| Cereal foods, fibres and the prevention of cancers
Graeme H. McIntosh
Abstract Wholegrain and wholemeal cereal foods are important components of a healthy diet, making a major contribution, via their dietary fibre and associated phytochemicals, to disease prevention. Outer layers of grains are particularly rich in dietary fibre and also contain a range of other components which may have anticancer effects, at the levels normally found in a healthy diet. Although wholegrains have been identified as a significant contributor to cancer prevention along with fruits and vegetables in a report of a committee from the National Academy of Sciences on Diet, Nutrition and Cancers in 1983, most emphasis since then has been given to fruits and vegetables, almost to the exclusion of cereals. The relevance of cereals to a healthy protective diet therefore needs more evaluation and recognition. Case-control cancer studies in which wholegrain cereal foods and foods rich in cereal fibre were adequately identified have shown them to protect against colorectal cancers, gastric cancers and possibly also breast, endometrial and prostate cancers. Reduction of colorectal cancer risk in the order of 30% to 40% has been observed for people ingesting wholegrain or wholemeal cereal foods as part of a regular dietary pattern, as recommended in the Australian dietary guidelines. Improved methods for measuring dietary fibre and assessing intakes of foods rich in cereal fibre in the last decade have assisted in providing more reliable epidemiological evidence. The evidence with regard to significant wholegrain or wholemeal cereal food intakes and reduced risk of other endemic degenerative diseases such as coronary heart disease and type 2 diabetes is as strong or even stronger. Overall, the evidence with regard to wholegrain ingestion and prevention of several major chronic diseases is impressive. There is a good case, based on recent dietary survey data, for recommending that Australians increase dietary fibre intake by 20% to 25%, and this could best be achieved by substituting wholegrain and wholemeal foods for refined cereal foods in at least half of the recommended cereal servings (six to seven daily). Assistance to consumers with identification of wholegrain and wholemeal foods in an increasingly complex array of supermarket foods is desirable, and the US approach of labelling wholegrain foods as those containing more than 50% wholegrain or equivalent might be a useful approach to adopt in Australia.
(Aust J Nutr Diet 2001;58 Suppl 2:S35-S48)
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Australian Journal of Nutrition and Dietetics, Volume 58, Supplement 2, December 2001