Differences in intake of specific food plants by Polynesians may explain their lower incidence of colorectal cancer compared with Europeans in New Zealand

Abstract

Epidemiological studies have implicated obesity; high intakes of alcohol, fat, and energy; and low intakes of food plants as risk factors for colorectal cancer. In New Zealand, Polynesians (including Maoris and people from several Pacific Islands) are more likely to be overweight and have higher intakes of fat and energy than Europeans, and they are likely to have similar total intakes of food plants. Yet, in New Zealand, Polynesians have a significantly lower incidence of colorectal cancer than the Europeans. It is possible that the difference in incidence of colorectal cancer is due to differences in consumption of specific food plants by Polynesians and Europeans in New Zealand. Here we have compared the consumption of specific food plants by 429 Maoris, 643 Pacific Islanders, and 4,451 Europeans in paid employment in New Zealand. Of the 51 food plants eaten by New Zealanders, 6 were eaten significantly more frequently and 17 significantly less frequently by the two Polynesian groups than by Europeans. The quantity of any protective chemical components (or other as yet unknown protective factors) in food plants is likely to be related to their botanical classification. Differences in the intake of specific food plants may at least partly explain differences in the incidence of colorectal cancer between Polynesians and Europeans.