INCREASING COMPLEX CARBOHYDRATE IN THE DIET - ARE THE BENEFITS DUE TO STARCH, FIBER OR DECREASED FAT INTAKE

'Nutrition Recommendations' suggests that Canadians should consume 30% of the dietary energy as fat and 55% of energy as carbohydrate, from a variety of sources. While much emphasis has been placed on reducing fat intake, less work has been done on changing carbohydrate intake, with the result that little change in intake of this nutrient has been seen over the last twenty years. New evidence indicates that there may be direct advantages for health of increasing carbohydrate consumption, rather than just as a substitute energy source when fat is removed. Research since 1980 has indicated that not all starch consumed is digested and absorbed in the small intestine, but that 8-10% may reach the colon, where it is fermented by the resident microflora. Fermentation of starch results in a higher proportion of the short chain fatty acid butyrate than fermentation of dietary fibre; this may be of importance since butyrate is a preferred energy source for the colonic mucosal cells, and has been shown to have anticancer properties in vitro. Benefits for health of starch consumption are emerging with new research; the public must be informed of these findings and encouraged to consume a high starch diet.