Lycopene Benefits & Prostate Cancer

Prostate cancer is a disease that grows slowly in the prostate gland that surrounds the neck of the bladder and the urethra and is sometimes advanced before it is detected. Prostate cancer is rarely found in men under the age of 40, but it is found in about 50% of men over 70 and in the majority of men aged 80+. It is treatable when diagnosed early.

If your doctor thinks that you may have a prostate problem, a sample of your blood will be taken and sent to a laboratory to test for PSA (Prostate Specific Antigen). PSA is a protein produced by the prostate gland. All men have some PSA in their blood, the level can be affected by several factors including age, infection and some medicines. The PSA test can be a useful indicator of any problem with your prostate.

Prostate Cancer Research

The first major study to propose a link between tomatoes and a benefit in the fight against contracting prostate cancer came from Professor Giovannucci from Harvard Medical School, USA. He has been following ~50,000 men for over 15 years and has found a strong correlation between a high tomato intake and a reduced incidence of prostate cancer. His work is continuing and has prompted a multitude of follow-up studies around the world.

Even though much is understood about the stepwise process leading to invasive prostate cancer, there are still gaps in our knowledge. For example, African-American men are more at risk than other ethnic groups and overall have one of the highest rates of prostate cancer in the world. Studies have taken account of socio-eceonomic factors and the cause of this racial difference remains unclear.

Notable Trials

• Professor Giovannucci from Harvard Medical School, USA studied 50,000 men and found eating (cooked) tomato products several times a day significantly reduced the risk of developing prostate cancer. These results, still on-going, show a reduced risk of prostate cancer for men with high Lycopene dietary intake. 
• Omer Kucuk, Professor of Oncology at the Cancer Institute, Detroit studied men with established prostate cancer who were to have their prostates removed (known as radical prostatectomy). They were split into two groups, one group taking 15mg of lycopene per day and the other taking a simple placebo. Subsequent examination of the prostates by an independent laboratory (who didn't know which prostates were from which group) showed that in the lycopene group more than 66% had the prostate cancer confined to the prostate compared to less than half of those on the placebo. Furthermore, the tumours of those from the lycopene group were mostly smaller in volume than those from the placebo group, suggesting that the tumours in patients who eat lycopene showed signs of regression and decreased malignancy.
  
  This dramatic result surprised us and other medical scientists - could just three weeks of lycopene supplementation really be so beneficial to those with established prostate disease? Professor Kucuk is a respected medical scientist and no one to date has produced any data to contradict his findings but there is clearly a need to repeat and enlarge this small trial before any definite conclusions can be drawn.
• Another American research group led by Professors Bowen and Clei from the University of Illinois at Chicago has published studies on tomato lycopene and prostate cancer in the Journal of the National Cancer Institute. A very small trial, they studied 32 men aged between 60-74 years old with localised prostate cancer. Increasing the lycopene in their diets to 15mg per day each led to a three-fold increase of the lycopene in the body, a significant reduction in PSA levels and less oxidative DNA damage compared to the control group. These well-known and very experienced scientists conclude 'tomato lycopene may have a role in the treatment of prostate cancer'.
• In 2006, we supported a trial at King's College Hospital, London, using two capsules of LycoPlus (10mg natural lycopene with added vitamin C) per day for 1 year on 41 men, average age 73, all previously diagnosed with prostate cancer. The men underwent no treatment for the condition during the trial and PSA counts were monitored during and at the end of the study.
  
  In about one third of the participants, no effect was observed. However, in the remaining two thirds, there was evidence of a reduction in the rate of PSA increase and in 22% of the men, an actual fall in PSA level was recorded.

Possible Mechanisms

Firstly, we note that tomato lycopene accumulates preferentially in the prostate – from a simplistic perspective, this seems essential if lycopene is to benefit the prostate.

Then, almost certainly more than one mechanism applies to fight prostate cancer.

• For the prevention of prostate cancer and in long time studies (12 months or longer), the anti-oxidant theory based on lycopene removal of damaging free radicals and hence the protection of DNA from oxidative damage, is most popular. The oxidative damage of DNA is almost certainly how chronic diseases such as cancer can be started. However, for shorter times periods (as in the Kucuk study described above) the anti-oxidant theory is most unlikely to apply.
• In our opinion, the most attractive other theory is based on cell to cell communication (the jargon is lycopene improves the gap junction intercellular communication by increasing expression of a gap junction gene called connexion 43). This improved communication between cells allows the transfer of growth regulatory signals between normal (growth inhibited) cells and neo-plastic (growth uninhibited cancer cells). In a recent study when the neoplastic cells are forced into communication with normal cells the neoplastic cells become growth arrested, that is, like normal cells.

There are other mechanisms associated with various stages of the disease progression and more work is needed to resolve this debate on the mechanisms of the benefits of lycopene in the fight against both the start of, and treatment of, prostate cancer.

References

• Kucuk, O., Sarkar, F.H., Sakr, W., Djuric, Z. et al. (2001) Phase II randomized clinical trial of lycopene supplementation before radical prostatectomy Cancer Epidemiol., Biomarkers Prev. vol 10, pages 861-868.
• Giovannucci, E., Rimm, E.B., Liu, Y., Stampfer, M.J., Willett, W.C. (2002) A prospective study of tomato products, lycopene and prostate cancer risk J. Natl. Cancer Inst. vol 94, pages 391-398.
• Giovannucci, E. (2005) Tomato products, lycopene, and prostate cancer: A review of the epidemiological literature J. Nutr., vol 135, pages 2030S-2031S.
• Barber, N.J., Zhang, X., Zhu, G., Pramanik, R. et al. (2006) Lycopene inhibits DNA synthesis in a primary epithelial cells in vitro and its administration is associated with a reduced prostate-specific antigen velocity in a phase II clinical study Prostate Cancer and Prostatic Disease, 1-7.
• Kristal, A.R., Arnold, K.B., Neuhouser, M.L., Goodman, P. et al. (2010) Diet, supplement use, and prostate cancer risk: Results from the prostate cancer prevention trial Am. J. Epidemiol. vol 172, pages 566-577.
• Salem, S., Salahi, M., Mohseni, M., Ahmadi, H. et al. (2011) Major dietary factors and prostate cancer risk: a prospective multicenter case-control study Nutr. Cancer, vol 63, pages 21-27.

From £13.95 per box

Newsletters

Free Prize Draw

Headlines