Agriculture Reference
In-Depth Information
food to fortify, what form of the fortificant is used, and the level of fortification are
all important.
More recently, large randomized, placebo-controlled, double-blind trials of iron
and zinc supplementation in infants were conducted in Southeast Asia (Wieringa
et al. 2007). These studies showed that iron supplementation alone had no effect
on zinc status (plasma zinc), either iron or the combination of iron and zinc supple-
mentation reduced anemia prevalence, but zinc supplementation alone reduced iron
status (plasma ferritin). Although vitamin A was given to most of the infants, other
erythropoietic nutrients were not considered, including folic acid, which may have
been relevant, as it was in Mexico (Duque et al. 2007).
Thus, consideration must also be paid to whether nutrients should be provided as
single or multiple supplements.
mAlnutRItIon
Malnutrition , defined as “bad nutrition,” includes obesity, individual nutrient defi-
ciencies, and the various “underweight” syndromes associated with poverty in the
developing world.
Underweight children under 5 years old comprise about a quarter of the world's
children, about 150 million at present. These numbers are falling slowly except in
Africa (de Onis et al. 2004). Underweight syndromes used to be differentiated on the
basis of their major clinical features. The Wellcome classification (Anonymous 1970)
redefined marasmus as “under 60% weight-for-age, without oedema;” kwashiorkor
as “60-80% weight for age with oedema;” and marasmic-kwashiokor as “under 60%
weight for age with oedema.” However, weight for age (child's weight as a percentage
of reference weight of children of the same age) changes due to both change in linear
growth (mainly skeletal) and change in soft tissue growth (lean and adipose tissues).
r e D u C t i v e a D a P t a t i of n
Reductive adaptation has been mentioned. It is the body's response to a supply of
energy and nutrients insufficient to meet their demand; the demand falls. Thus,
physical activity and growth rates fall. Weight may be lost as adipose tissue gives up
its stored energy to more vital functions and muscle gives up its nutrients to replace
inevitable losses. Two cell functions, the Na-K-ATPase (adenosine triphosphatase)
pump and protein synthesis, normally consume about two thirds of maintenance
energy. These functions decline, thereby reducing the demand for energy further.
The costs of reductive adaptation are large. The young child stops exploring the
environment, and milestones regress or are not reached. The child loses reserve
capacity, so cannot deal with stress (e.g., a large protein meal). The child's barriers
to infection atrophy. The inflammatory response is reduced, as are the complement
output and cell-mediated immune responses. Homeostasis is compromised. The
child cannot keep warm in a cold room or vice versa. The cell potassium falls while
sodium rises. This cannot continue, and eventually death is the only outcome. It is
usually precipitated by overwhelming infection, even in the hospital.
Search WWH ::




Custom Search