Science Nook: Plant and Animal-Based Foods and Colorectal Cancer Survivorship

by Jenna Koroly, MS, RD, CSOWM, CDN

Although there are numerous nutritious ways to eat, many foundational principles across nutritious eating patterns include an emphasis on plant-based foods such as vegetables, fruit, legumes, and nuts and seeds. In the below study, the authors investigate how plant-based eating patterns are related to colorectal cancer (CRC) survivorship.

Study

Post-diagnostic reliance on plant- compared with animal-based foods and all-cause mortality in omnivorous long-term colorectal cancer survivors

The American Journal of Clinical Nutrition

This prospective cohort study included over 1400 CRC survivors in Northern Germany. Food Frequency Questionnaires (FFQs) were administered at a median of 6 years after diagnosis. Three indices were used: overall plant-based diet index (PDI) including more plant-based foods and less animal-based foods, a healthful plant-based diet index (hPDI), and an unhealthful plant-based diet index (uPDI). A higher healthful plant-based diet score represented higher intake of whole grains, vegetables, fruits, legumes, nuts, oils, and tea/coffee and lower intake of animal foods, refined grains, fruit juices, sugar-sweetened beverages, potatoes, and sweets/desserts, and the reverse for a higher unhealthful plant-based diet score. The authors looked at mortality using population registries after a median of 7 years after FFQ administration [i].

Findings

The authors found:

1. The PDI was significantly associated with lower all-cause mortality

2. A higher healthful plant-based diet score displayed a strong tendency towards lower mortality, although this was not statistically significant

3. A higher unhealthful plant-based diet score was significantly associated with higher mortality only for less physically active participants (<95 MET-hours per week based on the 2000 Compendium of Physical Activity)

4. Consumption of whole grains, nuts, legumes, and vegetable oils showed some evidence of an inverse association with all-cause mortality. Of these, a significant inverse association was found only for nuts

5. Consumption of sugar-sweetened beverages was associated with a higher risk of all-cause mortality, while moderate fruit juice consumption was significantly associated with a lower risk of all-cause mortality compared to low fruit juice consumption

6. Greater animal fat consumption was associated with a higher risk of all-cause mortality compared with lower animal fat consumption [i]

For the Patient and Caregiver

Based on this research, a plant-based eating pattern may be beneficial for CRC survivors. If you are interested in increasing intake of plant-based foods, you may first consider trying some plant-based proteins including edamame, lentils, quinoa, nuts, and seeds in a few of your meals. Salads and quinoa bowls with your favorite vegetables, edamame, walnuts, sunflower seeds, and dressing are some tasty options! For more ideas on creating plant-based recipes, check out our recipe bank as well as the Blue Zones’ recipes [ii]. The findings also indicate that a healthy plant-based eating pattern may be even more protective for those that are less physically active, or increasing physical activity may offer benefits for those that include many of the foods in their diet that were scored as unhealthful plant-based foods.

For the Healthcare Team

This study is compelling as it compares a healthy plant-based diet to an unhealthy plant-based one, whereas much research compares a plant-based diet to an animal-based diet. It would be helpful to learn more about the indices, as many animal-based diets include nutritious foods such as fatty fish, lean meats, Greek yogurt, and eggs, and perhaps this partially explains some of the associations not finding significance (as intake of these foods would be scored as unhealthful plant-based in this study). It would also be interesting to learn more about the specific consideration behind scoring intake of potatoes (such as oftentimes potatoes are fried or mashed without the skin), as the skin of potatoes is rich in fiber and sweet potatoes are particularly rich in vitamin A.

References:

[i] Ratjen I, Enderle J, Burmeister G, Koch M, Nothlings U, Hampe J, Lieb W. (2021). Post-diagnostic reliance on plant- compared with animal-based foods and all-cause mortality in omnivorous long-term colorectal cancer survivors. The American Journal of Clinical Nutrition, nqab061, https://doi.org/10.1093/ajcn/nqab061

[ii] Blue Zones. Recipes. https://www.bluezones.com/recipes/