THE type of fibre we eat may be far more important essential than the quantity alone, according to CSIRO senior chief research scientist with CSIRO Food Futures and Preventative Health Flagships, Health Sciences & Nutrition, Dr David Topping.
Dr Topping says some western populations have low fibreer intakes Americans have a serious fibre gap, , which not only affect ‘regularity’ but also can heighten risk for several non-infectious diseases.
While the minimum threshold for regularity is about 23 grams of dietary fibre a day, most Americans get only 15g or so in their diets. And, since fibre has other benefits, the 2005 Dietary Guidelines recommend
people consume between 25-38 grams of fibre each day.
Dietary fibre comprises largely non-starch polysaccharides (NSP) which resist human small intestinal digestion completely. This explains their excellent faecal bulking and laxative properties.
“Average fibre intakes are too low to obtain these benefits and need to be increased in the USA,” Dr Topping said.
“However, resistant starch (RS) is emerging as an even more important bowel health promoter than NSP.”
“The intake of RS in the US, Australia and other advanced countries is extremely low. CSIRO is working actively to develop new high RS grains and foods to meet the need for greater RS consumption.
“The Food Futures Flagship is developing novel wheat varieties to meet the community’s emerging health needs,” the Flagship’s Director, Dr Bruce Lee, said.
“These high RS wheats produce nutritionally significant levels of RS and can be incorporated into breads, cereals and other foods.”
The Flagship’s research in this area is an example of the successful collaboration of multi-disciplinary scientific expertise drawn from CSIRO Human Nutrition and CSIRO Plant Industry and, Food Science Australia - a joint venture between CSIRO and the Victorian Government.
“Unlike NSP, RS promotes large bowel function not through bulking but the short chain fatty acids produced by its metabolism by colonic bacteria. Of the major fatty acids, butyrate, is considered to be the most important.
“A wealth of experimental data shows that it is the major metabolic fuel for normal colon cells and that it inhibits the growth of cancerous ones.”