A new European prospective study has reported that fruit and vegetable intake has only a small influence on overall cancer risk (all types of cancer). The study included 142,605 men and 335,873 women in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort to assess associations between risk of cancer and (1) intake of total fruits; (2) intake of total vegetables; and (3) intake of total fruits and vegetables combined during 1992-2000. Analyses were also conducted with respect to cancers associated with tobacco and alcohol use after taking into account tobacco smoking and alcohol drinking.

During a median follow-up period of 8.7 years, 9,604 men and 21,000 women were diagnosed with cancer. Associations between cancer risk and intake of total vegetables were similar to those of total fruits and vegetables combined. Only a 2% reduction in cancer risk for every 100 g/day increased consumption of vegetables was found compared to a 3% reduction for 200 g/day increased intake of fruits and vegetables combined. Considered separately, fruit consumption was found to have an even weaker inverse association with risk of cancer- only a 1% reduction in risk was found for 100 g/day increased intake of total fruits. A stronger reduction in cancer risk in heavy drinkers was found for fruit and vegetable consumption for cancers caused by smoking and alcohol. The authors conclude that only a very small inverse association between intake of total fruits and vegetables and cancer risk was found in this study.

A healthy diet is not enough — specific foods reduce breast cancer risk

Generally speaking, cancers strongly influenced by hormones (e.g., breast, ovarian, endometrial, and prostate cancer) appear to be the most influenced by overall diet. However, the development of other cancers are often influenced by a smaller group of foods and often avoiding certain foods is more important than consuming an overall healthy diet. For example, gastric cancer may be promoted by the consumption of salty foods and lung cancer may arise from breathing hot oil fumes during cooking.

It is remarkable that the same ground is covered repeatedly with respect to studies of diet and cancer. Every now and then, a new study such as this one is published that appears to offer a simple conclusion. The progress that has been made in studying particular foods or food groups and their specific interaction with cancer development tends to be ignored by reporters when the new study is covered. In fact, not all fruits and not all vegetables are equal (a few may even be harmful). While it is complicated, it is worth making the effort to identify diets that prevent cancer or its recurrence. Apparently, the advice to eat five servings of fruits or vegetables per day is not specific enough.