High Intake of Specific Carotenoids and Flavonoids Does Not Reduce the Risk of Bladder Cancer

Abstract

An analysis of a previously completed Spanish multicentric case-control study of bladder cancer was carried out using new available data on the contents in foods of specific carotenoids (alpha-carotene, beta-carotene, lutein, and lycopene) and flavonoids (quercetin, kaempferol, myricetin, and luteolin) to investigate the relationship of these phytochemicals with bladder cancer. The study included 497 cases first diagnosed with bladder cancer, 547 neighborhood controls, and 566 hospitals controls, matched by gender, age, area of residence, and hospital. Usual food intake was estimated using a dietary history questionnaire administered by trained interviewers. None of the specific carotenoids and none of the specific flavonoids have been found to be significantly associated with bladder cancer risk in this analysis. The adjusted odds ratios for subjects in the highest quartile of intake with respect to subjects in the lowest quartile were 1.36 (95% confidence interval = 0.94-1.95) for total carotenoid intake and 1.23 (95% confidence interval = 0.85-1.79) for total flavonoid intake. The results of this study does not support the hypothesis that intake of specific carotenoids and flavonoids is protective against bladder cancer risk.

Flavonoids: Promising anticancer agents

“…There are few contrary reports [28][29][30] that may be due to differences in bioavailability of the various flavonoids, and their effects on individual cancer sites cannot be excluded meriting further investigation.…”

Intakes of fruits and vegetables, carotenoids and vitamins A, E, C in relation to the risk of bladder cancer in the ATBC cohort study

“…To our knowledge, only three studies (Garcia et al, 1999;Michaud et al, 1999;Zeegers et al, 2001a) have published findings for the relation between individual carotenoid intakes and bladder cancer risk. No associations were observed for alphacarotene, beta-carotene, lycopene or lutein intakes in these publications, but an inverse association was reported for betacryptoxanthin in the Netherlands Cohort Study, which was particularly strong among heavy smokers (Zeegers et al, 2001a).…”

Cancer chemoprevention and chemotherapy: Dietary polyphenols and signalling pathways

“…Clinical trials attempt to correlate polyphenolic intake with prevention of a particular cancer, showing a decreased risk for different types of cancer [7 -10] or a diminished recurrence of cancer [11,12] after the consumption of flavonoids or certain foods or drinks (tea) rich in these phenolic compounds. In contrast, certain human studies have also shown no beneficial effects [13,14] or have failed to find a positive association between intake of flavonoids and reduced risk for different types of cancer [15,16]. However, it should be highlighted that assessing the real impact of such constituents on human health is difficult, when consider that in many cases the exact composition of foods and the bioavailability of active molecules are not known.…”