Carbohydrates and Health

Table 9.2: Inconsistent evidence - randomised controlled trials
Measure
Eating motivation
Exposure
non-digestible oligosaccharides
Summary and Conclusions
9.80 This assessment is based on randomised controlled trials investigating the
relationship between supplements of resistant starch, oligosaccharide or inulin
and cardio-metabolic and colo-rectal outcomes. There were no prospective
cohort studies investigating the relationship between oligosaccharides and the
relevant health/disease outcomes. There was no relevant evidence, which met
the inclusion criteria for this report, identified on non-digestible oligosaccharides,
inulin or resistant starch intake in relation to oral health outcomes.
9.81 Nearly all the trials investigating non-digestible oligosaccharides supplemented
subjects’ diets with arabinoxylan-oligosaccharide, fructo-oligosaccharide, galactooligosaccharide
or inulin. The data are too limited to draw conclusions on other
non-digestible oligosaccharides that may be found naturally in foods or are
produced using industrial processes. The non-digestible oligosaccharides and inulin
used in trials often differ in their degree of polymerisation, but it is unclear from
the data whether these differences have an impact on the outcomes investigated.
The doses required for some of the observed effects may vary depending on the
specific oligosaccharide preparation. Different enzymatic preparations can result
in different molecular structures which may affect functionality.
9.82 Randomised controlled trials that supplemented subjects’ diets with nondigestible
oligosaccharides or inulin indicate a beneficial effect on fasting LDLcholesterol
concentration, but no effect is indicated on fasting total cholesterol,
HDL-cholesterol or triacylglycerol concentration. Trials indicate no effect of
non-digestible oligosaccharide supplementation on fasting glucose, fasting
insulin concentration or energy intake. The trials do indicate that non-digestible
oligosaccharides cause an increase in faecal weight and effect faecal bacterial
content, including increases in the content of Bifidobacterium spp., but have no
effect on faecal short chain fatty acid content. Trials indicate that non-digestible
oligosaccharides or inulin supplementation increases the fractional absorption of
calcium in children and adolescents, but not in adults.
9.83 Randomised controlled trials that supplemented subjects’ diets with resistant
starch indicate no effect of resistant starch on energy intake. Resistant starch
supplementation (types 1, 2 and 3 analysed together) is shown to cause an
increase in faecal weight, has no effect on faecal bacterial content, but modifies
faecal short chain fatty acid content, with an increase in the concentration or
proportion of butyrate and a lowering of pH. A limited number of trials indicate
little effect of resistant starch type 4 on these faecal parameters.
9.84 The supplement doses of resistant starch, non-digestible oligosaccharide or inulin
at which the effects described above become apparent is above levels currently
consumed in typical diets in the UK, but recent and future developments of novel
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