The analysis of more than 3,500 men, led by researchers at NYU Grossman School of Medicine and the Harvard TH Chan School of Public Health, explored the relationship between diet and quality-of-life outcomes reported after prostate cancer treatment.
The findings provide “supportive evidence that greater consumption of healthful plant-based foods is associated with modestly higher scores in quality-of-life domains among patients with prostate cancer”, the authors concluded.
The study, published this week in the journal Cancer, is believed to be the first of its kind to show better urinary health in these patients based on nutrition, according to lead author Stacy Loeb, professor in the departments of urology and population health at NYU Langone Health.
“Our findings offer hope for those looking for ways to improve their quality of life after undergoing surgery, radiation, and other common therapies for prostate cancer, which can cause significant side effects,” she said.
“Adding more fruits and vegetables to their diet, while reducing meat and dairy, is a simple step that patients can take.”
Prostate cancer: A leading cause of death among men
The scientists sorted participants into quintiles based on the proportion of plant versus animal foods they reported eating and found that the quintile that consumed the most plants scored 8 to 11% better in measures of sexual function compared with the group that consumed the least.
Similarly, the results revealed up to 14% better scores for urinary health – with fewer instances of incontinence, obstruction, and irritation – and up to 13% better scores in hormonal health (which assesses symptoms like low energy, depression, and hot flashes) among the highest quintile.
In Europe, prostate cancer is the most common cancer in men and one of the deadliest. In 2020, it accounted for 23.2% of all cancer diagnoses (excluding non-melanoma skin cancers) in men and 9.9% of all deaths due to cancer in men.
Previous research by the same team has shown that eating a plant-based diet may reduce the risk of developing the disease in the first place. Other investigations have found that a diet that limits meat and dairy but is rich in fruits, vegetables, grains, and nuts is associated with a lower risk of sexual dysfunction in general, but not specifically for those with prostate cancer, who are at particularly high risk for such issues.
Long-term project aims to understand the influence of nutrition on serious diseases
Alongside the research, the team analysed data from the Health Professionals Follow-Up Study, an ongoing investigation begun in 1986 and sponsored by Harvard Chan School. The project, which comprises information on more than 50,000 male health practitioners, was designed to better understand the influence of nutrition on cancer, heart disease, and other serious illnesses.
Participants in the long-term study answered a questionnaire every four years about the kinds of foods they ate and in what proportions. Another survey, administered every two years, assessed frequency of incontinence, difficulties maintaining an erection, and problems with bowels, energy, and mood, among other health concerns.
Most of the patients (more than 83%) had received prostate cancer treatment, Loeb said. The team considered confounding factors such as weight and physical activity when exploring potential connections between plant-based diets and health, she added.
Plant-based diets linked to better sexual and urinary health, vitality, and bowel function
Eating high amounts of any plant-based food was linked to better sexual health, urinary health, and vitality scores, regardless of demographic factors, lifestyle differences, or history of other medical issues such as diabetes.
Eating more healthy plant-based food was also associated with better bowel function, Loeb said, which may be explained by the dietary fibre found in plants.
“These results add to the long list of health and environmental benefits of eating more plants and fewer animal products,” she added. “They also clearly challenge the historical misconception that eating meat boosts sexual function in men, when in fact the opposite seems to be the case.”
However, the study was not without its limitations, she admitted, as most participants were white healthcare professionals.
The team now plans to expand their research to a more diverse group of patients and to people with more advanced stages of the disease.
