Absorption of macronutrients from a rice-vegetable diet before and after treatment of ascariasis in children

Soil-Transmitted Helminthiasis and Vitamin A Deficiency: Two Problems, One Policy

Vitamin A deficiency (VAD) and soil-transmitted helminthiasis (STH) represent two widely prevalent and often overlapping global health problems. Approximately 75% of countries with moderate or severe VAD are coendemic for STH. We reviewed the literature on the complex relationship between STH and VAD. Treatment for STH significantly increases provitamin A (e.g., β-carotene) levels but is associated with minimal increases in preformed vitamin A (retinol). Interpretation of the data is complicated by variations in STH infection intensity and limitations of vitamin A biomarkers. Despite these challenges, increased coordination of STH and VAD interventions represents an important public health opportunity.

Nutritional aspects of Ascaris infection in young protein-deficient pigs

Experiments were carried out to investigate the effects of Ascaris suum infection on the growth, food intake, nitrogen and fat utilization and intestinal function of young pigs receiving diets low in protein. An infection procedure was developed which provided relatively uniform and heavy infections in pigs under study. Ascaris-infected pigs showed statistically significant reduction in growth rate and food intake compared to uninfected controls. The reduction in growth rate was observed after the A. suum were mature and eggs were observed in the faeces of pigs. The degree of growth retardation was significantly correlated with worm burden. Infected pigs showed no consistent reduction in nitrogen and total solids digestibility compared to controls but fat digestion was reduced. The infected pigs showed reduced nitrogen retention compared to uninfected controls. Ascaris-infected pigs had heavier intestinal tracts with increased size of the tunica muscularis. Lactase activity in mucosa from infected pigs was significantly lower than in controls, whereas no consistent effect was observed in mucosal sucrase and maltase activity. When Ascaris-infected pigs were given an oral lactose load, blood glucose levels rose less than in control pigs, suggesting that the infection resulted in impaired lactose tolerance.

Gastrointestinal nematodes, nutrition and immunity: breaking the negative spiral

Nutritionists have long understood that intestinal nematode parasites have deleterious effects on host nutritional status, but only recently has the importance of malnutrition as a predisposing factor to intestinal nematodes been recognized. Here we review experimental and field studies on the effects of protein, energy, zinc, vitamin A, and iron deficiencies on gastrointestinal (GI) nematodes of humans, livestock, and laboratory rodents, and draw certain conclusions about the state of our current understanding. In general, malnutrition promotes the establishment, survival, and fecundity of these parasites, but the magnitude of the effect depends on factors such as host species, parasite species, particular infection protocol used, magnitude of the infection, severity of the nutritional deficiency, and presence of single or multiple infections and single or multiple nutritional deficiencies. We highlight the Th2 arm of the immune system as a component of primary importance in the association between malnutrition and GI nematode infections. We summarize what is known about underlying mechanisms that may account for the observed patterns. Finally, we suggest future research directions.

Comparison of the effects of supplemental red palm oil and sunflower oil on maternal vitamin A status

BACKGROUND

Conflicting results have been reported on the ability of dietary carotenoids to improve vitamin A status in lactating women. Red palm oil is one of the richest dietary sources of beta-carotene.

OBJECTIVE

We aimed to determine the efficacy of red palm oil in increasing retinol and provitamin A status in pregnant and lactating women.

DESIGN

Ninety rural, pregnant Tanzanian women from 3 randomly selected villages were recruited during their third trimester to participate in 3 dietary intervention groups: a control group, who were encouraged to maintain the traditional practice of eating staples with dark-green leafy vegetables, and 2 study groups, who were given either sunflower or red palm oil for use in household food preparations. The intervention lasted 6 mo. Plasma samples were collected at the third trimester and 1 and 3 mo postpartum, and breast-milk samples were collected 1 and 3 mo postpartum.

RESULTS

Supplementation with red palm oil, which is rich in provitamin A, increased alpha- and beta-carotene concentrations significantly (P < 0.001) in both plasma and breast milk. Plasma retinol concentrations were similar in all dietary groups. Breast-milk retinol concentrations tended to decrease from 1 to 3 mo postpartum in the control group, but were maintained in both oil groups. The difference in change in breast-milk retinol concentration between the red palm oil group and the control group was significant (P = 0.041).

CONCLUSIONS

Consumption of red palm oil increases concentrations of alpha- and beta-carotene in both breast milk and serum and maintains breast-milk retinol concentrations. Sunflower oil consumption seems to conserve breast-milk retinol similarly to consumption of red palm oil. Breast-milk retinol might be maintained through increased dietary intake of these vegetable oils and use of mild cooking preparation methods (such as the addition of oil at the end of cooking and avoidance of frying).

Relationships between soil-transmitted helminthiases and growth in urban slum schoolchildren in Ujung Pandang, Indonesia

This study examined the relationship between intestinal helminthiases and growth in urban slum schoolchildren. Children (n = 330) who received single doses of either pyrantel, albendazole, or placebo at baseline and again at 6 months were followed and examined fully at 0, 3, 6, and 12 months for helminth infections and anthropometry. Results of treatments indicated that all groups reduced their prevalence and intensity toward the period of the study. Reductions in intensity of both infections in the treatment groups were observed large in 3 and 12 months, whereas at 6 months reached mostly the initial level of infection. There was no significant difference in growth changes between the dewormed (once and twice) and the placebo groups. However, after controlling for some potential confounding factors, there was a significant relationship between reduction of A. lumbricoides infection and height gain at 3 and 12 months (both P < 0.05). In addition, there was a significant association between reduction in T. trichiura infection and increased midarm circumference at 3 and 12 months (P < 0.002 and P < 0.08, respectively). We conclude that treatment of helminth infections in school-age children may improve growth in areas where malnutrition and helminth infections are prevalent.

Improvements in appetite and growth in helminth-infected schoolboys three and seven weeks after a single dose of pyrantel pamoate

Appetite and growth were studied in primary schoolboys (6-10 years) infected with Ascaris lumbricoides (86%) and Trichuris trichiura (100%) who received a single dose of pyrantel pamoate (which has little or no effect on Trichuris trichiura) or a placebo. Boys were examined, allocated at random by descending Ascaris egg count to pyrantel (PR, n = 36) or placebo (PL, n = 36) groups, treated, and re-examined 3 and 7 weeks later. The 2 groups did not differ significantly before treatment in helminth infections, appetite, or growth. Three and 7 weeks after treatment, the PR group exhibited significantly greater increases than did the PL group in weight (0.2 kg and 0.4 kg more, respectively) and percentage weight-for-age (0.6% and 1.7% points more, respectively). Appetite increased significantly in the PR group at 3 and 7 weeks (P < 0.0005 and P < 0.01, respectively) but not in the PL group. The prevalence and intensity of A. lumbricoides infection were greatly reduced in the PR group at 3 and 7 weeks (both P < 0.0001) but not in the PL group. We conclude that treatment with pyrantel pamoate may improve appetite and growth in school children in areas where A. lumbricoides infections and poor growth are highly prevalent.

Effect of intestinal helminthiasis on intestinal permeability of early primary schoolchildren

Intestinal permeability of 246 early primary schoolchildren at 2 schools (106 of whom were infected with intestinal helminths) was assessed by using the lactulose/mannitol differential absorption test. The ratio of the urinary recoveries of lactulose and mannitol was determined after oral administration of a standard solution of the 2 sugars. Assessment of intestinal permeability was repeated on 100 infected children after treatment and on a cohort of 68 uninfected children. Infected and uninfected groups were compared with respect to baseline lactulose/mannitol ratio (L/M1) and change in lactulose/mannitol ratio between assessments (delta L/M). The correlations between baseline intensity of infection and L/M1, and between fall in intensity and delta L/M, were evaluated. Based on a crude index of socioeconomic status, each child was assigned to one of 3 socioeconomic groups; all but 3 children belonged to either groups 2 or 3. Trichuris trichiura and Ascaris lumbricoides were the 2 predominant infections; the hookworm infection rate was relatively low. The results suggested that helminthiasis exerted only a marginal effect on intestinal permeability, the impact of which in children from lower socioeconomic backgrounds was negligible in comparison with the cumulative effects of other factors.

Pathways to the impairment of human nutritional status by gastrointestinal pathogens

Gastrointestinal pathogens are of three varieties, those that can, and often do, take the life of the host, those that infect transiently and rarely are life-threatening, and those (parasites) that establish a relatively prolonged residence or colonization of the host's alimentary tract. In the case of the second form, if infections are recurrent, both catabolic effects during the episode and failure to digest foods and/or absorb nutrients results. Similarly, catabolic wastage through activation of the acute phase response, and interference with the host's acquisition of nutrients by maldigestion, malabsorption, intestinal losses and competition with the parasite burden can impair growth and nutrition with helminthic infections. Growth and nutrition with respect to all of the macronutrients and virtually all of the micronutrients have been documented to be adversely affected by gastrointestinal pathogens. For its burgeoning importance as a worldwide health problem, both with the HIV virus as a direct intestinal pathogen and with the opportunistic gut infections occurring in the immunocompromised host, AIDS represents the emerging context of the impairment of nutritional status by intestinal pathogens.

Absorption of glucose polymers from rice in oral rehydration solutions by rat small intestine

BACKGROUND

This study aims to determine the effect of replacing glucose in oral rehydration solution (ORS) with starch hydrolysates from rice on absorption in the small intestine and levels of glucose in portal venous blood and on disaccharidase levels and morphometric measurements in intestines of rats.

METHODS

ORS containing standard composition of salts and 2% glucose (WHO ORS) or 2%, 5%, or 10% starch hydrolysates were infused into duodena of 60 Sprague-Dawley rats (250-350 g). Portal venous blood glucose levels were determined at 0, 30, 60, 90, and 120 minutes.

RESULTS

Significantly larger areas under the curve of glucose absorption (AUCs) were produced by ORS containing 10% unfractionated starch hydrolysates (123.2 +/- 3.8), 2%, 5%, and 10% starch hydrolysates with long-chain ( > 9 molecules) glucose polymers (109.5 +/- 10.6, 109.3 +/- 7.4, and 115.3 +/- 7.1, respectively), and 5% and 10% starch hydrolysates with short-chain (2-9 molecules) glucose polymers (124.4 +/- 6.1 and 128.1 +/- 6.8). ORS with 2% and 5% unfractionated starch hydrolysates and 2% short-chain glucose polymers produced AUCs comparable with those of WHO ORS (96.48 +/- 5.7). Disaccharidase levels and morphometric measurements were not significantly different.

CONCLUSIONS

Starch hydrolysates from rice containing glucose polymers can be used in ORS in higher concentrations than glucose to provide higher caloric density without increased osmolality.

Ascariasis and childhood malnutrition

The present review will examine epidemiological perspectives and be confined mainly to the results of those field studies published since 1975 in order to provide concrete scientific evidence of the effect of ascariasis on childhood malnutrition, particularly on growth. The field studies were done in many developing countries from Africa, Asia and Latin America, using cross-sectional and intervention studies in which anthelmintics were employed, with different dosing frequency and follow-up periods ranging from 33 days to 2 years. In general, a better nutritional status in terms of growth, lactose tolerance, vitamins A and C, and albumin levels were observed among Ascaris-free or treated than among Ascaris-infected or untreated children even in cross-sectional or non-randomized studies. More importantly, the improvement in weight or height after chemotherapeutic treatment was found to be significant particularly in those randomized controlled studies with an initially high prevalence of ascariasis and malnutrition, a low prevalence of other intestinal parasites, repetitive and regular treatments of children with tetramisole, levamisole or pyrantel, within a period of 12 or 24 months. Reasons for failures to detect improved growth in some studies are provided. This review strongly indicates that A. lumbricoides infection definitely retards childhood growth.

An optimal rice-based oral rehydration solution: the effect of different concentrations of amylase on production of short chain polymers of glucose

As part of a plan to develop a rice-based oral rehydration solution containing short polymers of glucose instead of glucose, we determined the concentration of amylase that would yield the largest amount of short chain polymers. Thai rice (25 g) was boiled with 500 ml of distilled water for 30 min. Of 200 ml supernatant rice water obtained, 100 ml were digested with different amounts of amylase after cooling to 50 degrees C for 60 min, boiled for 5 min, and centrifuged (10,000 g, 25 degrees C) for 60 min. The resulting supernatant (80 ml) was freeze-dried; 1.75 g of the powder obtained were dissolved in 3.5 ml of water, passed through a Bio-Gel P2 column to separate short chain polymers (2-9 molecules of glucose) and long chain polymers (> 9 molecules of glucose), which were identified by spectrophotometry (lambda = 190 nm) or by high performance liquid chromatography. Ten mg of amylase (equivalent to 12,000 modified Wohlgemath units) per 100 ml of rice water was optimal for the production of short polymers of glucose from rice.

A controlled chemotherapeutic intervention trial on the relationship between Ascaris lumbricoides infection and malnutrition in children

A 2-year investigation, consisting of a controlled, non-blind, 3-monthly chemotherapeutic intervention trial, based on transmission dynamics of Ascaris lumbricoides infection, was undertaken to prove or refute the role of A. lumbricoides as a contributor to childhood malnutrition. The study involved 1206 children aged 2-12 years in 21 villages in Myanmar [Burma] starting in August 1984. The intervention and non-intervention villages were comparable regarding almost all the important baseline variables, including prevalences of Ascaris infection (80.8 vs 83.0%) and of malnutrition of grade 2 and above for height-for-age (58.4 vs 55.8%) and for weight-for-age (48.2 vs 47.8%). The intensity of Ascaris infection was related to the degree of malnutrition. A significant increment of height gain was found, starting after the 6th month, and of weight gain after the 24th month, of the study among the treated 2-10 years old children when compared with the non-treated ones. By the end of 24 months, the height and weight gains per child were 0.65 cm and 0.93 kg respectively. Lesser increments in height-for-age and weight-for-age were also observed after successive treatments among the treated children with initially higher mean worm burdens. The findings are discussed in the context of causal relationship between ascariasis and malnutrition in children.

Contributions of ascariasis to poor nutritional status in children from Chiriqui Province, Republic of Panama

Relationships between ascariasis and lactose digestion and between ascariasis and food transit time from mouth to caecum were investigated in young children from Chiriqui Province, Republic of Panama. The breath hydrogen method was used in both studies. Ascaris-infected children showed a significantly poorer degree of lactose digestion following a test oral load than uninfected children. Recovery of the capacity of the children to digest lactose was still not fully complete for at least 3 weeks following anthelmintic treatment. On average, the mouth-to-caecum transit time was similar in infected and uninfected children, but among the Ascaris-infected children the transit time tended to be shorter in relation to the intensity of infection. Evidence from a cross-sectional survey indicated that ascariasis was significantly associated with reduced plasma vitamin A and carotenoid concentrations. This relationship remained after controlling for a range of socio-economic variables. Ascaris-infected children were frequently found to have lower haematocrits and blood haemoglobin concentrations than uninfected children, but these relationships could not be attributed to ascariasis alone.

Plasma albumin concentrations and intestinal permeability in Bangladeshi children infected with Ascaris lumbricoides

Plasma albumin concentration and intestinal permeability have been investigated in Bangladeshi children before and 9-14 d after successful treatment for ascariasis. Children infected with A. lumbricoides had lower plasma albumin concentrations than counterparts not harbouring this worm and values increased with successful treatment. Intestinal permeability tests indicated that the children had impaired gastrointestinal function and some loss of mucosal integrity; these factors had not improved 9-14 d after A. lumbricoides expulsion. The lowered nitrogen nutritional status implied by the reduced plasma albumin values in infected children, and the improvement following treatment, are in keeping with previous reports that A. lumbricoides impairs protein digestion or absorption. This may be the basis of the better growth rates of dewormed children in this area.

The epidemiology and control of intestinal helminths in the Pulicat Lake region of Southern India. I. Study design and pre- and post-treatment observations on Ascaris lumbricoides infection

The study design of a project to investigate the epidemiology, population dynamics and control of intestinal nematode infections in fishing village communities in Southern India is described. The paper focuses on Ascaris lumbricoides infection and describes changes in prevalence and intensity (worm burdens) with host age, the aggregated frequency distributions of parasite numbers per person, a density-dependent relationship between parasite fecundity and worm burden and rates of reinfection following chemotherapeutic treatment. The age-intensity of infection profile is convex in form, where maximum worm burdens are attained in children in the age range five to nine years. On the basis of juvenile to adult worm ratioos, the life expectancy of Ascaris in man is estimated to be of the order of one year. Rates of reacquisition of worms after chemotherapy are shown to be dependent on host age. Wormy individuals with heavy infections are shown to be predisposed to this state such that they reacquire heavier than average worm burdens following treatment.

Nutritional aspects of infection

Current knowledge is examined about the means whereby ascariasis, hookworm disease, strongyloidiasis and trichuriasis may contribute to the aetiology of human malnutrition. Results from experiments with related parasites in the laboratory have demonstrated the role of gastrointestinal helminthiases in animal malnutrition. Some evidence shows that in children, infection with the intestinal stages of Ascaris lumbricoides is associated with reduced growth rate, disturbed nitrogen balance, malabsorption of vitamin A, abnormal fat digestion, lactose maldigestion and an increased intestinal transit time. The main impact of hookworm infection is its relationship with iron-deficiency anaemia which may have effects at the community level as regards work and productivity in adults and learning and school performance in children. More research is needed to extend knowledge of the nutritional impact of ascariasis and hookworm disease in order to establish their public health significance. Research is needed also to identify the range of nutritional effects on man that occur as a result of trichuriasis and strongyloidiasis. The significance of less prevalent and more localized gastrointestinal helminthiases should not be ignored.

Selected economic issues in helminth control

This paper examines four main economic issues in the formulation of helminth control policies: whether, what, how and with whose resources to control helminthiasis. The paper argues that (i) although helminth control would have a negligible impact on mortality, its nutrition-mediated effects on improved labor productivity and intellectual performance may be significant; (ii) that reduction of helminth disease rather than infection should be the target of control policy, although the preferred intervention may still be eradication rather than continuous control; and (iii) that although the case for public subsidy of helminth control interventions is strong, the existence of serious fiscal constraints and some evidence of private willingness-to-pay for anthelminthic chemotherapy indicates a potential for partial cost recovery which should be explored.