Walnuts and Breast Cancer
Intensive research is indicating that walnuts (Juglans regia) can suppress breast cancer tumors and help prevent breast cancer. This is the conclusion derived from laboratory research, research on animals and human clinical research.
Breast cancer kills many women
Breast cancer is by far the most common form of cancer affecting woman around the world. In 2018 there were more than two million new cases of breast cancer. Western countries by far had the most cases, with countries such as France, Australia, UK, Italy, New Zealand, Germany, the U.S. and Canada all rounding out the top 25 countries in the world in terms of breast cancer incidence. (Western diet anyone?)
Approximately 12 percent of U.S. woman will develop invasive breast cancer during their lifetimes according to the newest research. This equates to one in eight U.S. women. Over 40,000 women will die from breast cancer in 2019 in the U.S.
Note that men also contract breast cancer. A man’s risk of breast cancer is much lower than a woman’s, at about 1 in 883.
Walnuts suppress breast cancer tumors
After studying walnuts for breast cancer in laboratory research, doctors at Marshall University investigated breast cancer in 10 women whose biopsies indicated they had breast cancer tumors.1
After their biopsies, the researchers had half of the women consume two ounces of walnuts per day for about two weeks. This occurred in between their biopsies and their surgeries to remove the tumors.
The doctors took another biopsy after two weeks – prior to their surgery. The researchers found the walnut group’s tumors had radically changed genetically. They found that in the walnut group that gene expression had changed in 456 different genes. These included gene expressions that suppress tumor growth. This finding is significant, because it shows the extent of the effects of walnuts upon the tumors.
Dr. Elaine Hardman, who led the study, stated,
“These results support the hypothesis that, in humans, walnut consumption could suppress growth and survival of breast cancers.”
Walnuts with other nuts
The hypothesis that walnuts suppress breast cancer doesn’t come without cause. A 2015 study from Mexico’s University of Colima investigated 97 patients with breast cancer, along with 104 healthy people.2
The researchers conducted a review of the subjects’ diets. They found that those who ate more walnuts, peanuts and/or almonds had a decrease in their risk of breast cancer by two to three times. Those who ate only small amounts of these nuts had negligible effects.
Other studies have also found that tree nuts reduce the risk of colon cancer.
Breast cancer cell growth halted
A 2016 study tested walnuts on human breast cancer cells and colon cancer cells.3 The researchers found that walnut proteins inhibited breast cancer cells by about 63 percent. Walnuts also inhibited the colon cancer cells by 51 percent.
Another 2016 study tested walnut against MCF-7 human breast cancer cells.4 These researchers found that exposure to small amounts or walnut proteins halted cancer proliferation and killed cancer cells at a rate of about 80 percent.
Other breast cancer cell research has showed similar findings.
Walnut constituents fight breast cancer
Walnuts contain a chemical called juglanin. Juglanin was investigated in a 2017 study from China’s Henan University.5 The researchers tested juglanin on human breast cancer cells in the laboratory.
The scientists found that the juglanin killed breast cancer cells. It also acted as a free radical scavenger to help prevent further breast cell damage.
The scientists also found that juglanin stopped tumor growth in mice with breast cancer.
Another study from Marshall University also studied breast cancer in mice,6 and found that whole walnut added to the diet reduced mammary gland tumors. They found that multiple compounds in walnuts (including juglanin) had a synergistic anticancer effect.
Walnuts also reduce weight and inflammation
One of the biggest risk factors for breast cancer is obesity. Insulin resistance follows as a connected risk factor for breast cancer.
It turns out that walnuts can help with both. In a 2015 study of 245 overweight or obese women,7 subjects were given different diets. These included low-fat diets and others. One group did not change their diet, but merely added walnuts to their current diet. The study lasted for one year.
The researchers found that just adding walnuts to the diet worked almost as well as a standard low fat diet for weight loss, and reducing insulin resistance. The researchers stated:
“Prescribing walnuts is associated with weight loss comparable to a standard lower fat diet in a behavioral weight loss intervention. Weight loss itself may be the most critical factor for reducing the chronic inflammation associated with increased breast cancer risk and progression.”
Interestingly, walnuts also help boost sperm counts in men.
1. Hardman WE, Primerano DA, Legenza MT, Morgan J, Fan J, Denvir J. Dietary walnut altered gene expressions related to tumor growth, survival, and metastasis in breast cancer patients: a pilot clinical trial. Nutr Res. 2019 Mar 10. pii: S0271-5317(18)31190-4. doi: 10.1016/j.nutres.2019.03.004.
2. Soriano-Hernandez AD, Madrigal-Perez DG, Galvan-Salazar HR, Arreola-Cruz A, Briseño-Gomez L, Guzmán-Esquivel J, Dobrovinskaya O, Lara-Esqueda A, Rodríguez-Sanchez IP, Baltazar-Rodriguez LM, Espinoza-Gomez F, Martinez-Fierro ML, de-Leon-Zaragoza L, Olmedo-Buenrostro BA, Delgado-Enciso I. The protective effect of peanut, walnut, and almond consumption on the development of breast cancer. Gynecol Obstet Invest. 2015;80(2):89-92. doi: 10.1159/000369997.
3. Liao W, Lai T, Chen L, Fu J, Sreenivasan ST, Yu Z, Ren J. Synthesis and Characterization of a Walnut Peptides-Zinc Complex and Its Antiproliferative Activity against Human Breast Carcinoma Cells through the Induction of Apoptosis. J Agric Food Chem. 2016 Feb 24;64(7):1509-19. doi: 10.1021/acs.jafc.5b04924.
4. Jahanbani R, Ghaffari SM, Salami M, Vahdati K, Sepehri H, Sarvestani NN, Sheibani N, Moosavi-Movahedi AA. Antioxidant and Anticancer Activities of Walnut (Juglans regia L.) Protein Hydrolysates Using Different Proteases. Plant Foods Hum Nutr. 2016 Dec;71(4):402-409.
5. Sun ZL, Dong JL, Wu J. Juglanin induces apoptosis and autophagy in human breast cancer progression via ROS/JNK promotion. Biomed Pharmacother. 2017 Jan;85:303-312. doi: 10.1016/j.biopha.2016.11.030.
6. Hardman WE. Walnuts have potential for cancer prevention and treatment in mice. J Nutr. 2014 Apr;144(4 Suppl):555S-560S. doi: 10.3945/jn.113.188466.
7. Rock CL, Flatt SW, Pakiz B, Quintana EL, Heath DD, Rana BK, Natarajan L. Effects of diet composition on weight loss, metabolic factors and biomarkers in a 1-year weight loss intervention in obese women examined by baseline insulin resistance status. Metabolism. 2016 Nov;65(11):1605-1613. doi: 10.1016/j.metabol.2016.07.008.
Spence S. Scientists tie walnuts to gene expressions related to breast cancer. Marshall University School of Medicine. Thursday, March 28, 2019.