The researchers said dietary fat and fiber can affect hormone levels and may influence cancer progression. Flaxseed is high in fiber and is the richest source of plant-based, omega-3 fatty acids. Studies suggest that dietary fiber reduces cancer risk, and omega-3 fatty acids also have shown a protective benefit against cancer. Flaxseed is also a rich source of lignan, a specific family of fiber-related compounds that appear to play a key role in influencing both estrogen and androgen metabolism.
We thought flaxseed would be the perfect food for prostate cancer patients, said lead author Wendy Demark-Wahnefried, associate research professor in the department of surgery at Duke. Its full of omega-3 fatty acids, fiber and lignan. Testosterone may be important in the progression of prostate cancer, and lignan in the flaxseed binds testosterone, so we thought the flaxseed might suppress the growth of prostate cancer cells. By pairing a low-fat diet with the flaxseed supplement, we also thought we could maximize the effect of the omega-3 fatty acids, since studies in animals show that the kind of fat we eat may be important for cancer progression.
The pilot study involved 25 patients with prostate cancer who were awaiting prostatectomy (surgical removal of the prostate). Baseline levels of prostate-specific antigen (PSA), testosterone, free androgen index and total serum cholesterol were determined at the beginning of the study. The tumors of those on the diet were then matched with 25 historic cases, equal in age, race, PSA level at diagnosis and biopsy Gleason sum (a scoring system used to grade prostate tumors) to compare tumor progression and biomarkers after the dietary intervention.