An apple a day may hold colorectal cancer at bay: recent evidence from a case-control study

Rev Environ Health. 2009 Jan-Mar;24(1):59-74. doi: 10.1515/reveh.2009.24.1.59.


Environmental factors play an important role in the etiology of colorectal cancer, the second-most common malignancy in both genders in developed countries. Evidence has shown that potential cancer-inducing oxidative damage might be prevented or restricted largely by the presence of dietary antioxidants of plant origin, such as fruits or vegetables. The protective antioxidant effect of fruits and vegetables has been attributed to flavonoids, a major class of phytochemicals naturally occurring in fruits, vegetables, and various foods of plant origin. Yet, epidemiologic cohort studies relating flavonoid intake to risk of colorectal cancer have been sparse and inconclusive. Apples are a rich source of flavonoids and have the second highest level of antioxidant power among all fruits, with peels having a stronger antioxidant activity than apple flesh. A recent reanalysis of several case-control studies in Italy demonstrated a consistent inverse association between apple consumption and the risk of various cancers, and among them ofcolorectal cancer. Here we assessed the potential protective impact of apples on risk of colorectal cancer in the course of a recently performed hospital-based case-control study in a country with dietary habits very different from those of Mediterranean region. The results showed that highest risk of colorectal cancer was among older persons and those who were residents of villages or small towns. The risk of colorectal cancer was inversely correlated with daily number of apple servings, but the most significant reductions of OR estimates were observed for an intake one or more apple servings daily (OR = 0.37, 95% CI: 0.15-0.91). No other fruit was significantly associated with altering the risk of colorectal cancer.

MeSH terms

  • Aged
  • Antioxidants / pharmacology
  • Case-Control Studies
  • Colorectal Neoplasms / epidemiology*
  • Colorectal Neoplasms / prevention & control*
  • Confounding Factors, Epidemiologic
  • Diet
  • Female
  • Flavonoids / pharmacology
  • Fruit
  • Hospitals
  • Humans
  • Logistic Models
  • Male
  • Malus*
  • Middle Aged
  • Poland / epidemiology
  • Risk Factors
  • Surveys and Questionnaires
  • Vegetables


  • Antioxidants
  • Flavonoids