Fructo-oligosaccharides (FOS) belong to a group of compounds known collectively as prebiotics. Prebiotics are not digested by the human body, but they are considered to improve health due to the stimulating effect they have on the beneficial gut bacteria.
The average diet provides as little as 2 to 3 grams of FOS a day through the consumption of vegetables such as onions, whilst it is estimated that the optimum intake should be 5 to 10 grams. Research has shown that after just 2 weeks of taking FOS there is a significant increase in the number of friendly bacteria in the bowel, in some by up to 10 times!
Currently practitioners mainly use FOS as a prebiotic or for digestive difficulties such as constipation. Yet interestingly research has now highlighted other areas that we feel will be of significant interest for use in practice.
Improvement of digestive health Supplementation with FOS has been shown to modify bowel function in healthy individuals. However the main benefits appear to be in those sections of the population who may have an abnormal gut ecology, such as infants, the elderly, those with existing gut conditions or people on antibiotic therapy. Lower levels of beneficial bacteria have been found in those with IBS and IBD.
Studies on both pre-term and full term infants showed that including FOS in formula milk led to a decrease in the number of pathogenic bacteria such as E.coli and clostridia found in the stools.
An additional study of children aged 7 to 19 months showed that FOS increased bifidobacterium levels, decreased potential pathogen levels and reduced symptoms of flatulence, diarrhoea, vomiting and fever.
There is also evidence to suggest that FOS may be beneficial in symptoms associated with C.difficile infection. FOS appeared to reduce the incidence of a relapse of diarrhoea in those infected with C.difficile, whilst reducing the length of hospital stay and the time treatment took to have effect.
As FOS is a form of fibre it has been widely used to relieve constipation and transit time. Evidence suggests that a dose of 10 to 20g per day significantly increased frequency and softened stools in adults.
Several studies have linked supplementation of FOS with an increase in bone mineralisation. One human study found that in people with both low and high absorption of calcium, FOS improved calcium absorption, bone mineral content and density. This effect is thought to be caused by a number of different mechanisms: increase in production of short chain fatty acids leading to an increased solubility of the minerals; improvement of gut health; enlargement of absorption surface; increased expression of calcium binding proteins; degradation of phytic acid and several other factors.
Evidence also suggests that FOS may improve absorption of magnesium, iron, zinc and copper.
Dosage & sources of FOS
Studies have shown beneficial effects of FOS at doses as low as 5g per day in adults (as a prebiotic), and as high as 20g per day (for constipation). At a dose of up to 20g per day FOS is considered to be safe and well-tolerated.
Use FOS that is derived naturally from chicory root, since it is only the natural form of FOS that has been scientifically proven to support bowel health. ‘Synthetic’ versions, usually made from sugar beet, do not offer the same health benefits.
References available on request.