Researchers have found that eating tree nuts which include almonds, walnuts, hazelnuts, cashews, and pecans, among others, is associated with significant reduced risk of colon cancer recurrence.

The observational study of 826 patients with stage III colon cancer showed that those who consumed two ounces or more of tree nuts per week had a 46 per cent lower chance of cancer recurrence and 53 per cent lower chance of death than those who did not.

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 represent a state of excess energy and are each associated with a higher risk of recurrence and death from colon cancer.

"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, a clinical fellow in medicine at Dana Farber Cancer Institute in Boston, Massachusetts, US. 

"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," Fadelu said.

The findings are scheduled to be presented at the upcoming 2017 American Society of Clinical Oncology (ASCO) annual meeting in Chicago from June 2-6.

There was no associated reduction in cancer recurrence and death among patients who consumed peanuts or peanut butter. 

The reason may be that, being legumes, peanuts have a different metabolic composition than tree nuts, according to the study authors.

In their next step, the researchers hope to conduct a randomised, 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.

"We need to look at the potential positive impact of nut consumption on survival at other stages of colon cancer, particularly stage IV. Ultimately, we need to understand how nuts confer this protective effect," Fadelu said.