Flaxseed, Soy Protein Offer Varying Results in the Treatment of Breast Cancer

TORONTOResearchers at the University of Toronto continue to investigate the role of flaxseed and soy protein isolate in the treatment of breast cancer (Journal of Toxicology and Environmental Health 2007; 70.22:1888-96). Researchers found that flaxseed (FS) reduced breast tumor growth in ovariectomized mice; while soy protein isolate (SPI) stimulated growth. Consequently, combining both SPI and FS resulted in the negation of SPI-induced tumor growth. The effect of SPI, FS and their combination were also examined on mouse bone and uterus to ensure overall safety of breast cancer treatment.The mice in the study had MCF-7 xeonografts and were fed either a controlled diet or one supplemented with 10 percent FS, 20 percent SPI or a combination of SPI and FS for 25 weeks. Their bones were analyzed for mineral density and biomechanical strength, such as yield load, stiffness and peak load. The SPI group possessed a higher femur bone mineral density and more strength, while the FS group possessed increased femur stiffness and peak load. Femur mineral density was not affected in the mice who consumed a combination of SPI and FS; however, the femur size was significantly reduced but the biomechanical parameters increased. Additionally, uterus weight was significantly increased by the combined SPI and FS diet, while the SPI diet induced an intermediate effect. Researchers concluded that while these treatments had beneficial effects on bone of postmenopausal cancer, other factors and parameters must be measured to determine the overall safety of FS, SPI and the combination of both as a treatment to breast cancer.