Posted on Mar 10, 2016, 6 a.m.
Walnuts contain compounds that trigger changes in the expression profile of micro-ribonucleic acids (miRNA).
Results of a study in mice suggest that adding walnuts to the diet may help to slow the growth of colon cancer. Researchers from Beth Israel Deaconess Medical Center and Harvard Medical School conducted the study of mice to determine whether walnuts would have any impact on specific micro-ribonucleic acids (miRNA), nucleotides that are involved in altering gene expression. The mice were injected with HT-29 colon cancer cells, and 7-days later were randomized to either control or walnut diets (equivalent to 2 ounces of walnuts per day in humans) for 25-days. At the end of the diet period results showed that key miRNA that may affect cancer cell inflammation, vascularization (blood supply) and proliferation were positively engaged in the walnut-fed mice. Further investigations revealed that the tumors of mice fed walnuts contained 10 times the amount of total omega-3 fatty acids, including plant-based alpha-linolenic acid (ALA), compared to the mice fed the control diet. In addition, tumors that contained a greater percentage of omega-3s were smaller, suggesting that ALA may provide a protective benefit. Tumor growth rate was also significantly slower in the walnut group compared to the control group. "Our research demonstrates that a walnut diet causes significant changes in the expression profile of miRNAs in localized colorectal cancer tissue, and that a walnut diet incorporates protective fatty acids in the colonic tumor either through its direct effects or through additive or synergistic effects of multiple other compounds present in walnuts," said study leader Dr Christos Mantzoros. "While future studies are needed, we're optimistic of the role of miRNAs as biomarkers of disease and prognosis, and may demonstrate a potential therapeutic target for colorectal cancer treatment."
Tsoukas MA, Ko BJ, Witte TR, Dincer F, Hardman WE, Mantzoros CS. Dietary walnut suppression of colorectal cancer in mice: Mediation by miRNA patterns and fatty acid incorporation. J Nutr Biochem. 2015 Apr 1. [Epub ahead of print]