Animal Source Foods - Adequate Food for All - page 188

m i C r o in u t r i e in t s t a t u s
Micronutrient malnutrition, which is widely prevalent among children in develop-
ing countries, has detrimental effects on their health and functional outcome (see
Chapters 10 and 11). In Kenyan schoolchildren, the high prevalence of low plasma
vitamin B 12 concentrations at the beginning of a food supplementation study was
predicted by a low intake of animal source foods (McLean et al. 2007). Children
received three isoenergetic food supplements that were based on maize and beans and
contained meat or no animal source foods or were served with milk during school
break. The snacks including meat or milk significantly increased plasma vitamin B 12
concentrations after 1 and 2 years, but no significant effects on other indicators of
micronutrient status were detected, possibly because of variation introduced by the
presence of malaria and other infections (Siekmann et al. 2003, McLean et al. 2007).
After 1 year, the prevalence of severe plus moderate vitamin B 12 deficiency fell from
80.7 to 64.1% in the children receiving meat and from 71.6 to 45.1% in the children
receiving milk. After 2 years, the supplementation with meat or milk almost com-
pletely eliminated low plasma vitamin B 12 concentrations (McLean et al. 2007). The
improved vitamin B 12 status of children fed meat or milk may reduce the risk of con-
sequences of vitamin B 12 deficiency, such as megaloblastic anemia, poor motor and
cognitive function, and subsequent poor school performance (Siekmann et al. 2003).
The children in the Kenyan study were severely depleted of vitamin A, assessed
by plasma retinol concentrations or on the basis of low liver retinol stores. Plasma
retinol improved during the first year of intervention but fell to even lower values
than baseline by the end of the second year. The majority of children had depleted
liver retinol after 2 years, which was unaffected by the food supplements (Zubieta
et al. 2005).
g r o w t h
There is a strong probability that growth is limited by multiple simultaneous defi-
ciencies in children in many areas in developing countries. Micronutrient deficiencies
may also contribute indirectly to growth retardation through anorexia or increased
morbidity (Rivera et al. 2003). Stunting has detrimental consequences not only dur-
ing childhood, but also lifelong, including low physical activity, impaired motor
and mental development, lowered immunocompetence, reduced work productivity,
greater severity of infections, and increased mortality (Norgan 2000). More details
on the effects of nutrient deficiencies on stunting can be found in Chapter 11. Animal
source foods provide high amounts of bioavailable micronutrients that are needed for
optimal growth, such as iron, zinc, calcium, and vitamin A.
Stunted Jamaican children were found to consume significantly fewer servings of
dairy products and fruits than the nonstunted children (Walker et al. 1990). The per-
centage of protein intake from animal sources was positively associated with growth
in Peruvian children (Graham et al. 1981), and because the protein intakes were
considered adequate, it was suggested that other nutrients contained in the animal
products, such as heme iron, zinc, and vitamin B 12 , may explain the observed effect.
Linear growth was also positively associated with intake of animal source foods