Disclosed is a nutritional composition comprising a combination of non-digestible oligosaccharides and a product obtained by incubating an aqueous substrate by bifidobacteria and optionally a product obtained by incubating an aqueous substrate by S. thermophilus. Said combination synergistically improves the immune system by stimulating the Th1 response, and/or decreasing the Th2 response, improving the vaccination response, improving the resistance against infections and/or decreasing allergy.
