Plant-based diet may improve survival of colorectal cancer survivors

A diet rich in fruits and vegetables appears to provide survival benefits to long-term colorectal cancer (CRC) survivors, suggests a study.

The investigators evaluated diet using food frequency questionnaires at a median of 6 years after diagnosis in 1,404 CRC survivors (median age 69 years, 56 percent male) in a Northern German prospective cohort study.

They derived an overall, healthful plant-based and an unhealthful plant-based diet index by scoring intakes of animal foods reversely and intakes of healthy (eg, whole grains, vegetables, fruits, legumes, nuts, oils, tea/coffee) and less healthy plant foods (eg, refined grains, fruit juices, sugar-sweetened beverages, potatoes, sweets/desserts) positively or reversely, depending on the index.

Population registries were also used to perform a vital status follow-up. Finally, hazard ratios (HRs) for all-cause mortality according to plant-based diet adherence was estimated using Cox proportional hazards regression.

Two hundred four deaths were recorded over a median of 7 years following diet assessment. The overall plant-based diet index inversely correlated with all-cause mortality (HR per 10-point increase in diet index, 0.72, 95 percent confidence interval [CI], 0.57–0.91). Higher healthful plant-based diet scores also correlated with lower mortality (HR, 0.82, 95 percent CI, 0.67–1.01), albeit not statistically significant.

In contrast, the unhealthful plant-based diet index appeared to increase the risk of mortality. This association, however, lost statistical significance after adjustment for confounders (HR, 1.19, 95 percent CI, 0.96–1.48). In a subgroup analysis, the tendency towards a positive association between unhealthful plant-based diet and mortality was limited to less physically active individuals (<95 metabolic equivalent of task hours/week).

“[M]ore research is needed to further disentangle the impacts of different qualities of plant-based diets on cancer survivors’ health,” the investigators said.