JNCI Editorial: Fruits, Vegetables, and Cancer Prevention: Turmoil in the Produce Section

Some key excerpts - full text of Editorial available without cost:

•  In this issue of the Journal, Boffetta et al. (6) report findings from a European cohort of nearly 400 000 men and women who developed approximately 30 000 cancers at all sites combined over nearly 9 years of follow-up. After accounting for measurement error, a very weak but statistically significant inverse association was seen—a 4% lower incidence of all cancers combined for an increment of 200 g of total fruits and vegetables per day, which corresponds to about two extra servings per day.

• Most fundamentally, this study strongly confirms the findings from other prospective studies that the results of case–control studies were overly optimistic and that any association of intake of fruits and vegetables with risk of cancer is weak at best.

• Their more detailed analyses suggesting a stronge rbenefit among heavier consumers of alcohol lend some weight to a causal interpretation because other studies (7,8) have suggested that folate, primarily from fruits and vegetables,may be more beneficial in the context of regular alcohol consumption.

• A very weak or undetectable association between fruits and vegetables and risk of cancer does not exclude the possibility that oneor a small group of fruits or vegetables, or a specific substance in some of these foods, has an important protective effect.

• Even if we assume that the weak association seen in the EPIC cohort represents a true protective effect of fruits and vegetables,the question would still remain whether an effect of this magnitude should lead to clinical interventions or public health actions.Conveniently, although the evidence for benefits of fruits and vegetables against cancer was waning, data supporting benefits for cardiovascular disease were accumulating.

•  In summary, the findings from the EPIC cohort add further evidence that a broad effort to increase consumption of fruits and vegetables will not have a major effect on cancer incidence.