Different observational studies found that consumption of moderate amounts of cooked tomatoes, tomato products or lycopene may be good for reducing the risk of prostate cancer. Studies also found that lycopene and tomato consumption may also help in reducing PSA levels, improving a specific drug efficacy and reducing chemo-induced kidney damage in prostate cancer patients.
Prostate cancer is the second most common cancer in men and the fourth most commonly occurring cancer overall. (World Cancer Research Fund/American Institute of Cancer Research, 2018) The American Cancer Society estimated about 191,930 new cases and 33,330 deaths from prostate cancers in the United States in 2020. In most of the cases, prostate cancer grows extremely slowly and men often do not realize that they have cancer. Prostate cancer may also spread or metastasize to other parts of the body away from the prostate including bones, lungs, brain and liver.
There are different treatment options available for locally advanced prostate cancer including hormone therapy, chemotherapy, chemotherapy with hormone therapy, radiotherapy with hormone therapy, immunotherapy or surgery followed by hormone therapy and radiotherapy. However, eating the right food before, during and after the treatment is equally important to support the treatment as well as help the patient to have a better quality of life and stay stronger. What is more ideal is to take the right foods, do regular exercises and maintain a healthy lifestyle to prevent or reduce the risk of these cancers.
When it comes to cancer diagnosis or prevention, the foods and supplements that are included as part of the daily diet/nutrition becomes crucial. It is always best to follow a healthy, balanced diet, which includes fruits and vegetables including legumes and pulses, cruciferous vegetables, whole grains and so on. However, corresponding to each disease type, there are foods that may help in reducing the risk of the specific cancer or may increase the risk or even interfere with the cancer treatment. When it comes to prostate cancer, many queries related to the use of tomatoes are being searched over the internet.
“Are tomatoes good or bad for prostate cancer?” This is one of the most common queries floating around in the internet.
In this blog, we will elaborate on the nutritional value and health benefits of tomatoes as well as different studies which evaluate the association between tomatoes and prostate cancer, and infer whether tomatoes are good or bad for prostate cancer risk and treatment.
Are Tomatoes good for you?
Tomatoes are high in fiber and a good source of a variety of nutritional compounds which may benefit you, including :
- Vitamin C
- Citric acid
- Vitamin K1
- Linoleic acid
- Linolenic acid
- Methyl salicylate
- Oleic acid
- Chlorogenic acid
- Palmitic acid
Consuming tomatoes are good for you due to a variety of health benefits such as :
- Improving heart health
- Decreasing the risk of stroke
- Lowering bad cholesterol
- Protecting skin from UV damage
- Boosting immunity
- Improving digestion
- Maintaining strong bones
- Strengthening hair
- Improving eyesight
Taking tomatoes in moderate amounts is good for you. However, taking tomatoes in excess amounts daily may not be good and can lead to increased levels of potassium resulting in hyperkalemia, which if not addressed, may result in bad/undesired outcomes such as abnormal heart rhythms. Also, according to American Cancer Society, daily consumption of more than 30 mg of lycopene present in tomatoes may have bad effects such as nausea, bloating and diarrhea.
Are Tomatoes good for reducing Prostate Cancer Risk?
Researchers across the world have done several observational studies to evaluate the association between consumption of tomato, tomato products or lycopene and prostate cancer risk. Examples of some of these studies and their inference on whether tomatoes are good for reducing prostate cancer risk are mentioned below.
Study by Zhongnan Hospital of Wuhan University in China
In a study published in 2015, the researchers from Zhongnan Hospital of Wuhan University, China evaluated the association between lycopene consumption and the risk of Prostate Cancer. Data for the study was obtained through literature search in Pubmed, Sciencedirect Online, Wiley online library databases and manual search till April 10, 2014. A total of 26 studies were included with 17,517 prostate cancer cases from 563,299 participants. (Ping Chen et al, Medicine (Baltimore)., 2015)
The study found that higher lycopene intake may be associated with a reduced risk of prostate cancer. The dose-response meta-analysis also found that higher lycopene consumption was linearly associated with a reduced risk of prostate cancer with a threshold between 9 and 21 mg/day.
Study by School of Medicine, Zhejiang University in China
In a study published in 2016, the researchers from School of Medicine, Zhejiang University in China, evaluated the association between tomato consumption and prostate cancer risk. Data for the study was obtained from 24 published studies with 15,099 cases based on literature search in PubMed and Web of Science databases till June 2016. (Xin Xu et al, Sci Rep., 2016)
The study found that tomato intake may be associated with a reduced risk of prostate cancer. The study also mentioned that significant protective effects were observed in Asian and Oceania populations, but not in other geographical populations.
A Case-Control Study from Vietnam
In a study published in 2018, the researchers from Vietnam and Australia evaluated the association of carotenoids and their food sources with prostate cancer risk. The study included food frequency questionnaire based data from 652 participants including 244 incident prostate cancer patients who are aged between 64 and 75 years, and 408 age frequency-matched controls who were recruited in Ho Chi Minh City during the period between 2013 and 2015. (Dong Van Hoang et al, Nutrients., 2018)
The study found that Vietnamese men who had a higher intake of lycopene, tomatoes, and carrots may have a reduced risk of prostate cancer. However, the researchers suggested large prospective studies to establish these findings.
The Adventist Health Study-2
In a study published in 2020, the researchers from the United States evaluated the association between the intake of tomatoes and lycopene and the risk of prostate cancer. The study used data from 27,934 Adventist men without prevalent cancer who participated in the Adventist Health Study-2. During a mean follow-up of 7.9 years, 1226 incident cases of prostate cancer were identified of which 355 were aggressive. (Gary E Fraser et al, Cancer Causes Control., 2020)
The study found that the intake of canned and cooked tomatoes which contains lycopene may reduce the risk of prostate cancer.
Study by University of Illinois at Urbana-Champaign, United States
In a study published in 2018, the researchers from the University of Illinois at Urbana – Champaign, United States evaluated the association between consumption of various types of tomato products and the risk of prostate cancer risk. Data for the study was obtained from 24,222 cases and 260,461 participants identified based on literature search in PubMed, Web of Science, and the Cochrane Library databases till April 10, 2017. (Joe L Rowles 3rd et al, Prostate Cancer Prostatic Dis., 2018)
The study found that a high consumption of tomato foods and cooked tomatoes and sauces may be associated with a reduced risk of prostate cancer. However, this study did not find any significant association between raw tomatoes and prostate cancer risk.
Study by Researchers in Columbia
In a study published in 2018, the researchers from Columbia evaluated the efficacy of lycopene intake in primary prevention of prostate cancer. The study obtained data from 27 articles including 22 case-control and 5 studies based on a systematic search of the literature published between the years 1990-2015. The case-control studies included 13,999 prostate cancer patients and 22,028 controls and the cohort studies included 187,417 patients out of which 8,619 were diagnosed with prostate cancer. (Juan Guillermo Cataño et al, Arch Esp Urol., 2018)
The study found that high lycopene intake significantly reduced the risk of prostate cancer. However, since most of these findings were from observational studies, the researchers suggested high-quality clinical trials to establish these findings.
Overall, intake of cooked tomatoes, lycopene and tomato products in moderate amounts may be good for reducing the risk of prostate cancer. Other studies also suggest that tomatoes or tomato products ingested daily may help in protection from DNA damage, a surrogate endpoint biomarker for prostate cancer. (Sabine Ellinger et al, Curr Opin Clin Nutr Metab Care., 2006)
However, high quality trials are suggested to establish these facts.
Are Tomatoes good for Prostate Cancer Patients?
Impact of Tomato Consumption on PSA levels
In a study published in 2017, the researchers from the University of Oslo, Norway, evaluated whether lycopene-rich tomatoes could reduce the levels of prostate specific antigen (PSA) in prostate cancer patients. The study used data from 79 patients with prostate cancer. The study found that three week nutritional intervention with tomato-products alone or in combination with selenium and n-3 fatty acids may reduce PSA levels in patients with non-metastatic prostate cancer. (Ingvild Paur et al, Clin Nutr., 2017)
Impact of Lycopene on Drug Efficacy
In a study published in 2011, the researchers from the University of California, Irvine, evaluated how carotenoids such as lycopene could enhance the effect of a specific drug on prostate cancer. The researchers found that lycopene along with this drug may have more pronounced growth inhibitory effects than that of the drug alone. The study also mentioned that lycopene may significantly enhance the antitumor efficacy of this drug by approximately 38%. (Tang Y et al, Neoplasia, 2011)
Impact of Lycopene on Chemo-induced Kidney Damage
In a study conducted in 2017, the researchers from the Shahrekord University of Medical Sciences in Iran evaluated the effects that lycopene found in tomatoes could have on a specific chemo-induced kidney damage in patients. In a double-blinded randomized trial, by splitting 120 patients into two groups, the researchers found that lycopene may be effective in decreasing the complications due to the specific chemo-induced nephrotoxicity by affecting different markers of renal function. (Mahmoodnia L et al, J Nephropathol. 2017)
Different observational studies suggest that taking moderate amounts of cooked tomatoes, tomato products or lycopene (present in tomatoes) may be good for reducing the risk of prostate cancer. Large scale clinical trials are suggested to confirm these findings. Studies also suggest that lycopene and tomato consumption may help in reducing PSA levels, improving specific drug efficacy and reducing a particular chemo-induced kidney damage in prostate cancer patients.
However, taking tomatoes in excess amounts daily may lead to undesired outcomes such as increased levels of potassium resulting in hyperkalemia, which if not addressed may result in abnormal heart rhythms. Also, reduce daily consumption of lycopene ( seen in tomatoes) to less than 30 mg to avoid bad effects such as nausea, bloating and diarrhea.
Cancer patients often have to deal with different chemotherapy side effects which affect their quality of life and look out for alternative therapies for cancer.Taking the right nutrition and supplements based on scientific considerations (avoiding guesswork and random selection) is the best natural remedy for cancer and treatment related side-effects.