Dietary Nutrients and Oncogenic HPV Infections
Additional large, well-designed studies are needed to clarify the roles of dietary nutrients in HPV infection persistence and cancer risk.
Human papillomavirus (HPV) is a common sexually transmitted infection of genital and oropharyngeal tissues. When infections involving certain oncogenic HPV strains are persistent, they can lead to dysplasia, premalignant lesions, and eventually, tumors of the cervix, vulva, penis, or oropharynx.1,2
Nutritional status has long been recognized as a potential cofactor involved in HPV persistence and carcinogenesis.3 HPV's role in aberrant gene methylation is believed to play a role in tumor formation and progression. Because dietary folate, vitamin B6 and B12, and methionine also modulate methylation patterns, research has focused on those nutrients as agents that might protect against persistent oncogenic-strain HPV infection and associated cancers.
Because iron metabolism is changed by viral infections, it is hypothesized that elevated iron levels might be a separate cofactor for HPV infection duration.
Results are mixed, and additional large, well-designed studies are needed to clarify the roles of dietary nutrients in HPV infection persistence and cancer risk.
Evidence in Favor of A Link
There is limited evidence that dietary nutrients can reduce HPV-associated cancer risk.
One 2002 study of 201 women in Arizona who had transient or persistent HPV infections found that higher circulating levels of vitamin B12 were associated with more transient and fewer persistent HPV infections. This result remained significant after controlling for potentially confounding variables like age, tobacco smoking, ethnicity, body mass index, and sexual and marital history.2
Women with circulating B12 levels exceeding 493 pg/mL were less likely to have persistent HPV infections (adjusted odds ratio [aOR] 0.40; 95% confidence intervals: 0.17-0.96; Ptrend = .037).2
Yet when only dietary intake (from food) of vitamin B12 was considered, and intake associated with dietary supplements was excluded from analysis, the association with HPV persistence disappeared.