# The Role of Plant-Based Diets for Cancer Survivors and Planetary Health

## TL;DR

This paper reviews how plant-based diets may improve health outcomes for cancer survivors and benefit the planet.

## Contribution

It provides evidence-based guidance on plant-based diets for breast, colorectal, and prostate cancer survivors, linking dietary choices to both personal and planetary health.

## Key findings

- Higher fiber intake from fruits, vegetables, and whole grains is linked to lower breast and colon cancer mortality.
- Replacing refined grains with whole grains improves disease-free survival in colon cancer survivors.
- Tree nut consumption is associated with better outcomes for breast, colorectal, and prostate cancer survivors.

## Abstract

Many cancer survivors ask for guidance on what foods to eat to support their health after treatment. The role of diet in cancer survivorship is a growing area of research. This article summarizes current evidence on dietary patterns associated with health outcomes in cancer survivors, with a focus on plant-based diets. Evidence suggests that dietary patterns high in fruits, vegetables, whole grains, legumes, nuts, and soy foods, and low in red and processed meats and refined grains, may be associated with improved outcomes after a diagnosis of breast, colorectal, or prostate cancer. The article also offers guidance on food groups that may be prioritized or limited based on cancer type. In addition, the potential environmental benefits of plant-based dietary patterns are discussed, highlighting links between food choices and personal and planetary health.

Purpose: A growing body of evidence has emerged on the role of diet for health outcomes in cancer survivors. Patients transitioning to post-treatment care may seek guidance on dietary changes, and summaries of the evidence for dietary patterns recommended by guidelines can support providers in effectively answering questions. Increasing evidence suggests that food choices impact planetary health. Plant-based diets are one eating pattern that may improve patient outcomes and planetary health. Methods: We performed a literature review and used narrative reporting to summarize evidence for plant-based diets and offer specific guidance for breast, colorectal, and prostate cancer patients who are post-diagnosis. Specifically, we reviewed impacts on recurrence, all-cause, and cancer-specific mortality. Results: Increased fibre intake by consuming foods like fruits, vegetables, and whole grains is associated with a decreased risk of breast cancer-specific and all-cause mortality, as well as reduced colon cancer-specific mortality. Replacing refined grains with whole grains is associated with improved disease-free survival for colon cancer survivors. Higher tree nut consumption is associated with improved disease-free survival for breast, colorectal, and prostate cancer survivors. Soy is safe to consume for breast cancer survivors and is associated with a reduced risk of recurrence. Conversely, more Western dietary patterns high in processed meat intake are associated with an increased risk of colon cancer recurrence and prostate cancer mortality. There are also environmental benefits of a shift towards plant-based diets to address the adverse health outcomes associated with climate change and its potential impact on cancer care delivery as previously outlined in a 2024 ASCO policy statement. Conclusions: Based on the best existing evidence, providers can suggest that patients consider plant-based dietary patterns in the post-treatment phase of their cancer care to support health outcomes and planetary health.