Study on Diet and Cognition after Cancer Treatment
The Perceived Relationship between Diet and Cognitive Function in Breast and Colorectal Cancer Survivors: A Qualitative Study
- Summary of main findings –
The aim of this study was to identify what cancer survivors thought about the relationship between their diet and cognitive function, and, how their cancer-related cognitive changes have influenced their diet. Cognition could refer to any aspect of thinking including someone’s ability to think, their memory, to focus or concentrate on something, to respond or react to things, or to make decisions. We also looked at what kind of changes survivors made to their diet since being diagnosed with cancer, what survivors’ perceived as contributing to those changes, and what prevented them making changes to their diet.
Interviews were conducted with 15 cancer survivors. Thirteen participants were breast cancer survivors and two participants were colorectal cancer survivors. On average, survivors had been diagnosed with cancer 27 months before their interview. ‘Thematic analysis’ was used to identify the most common themes across all participants. Not all themes were applicable to all participants, nor were the main themes able to capture all the unique elements of survivors’ stories, however the most common themes are listed here. There was an abundance of interesting and rich data that participants shared; only the data relating to the main research questions are mentioned here.
- There were four common themes relating to how survivors perceived diet impacted their cognition:
i) Directly (e.g. a healthy diet improves cognition and thinking and a worse diet makes it harder)
ii) Indirectly (e.g. diet affects things like energy and tiredness, which in turn affect cognition and thinking)
iii) No impact (e.g. diet doesn’t affect cognition or thinking)
iv) Potentially (e.g. survivors’ diet quality was generally good, but if they had poorer diet quality they believed their cognition would probably be worse)
- Three main themes emerged for how cancer-related cognitive changes impacted survivors’ diets:
i) Meal planning was more difficult (e.g. it’s harder to think of what to cook, come up with menu plans and do the shopping)
ii) The process of cooking became more challenging and more complex (e.g. it’s harder to follow recipes; it’s a greater effort to cook foods/meals that used to be easier)
iii) It’s harder to say no to less healthy food (e.g. cognitive fatigue makes it harder to resist cravings; difficulties with meal planning leads to grabbing more convenient foods).
- For survivors who had made changes to their diet since being diagnosed with cancer (which had continued after active treatment stopped), there were four changes that were most common:
i) Changes to meal timing (e.g. eating when they are hungry and not by the clock or to an external schedule)
ii) Less overall variety (e.g. using less variety of ingredients in recipes, or using fewer types of recipes)
iii) More plant-based food (e.g. introducing more vegetables and legumes)
iv) Using more convenient food (e.g. using more frozen, jar, packet or ready-made meals).
- Survivors perceived four main causes of these dietary changes (in addition to those that perceived their cognitive changes also contributed to the changes):
i) Persisting side-effects from treatment (e.g. fatigue, changes to sense of taste, gastrointestinal discomfort)
ii) Persisting habits from treatment (e.g. avoiding foods that they weren’t able to eat when they were going through primary treatment)
iii) Changes to work schedule (e.g. working less now meant greater flexibility with what and when they could eat)
iv) Preventative health (e.g. avoiding possible negative outcomes of treatment).
- There were three main barriers that survivors experienced to making positive dietary changes
i) Too much to think about (e.g. there’s a lot of other important things that need focussing on so diet can’t always be a priority)
ii) Tiredness (e.g. feeling more fatigue means less energy to make dietary changes)
iii) Other people’s needs (e.g. they prepare meals for family members and are limited by what foods can be enjoyed by the whole family).
One paper has recently been published in the European Journal of Cancer Care, an academic journal that disseminates research worldwide relating to cancer patients and survivors, and cancer care (https://onlinelibrary.wiley.com/doi/10.1111/ecc.13303).
We are currently preparing a second paper for publication, and are also recruiting for a related study.
Many participants perceived that their diet and cognition can impact one another in various ways. As this was a small study, more research is needed on how diet and cognition might affect one another in cancer survivors, before any specific recommendations can be made. However, initial findings from this study suggest that dietary assistance with meal planning and preparing, especially in ways that accommodate cognitive changes such as difficulty focussing and concentrating, memory challenges, and physical and mental tiredness, may be beneficial for those experiencing cognitive changes.
While some of these findings may seem common-sense or expected, this is one of the first studies that has begun to look at these important issues in this way. More research can now build on these findings. This may include trialling different dietary plans to see if diet can improve cancer-related cognitive changes. It may also lead to the development of dietary resources that support people who have survived cancer with meal planning and cooking.
We would like to thank all those involved in the project, especially the participants for sharing their stories and experiences.
On behalf of the study team: Mr. Daniel Coro, Dr. Amanda Hutchinson, Prof. Siobhan Banks, & Prof. Alison Coates
(Chief Investigator and project supervisor: Dr. Amanda Hutchinson; e: [email protected]; p: +61 8 8302 4468)