Flavonoid intake improves survival after CRC diagnosis

Patients who have been diagnosed with colorectal cancer (CRC) may benefit from increased flavonoid intake, which has been shown to reduce CRC-specific mortality in a recent study.

“Small, readily achievable increases in the intake of flavan-3-ol–rich foods, such as tea, may help improve survival in patients with CRC,” the researchers said.

The association of postdiagnostic flavonoid intake with CRC-specific and all-cause mortality was prospectively evaluated in 2,552 patients diagnosed with stage I‒III CRC in two cohort studies, namely the Nurses’ Health Study and the Health Professionals Follow-up Study. The researchers used validated food frequency questionnaires to assess the total flavonoids intake and subclasses.

An inverse probability‒weighted multivariable Cox proportional hazards regression model was used to calculate the hazard ratio (HR) of mortality after adjusting for prediagnostic flavonoid intake and other potential confounders. Additionally, a spline analysis was done to assess dose‒response relationships.

At diagnosis, the mean age of patients was 68.7 years. During 31,026 person-years of follow-up, a total of 1,689 deaths occurred, of which 327 were due to CRC.

Total flavonoid intake showed no association with mortality, but a higher intake of flavan-3-ols appeared to contribute to lower CRC-specific (multivariable HR per 1-SD increase, 0.83, 95 percent confidence interval [CI], 0.69‒0.99; p=0.04) and all-cause mortality (HR, 0.91, 95 percent CI, 0.84‒0.99; p=0.02).

In the spline analysis, postdiagnostic flavan-3-ol intake had a linear association with CRC-specific mortality (p=0.01 for linearity). Specifically, tea consumption was inversely associated with CRC-specific (multivariable HR per 1 cup/day, 0.86, 95 percent CI, 0.75‒0.99; p=0.03) and all-cause mortality (HR, 0.90, 95 percent CI, 0.85‒0.95; p<0.001).

Other flavonoid subclasses showed no beneficial associations.