FOS is short for Fructooligosaccharides. FOS occurs naturally and can be found is popular vegetables and fruits such as bananas and asparagus.
FOS is extracted from natural foods and used as a supplement for animals and humans because of the beneficial effects it's believed to have. Some of the benefits are especially useful to dogs, and thats why it's becoming a popular supplement in many dogs foods.
FOS is a short chain of sugar molecules that will not be digested. These molecules pass through the stomach into the intestines when it is used by the beneficial or 'friendly' bacteria to feed on. This promotes the growth of these probiotics, increasing immunity, improving digestion and stool quality.
Mannan-oligosaccharide, also known as MOS is a natural additive widely used as a nutritional supplement.
MOS is becoming a popular ingredient in dog foods because it's believed to be beneficial to overall gut health. MOS is known for its pre-biotic benefits and aids nutrient digestibility.
'Research shows an increase in serum lymphocytes and lower plasma neutrophils when adult dogs were supplemented with MOS and FOS. These findings indicate an improvement in immunity that, in turn, gives rise to increased protection against intestinal pathogens.'
Swanson, KS; Grieshop, CM; Flickinger, EA; Healy, HP; Dawson, KA; Merchen, NR; Fahey Jr, GC (2002)