Written by Marcia Egles, MD. Studies suggest that increasing omega-3 PUFA’s (polyunsaturated fatty acids) in the diet might help reduce the risk of aggressive prostate cancer. Both omega-6 and omega-3 PUFA’s are not produced in the body and must be obtained from ones diet.
Excluding skin cancer, prostate cancer is the most common cancer in American men and accounts for 9% of all cancer deaths. The American Cancer Society projects that over 27,000 American men will die of metastatic prostate cancer in 2006. Most prostate cancers grow slowly and can stay for years within the confines of the prostate gland. If the cancer spreads beyond the prostate in a process called metastasis, the consequences can be deadly. In American men diagnosed with metastatic prostate cancer, only 35% will survive 5 years.(1,2) A study published in the British Journal of Cancer presents evidence that omega-3 fatty acids can inhibit the spread of metastatic prostate cells grown in cell cultures. (3)
Prostatic cancer cells and normal human rib bone marrow cells were used in this study. Bone marrow is the most common site of prostate cancer metastasis. In a real person, in order for the prostatic cancer cells to get beyond the prostate and invade the marrow, the cancer cells must first get past membrane barriers. The researchers achieved a simulation of these membrane barriers by growing the two sets of cells in what they termed an “invasion chamber”. In these chambers, the growing bone marrow inserts were separated from the growing prostatic cancers cells by artificial membrane barriers. After time within the chambers under various conditions(described below), the patterns of the cell growth, including metastatic migration, were viewed under microscopic examination. The quantities of fats within cells were microscopically tracked using special stains.
The researchers were interested in determining the effects of fatty acids within their invasion chambers. Worldwide the incidence of prostate cancer varies regionally. It is three times more common in the United States than in developing countries. (4) These researchers hypothesize that the differences in prostate cancer rates may be attributable to the differences in the quantities and types of fats consumed in the diets. Past research4 suggests that both the amount and kind of fats may influence the risk of prostate cancer. Omega-6 poly-unsaturated fatty acids (omega-6 PUFAs), may promote prostate cancer, while Omega -3 poly-unsaturated fatty acids may inhibit them. (5)
Prostatic cancer cells were observed to migrate toward the fat cells of the bone marrow and form colonies around fatty areas. If the bone marrow’s ability to grow fat cells was deprived by the addition of hydrocortisone, the prostatic cancer cells were only weakly attracted to the fat-depleted bone marrow. Prostatic cancer cells could again invade the bone marrow if the omega-6 PUFA, arachidonic acid, was added to the fat cell-free bone marrow. However, if either of the omega-3 PUFAs, eicosapentanenoic acid or docasahexaenoic acid, were added to the mix, the prostatic cancer cells did not invade. A range of concentrations was tested. Omega-3 PUFAs, in a ratio of one omega-3 to two omega-6, resulted in inhibition of metastatic migration.
The researchers suggest that an increase in omega-3 PUFA’s in the diet might be of benefit in reducing the risk of aggressive prostate cancer. Both omega-6 and omega-3 PUFA’s are essential fatty acids that are required by the human body, but cannot be synthesized by the body. They come from food sources. Omega-6 PUFAs are relatively plentiful and are found in dairy, meats, fish, and plant sources. Omega-3’s are far scarcer, particularly in the American diet, but are found in cold water marine animals such as wild salmon, and some plant oils such as flax oil. (6)
Source: Brown, Michael D., et al. “Promotion of prostatic metastatic migration towards human bone marrow stoma by Omega 6 and its inhibition by Omega 3 PUFAs.” British journal of cancer 94.6 (2006): 842-853.
© 2006 Cancer Research UK
Posted July 22, 2008.
References:
- March,2006 American Cancer society website.
- March, 2006 National Cancer Institute website.
- Brown MD et al. Promotion of prostatic metastatic migration towards human bone marrow stroma by Omega 6 and its inhibition by Omega 3 PUFAs. British Journal of Cancer, 2006 March 27; 94 (6): 842-53. Published online March 7, 2006 at The British Journal of Cancer website.
- Parkin DM et al. Global cancer statistics, 2002. CA Cancer J Clin 55: 74-108
- Norrish AE et al. Prostate cancer risk and consumption of fish oils: a dietary biomarker-based case-control study. Br J Cancer 81: 1238-1242
- Essential Fatty Acids at Wikipedia website.
