 2) the controversy over the true bioconversion efficiency of provitamin A from plant sources into the biologically-available active vitamin.

Comparison of three methods for estimating daily individual discretionary salt intake: 24 hour recall, duplicate-portion method, and urinary lithium-labelled household salt excretion.

OBJECTIVE: To compare methods for estimating discretionary salt intake, that is, salt added during food preparation and consumption in the home. SETTING: The study was carried out in a rural Guatemalan village. SUBJECTS: Subjects were selected non-randomly, based on their willingness to cooperate. Nine mother-son dyads participated; the sons were aged 6-9 y. INTERVENTIONS: Three approaches for estimating the discretionary salt consumption were used: 24 h recall; collection of duplicate portions of salt; and urinary excretion of lithium during consumption of lithium-labelled household salt. Total salt intake was assessed from the excretion of chloride over 24 h. RESULTS: The mean discretionary salt consumption based on lithium excretion for mothers was 3.9+/-2.0 g/d (mean +/- s.d.) and for children 1.3+/-0.6 g/d. Estimates from the 24 h recalls and from the duplicate portion method were approximately twice and three times those measured with the lithium-marker technique respectively. The salt intake estimated from the recall method was associated with the lithium-marker technique for both mothers and children (Spearman correlation coefficient, 0.76 and 0.70 respectively). The mean daily coefficient of variation in consumption of discretionary salt measured by the three methods, for mothers and boys respectively, were: lithium marker, 51.7 and 43.7%; 24 h recall, 65.8 and 50.7%; and duplicate portion, 51.0 and 62.6%. CONCLUSIONS: We conclude that an interview method for estimating discretionary salt intake may be a reasonable approach for determining the relative rank-order in a population, especially among female food preparers themselves, but may grossly overestimate the actual intake of salt added during food preparation and consumption.

Effects of discontinuing coffee intake on iron deficient Guatemalan toddlers' cognitive development and sleep.

Coffee is commonly given daily to toddlers in Guatemala. Possible negative effects of coffee ingestion on cognitive development and sleep patterns were assessed in 132 children 12-24 months of age who had received coffee for > 2 months and were iron deficient on at least one indicator. Children were stratified by initial hemoglobin (A= anemic, Hgb < 10.5 g/dl; NA = 'non-anemic', Hgb > or = 10.5 g/dl) and were randomly assigned to an experimental group (S = substitute consisting of sugar and coloring), and a control group (C = continuation of coffee) (42 C-NA; 53 S-NA; 18 C-A; and 19 S-A). Anemic children were provided Fe supplements for 2-3 months. Compliance was assessed every 2 weeks. After 5 months, testers masked to treatment group and anemia evaluated children with the Bayley Scales of Infant Development II in a central location. Scores were the Mental Development Index (MDI), the Psychomotor Development Index (PDI), and scales from the Behavior Rating Scale (BRS). The child's sleep in the previous 24 h was assessed with a set of standardized sleep questions to the care giver on the first visit and every 2 weeks thereafter. No significant effects of treatment on test scores or BRS ratings were found. In the 24 h period reported on at the final visit, children in the Substitute group slept more during the night and overall (night plus naps) than children in the Coffee group, a difference not found at the first visit. No differences were found in sleep difficulty or number of times waking at night. Women's reported coffee intake per day during pregnancy was associated with lower BRS ratings, even after controlling for SES and child age. The effects of postnatal coffee ingestion in Guatemala were seen for sleep duration, but not for cognitive development. Prenatal coffee ingestion was negatively associated with Behavior Rating Scales and should be investigated further.

Intestinal helminths and their influence on the indicators of iron status in the elderly.

The intestinal helminthiasis and hematological status was assessed in 100 elderly residents of two low-land communities, one at sea-level and the other at 61; m, equally representative of men and women. These are beth low-income communities. The population showed a 48% helminth infection rate which consisted of hookworm, Trichuris, and Ascaris infection. The prevalence of each of the individual parasites was considered light to moderate and the intensity of infection was generally low in this population. A strong inverse association between intensity of hookworm infection and hemoglobin levels was observed but only at intensities greater than 2,000 eggs/gram feces. Lower intensities of infection had no apparent influence on hematological status. The evaluation of hematological status using hematocrit and hemoglobin showed different prevalences of risk of anemia of 14.1% and 43.8%, respectively. These differences may reflect the chosen cut-off values. Iron deficiency does not appear to be a major problem in this population with only 5% or 11% having absent stores using the low and high cut-off values of circulating serum ferritin, respectively.

[Dietary pattern and nutrient intake in preschool children from three rural villages in the Province of Santa Rosa, Guatemala]. / Patrón dietético e ingesta de nutrientes de niños pre-escolares de tres aldeas rurales del departamento de Santa Rosa, Guatemala.

We present here the results of a nutritional survey to show the pattern of food consumption, as well as nutrient intake, of 303 pre-school children (six to 71 months old) from three rural hamlets of the South-East region of Guatemala. This survey was performed prior to the establishment of a nutritional intervention in the same geographical area. Information was gathered from June through August 1991, by personnel from the Center for Studies of Sensory Impairment, Aging, and Metabolism (CeSSIAM) using two data collection instruments during home visits. Informats were mothers or other caretakers in charge of the children feeding. Data collected were initially converted to individual food item weight, and then, to micronutrients values. These values were used to establish their adequacy to standard requirements for children of these ages. Results showed a pattern in which corn tortilla, and beans were the most commonly consumed food items. Those items were also the relatively most important sources of calories, protein, and iron. Vitamin A intake was low, and it came mainly from plant sources. Nutrients intake was below the recommended dietary allowances, except for protein and iron.

Haematological response to haem iron or ferrous sulphate mixed with refried black beans in moderately anaemic Guatemalan pre-school children.

OBJECTIVE: Combating iron deficiency in toddlers with iron-fortified food has proved difficult in countries with phytate-rich diets. For this purpose, a new haem iron preparation was developed. The study compared changes in iron status after administration of refried beans with beans fortified with a haem iron preparation or ferrous sulphate (FeSO4). DESIGN: In a masked, stratified-randomised intervention trial, children received five 156-g cans of refried black beans per week for 10 consecutive weeks. The beans-only (control), FeSO4 and haem iron groups were offered a cumulative dose of 155 mg, 1625 mg and 1700 mg of iron from the bean intervention, respectively. Haemoglobin (Hb) and ferritin concentrations were determined at baseline and after 5 and 10 weeks. Compliance was examined weekly. SETTING: A low-income community in Guatemala City. SUBJECTS: One hundred and ten children aged 12-36 months with initial Hb values between 100 and 115 g l(-1). RESULTS: The cumulative intake of beans was approximately 80% of that offered, signifying an additional approximately 1300 mg of either haem or inorganic iron in the corresponding treatment groups over 10 weeks. Hb concentrations increased by the order of 7.3-11.4 g l(-1) during the intervention, but without significant differences across treatments. Average ferritin concentrations were unaffected by treatment assignment. However, post hoc analysis by subgroups of initial high ferritin and initial low ferritin found the Hb increments after 10 weeks in the haem iron group (13.1+/-7.7 g l(-1)) to be significantly greater than the respective increases (6.8+/-11.2 and 6.4+/-8.5 g l(-1)) in the inorganic iron and beans-only groups. CONCLUSIONS: Canned refried beans are a candidate vehicle for fortificant iron. Given the improved colour and organoleptic properties imparted by haem iron added to refried beans, its additional potential for benefiting the iron status of consumers with iron deficiency may recommend it over FeSO4.

Blood retinol and beta-carotene levels in rural Guatemalan preschool children.

Plasma retinol and beta-carotene levels were measured in 502 preschool Guatemalan children from five rural hamlets. Their ages ranged from 6 to 78 months (mean: 42.9 +/- 19.2 months); 45% males and 55% females. The mean retinol value in the whole group was 0.9 +/- 0.4 mumol/l (range: 0.1 to 8.4 mumol/l). There was no significant difference between sexes in retinol mean values nor in the incidence of retinol values less than 0.7 mumol/l (22% in males, 18% in females). When grouped by age and community, significant low retinol mean values were found in two hamlets in the youngest age group (12 to 23 months) as compared to the other age-groups (p < 0.05). In the other two hamlets, there were no significant differences among retinol means by age-group. The highest prevalence of deficient retinol values by age-group was in the 12 to 23 months group (40%), and decreased as age increased. The mean value for beta-carotene in the whole group was 0.13 +/- 0.18 mumol/l (range: 0.01 to 2.23 mumol/l). There were no significant differences in beta-carotene means between sexes in the whole group. Stratifying the beta-carotene data by age-groups and community, values were significantly higher in the 48-59 months and 72-83 months groups, as compared with the other age groups in two of the communities (p < 0.05). Significant differences across communities for beta-carotene were found only in the 12 to 23 months group.

The plasma beta-carotene response to a single meal of carrots in Guatemalan schoolchildren.

Plasma samples were obtained before, and 8 and 24 h after the ingestion of an ad libitum amount of cooked carrots by 23 school children from a peri-urban community in Guatemala City. The single-meal consumption of cooked carrots ranged from a low 122 g to a high of 961 g (mean: 370.5 +/- 237.2 g; median: 268.4 g). The measured beta-carotene content of the carrots was 10.1 mg per 100 g of edible portion; therefore, the range of intake of beta-carotene was 12.4 to 97.0 mg (mean: 37.4 +/- 24 mg; median: 27.1 mg). Changes in plasma beta-carotene levels at 8 h ranged from a decrement of -0.32 mumol/l (-16.98 micrograms/dl) to an increment of 0.79 mumol/l (42.44 micrograms/dl), with a mean of 0.11 +/- 0.24 mumol/l (5.97 +/- 12.82 micrograms/dl). Changes at 24 h were less dramatic than those at 8 h. A regression of the 8-h changes in plasma beta-carotene on the amount of carrot carotene consumed (corrected by body weight) had an r-value of 0.12. Baseline levels of plasma retinol were poor predictors of the plasma beta-carotene response with this sample size (r = 0.10). The magnitude of the plasma response to beta-carotene from carrots appears to be lower than that observed with pure, powdered, crystalline carotenes; moreover, the variability of the post-carrot response seems to be greater--and its association to dosage appears to be weaker--than with the pharmacological beta-carotene.