The role of diet and nutrition in cervical carcinogenesis: a review of recent evidence.

Our objective was to provide an update on recent epidemiologic evidence about the role of diet and nutrition on the risk of human papillomavirus (HPV) persistence and cervical neoplasia, taking HPV into account.

We conducted a systematic review and qualitative classification of all observational studies controlling for HPV infection published between March 1995 and November 2003 and of all randomized clinical trials published between January 1991 and November 2003.

Scientific evidence was classified as convincing, probable, possible or insufficient, as used in a previous study on diet and cancer. Thirty-three studies were eligible for this review (10 clinical trials, 8 observational prospective studies and 15 case-control studies). The few studies on HPV persistence showed a possible protective effect of fruits, vegetables, vitamins C and E, beta- and alpha-carotene, lycopene, luterin/zeaxanthin and cryptoxanthin. Evidence for a protective effect of cervical neoplasia was probable for folate, retinol and vitamin E and possible for vegetables, vitamins C and B12, alpha-carotene, beta-carotene, lycopene, lutein/zeaxanthin and cryptoxanthin. Evidence for an increased risk of cervical neoplasia associated with high blood homocysteine was probable.

Results did not differ between studies looking at preneoplastic and invasive lesions or between retrospective and prospective studies. The available evidence for an association between diet and nutritional status and cervical carcinogenesis taking HPV infection into account is not yet convincing. Large cohort studies are needed to adequately assess the role of foods and nutrients in cervical HPV carcinogenesis.