Investigators from the EnCoRe study in the Netherlands found that survivors of colorectal cancer who followed World Cancer Research Fund’s (WCRF) dietary recommendations reported better quality of life and functioning, and less fatigue. These findings were recently published in the British Journal of Nutrition, and one of the authors, Martijn Bours, explains the study and results.
Why did we study colorectal cancer?
The number of people surviving colorectal cancer is increasing worldwide. Also known as bowel cancer, the rising numbers of survivors is partly due to improved treatments and population screening for colorectal cancer. Although increased survival is good news, many survivors keep suffering the negative consequences of a cancer diagnosis and aggressive cancer treatments in the years that follow. For instance, about one in three survivors report persistent complaints of fatigue.
These complaints can have a large impact on their quality of life and level of functioning, such as the ability to carry out usual activities of daily living and participate in social events and work. Not much is known, however, about how these health and functioning problems could be influenced by the lifestyle habits of colorectal cancer survivors, particularly their dietary habits.
What were our research findings?
We studied the relationship between WCRF’s dietary recommendations and quality of life, functioning and fatigue in colorectal cancer survivors using data from our EnCoRe study (Energy for life after ColoRectal cancer). WCRF recommends a diet high in fruit and vegetables and dietary fibre, and low in high-calorie foods (fast foods), red & processed meat, and sugary drinks and alcohol.
Marlou-Floor Kenkhuis, a PhD student supported by a grant from WCRF, analysed data from 150 individuals who had been living with a colorectal cancer diagnosis for 2–10 years. These individuals were asked to keep a food diary for one week and to fill in several questionnaires on their quality of life, functioning, and fatigue. Marlou-Floor found that survivors who ate more fruit and, especially, more vegetables reported better quality of life and physical functioning and less complaints of fatigue. Survivors who ate less high-calorie foods also reported better physical functioning.
What do our findings mean?
Our findings suggest that a diet high in fruit and vegetables and low in high-calorie foods could have beneficial health effects for colorectal cancer survivors, even 2–10 years after the diagnosis and treatment. For example, survivors who took one extra portion of 100 grams of vegetables – approximately two serving spoons – a day experienced a higher quality of life, better physical functioning, and less complaints of fatigue.
We must note several cautions though. First, the influence of the dietary recommendations on quality of life, functioning, and fatigue was relatively small, but nonetheless real. Second, because the influence of diet was measured at one point in time, we cannot draw any firm conclusions regarding cause and effect. Further research is needed for that. Third, WCRF’s recommendations focus not only on diet but also on physical activity and body composition. It must be emphasised that a healthy lifestyle is a complete package, which does not consist of only one isolated aspect of the diet but of a combination of lifestyle habits.
With the support of WCRF, we are currently studying how WCRF’s lifestyle recommendations regarding diet, nutrition, and physical activity influence the quality of life of colorectal cancer patients in the first two years after the end of treatment. For that, we have collected information on lifestyle habits and quality of life at numerous time points after treatment to enable detailed investigation. The findings will provide new insights into the relationship over time between lifestyle and quality of life after colorectal cancer. We hope to report our findings in the near future.