Written by Marcia J. Egles, MD. Mice on a diet high in polyunsaturated fatty acids (PUFAS) had a significantly slower rate of breast cancer tumor growth as well as a significantly longer survival time than the mice on a melatonin diet or the control mice.
Dietary melatonin and polyunsaturated fatty acids (PUFAs), both from walnuts, may work together for beneficial effects against the progression of breast cancer according to a research study done in mice (1). The study noted a “ ” effect of two components of walnuts, the melatonin and the polyunsaturated fatty acids (PUFAs), which showed a combined anti-tumor effect against a breast cancer model in mice.
Walnuts naturally contain both melatonin and PUFAs. Melatonin, famous for its role in mammalian sleep cycles, is also a potent anti-oxidant produced in a variety of plants. Melatonin and PUFA’s have individually been identified in other laboratory studies to inhibit the growth of certain breast cancers (2,3). Garcia’s study examines the combined role of melatonin and PUFA’s from walnuts against breast cancer invasion and metastasis. (1).
The experiment used three groups of twenty healthy young mice. Each group of mice was fed one of three diets for three months. The three diets were termed the “walnut diet”, the “melatonin diet”, and the “control diet”. Each diet contained the same basic food with the same amount of total calories but differed by supplements.
The walnut diet, supplemented with 6% walnut oil and 8% walnut flour, was rich in both omega-3 PUFAs and walnut melatonin. The melatonin diet was supplemented with 6% corn oil plus commercial melatonin. The control diet was supplemented with 6% corn oil. Corn oil has scarce omega-3 PUFAs as compared to walnut oil, so both the melatonin diet and the control diet were lacking in omega-3 PUFAs. Both the walnut diet and the melatonin diet had similar amounts of melatonin, and the control diet was without melatonin. (The daily melatonin intake for the walnut diet mice was 1.8 ng per day, and 1.5 ng per day for the melatonin mice.)
Simplified, the “walnut “diet was the basic diet supplemented with omega-3 PUFAs and melatonin, both from walnuts. The “melatonin” diet was supplemented with melatonin alone. The control diet was without melatonin or omega-3 PUFA supplements.
After the three months of the diets, the mice were each subjected to an injection of mouse breast cancer cells. Thirty-five days after receiving this tumor inoculation, the mice were sacrificed. The subsequent rates of tumor growth and several other tumor related parameters were examined in the context of the differences between the diets. For breast cancer survival rates, a second parallel mouse diet study was conducted in which tumor inoculated mice were allowed to die naturally.
The study found several favorable effects especially in the walnut diet group against breast cancer progression. The time taken for tumors to appear in the mice after tumor inoculation was significantly (p less than 0.02) greater in the walnut diet mice ( 10.4 days) than the melatonin diet mice ( 8.4 days) or the control mice ( 5.7 days). Mice from the walnut diet showed the highest survival time (63.3 days) as compared with the melatonin diet group (47.9 days) or the control group (40.0 days). Much of the study’s data involved tumor cell membrane analysis involving fatty acid composition, with favorable and synergistic anti-tumor effects demonstrated in the walnut diet group.
In conclusion, the study (1) suggested that PUFAs and melatonin from a walnut enriched diet can together favorably modulate tumor cell membranes, resulting in antitumor actions in invasive breast cancer in mice.
Source: Garcia, Carolina P., Alicia L. Lamarque, Andrea Comba, María A. Berra, Renata A. Silva, Diana O. Labuckas, Undurti N. Das, Aldo R. Eynard, and Maria E. Pasqualini. “Synergistic anti-tumor effects of melatonin and PUFAs from walnuts in a murine mammary adenocarcinoma model.” Nutrition 31, no. 4 (2015): 570-577.
© 2015 Elsevier Inc.
Posted February 29, 2016.
References:
- Garcia, Carolina P. et al., Synergistic anti-tumor effects of melatonin and PUFAs from walnuts in a murine mammary adenocarcinoma model, Nutrition 31 (2015) 570-577.
- Grant SG et al. Melatonin and breast cancer: cellular mechanisms, clinical studies and future perspectives. Expert Rev Mol Med 2009: 11:e5.
- Maclennan M, et al. Role of dietary fatty acids in mammary gland development and breast cancer. Breast Cancer Research 2010;12:211.
