Nutritional compositions are provided that comprise a fructo-oligosaccharaide (FOS) in an amount of 35 to 44% by weight; a polysaccharide that is not a partially hydrolyzed guar gum such as, for example, an arabinogalactan in an amount of 50% to 38% by weight; and inulin in an amount of 12% to 24% by weight. The FOS and the polysaccharide may be present in a weight ratio of about 1:1. More specifically, the FOS and inulin may be present in a weight ratio of about 7:3. Also provided are methods of promoting gut micro biota balance and health. The methods include administering an effective amount of the nutritional composition to patients in need of same.