Lycopene and Prostate Cancer - Objective Review

By Raphael Nyarkotey Obu

In the Naturopathic Urological community, especially prostate health, two of the most popular ingredients are probably lycopene and saw palmetto. Saw palmetto is a plant whose berries are frequently used to help manage symptoms of an enlarged prostate (benign prostatic hyperplasia).

With prostate cancer being a killer in the black community ,finding ways to avoid developing the disease, naturally there is a great deal of interest and it has been my research interest. So far,conventional medicine hasn't been very successful in this area, so some men are turning to a more natural approach, which has ledto public outcry!

What is lycopene?

Lycopene is a potent antioxidant, a member of the carotenoid family, and a pigment that gives some fruits and vegetables their red color including pawpaw. Tomatoes and processed tomato foods (e.g., tomato soup, sauce, juice, puree, ketchup) are perhaps the most recognized food sources of lycopene and also comprise about 80 percent of the lycopene intake in the average American diet. However, other food sources include red grapefruit, guava, red bell peppers, and watermelon.

Numerous studies have indicated that lycopene can help prevent or reduce the risk of certain cancers, including prostate, stomach, lung pancreas, esophagus, colon, breast, and cervix. Here we are interested in the relationship between lycopene and prostate cancer, and thus far the evidence has been mixed. Here are some of the more recent results of research regarding this topic.

Lycopene and prostate cancer

The idea that lycopene might help prevent or manage prostate cancer came up in 1995 when the Health Professionals Follow-Up study, which was the first to note that lycopene in tomatoes may

Lycopene is commonly associated with prostate health and prostate cancer in particular. Numerous studies have found a positive relationship between dietary intake of lycopene, typically from tomatoes and tomato products, and prostate cancer. Note that the researches are referring to "dietary intake" of lycopene and not "supplement".

Back in 1999, a pivotal review article was published in the Journal of the National Cancer Institute. Of 57 studies that showed an inverse association between eating tomatoes or blood lycopene levels and the risk of cancer, 35 were statistically significant. The reviewers pointed out that "evidence for a benefit was strongest for cancers of the prostate, lung, and stomach," and that "the consistently lower risk of cancer for a variety of anatomic sites that is associated with higher consumption of tomatoes and tomato-based products adds further support for current dietary recommendations to increase fruit and vegetable consumption."

Successive research endeavors showed that consuming tomatoes and tomato products was associated with a lower risk of cancer and prostate cancer in particular. For example:

The authors of a 2015 study in Nutrition and Cancer reported that tomato paste appeared to protect against the development of prostate cancer by modulating the activity of nuclear factor kappaB (which plays a key role in cancer development) and cancer-related gene expression in prostate cancer cells. The authors concluded that their findings supported "biological activity of tomatoes in cancer-related inflammation."

A 2014 study appearing in the Journal of the National Cancer Institute examined the relationship between dietary lycopene (from tomatoes and tomato products) and prostate cancer. Using data from 49,898 male health professionals, the authors determined that higher intake of lycopene was associated with a reduced risk of prostate cancer and especially lethal prostate cancer.

Other research, however, has been less positive.

The authors of a review of eight randomized controlled trials of lycopene for the prevention and treatment of benign prostatic hyperplasia (BPH) and prostate cancer concluded that "it is not possible to support, or refute, the use of lycopene for the prevention or treatment of BPH or prostate cancer."

A 2013 meta-analysis appearing in the Journal of Nutritional Science and Vitaminology set out to determine whether intake of lycopene and tomatoes/tomato products could reduce a man's risk of prostate cancer. Seventeen studies were evaluated, and the reviewers looked at high and low intake of raw tomatoes and cooked tomatoes as well as high and low intake of lycopene and concluded that "further research would be needed to determine the type and quantity of tomato products regarding their potential in preventing prostate cancer."

As interest in lycopene, tomatoes, and prostate health continued, lycopene supplements were introduced manufacturing companies

Could lycopene supplements be the savior in a simple pill or capsule form?

Let's look at whether lycopene supplements are good for prostate health. Interestingly enough, research does not support the use of lycopene supplements for prostate health. Research of lycopene supplementation is lacking or non-existent. One of the few available studies recently (April 2015) appeared in the journal Prostate.

The researchers conducted a randomized, double-blind, placebo-controlled phase I-II trial for six months of the effects of dietary supplements (lycopene, selenium, green tea catechins) in 60 men who had precancerous prostatic lesions--either multifocal high-grade prostatic intraepithelial neoplasia and/or atypical small acinar proliferation.

At six months, 53 men underwent re-biopsy and 13 men were diagnosed with prostate cancer. Ten of the men had been in the supplement group while the remaining three had taken a placebo. At a 37-month follow-up, the scientists saw stronger modulation of microRNAs in the supplement group than in the placebo group. This factor is associated with progression of prostate cancer. The authors of the study concluded that "the use of these supplements should be avoided."

Hey! So what should men do? It seems reasonable to assume that including plenty of raw tomatoes and cooked tomato-based products (but not canned tomato products) such as tomato paste, tomato sauce, tomato juice, and tomato soup in your diet on a regular basis could be beneficial for prostate health and prevention of prostate cancer. (Naturally, choose organic whenever possible.) Other foods that contain lycopene include pink grapefruit, watermelon, red cabbage, guava, and carrots.

In a subsequent animal study, the authors found that mice with human prostate cancer cells who received both lycopene and chemotherapy had smaller tumors and lived longer than their peers who received chemotherapy alone. In 2013, investigators discovered that men who consumed a lot of raw or cooked tomatoes had a slightly lower risk of prostate cancer.

The influence of lycopene on an enlarged prostate (benign prostatic hyperplasia), urination, and levels of PSA (prostate specific antigen) also were evaluated. PSA levels are considered to be a marker for prostate cancer risk, and these levels are often higher than normal in men who have prostate cancer.

In 2015, a team of experts reviewed 26 studies involving 17,517 cases of prostate cancer and 563,299 participants. The reviewers noted a trend toward higher lycopene consumption and lower risk of prostate cancer, although this was not true in every study. In addition, higher intake of lycopene was associated with a reduced risk of prostate cancer with a threshold between 9 and 21 mg per day.

Although the evidence thus far suggests that higher lycopene consumption is associated with a lower risk of developing prostate cancer, further studies are needed to identify why this relationship occurs and if there are other factors in tomatoes and tomato foods that contribute to this reduced risk of prostate cancer.

The most recent exploration of the link between lycopene and prostate cancer was published in March 2018 in the Archivosespanoles de urologia. A review of the literature from 1990 to 2015 was conducted and included research in humans. Twenty-seven studies were ultimately chosen for the systematic review, with 13,999 patients in the 22 case-control studies and 187,417 in the five cohort studies. The authors concluded that although they found "statistically significant inverse association between lycopene intake" and the risk of prostate cancer, this evidence came solely from observational studies. They recommended conducting "high-quality randomized clinical trials" to clarify the evidence at hand.

Getting lycopene in your diet

One would think that, lycopene supplements may be the best way to get this phytochemical, but sorry to say that, research does not support it in a supplement form. In fact, it appears lycopene supplements don't work and in fact are associated with the risk of nausea, vomiting, stomach upset, and diarrhea. These side effects can be lessened or eliminated if the supplements are taken with food.

Lycopene Supplements: Waste of Money?

From the research and scientific reviews, the optimal choice seems to be to eat organic foods rich in lycopene. Other phytochemicals present in tomatoes (and other lycopene foods) may contribute toward the antioxidant's health benefits, which would not be available in supplements.

Best Sources of Lycopene?

From the research and scientific reviews, it is best toeat cooked tomatoes in a healthy oil, such as extra-virgin olive oil, because the body absorbs lycopene better than if you eat tomatoes raw and without oil. For example, an organic tomato sauce with olive oil and garlic served is a healthy option, as is a fresh tomato soup prepared with, olive oil, and garlic.

So in conclusion, don't waste your money on lycopene supplements, as there is just no evidence that they work. Instead, include a variety of natural foods rich in lycopene in your diet on a regular basis and consider adding to your diet other natural ingredients that have been proven in the studies that work synergistically to promote better general prostate health.Dr. Raphael Nyarkotey Obu, RND, PhD, is honorary professor of Naturopathic Urology

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