Intake of a diet with foods containing dietary carotenoids such as beta-cryptoxanthin, alpha/beta-carotene, lutein and zeaxanthin, Vitamin E, Selenium, yogurt, dried fruits, cruciferous vegetables such as broccoli, brussels sprouts, cabbage, cauliflower and kale, and fruits may reduce the risk of bladder cancer. However, high intake of red and processed meat, chewing areca nuts, consuming arsenic containing water, taking fried eggs and lifestyle factors such as smoking tobacco, may increase the risk of bladder cancer, impact the prognosis and treatment outcomes, worsen symptoms, or increase the chances of cancer recurrence.
Bladder Cancer Incidence
Bladder cancer is the cancer that starts in the lining of the urinary bladder. It is the 6th most commonly occurring cancer in men and the 17th most commonly occurring cancer in women. It is also one of the top 10 commonly occurring cancers in the world. In 2018, 5,49,393 new cases were reported. (Globocan 2018)
Over 90% of people with this cancer are older than 55 years. The mean age of people diagnosed with this cancer is 73 years. The prognosis of bladder cancer may range from good to poor depending on the type, grade and stage of the cancer. Bladder cancer prognosis may also depend on how well the patient responds to the treatment, and factors such as age, general health and medical history. The 5-year survival rate for people with this cancer is 77%. (American Society of Clinical Oncology)
The most common risk factors of bladder cancer include:
- Exposure to harmful substances
- Smoking Tobacco
- Contact with certain chemicals used in manufacturing
Types of Bladder Cancer
Based on the extent of spread of the cancer, bladder cancer is usually classified as:
- Non-muscle-invasive Bladder Cancer : where the cancerous cells are contained inside the lining of the bladder.
- Muscle-invasive Bladder Cancer : where the cancerous cells spread beyond the lining, into the surrounding bladder muscle.
- Metastatic Bladder Cancer : when the cancer spreads to other parts of the body
Based on how the cancer cells look under the microscope, this cancer may also be classified as:
- Urothelial carcinoma or Transitional Cell Carcinoma or TCC : which begins in the urothelial cells found in the urinary tract.
- Squamous cell carcinoma : which develops in the bladder lining in response to irritation and inflammation.
- Adenocarcinoma : which develops from glandular cells.
Patients with metastatic bladder cancer generally have a poor prognosis.
Symptoms of Bladder Cancer
One of the most common symptoms of bladder cancer include blood in urine, medically known as hematuria, which may cause urine to appear bright red and is usually painless.
Other less common signs and symptoms of bladder cancer include:
- Increased frequency of urination
- Sudden urges to urinate
- Burning sensation during urination
Advanced stages of bladder cancer may also show the following symptoms:
- Unintentional weight loss
- Back pain
- Pelvic pain
- Bone pain
- Swelling of the legs
If any of these signs or symptoms of bladder cancer are noticed, one should get it checked by a doctor.
Treatments for Bladder Cancer
The treatment for bladder cancer depends on various factors such as the type of cancer, stage and grade of the cancer, general health and medical history of the patient. The treatment options for bladder cancer include surgery, chemotherapy, radiation therapy, immunotherapy and targeted therapy. Surgery or Radiation treatment may be used to remove or destroy the cancer cells. Intravesical chemotherapy or chemotherapy in the bladder is done if the cancer with a high risk of recurrence or progression to higher stages is restricted to the bladder. Systemic Chemotherapy or chemo for the whole body is done to increase the chance of curing the patient undergoing surgery to remove the bladder. It may also be used as the mainline treatment when surgery cannot be done. Immunotherapy may also be used for bladder cancer treatment by triggering the body’s immune system to fight the cancer cells. When these treatments do not work, targeted therapies may also be used for the treatment.
Role of Diet in Bladder Cancer
Although tobacco smoking and exposure to chemicals are considered as the major risk factors/causes for bladder cancer, diet may also play an important role in increasing or reducing the risk of this cancer. In this blog, we will elaborate on some of the studies carried out by researchers across the world, which evaluated the association between the intake of different types of foods/diet and the risk of bladder cancer.
Red and Processed Meat Intake may Increase the Risk of Bladder Cancer
In a meta-analysis done by the researchers from Karolinska Institutet in Sweden, they analyzed dietary data from 5 population based studies, which included 3262 cases and 1,038,787 participants and 8 case-control/ observational clinical studies which included 7009 cases and 27,240 participants, obtained through literature search in Pubmed database through January 2016. The researchers found that a high intake of processed meat consumption increased the risk of bladder cancer in both case-control and population based studies. However, they found an increased risk of bladder cancer with increased red meat intake only in the case-control studies, but not in the cohort/population-based studies. (Alessio Crippa et al, Eur J Nutr., 2018)
Chewing Areca Nut may Increase the Risk of Cancer Recurrence in Non-Muscle-Invasive Bladder Cancer
A study done by the researchers from The Second Xiangya Hospital in China and The Queen’s Medical Research Institute in the United Kingdom, involving 242 patients with non-muscle-invasive bladder cancer (NMIBC), who underwent transurethral resection surgery, evaluated the risk factors for cancer recurrence. The researchers found that high areca nut chewing was associated with an increased risk of cancer recurrence in the NMIBC patients. (Jian Cao et al, Sci Rep., 2016)
Chewing Areca Nut may even impact the prognosis of bladder cancer.
Intake of Rice Cooked in Arsenic containing Water and Bladder Cancer Risk
Analysis of dietary information from a U.S. population-based case–control study of bladder cancer with 316 cases identified through the New Hampshire State Department of Health and Human Services’ Cancer Registry and 230 controls selected from the New Hampshire residents and obtained from the New Hampshire Department of Transportation and Medicare enrollment lists found evidence of an interaction between very high consumption of brown rice and water arsenic concentrations. (Antonio J Signes-Pastor et al, Epidemiology. 2019)
The researchers highlighted that a higher arsenic content may be present in brown rice compared to white rice and also a potential increase in arsenic burden may be seen in cooked rice if arsenic-contaminated cooking water was used.
However, the study did not provide any strong evidence that regular brown rice consumption may contribute to the overall incidence of bladder cancer. However, since bladder cancer could have been a potential health hazard due to arsenic contents, the researchers suggested further detailed research including larger studies to evaluate any association between brown rice consumption and bladder cancer risk.
Egg Consumption and Bladder Cancer Risk
A meta-analysis done by the researchers from the Nanfang Hospital, Southern Medical University, Guangzhou in China based on data from 4 cohort studies and 9 case-control studies involving 2715 cases and 184,727 participants, obtained through literature search in the PubMed database till February 2012 found no significant association between egg consumption and bladder cancer risk. (Fei Li et al, Nutr Cancer., 2013)
However, based on a limited number of studies, a possible relationship with increased intake of fried eggs with bladder cancer risk was suggested.
Dietary Carotenoid intake may Reduce the Risk
A meta-analysis of 22 observational studies done by the researchers at the University of Texas Health Center in San Antonio which included 516,740 adults, obtained through literature search in PubMed and Scopus databases and the Cochrane Library till April 2019, found that for every 1 mg increase in daily intake of dietary carotenoids such as beta-cryptoxanthin (which is commonly found in oranges and tangerines), the risk of bladder cancer was reduced by 42%, while total dietary carotenoid intake reduced the risk by 15%. (Wu S. et al, Adv. Nutr., 2020)
The study also found that the risk of bladder cancer was decreased by 76% for every 1 micromole increase in circulating concentration of alpha-carotene and was decreased by 27% for every 1 micromole increase in beta carotene. Carrots are great sources of alpha and beta carotene. Additionally, they also found that the risk of this cancer was decreased by 56% for every 1 micromole increase in circulating concentrations of lutein and zeaxanthin. Broccoli, spinach, kale, asparagus are some of the food sources of lutein and zeaxanthin.
Hence, including carotenoids as part of the diet may reduce the risk of bladder cancer.
Selenium Intake may Reduce the Risk
A meta-analysis done by the researchers from the Spanish National Cancer Research Centre based on data from 7 studies including 6 case-control studies and 1 one population based study published before March 2010, evaluated the association between levels of selenium and bladder cancer. The study found a 39% decreased risk of bladder cancer with the highest levels of selenium. The study also highlighted that the protective benefit of selenium was seen mostly in women. (André F S Amaral et al, Cancer Epidemiol Biomarkers Prev., 2010)
Probiotic Yogurt Intake may Reduce the Risk
A meta-analysis done by the researchers of Sichuan University in China, based on 61 studies, involving 1,962,774 participants and 38,358 cancer cases, obtained through literature search in PubMed, Embase and CNKI databases through July 2018, found that probiotic yogurt consumption was associated with a reduced risk of bladder and colorectal cancers. (Kui Zhang et al, Int J Cancer., 2019)
Hence, including yogurt as part of the diet may reduce the risk of bladder cancer.
Cruciferous Vegetable Intake may Reduce the Risk
Researchers from the First Affiliated Hospital, College of Medicine, Zhejiang University in China carried out a meta-analysis using data from 10 observational studies, covering 5 case-control and 5 cohort studies, obtained through literature search for studies published between 1979 and June 2009 in the Pubmed/Medline and Web of Science databases and found a significantly decreased risk of bladder cancer with a high intake of cruciferous vegetables, especially in case-control studies. (Liu B et al, World J Urol., 2013)
Hence, including cruciferous vegetables such as broccoli, brussels sprouts, cabbage, cauliflower and kale as part of the diet may reduce the risk of bladder cancer.
Vitamin E Intake may Reduce the Risk
A meta-analysis done by the researchers from the Second Military Medical University and Tongji University in China using 11 prospective studies including 3 clinical trials and 8 population based studies with 575601 participants, obtained through literature search in online databases found that vitamin E intake was associated with a reduced risk of bladder cancer. (Jian-Hai Lin et al, Int J Vitam Nutr Res., 2019)
Hence, including Vitamin E rich foods such as sunflower seeds, almonds, spinach, avocados, squash, kiwifruit, trout, shrimp, olive oil, wheat germ oil, and broccoli as part of the diet may reduce the risk of bladder cancer.
Vegetable and Fruit Consumption may Reduce the Risk
A meta-analysis done by the researchers from the Tongji University and Nanjing Medical University in China based on data from 27 studies (12 cohort and 15 case-control studies) obtained through a computer search of PubMed, Embase and the Cochrane library and through a manual review of references found that vegetable and fruit intake reduced the risk of bladder cancer by 16% and 19% respectively. The dose-response analysis also highlighted that the risk of this cancer decreased by 8% and 9% for every 200 g/day increment in vegetable and fruit consumption, respectively. (Huan Liu et al, Eur J Cancer Prev., 2015)
Dried Fruit Consumption may Reduce the Risk
Researchers from the University of Missouri, Harvard TH Chan School of Public Health and Brigham and Women’s Hospital in the US did a systematic review of 16 observational studies that were published between 1985 and 2018 to assess the possibility of any association between traditional dried fruit consumption and cancer risk in humans. The studies included in the analysis were mostly conducted in the United States, Netherlands and Spain with a total of 12,732 cases from 437,298 participants. They found that increasing the intake of dried fruits to 3-5 or more servings per week may reduce the risk of cancers of the digestive system such as stomach, bladder and colon cancers. (Mossine VV et al, Adv Nutr. 2019)
These observational studies suggest that intake of foods containing dietary carotenoids such as beta-cryptoxanthin, alpha/beta-carotene, lutein and zeaxanthin, Vitamin E, Selenium, yogurt, dried fruits, cruciferous vegetables and fruits may reduce the risk of bladder cancer. However, consumption of red and processed meat, chewing areca nuts, using arsenic containing water or taking fried eggs and lifestyle factors such as smoking tobacco, may increase the risk of bladder cancer, impact the prognosis and treatment outcomes, worsen symptoms, or increase the chances of cancer recurrence. Avoid smoking tobacco, eat the right foods, be physically active and do regular exercise to stay away from bladder cancer and improve prognosis.
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.