Zinc supplementation could favor recovery from
diarrhea in malnourished children. As the recent experimental evidence suggests that oxidative stress and intestinal
anaphylaxis may contribute to the intestinal dysfunction associated with
malnutrition, we postulated that
zinc could act through
antioxidant or antianaphylactic properties. Control (C), malnourished (M), and malnourished
zinc-treated (MZ) guinea pigs were, respectively, fed a normal 30%
protein diet, a low 4%
protein diet, and a low 4%
protein diet plus 1800 ppm of
zinc.
Milk proteins were included in the diets to trigger intestinal
anaphylaxis. Milk sensitization was assessed by passive cutaneous anaphylaxis (PCA) against
beta-lactoglobulin and by intestinal
anaphylaxis measured in Ussing chambers by the increase in short circuit-current after addition of
beta-lactoglobulin (deltaIsc(betaLg)). Oxidative stress was assessed by intestinal lipid peroxidation. The intestinal secretion was assessed by deltaIsc induced by inflammatory mediators.
Malnutrition increased the level of anti-betaLg reaginic
antibodies [PCA = 1.19 +/- 0.79 and 0.69 +/- 0.67 log(l/titer) in M versus C guinea pigs, p = 0.07] and enhanced intestinal
anaphylaxis (deltaIsc(betaLg)) = 16.4 +/- 9.9 and 9.1 +/- 5.8 microA/cm2 in M versus C guinea pigs, p = 0.07), without inducing intestinal lipid peroxidation. Moreover,
malnutrition enhanced significantly the intestinal secretory response to
histamine and
5-hydroxytryptamine. Administration of pharmacologic doses of
zinc during
malnutrition inhibited the increase in milk sensitization induced by
malnutrition, both at the systemic [PCA = 0.35 +/- 0.55 log(l/titer) in MZ guinea pigs, p = 0.03 versus M] and intestinal (deltaIsc(betaLg)) = 2.8 +/- 2.5 microA/cm2 in MZ guinea pigs; p = 0.001 versus M) level, and prevented the hypersecretion in response to
histamine and
5-hydroxytryptamine. These data suggest that
zinc has antianaphylactic and antisecretory properties that may contribute to its capacity to prevent intestinal dysfunction during
malnutrition.