Superfoods Fibre - Fermentable and Insoluble
Dr Paul Clayton 2006
One of the major dietary problems in the West is a lack of fibre; and this is not just the old-fashioned roughage you find in all those rather grim bran cereals. The emphasis in clinical research has switched to fermentable fibres, such as inulin.
Fermentable fibres are also called pre-biotics, because they stimulate the growth of healthy bacteria ('probiotics') in our intestines. Recent archeological research has found that our ancestors routinely consumed large amounts of plant foods rich in these fibres.
Jeff Leach, an archaeologist working at the Paleobiotics lab in New Mexico, was one of the first to explore this idea. According to Leach, "As our early ancestors moved from the rainforest to the parched savanna-woodlands of subtropical Africa, subsurface tubers, rhizomes, corms, and perennial bulbs would have been a ready and important source of energy; and many of these plant foods, such as onions and agave root, are very rich sources of inulin. Our ancestors were effectively inulin farmers." (Leach et al '05)
Dr Leach's theories are supported by widespread findings of earth ovens, which were used until very recently to cook these types of foodstuffs. They generate high enough temperatures to destroy the digestion-inhibiting and toxic compounds present in many tubers and bulbs, but not enough to destroy their inulin and other nutritional content. Thus, it was the discovery of fire that made this important source of food available.
The archaeological record shows the pits used for these earth ovens got bigger and bigger over time, with some industrial-sized ovens in the American Southwest capable of cooking batches of up to four thousand pounds of agave root. These and other findings indicate that our ancestors derived about 60% of their calories from these foods, which would mean that they consumed between 50 and 100 grams of fermentable fibre every day; compared to the 5 to 15 grams (10 grm average) contained in the modern diet. And that would mean that the range of bacteria in our ancestors' guts would have been very different from the pattern found in most people's insides today, an unhealthy pattern linked to a variety of gut problems from constipation to cancer.
It is high time that we all increased our intake of inulin and the other fermentable fibres such as resistant starch. Do not, however, include fructo-oligo-saccharides (FOS) in this group. Touted by some 'health' companies as a cure-all, FOS may do more harm than good by over-promoting probiotic bacteria and then leaving them to starve; a situation which can lead them to produce a variety of toxic and carcinogenic metabolites (Gibson '06).
|