A nutritional composition having beneficial effect in the gastrointestinal tract, especially an anti-adhesion effect on pathogenic micro-organisms and a bifidogenic effect, contains non-digestible oligosaccharides, said oligosaccharides comprising, per daily dosage, 0.3-10 g of oligosaccharides containing at least one terminal arabinose unit. The nutritional composition may furthermore comprise 0.5-10 g of other non-digestible oligosaccharides selected from fructo-oligosaccharides, galacto-oligosaccharides, xylo-oligosaccharides and manno-oligosaccharides. The arabino-oligosaccharides can be obtained conveniently by controlled hydrolysis of arabinose-containing polysaccharides from natural (vegetable) origin.