Colon Cancer Survival Helped by Nut Consumption

 A new study sponsored by the Dana Farber Cancer Institute in Boston looked at people diagnosed with colon cancer, and found that eating tree nuts  lowered their chances of cancer recurrence. An observational study of 826 patients with stage III colon cancer showed that those who consumed two ounces or more of nuts per week had a 42% lower chance of cancer recurrence and 57% lower chance of death than those who did not eat nuts. The questionnaire was given after completion of chemotherapy in a study that began in 1996.  Stage III colon cancer is defined as cancer that has spread to surrounding lymph nodes.

 “Basic healthy eating can often be overlooked during cancer treatment. This study shows that something as simple as eating tree nuts may make a difference in a patient's long-term survival," said Dr. Daniel F. Hayes. "Nut consumption and a healthy diet are generally factors that clinicians and patients should perhaps pay attention to as they design the approach to treatment for colorectal cancer." A secondary analysis revealed the benefit of nut consumption was limited to tree nuts. Tree nuts include almonds, walnuts, hazelnuts, cashews, and pecans, among others. There was no associated reduction in cancer recurrence and death among patients who consumed peanuts or peanut butter. According to the authors, the reason may be that, being legumes, peanuts have a different metabolic composition than tree nuts

"Numerous studies in the fields of heart disease and diabetes have shown the benefits of nut consumption, and we felt that it was important to determine if these benefits could also apply to colorectal cancer patients," said lead study author Temidayo Fadelu, MD, a clinical fellow in medicine at Dana Farber Cancer Institute. "Patients with advanced disease who benefit from chemotherapy frequently ask what else they can do to reduce their chances of recurrence or death, and our study is an important contribution to the idea that modifying diet and physical activity can be beneficial."

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Researchers were particularly interested in nut consumption because it has been linked to lower incidence of obesity, type 2 diabetes, and reduction in insulin resistance. These health conditions are each associated with a higher risk of recurrence and death from colon cancer. The benefit of eating nuts was consistent across known factors that can influence cancer recurrence, including patient age, body mass index, gender, and common genomic changes in the tumor.

"It should be emphasized that the authors are not suggesting that eating nuts should be considered a substitute for standard chemotherapy and other treatments for colon cancer, which have dramatically improved survival," said Dr. Hayes. "Rather, patients with colon cancer should be optimistic, and they should eat a healthy diet, including tree nuts, which may not only keep them healthier, but may also further decrease the chances of the cancer coming back."

"We need to look at the potential positive impact of nut consumption on survival at other stages of colon cancer, particularly stage IV. (Stage IV colon cancer is defined as cancer that has spread to other organs, such as liver or lungs.) Ultimately, we need to understand how nuts confer this protective effect, as well as possibly conduct a randomized, controlled clinical trial where diet recommendations are given at the start of the study to prove that tree nuts can reduce recurrence and death after treatment for colon cancer," said Dr. Fadelu.

Here’s a take-home message from this positive finding.  It’s a good idea to put nuts into your diet now – they can also help to prevent overweight, diabetes and heart disease.  Peanuts have also been found to have positive effects on our health.  If they fill you up with healthy fat, you’ll be ahead when it comes to super-sweet deserts!

Sadja Greenwood, MD, MPH