Dietary walnuts inhibit colorectal cancer growth in mice by suppressing angiogenesis

Abstract

Objective Animal studies have demonstrated that dietary supplementation with flaxseed oil inhibits colorectal cancer growth. Recent data indicate that walnuts have strong antiproliferative properties against colon cancer cells in vitro but no previous study has assessed the effects of walnuts in vivo or performed a joint evaluation of flaxseed oil and walnuts. The aim of the present study was to examine the effect of dietary walnuts on colorectal cancer in vivo and to comparatively evaluate their efficacy in relation to flaxseed oil. Methods HT-29 human colon cancer cells were injected in 6-wk-old female nude mice. After a 1-wk acclimation period, mice (n = 48) were randomized to diets containing ~ 19% of total energy from walnuts, flaxseed oil, or corn oil (control) and were subsequently studied for 25 d. Results Tumor growth rate was significantly slower in walnut-fed and flaxseed-fed mice compared with corn oil-fed animals (P < 0.05) by 27% and 43%, respectively. Accordingly, final tumor weight was reduced by 33% and 44%, respectively (P < 0.05 versus control); the differences between walnut and flaxseed diets did not reach significance. We found no differences among groups in metabolic and hormonal profile, serum antioxidant capacity, or inflammation (P > 0.05). However, walnuts and flaxseed oil significantly reduced serum expression levels of angiogenesis factors, including vascular endothelial growth factor (by 30% and 80%, respectively), and approximately doubled total necrotic areas despite smaller tumor sizes (P < 0.05 versus control). Dietary walnuts significantly decreased angiogenesis (CD34 staining; P = 0.017 versus control), whereas this effect did not reach significance in the flaxseed oil group (P = 0.454 versus control). Conclusion We conclude that walnuts in the diet inhibit colorectal cancer growth by suppressing angiogenesis. Further studies are needed to confirm our findings in humans and explore underlying mechanisms.

Effects of Walnut Consumption on Colon Carcinogenesis and Microbial Community Structure

“…Walnuts may be a particularly attractive whole food approach for cancer prevention. They are readily available, widely consumed, and contain an excellent profile of bioactive components that may exert complex and synergistic effects on tumorigenesis (16,22,(24)(25)(26)(27)(28)(29)(30).…”

“…Whole walnut halves were provided by the California Walnut Commission. The amount of walnuts added to the diets was determined on the basis of previous in vivo studies (15,16). In Study 1, mice (4 week-old) were fed AIN-76A diet (Harlan Laboratories, Inc.) supplemented with 0%, 9.4%, 14.1%, or 18.8% of walnuts by weight, which are equivalent to 0%, 15%, 22.5%, or 30.2% of energy from walnuts, respectively.…”

Therapeutic Effects of Phytochemicals and Medicinal Herbs on Chemotherapy-Induced Peripheral Neuropathy

“…Dietary walnut suppressed mammary gland tumorigenesis in the C(3)1 TAg mouse [90] and growth of implanted MDA-MB 231 human breast cancer cells in nude mice [91]. It has also been demonstrated that walnut reduces growth of prostate cancer [92,93] and colorectal cancer [94].…”

Health benefits of walnut polyphenols: An exploration beyond their lipid profile

“…In an in vivo study using HT-29 cells (colon carcinoma) injected to (Nagel et al, 2012). Consequently, final tumor weight was reduced by 33% versus control.…”