|Malnutrition and Infection - A review - Nutrition policy discussion paper No. 5 (UNSSCN, 1989, 144 p.)|
|MALNUTRITION AND INFECTION - by Andrew Tomkins and Fiona Watson1|
|3. INFECTION AND RISK OF MALNUTRITION|
There is very little evidence of any impact of infection among exclusively breast fed infants. A cohort of Sudanese infants receiving breast milk only, had a prevalence of diarrhoea of around 30% at each home visit and yet there was minimal impact on rates of weight gain calculated by regressing weight gain against numbers of days ill (Zumwari et al 1987). o9o5 Similarly there was little impact of diarrhoea on growth among the exclusively breast fed urban Gambian infants studied by Rowland et al (1988).
Measurements of breast milk intake by Bangladeshi children showed remarkably little reduction during diarrhoea (Hoyle et al 1980). Interviews with mothers to determine their feeding practice indicated that the majority of Bangladeshi mothers did not reduce the number of times they suckled their infants during diarrhoea (Khan & Ahmed 1986).
The danger of contamination of infant foods with diarrhoea-causing pathogens has been emphasised repeatedly (Black et al 1989). Attention to lifestyle and food technology (e.g., fermentation) may help to reduce the microbial load in food.
Diarrhoea has less impact on the nutritional status of younger infants than on that of older children. Children receiving solid foods in Guatemala (Mata et al 1977), the Gambia (Tomkins 1983) and Bangladesh (Hoyle et al 1980, Molla et al 1983), have been shown to reduce intake of solids during diarrhoea. Interestingly a subsequent study in Bangladesh (Brown et al 1985) showed no significant decrease in solid food intake.
The impact of diarrhoea on intestinal absorption has been reviewed (Tomkins 1981). During acute diarrhoea a high level of absorption of macronutrients (Molla et al 1983) is maintained but in persistent diarrhoea there may be more severe malabsorption with endogenous nutrient loss. This occurs in diseases such as the protein losing enteropathy, complicating post-measles diarrhoea (Sarker et al 1985).
There are many unanswered questions relating to the diarrhoea/malnutrition complex, especially regarding an improved understanding of the mechanisms involved in anorexia, malabsorption and intestinal losses. Studies on appropriate regimes for feeding children during episodes of acute diarrhoea and during recovery show that in general there is as satisfactory an outcome if a rapid return to normal diet is employed as if a slow regrading regime is followed. A satisfactory intake of nutrients may depend on the type of food presented to the child. In this regard attention to household food technologies such as fermentation and germination (Tomkins et al in press) appear to be important. In particular the use of fermented food, a traditionally prepared weaning food in many societies, may have considerable advantages in terms of inhibition of pathogens as well as taste and digestibility (Mensah et al in press).
The nutritional problems associated with persistent diarrhoea (duration more than 14 days) seem to be more severe and less easily managed than those accompanying acute diarrhoea. The pathogenesis of diarrhoea in persistent diarrhoea syndrome is complex revolving around various infective agents, immunological abnormalities in the intestinal mucosa and variable contributions from dietary allergens and malnutrition (Manuel et al 1986).
In acute diarrhoea:
(1) The importance of breast feeding in prevention and management cannot be overemphasised.
(2) Growth faltering may occur in children receiving solid foods, but efforts to overcome this should be made by encouragement to eat, especially during convalescence. The use of foods with low dietary bulk and attractive taste may assist in feeding sick children.
(3) A reduction in solid food intake, malabsorption and endogenous nutrient loss may occur. Micronutrient malabsorption, especially of vitamin A, may occur.
(4) Impact of diarrhoea on rates of weight gain in exclusively breast fed infants is likely to be minimal.
(5) A favourable response to enthusiastic use of oral rehydration solutions in order to prevent dehydration may maintain appetite.
In persistent diarrhoea there may be:
(1) Severe growth faltering and development of clinical deficiency syndromes.
(2) Poor response to the use of oral rehydration fluids.
Improved disease control and management
(1) Development and evaluation of strategies to promote breast feeding more universally.
(2) Promotion of weaning foods that are less contaminated by diarrhoeal pathogens (e.g., fermented foods).
(3) Promotion of hygienic practices in food preparation.
(1) Development of methods for nutritional assessment (especially micronutrients).
(2) Investigation of mechanisms of malnutrition during episodes of pathogen-specific diarrhoea, including the immunological response to food.
(3) Investigation of cultural determinants of food intake during diarrhoea.
(4) Development and evaluation of appropriate, locally available feeding regimes during acute diarrhoea, persistent diarrhoea and convalescence.
(5) Investigation of the contribution of different dietary factors to prolongation of diarrhoea.
(6) Development and implementation of rehydration solutions using locally available cereals (e.g., rice, maize) aimed at reducing dehydration.
(7) Development of better regimes for the management of persistent diarrhoea syndromes (more than 14 days duration) and associated malnutrition. These will take account of the different factors contributing to the PDS such as infection, food allergy and underlying malnutrition.
(8) Evaluation of the effect of individual micronutrient supplements on outcome (e.g., zinc, vitamin A).
(9) Investigation of the biology of anorexia during diarrhoea.