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New research suggests that eating a plant-based diet may reduce sexual health side effects such as erectile dysfunction and urinary incontinence in men with prostate cancer. mixetto/Getty Images
  • New research suggests a plant-based diet may reduce sexual health side effects in prostate cancer patients.
  • These include reducing the risk of erectile dysfunction and urinary incontinence.
  • Urologists and oncologists say the research is important, especially given that prostate cancer is the top cancer diagnosis in men.

Plant-based diets like the Mediterranean diet have long been hailed for their ability to lower the risk of disease and all-cause mortality, including prostate cancer. For instance, a pair of studies in 2022 indicated that plant-based diets could reduce a person’s prostate cancer odds.

A new study indicates that these diets might also provide benefits to people already diagnosed with prostate cancer.

New research suggests that people who followed diets rich in fruits, vegetables, and grains while limiting dairy and meat consumption might experience less of prostate cancer’s common side effects, including erectile dysfunction and urinary incontinence.

“Patients with prostate cancer often ask if there is anything they can do to reduce side effects,” says study lead author and urologist Dr. Stacy Loeb, a urologist, NYU Langone Health professor, and the study’s lead author. “Our findings are important by showing for the first time an association between eating more plant-based food with better scores for quality of life among patients with prostate cancer.”

Prostate cancer is one of the most common cancers in the U.S., according to the National Cancer Institute. It’s the leading cancer diagnosis in men and second-leading overall, with more than 288,000 expected cases.

The American Cancer Society puts this number at closer to 300,000 expected diagnoses in 2024. While treatments can be life-saving, a urologic oncologist says the side effects can be stressful for a person — and any applicable partners, making studies like this one important.

“Reliable data on how lifestyle modifications and dietary changes can possibly improve a prostate cancer patient’s quality of life is significantly lacking, so this area of research is valuable and needed,” says Dr. Ramkishen Narayanan, a board certified urologist and urologic oncologist and the director of the Center for Urologic Health at The Roy and Patricia Disney Family Cancer Center at Providence Saint Joseph Medical Center.

Loeb says the impetus for this study came because researchers wanted to follow up on a 2022 study of more than 47,000 men that indicated that plant-based diets could lower a person’s risk of fatal prostate cancer by 19%.

To conduct this study, NYU Grossman School of Medicine and Harvard T.H. Chan School of Public Health professionals teamed up to analyze more than 3,500 men already diagnosed with prostate cancer to see if a plant-based diet could reduce side effects like erectile dysfunction, which can lower quality of life.

Loeb explains that researchers split the men into five groups based on dietary patterns.

The groups ranged from least plant-based and most animal-based to most plant-based and least animal-based.

Those who consumed the most plant-based and fewest animal-based foods reported better scores for sexual function (8-11%), urinary health (up to 14%), and vitality (up to 13%).

Those adhering to a more plant-based diet also had higher scores for bowel function than their peers consuming fewer plant-based and more animal-based foods by 12-27%.

Those are a lot of numbers. The top-line takeaway?

“The study suggests that for patients with prostate cancer, consumption of plant-based foods is associated with better quality of life domains, such as erectile dysfunction, urinary issues, and hormonal health,” says Dr. Mina M. Fam, MD, the medical director of urologic oncology at Hackensack Meridian Jersey Shore University Medical Center and Robotic Surgery, Ocean University Medical Center. “These quality-of-life issues affect patients with prostate cancer in varying degrees based on treatment, stage of disease, and other health conditions.”

“The study is not designed to answer the question of ‘why?,’ explains Dr. Evan Lacefield, a urologist with Memorial Hermann. “It leaves us to make assumptions off of previous research indicating benefits in cardiovascular and metabolic health.”

For example, Lacefield says that plant-based diets have been associated with lower rates of metabolic diseases or conditions that increase a person’s risk of heart disease, stroke, and diabetes. Think high blood pressure, cholesterol, and blood sugar.

A 2023 review of more than 30 studies indicated that pivoting from an animal-based diet with red and processed meat, eggs, dairy, poultry, and butter to one that emphasized nuts, legumes, whole grains, and olive oil, is beneficial to a person’s cardiometabolic health.

Narayanan says more research digging into the mechanism of why plant-based food can lower the risk of chronic diseases like prostate cancer — and their side effects if a person develops one — is needed.

“This an area that needs significantly more study, especially with respect to biochemical pathways of how plant-based diets can actually reduce inflammation specifically in the prostate cancer population,” Narayanan says. “A potential mechanism is likely the general anti-inflammatory effect of plant-based diets.”

Narayanan adds that individuals who have been consuming a diet rich in plant-based foods long-term may also keep other lifestyle habits that can reduce metabolic syndrome risk, like regular exercise.

“[These habits] help them avoid the metabolic syndrome that can plague optimal post-treatment recovery,” Narayanan says.

Fam is impressed with the quality of the research, saying that the study might help bust myths surrounding food and sexual health and give patients and providers tools for managing prostate cancer side effects.

“I think this is an excellent study that shows how prostate cancer patients may improve their quality of life and gives physicians information to promote a healthy lifestyle for our patients,” Fam says. “There have been societal misconceptions that a meat-based diet can improve sexual function and virility. However, this study shows that is not true.”

Others aren’t surprised based on the wealth of information about the benefits of plant-based diets.

“Most data in this and other areas of medicine demonstrate that a plant-based diet is widely beneficial for human health,” says Lacefield. “It has been linked to reduced risk of heart disease, diabetes, sexual dysfunction, urinary dysfunction, cancer, and dementia.”

Still, the study has some limitations. Dr. Jamin Brahmbhatt, a urologist with Orlando Health Medical Group, flagged:

  • Reliance on self-reported data
  • Intake from mostly white healthcare professionals
  • Observational design

“While the study is indeed promising, it’s important to approach its findings with a critical eye,” says Brahmbhatt. “It’s a stepping stone, not the final word, and it highlights the need for further research that encompasses a broader, more diverse patient population, and potentially, interventional studies to establish causality.”

Adapting a plant-based diet has its benefits, but the challenge of getting started may feel like a drawback to some. These expert tips might help.

Speak with your healthcare team

Fam agrees that plant-based diets are “excellent health choices.” However, he advises people, particularly those with an underlying condition, to speak with their healthcare team first.

“There may be certain nutritional considerations that differ for each person, and while a plant-based diet is typically a healthy choice, certain vitamin deficiencies such as B12 and Vitamin D can be associated with a plant-based diet, so it is important to discuss with your doctor,” Fam says.

Fam and Narayanan concur that speaking with a dietician or nutritionist can help fill potential nutrient gaps.

“They can help ensure you are getting enough iron, vitamin B12, [and other nutrients] that can potentially be lowered with a plant-based diet,” Narayanan says.

Start slow

If you’ve leaned on animal-based foods for a long time, experts suggest making small changes and building from there rather than drastically shifting all at once.

“Gradually increase the amount of plant-based foods in your diet while reducing meat and dairy intake,” Brahmbhatt says.

Variety is key

Plant-based meals need not be limited to spinach and kale, though these leafy-green veggies are staples of the diet.

“Ensure a wide range of fruits, vegetables, grains, and legumes to get all necessary nutrients,” Brahmbhatt says.

For instance, Brahmbhatt says you might blend a breakfast smoothie with leafy greens, berries, omega-3-rich flaxseeds, and a plant-based protein source, like pea protein. Lunch and dinner could be a salad with a rainbow of vegetable colors, quinoa, tofu, and nuts.

Combining a grain like quinoa with plant-based protein like tofu makes for a complete protein, he explains.

It’s also reasonable to continue to consume animal-based proteins — just be mindful of which ones you use regularly.

“A serving of…unprocessed animal protein such as fish per meal is perfectly acceptable,” Narayanan says.

New research suggests that consuming a diet rich in plant-based foods like produce and grains but lower in meats and dairy can reduce a person’s risk of experiencing side effects commonly associated with prostate cancer.

Healthcare providers who work with people with prostate cancer hypothesize it’s because the nutrient profile may have anti-inflammatory effects.

More research is needed, but doctors say the study is promising and that adopting a plant-based diet is likely beneficial.

Speak with your healthcare team before starting a diet to ensure it’s a good fit for you. A dietician or nutritionist can also help ensure you get all the necessary nutrients. Start slow, and eat various foods to ensure you’re getting nutrients and enjoying the meal plan.