In the study, prostate cancer patients who added about 3 heaping tablespoons of ground flaxseed daily to their diet had more slowly-dividing tumor cells and a greater rate of tumor cell death than men who did not follow this diet, after about 5 weeks.
The investigators found no significant difference in levels of prostate specific antigen (PSA), a protein in the blood that indicates prostate cancer progression, between the two groups -- although men in the early stages of the disease experienced a trend toward lower levels.
Flaxseed was commonly used in cereals and breads in the Middle Ages, but has not been a staple in the modern diet since the industrial age. It is rich in fiber and omega-3 fatty acids, which may affect levels of hormones that are involved in the progression of cancer.
Flaxseed also contains a fiber-like compound, lignan, which is thought to bind to testosterone and possibly help remove it from the body. This could, in turn, help suppress the growth of prostate cancer cells.
Prostate cancer is the most common cancer among American men, excluding skin cancers. The American Cancer Society estimates that more than 198,000 new cases of prostate cancer will be diagnosed in the US in 2001. While the cancer will be diagnosed in about 1 in 6 men, about 1 in 30 will die of the disease.
Urology July 2001;58