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Biomedical subjects

K H Brown

Publications and source records attributed to K H Brown.

At least 37 records · Page 2Linked to original sources
PubMed1999

Age of introduction of complementary foods and growth of term, low-birth-weight, breast-fed infants: a randomized intervention study in Honduras.

BACKGROUND: The optimal age at which to introduce complementary foods is a topic of considerable debate. OBJECTIVE: This study was designed to evaluate this issue in a nutritionally vulnerable population in Honduras. DESIGN: Mothers of low-birth-weight (1500-2500 g) term (ie, small-for-gestational-age) infants were recruited in the hospital and assisted with exclusive breast-feeding during the first 4 mo. At 4 mo, mothers were randomly assigned to either continue exclusive breast-feeding to 6 mo (EBF; n = 59) or to feed complementary solid foods (jarred rice cereal, chicken, and fruit and vegetables) twice daily from 4 to 6 mo while continuing to breast-feed at their initial frequency (SF; n = 60). At 4 and 6 mo, breast milk and total energy intake were measured for a nonrandom subsample (those who could stay overnight in a central unit: 32 EBF and 31 SF). RESULTS: At 4 mo, breast milk intake in the subsample was not significantly different between groups (EBF: 729 +/- 135 g/d; SF: 683 +/- 151 g/d: P >0.2); from 4 to 6 mo it increased (by 28 g/d) in the EBF group but decreased (by 39 g/d) in the SF group (P < 0.005). Nonetheless, total energy intake (including solid foods) increased more from 4 to 6 mo in the SF than in the EBF group. However, there were no significant differences between groups in weight or length gain during the intervention or subsequently (6-12 mo). CONCLUSION: There was no growth advantage of complementary feeding of small-for-gestational-age, breast-fed infants between 4 and 6 mo of age.

Adult↗
PubMed1999

A randomized, community-based trial of the effects of improved, centrally processed complementary foods on growth and micronutrient status of Ghanaian infants from 6 to 12 mo of age.

BACKGROUND: Koko, a fermented maize porridge used as the primary complementary food in Ghana, has been implicated in the high prevalence of child malnutrition. Weanimix, a cereal-legume blend developed by the United Nations Children's Fund and the Ghanaian government, has been promoted as an alternative. OBJECTIVE: We evaluated the effect of feeding Weanimix and 3 other locally formulated, centrally processed complementary foods on the nutritional status of 208 breast-fed infants. DESIGN: Infants were randomly assigned to receive 1 of 4 foods from 6 to 12 mo of age: Weanimix (W), Weanimix plus vitamins and minerals (WM), Weanimix plus fish powder (WF), and koko plus fish powder (KF). Dietary and anthropometric data were collected regularly. Blood was collected at 6 and 12 mo of age to assess iron, zinc, vitamin A, and riboflavin status. Before and after the intervention, cross-sectional data on the anthropometric status of infants not included in the intervention (NI; n = 464) were collected. RESULTS: There were no significant differences between intervention groups in weight or length gain or in hemoglobin, hematocrit, transferrin saturation, plasma zinc, or erythrocyte riboflavin values between 6 and 12 mo of age. From 9 to 12 mo of age, z scores were lower in NI infants than in the combined intervention groups [at 12 mo: -1.71 +/- 0.90 compared with -1.19 +/- 0.93 for weight and -1.27 +/- 1.02 compared with -0.63 +/- 0.84 for length (P < 0.001 for both), respectively]. The percentage of infants with low ferritin values increased significantly between 6 and 12 mo of age in groups W, WF, and KF but not in group WM. Change in plasma retinol between 6 and 12 mo of age was significantly greater in group WM than in the other 3 groups combined (0.14 +/- 0.3 compared with -0.04 +/- 0.3 micromol/L, P = 0. 003). CONCLUSIONS: All 4 foods improved growth relative to the NI group. Infants fed WM had better iron stores and vitamin A status than those fed nonfortified foods.

Adult↗
PubMed1999

Use of the deuterated-retinol-dilution technique to assess total-body vitamin A stores of adult volunteers consuming different amounts of vitamin A.

BACKGROUND: The deuterated-retinol-dilution (DRD) technique provides a quantitative estimate of total body stores of vitamin A. However, it is not known whether the technique can detect changes in vitamin A pool size in response to different intakes of vitamin A. OBJECTIVE: Our objective was to determine the responsiveness of the DRD technique to 3 different daily supplemental vitamin A intakes during a period of 2.5-4 mo. DESIGN: Two oral doses of [(2)H(4)]retinyl acetate [52.4 micromol retinol equivalent (RE)] were administered on study days 1 and 91 to 26 men (18-32 y of age) who were consuming controlled, low-vitamin A diets, and receiving daily either 0, 5.2, or 10.5 micromol RE of unlabeled supplemental retinyl palmitate during a 75- or 129-d period. Plasma isotopic ratios of [(2)H(4)]retinol to retinol on day 115 were used to estimate final vitamin A body stores per Furr et al (Am J Clin Nutr 1989;49:713-6). RESULTS: Final ( +/- SD) estimated vitamin A pool sizes were 0.048 +/- 0.031, 0.252 +/- 0.045, and 0.489 +/- 0.066 mmol in the treatment groups receiving 0, 5.2, and 10.5 micromol RE/d, respectively (P < 0.001). Estimated mean changes in vitamin A pool sizes were similar to those expected for the vitamin A-supplemented groups [estimated:expected (95% CI of change in pool size): 1.08 (0.8, 1.2) and 1.17 (1.0, 1.3)]. CONCLUSIONS: The DRD technique can detect changes in total body stores of vitamin A in response to different daily vitamin A supplements. However, abrupt changes in dietary vitamin A intake can affect estimates of total-body vitamin A stores.

Adolescent↗
PubMed1999

Epidemiology of altered intestinal permeability to lactulose and mannitol in Guatemalan infants.

BACKGROUND: Subclinical alterations of small intestinal function have been reported frequently in tropical countries. Studies of small intestinal permeability to lactulose and mannitol were therefore completed in Guatemalan infants from a low-income, periurban community to assess the prevalence of altered intestinal function and the factors associated with this condition. METHODS: Two hundred studies were successfully completed in 158 infants who had been free of diarrhea for at least 1 week before the day of study. Urinary concentrations of lactulose and mannitol during the 5-hour period after ingestion of 400 mg/kg body weight of lactulose and 100 mg/kg body weight of mannitol were measured by gas-liquid chromatography and compared by age group, feeding practices, anthropometric indexes, and serum iron and zinc concentrations. RESULTS: The overall prevalence of altered intestinal permeability (defined as a ratio of urinary recovery of lactulose to mannitol [L/M] > or =0.07) was 30%. The urinary L/M recovery ratio was positively associated with age; low weight for age; and, in infants less than 6 months of age, non-breast-feeding. Children with serum iron concentrations less than 7.16 microM/l (40 [microg/dl) had higher median L/M ratios (L/M = 0.068; 95% confidence interval [CI], 0.054, 0.085) than those with iron levels higher than this cutoff (L/M = 0.052; CI = 0.046, 0.058; p = 0.038). The median urinary L/M recovery ratio in 10 currently asymptomatic infants who had diarrhea during the week before testing (0.087; CI = 0.49, 0.154) was higher than that in children who had been free from diarrhea for at least 1 week (0.052; CI = 0.048, 0.056; p = 0.01). CONCLUSION: Age, feeding practices, low weight-for-age, low serum iron concentration, and recent diarrhea were all associated with altered intestinal function in this group of Guatemalan infants.

Aging↗
PubMed1999

Promoting exclusive breastfeeding for 4-6 months in Honduras: attitudes of mothers and barriers to compliance.

Prospective and retrospective data on maternal attitudes and obstacles to exclusive breastfeeding (EBF) were collected from Honduran mothers of low birthweight (1500-2500 g), term infants who were enrolled in an intervention study to compare infant outcomes in those who were randomly assigned to breastfeed exclusively for either 4 or 6 months. Perceived advantages of EBF were that it was easier, more practical and economical, and resulted in better infant health and growth. Disadvantages included the perceived time demand, concerns that the infant would accept solids less readily, and fears that breast milk alone was insufficient. The majority of study participants said that they would choose to exclusively breastfeed their next infant to 6 months. Although there were many obstacles to EBF, particularly in the first few weeks, women who persevered became enthusiastic proponents of EBF. Messages to promote EBF need to target the entire community, not just mothers, and should focus on addressing common misconceptions and alerting women to potential problems before they occur.

Adult↗
PubMed1998

Effects of age of introduction of complementary foods on iron status of breast-fed infants in Honduras.

To evaluate the effect of introducing complementary foods before 6 mo of age, we randomly assigned 164 infants who had been exclusively breast-fed for 4 mo to continue being exclusively breast-fed until 6 mo (EBF group) or to receive iron-fortified foods in addition to breast milk from 4 to 6 mo (BF+SF group). At 6 mo, the BF+SF group had higher mean iron intake (4 mg/d compared with 0.2 mg/d in EBF infants) and higher hemoglobin, hematocrit, and ferritin values than the EBF group (P < 0.05). The percentage with low hemoglobin (< 103 g/L) did not differ significantly between groups, but fewer infants in the BF+SF group had a low hematocrit (< 0.33; 21.4% compared with 32.0%, respectively; P < 0.05). The percentage of infants with ferritin concentrations < 12 microg/L at 6 mo was lower than the percentage with low hemoglobin or hematocrit, raising questions about the validity of the cutoffs at this age. Infants at greatest risk for anemia and low ferritin were those with birth weights < 2500 g; no infant with a birth weight > 3000 g had a low ferritin value at 6 mo. We conclude that the risk of iron deficiency is low among infants with birth weights > 3000 g who are exclusively breast-fed for 6 mo. Iron drops are recommended for low-birth-weight infants; for breast-fed infants with birth weights between 2500 and 3000 g, further research is needed to determine whether iron drops are more effective than complementary foods for preventing iron deficiency before 6 mo.

Age Factors↗
PubMed1998

Plasma kinetics of an oral dose of [2H4]retinyl acetate in human subjects with estimated low or high total body stores of vitamin A.

The deuterated retinol dilution technique is an indirect method for quantitatively estimating total body stores of vitamin A by using the postequilibration plasma isotopic ratio [2H4]retinol:retinol and the prediction model described by Furr et al (Am J Clin Nutr 1989;49:713-6). Limited data are available on the time required for an oral dose of labeled vitamin A to mix with vitamin A body stores in human subjects. This article describes the plasma retinol kinetics of an oral dose of [2H4] retinyl acetate in 4 healthy adults (2 men and 2 women) and 1 healthy female child in the United States and in 4 Bangladeshi women. After an oral dose of [2H4]retinyl acetate was administered, plasma samples were collected at 6, 12, and 24 h postdose during the first day and at 15 time points during the subsequent 90-d period for measurement of plasma [2H4]retinol:retinol. The mean respective plasma isotopic ratios on day 20 for US and Bangladeshi subjects (0.02 +/- 0.02 and 0.17 +/- 0.12, P = 0.03) and estimated total body vitamin A reserves (1.03 +/- 0.45 and 0.10 +/- 0.11 mmol, P = 0.003) were significantly different. The fraction of dose in plasma was plotted against time, and biexponential equations were fit to the kinetic data by using the time points from 24 h through day 90. The mean equilibration time (time required for the fraction of dose in plasma to reach a plateau) for all subjects was 16.6 +/- 3.8 d (11-23 d). There was no difference in estimated equilibration time between the group of US and Bangladeshi adult subjects (17.5 +/- 4.4 and 16.3 +/- 3.9 d, respectively, P = 0.69). Thus, the size of hepatic vitamin A reserves does not appear to affect equilibration time within the range of values observed.

Adolescent↗
PubMed1998

Effect of infections on plasma zinc concentration and implications for zinc status assessment in low-income countries.

The development of intervention programs to control zinc deficiency is hampered by the lack of sensitive, specific, low-cost indicators of zinc status. The mean plasma zinc concentration of groups of individuals has been suggested as a possible indicator of a population's zinc status because the plasma zinc concentration seems to predict whether growth will increase in response to zinc supplementation. However, experimental studies in both animal models and adult human volunteers as well as clinical studies of infected and noninfected adults indicate that systemic infections that produce an acute phase response also cause the plasma zinc concentration to fall. Therefore, concerns have been raised about the usefulness of plasma zinc concentration as an indicator of zinc status in populations with high prevalences of infections. By contrast with the aforementioned studies in adults, cross-sectional, community-based surveys of children with and without common infections have not found any association between the presence of infection and plasma zinc concentration, possibly because the severity of those infections observed in children in field settings was less than that of the infections studied in adults. Thus, it appears that the mean plasma zinc concentration may be a useful indicator of population zinc status for children in low-income countries despite the high prevalence of common childhood infections encountered in these settings.

Adolescent↗
PubMed1998

Effect of genetically modified, low-phytic acid maize on absorption of iron from tortillas.

BACKGROUND: Genetically modified, low-phytic acid strains of maize were developed to enhance mineral absorption, but have not been tested previously in humans. OBJECTIVES: We evaluated the mineral and phytic acid contents of a low-phytic acid "flint" maize (LPM, the lpa-1-1 mutant) and its parent, wild-type strain (WTM) and measured iron absorption from tortillas prepared with each type of maize and from a reference dose of ferrous ascorbate. DESIGN: Proximate composition and mineral and phytic acid contents were measured by standard techniques. Iron absorption from tortillas was evaluated by using the extrinsic tag method and was measured as the incorporation of radiolabeled iron into the red blood cells of 14 nonanemic men 2 wk after intake. RESULTS: The phytic acid content of LPM was 3.48 mg/g, approximately 35% of the phytic acid content of WTM; concentrations of macronutrients and most minerals were not significantly different between strains. Iron absorption results were adjusted to 40% absorption of ferrous ascorbate. Iron absorption was 49% greater from LPM (8.2% of intake) than from WTM (5.5% of intake) tortillas (P < 0.001, repeated-measures analysis of variance). CONCLUSION: Consumption of genetically modified, low-phytic acid strains of maize may improve iron absorption in human populations that consume maize-based diets.

Adult↗
PubMed1998

Zinc supplementation improves the growth of stunted rural Guatemalan infants.

The impact of zinc supplementation on the growth and body composition of Guatemalan infants was assessed in a community-based, double-blind intervention trial. Infants aged 6-9 mo were assigned randomly to receive 4 mL of a beverage containing 10 mg of zinc as zinc sulfate (n = 45) or a placebo (n = 44) daily (7 d/wk) for an average of 6.9 mo. The children's weight, length, mid-upper arm and head circumferences, and triceps skinfolds were measured at baseline and at 1-2 mo intervals until the end of supplementation. Midarm muscle area (MMA) was derived from the mid-upper arm circumference and triceps skinfolds measurements. Maternal anthropometry and family socioeconomic and demographic characteristics also were obtained. Zinc supplementation was associated with an overall increase of 0.61 cm2 in MMA (P = 0.02). Children who received zinc supplements had a mean length increment that was 0.75 cm greater than those who did not (P = 0.12). However, there was a significant interaction between treatment group and initial length-for-age status (P = 0.04), such that supplemented children who were stunted at baseline (length-for-age Z score less than -2) gained 1.40 cm more than stunted children who received the placebo. We conclude that zinc supplementation of these rural Guatemalan infants during 6. 9 mo increased accretion of fat-free mass and enhanced the linear growth of those who were stunted at baseline. Further research is required to determine whether zinc supplementation during longer periods of time may achieve larger and more generalized effects on physical growth.

Body Composition↗
PubMed1998

Formaldehyde-related textile allergy: an update.

Part I of this study explores whether clothing today contains formaldehyde levels likely to cause contact allergy in formaldehyde-allergic patients. Part II of this study examines whether current reactions to textiles may be due to allergy to textile resins and whether individuals with formaldehyde-related textile allergy will react to the newer low formaldehyde resins used in the textile industry. Part I: free formaldehyde was measured in 16 fabric specimens produced in the US and overseas. Additionally, since the textile industry has moved to the use of newer methods for measuring fabric formaldehyde content, the newer methodology was compared with the older methods used in the medical literature. Part II: 10 subjects with known textile contact allergy were patch tested to available Chemotechnique textile resins and 6 new low-formaldehyde resins used by the textile industry. Part I: 8 fabric specimens yielded no detectable formaldehyde and 7 specimens yielded <200 ppm free formaldehyde, using Schiff's reagent and Merck testing methods. 1 specimen showed approximately 2000 ppm formaldehyde, as measured by the Merck test, but only 24 ppm free formaldehyde when retested by the method described in Japanese Law #112. Part II: all subjects reacted strongly to formaldehyde and DMDHEU (the predominant resin currently used in textiles). 6 subjects reacted to EUMF. 2 subjects had mild reactions to the newer low-formaldehyde resins and 1 to the non-formaldehyde Fixapret NF. Our results suggest that most clothing today yields free formaldehyde levels unlikely to cause contact allergy in formaldehyde-allergic individuals. Japanese method #112 is the recommended methodology to measure free formaldehyde in future studies. DMDHEU may now represent the main cause of textile allergy and may be a better screen than EUMF for this problem. Newer resins yielding fabrics with <75 ppm free formaldehyde may cause occasional reactions, but are more likely to be tolerated by individuals with textile contact allergy. Treatment of these individuals should be directed at identification of reliable sources of garments utilizing these newer resins.

Adult↗
PubMed1997

Validation of single daytime samples of human milk to estimate the 24-h concentration of lipids in urban Guatemalan mothers.

The large within- and between-sample variability in breast milk lipid content greatly complicates the collection of representative samples in field studies. The main purpose of this study was to validate the ability of individual daytime samples to predict the 24-h lipid concentration of breast milk. We also studied maternal, child, and other factors (time of day and interval between feeds) associated with the within- and between-mother variability in milk lipid content. Fifty-two primiparous urban Guatemalan women between 1 and 4 mo postpartum were studied. Milk samples were collected during six 2-h intervals from 0600 to 1800, and throughout the night when the child breast-fed. On average, the 24-h pooled milk samples contained 4.2 +/- 0.92% (mean +/- SD) lipids and the best concordance with this value was obtained with samples collected between 0600 and 0800 (concordance correlation coefficient = 0.60, P < 0.05). None of the regression equations to predict the 24-h lipid content of breast milk based on daytime samples reached a sufficiently high predictive power to be recommended for the estimation of individual child intake. Time of day and time elapsed since the last feeding were significant determinants of diurnal variations in milk lipid content, whereas between-mother variability was explained by maternal weight (P = 0.05) and body mass index (P < 0.05). For the collection of milk samples in surveys and pre-post studies, we recommend standardization of time of day and interval between feeds.

Adult↗
PubMed1997

Effects of age at introduction of complementary foods to breast-fed infants on duration of lactational amenorrhea in Honduran women.

Lactational amenorrhea (LA) is associated with postpartum infertility and is known to be related to breast-feeding frequency and duration, but the exact role of complementary feeding of the infant has not been clearly defined. Data on LA were collected during and after a 2-mo intervention trial in which low-income Honduran women who had breast-fed fully for 4 mo were randomly assigned to one of three groups: continued full breast-feeding until 6 mo (FBF, n = 50), introduction of complementary foods at 4 mo with ad libitum breast-feeding from 4 to 6 mo (SF, n = 47), or introduction of complementary foods at 4 mo with maintenance of baseline breast-feeding frequency from 4 to 6 mo (SF-M, n = 44). Women were followed up until the infant was 12 mo of age, or later if menses had not occurred by then. All but six of the women continued to breast-feed for > or = 12 mo. With the exclusion of those whose menses returned before 18 wk postpartum (which could not have been due to the intervention), the proportion of women who were amenorrheic at 6 mo was 64.5% in the SF group, 80.0% in the FBF group, and 85.7% in the SF-M group (chi-square test = 4.13, P = 0.02; one-tailed test with the latter two groups combined). The total duration of LA did not differ significantly among groups. The most significant determinant of LA was time spent breast-feeding (min/d), which was in turn negatively associated (P = 0.06) with the infant's energy intake from complementary foods in regression analyses. These results indicate that there is a significant effect of introducing foods at 4 mo on the likelihood of amenorrhea at 6 mo postpartum, but not thereafter, and that this effect is not seen in mothers who maintain breast-feeding frequency.

Adolescent↗
PubMed1997

Assessment of vitamin A status by the deuterated-retinol-dilution technique and comparison with hepatic vitamin A concentration in Bangladeshi surgical patients.

Hepatic stores of vitamin A were estimated in 31 Bangladeshi surgical patients (15 males and 16 females) by the deuterated-retinol-dilution (DRD) technique and by analysis of the vitamin A concentration of a liver biopsy specimen obtained during previously scheduled abdominal surgery. Patients ranged in age from 21 to 65 y and had an average body mass index (BMI: in kg/m2) of 17.7 +/- 3.4. They received 0.753 mumol [2H4]retinyl acetate/kg body wt orally 9-11 d before surgery. Hepatic vitamin A reserves were estimated according to Furr et al (Am J Clin Nutr 1989;49:713-6) by using a single plasma isotopic-ratio measurement (18-25 d postdose). Estimated mean hepatic vitamin A stores were similar by both techniques, 0.110 +/- 0.072 mmol (by DRD) compared with 0.100 +/- 0.067 mmol (by biopsy). Regression analysis was used to compare results of the DRD and biopsy techniques. A significant linear relation was found between the two techniques (r = 0.75, P < 0.0001), and the least-squares regression line was not significantly different from y = x (P = 0.09). The results indicate that the DRD technique provided a very good estimate of hepatic vitamin A reserves for this population. However, a wide prediction interval was observed for estimates of hepatic vitamin A reserves for individual subjects. Thus, further refinement of the prediction model is necessary to improve estimates of hepatic vitamin A reserves for individual subjects.

Abdomen↗
PubMed1997

Zinc supplementation affects the activity patterns of rural Guatemalan infants.

Zinc deficiency has been associated with growth deficits, reduced dietary intake and appetite, and has been hypothesized to result in reduced activity. This randomized, double-blind, placebo-controlled study examined whether 10 mg of oral zinc as zinc sulfate, given daily for up to 7 mo, affected activity patterns of 85 Guatemalan infants recruited at 6-9 mo of age. Infant activity was assessed by time sampling-observation method at 10-min intervals during a 12-h data collection period, at base line, 3 and 7 mo follow-up. Motor development and the percentage of time infants were observed in various positions (being carried, lying down, sitting, crawling, standing or walking) and engaged in various activities (eating, sleeping, resting, crying/whining or playing) were compared by treatment group. No differences in motor development were observed by treatment group. However, at follow-up 2 (after 7 mo of supplementation), zinc-supplemented infants were significantly more frequently observed sitting up compared with lying down, and were playing during 4.18 +/- 1.95% (P < 0.05) more observations than unsupplemented infants. They were also somewhat less likely to be observed crying or whining (P < 0.10) compared with those receiving the placebo. These effects are independent of other factors including infant age, motor development, sex, maternal education, family socioeconomic status and nutritional status at base line. Further research must be conducted to determine the long-term developmental importance of these differences in activity patterns associated with zinc supplementation in this setting.

Administration, Oral↗