An increasing body of evidence links consumption of tomato products with reduced risk of prostate cancer. Here’s a look at what the latest science says.
The idea that something as simple as eating tomato products could potentially fend off prostate cancer is exciting. After all, the American Cancer Society estimates nearly 250,000 new cases of prostate cancer in the U.S. each year, resulting in more than 34,000 deaths. In fact, one man in eight will be diagnosed with prostate cancer during his lifetime. A body of evidence supporting the benefits of tomatoes for reducing the risk of prostate cancer has mounted over the past several years. And the latest research includes a number of studies that continue to demonstrate the promise of tomato consumption on prostate cancer protection.
What’s so special about tomatoes? They contain a variety of nutrients that may be responsible for cancer-fighting action, including vitamins A and C, fiber, and potassium, as well as a group of powerful plant compounds known as carotenoids, which give tomatoes their red, yellow, and orange colors. The most abundant carotenoid found in tomatoes is lycopene, followed by phytoene, phytofluene, zeta-carotene, gamma-carotene, beta-carotene, neurosporene, and lutein.
Numerous studies have linked lycopene consumption with cancer protection—in particular for prostate cancer. While lycopene is present in other fruits such as watermelon and pink grapefruit, tomatoes, which are the second most consumed vegetable (second to potatoes) in the U.S., account for more than 85% of the lycopene in the American diet. Interestingly, cooked tomato products—as in processed tomatoes, including tomato sauce and canned tomatoes—may hold particular significance. The lycopene from cooked and processed tomatoes is more bioavailable than that of fresh tomatoes. Heating or processing breaks down the tomato cell matrix and promotes isomerization of lycopene from all-trans isomers to the more bioavailable form of cis-isomers. Research shows that single daily servings of processed tomato products produce significant increases of lycopene concentrations in blood and buccal mucosal cells in healthy adults.
Tomatoes’ cancer protection isn’t merely due to lycopene. Compared to lycopene alone, more effective benefits have been linked with consumption of the whole tomato, which contains a full range of carotenoids and nutrients. Lycopene has strong antioxidant capacity that may provide cancer protection, but there may be other factors at play, such as altering gene expression, anti-inflammatory effects, and alterations in cancer cell cycle.
To add to the growing body of research on the mechanisms of action related to tomato products and cancer, a 2020 review of studies was published in Biomedicine & Pharmacotherapy. Researchers found that lycopene—the compound found in tomato products—has anti-cancer, anti-progressive, and apoptotic effects on prostate cancer. The clinical studies reviewed showed evidence supporting the continuous inclusion of dietary lycopene for different types of cancers, especially prostate cancer. Lycopene was found to effectively suppress progression and proliferation, arrest in-cell cycle, and induce apoptosis of prostate cancer. In addition, lycopene was shown to signal the pathways for the treatment and prevention of prostate cancer. A double-blind placebo-controlled study in the review showed that after 28 days of consuming lycopene-rich juices, patients’ serum lycopene levels were 80% higher compared to patients given a placebo, which could help reduce risk of disease. Another study in the review showed men with newly diagnosed prostate cancer who received lycopene twice a day for three weeks had decreased the risk and growth of prostate cancer cells.
In a prominent 2020 study from Loma Linda University, researchers examined how tomato consumption might impact the development of prostate cancer by looking for significant relationships between diet and prostate cancer in nearly 28,000 men as part of the landmark cohort Adventist Health Study-2 Among participants, who were cancer-free men at the outset and were followed for nearly eight years, those who consumed canned and cooked tomatoes more than four times a week were at lower risk of developing prostate cancer compared to those who did not eat cooked tomatoes and tomato products. Men who consumed them five to six times per week decreased their risk by 28% compared to those with no intake. The results from the Adventist Health Study-2 conclude that consumption of canned and cooked tomatoes may reduce risk of prostate cancer.
Including lycopene-rich foods, like tomato products, as a supplementary therapy for prostate cancer is the basis of some of the latest scientific research, which has shown the potential for limiting prostate cancer cell growth as well as inducing cell death. A 2020 study examined the role of lycopene on growth factors, which play important roles in cancer development and metastasis. Binding to insulin-like growth factor, lycopene has a protective effect, which affects the pathways of this growth factor, and stimulates cancer cell death. In the study, researchers removed cancer cells from patients with varying progression of prostate cancer and measured lycopene concentrations and levels of insulin-like growth factor. There was significant difference in the mean growth factor levels at various concentrations of lycopene, increasing it as lycopene increased. Researchers concluded that lycopene could be beneficial to prostate cancer patients as a supplementary therapy to increase cancer cell death and inhibit the progression of cancer cells.
There’s still more to learn about how tomatoes protect against prostate, but the evidence to date supports incorporating foods that contain lycopene. Consuming a few more tomatoes and tomato products in the diet each week is an easy and nutritious way to do so.
Written by Sharon Palmer, MSFS, RDN
References
- Fraser GE, Jacobsen BK, Knutsen SF, Mashchak A, Lloren JI. Tomato consumption and intake of lycopene as predictors of the incidence of prostate cancer: the Adventist Health Study-2. Cancer Causes Control. 2020;31(4):341-351. doi:10.1007/s10552-020-01279-z
- Key Statistics for Prostate Cancer. American Cancer Society. https://www.cancer.org/cancer/prostate-cancer/about/key-statistics.html. Accessed July 28, 2021.
- Mahdi, Mirahmadi, Shayan, Azimi-Hashemi, Ehsan, Saburi, Hossein, Kamali, Mandana, Pishbin, Farzin, Hadizadeh. Potential Inhibitory Effect of Lycopene on Prostate Cancer. Biomedicine & Pharmacotherapy. 2020;129. https://doi.org/10.1016/j.biopha.2020.110459
- Park, H., Kim, YJ. & Shin, Y. Estimation of daily intake of lycopene, antioxidant contents and activities from tomatoes, watermelons, and their processed products in Korea. Appl Biol Chem 63, 50 (2020). https://doi.org/10.1186/s13765-020-00534-w
- Potatoes and Tomatoes are the Most Commonly Consumed Vegetables. USDA Economic Research Service. https://www.ers.usda.gov/data-products/chart-gallery/gallery/chart-detail/?chartId=58340. Updated December 16, 2020. Accessed July 28, 2021.
- Tjahjodjati, Sugandi S, Umbas R, Satari M. The Protective Effect of Lycopene on Prostate Growth Inhibitory Efficacy by Decreasing Insulin Growth Factor-1 in Indonesian Human Prostate Cancer Cells. Res Rep Urol. 2020;12:137-143. Published 2020 Apr 17. doi:10.2147/RRU.S232745
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