Chemistry Reference
In-Depth Information
studies. The mechanism by which lowering of serum lipids and cholesterol may
occur has been speculated to be regulation of host de novo lipogenesis through
SCFA (particularly acetate) absorbed from the gut (Williams and Jackson,
2002) or by reduced intestinal fat absorption (Shimomura et al., 2005) (Figure
5.10). Although promising, not all feeding studies in humans using prebiotic
carbohydrates have resulted in clinically significant changes in serum lipid
profiles, and further research is needed to identify responsive populations,
interactions with diet and to show benefits of dietary intervention in clinical
end-points such as impact of cardiovascular disease.
Preliminary data have also suggested that lactulose (Ferchaud-Roucher
et al., 2005; Brighenti et al., 2006) and lactitol (Ju´kiewicz et al., 2006) could
improve insulin sensitivity. In a small human feeding trial, Brighenti et al.
(2006) demonstrated that feeding a meal containing lactulose diminished
post-prandial blood glucose response in a subsequent meal (''second meal
effect'') by reducing competition by non-esterified fatty acids for glucose
disposal, and to a minor extent, by affecting intestinal motility. The potential
of fermentable carbohydrates in the management of metabolic disorders
linked to insulin resistance may warrant further study.
5.9.5.
Farm and Companion Animals
Prebiotic oligosaccharides, including GOSs, have been evaluated for
use in both farm animal feeds and for companion animals, especially dogs.
The advantage of use with dogs is the positive impact of feeding oligosac-
charides on reduced odour and improved volume and consistency of faeces
(Swanson and Fahey, 2006). With respect to farm animals, prebiotics have
been studied for their potential to replace antibiotics in maintaining high-feed
conversion efficiencies and also to suppress methane production by rumi-
nants (Mwenya et al., 2004a,b; Sar et al., 2004; Santoso et al., 2004).
5.10.
Product Safety, Dose Rates and Regulatory Issues
5.10.1.
Galacto-oligosaccharides
The regulatory regimes for non-digestible carbohydrates have been
under active review in many countries in recent years. A marked development
since 2000 has been the inclusion of most non-digestible oligosaccharides in
the category ''dietary fibre'' (see definition in Section 5.6). This has been a
landmark development, because it allows recognition of these products as
having some health benefits. Prior recognition in a regulatory sense had been
restricted to Japan, where for many years the functional food sector was
regulated by the FOSHU system.
