The aim of this research was to evaluate the effect of short-chain fructo-oligosaccharides (FOS) and quercetin intake on TH₁/TH₂ balance by means of TNFα and IL-4 cytokines.

An experimental model of protein malnutrition was used to evaluate the effect of FOS and quercetin. Weanling rats of Wistar strain were fed a protein-free diet until they lost 25% of their initial body weight. Re-feeding was performed by the administration of an experimental diet containing 20% casein as the only source of protein (re-nourished group; R). Other experimental groups received this experimental diet plus Beneo P95 (oligofructose (degree of polymerisation: 2–8) 95%; glucose+fructose+sucrose, 5%; RFOS) at 2.5%, equivalent to 13 g/kg body weight per d or plus quercetin (RQ) (Q=280 μg/kg body weight per d), both added to drinking water during 40 d. Three well-nourished groups were fed with standard commercial diet and used as normal controls: C, CFOS and CQ. The small intestine was removed and the intestinal fluid obtained. IgE, IL-4 and TNFα were measured (ELISA). The animal protocol was approved by the ethical committee of the University of Buenos Aires.

Results showed that IgE levels (ng/ml) were significantly higher in R (59.8±1.29) than in C (52.9±0.98) (P=0.0001) revealing an allergic state of the in vivo model.

IL-4, a TH₂-derived cytokine characteristic of allergic states, was higher in R (114±6) than in C (99±7) and FOS consumption increased these values. Instead, quercetin diminished IL-4 to 65±8 for R and 80±6 for C, in both cases compared with the groups without supplements, all values expressed in pg/ml.

For TNFα R values were 201±17 pg/ml and FOS increased them, presenting RFOS the highest value (343±29). Quercetin consumption diminished TNFα to 171±26 (Figs 1 and 2).

Fig. 1. TNFα in renourished groups.

Fig. 2. IL-4 by supplement intake.

In brief, FOS intake increased IL-4 and TNFα. It was probably due to an increased intestinal permeability⁽Reference Rodenburg, Keijer and Kramer¹⁾ and a consequent disruption in barrier function and inflammation due to amplified contact with local microflora.

Quercetin instead, decreased IL-4 and TNFα, but the last one to a lesser extent. Quercetin provided improvements in barrier function⁽Reference Suzuki and Hara²⁾.

FOS intake gave a higher immunological surveillance and quercetin did a change in TH₁/TH₂ balance towards TH₁ phenotype.