News · Nutrition & Diet
Ultra-processed food and prostate cancer: a 30% higher risk signal in US survey data, and its limits
A new analysis of US national nutrition surveys found men eating more ultra-processed food more often reported prostate cancer. The design is weak, and the authors say it needs proper testing.
- An observational analysis of 17,024 US men from national nutrition surveys run between 2003 and 2023.
- Diet came from two 24-hour food recalls; prostate cancer came from what men reported, not medical records.
- Men in the top half for ultra-processed food had about 30% higher odds of reporting prostate cancer.
- The top quarter alone showed a 31% increase that did not reach the study's threshold for chance.
- Diet and cancer were measured at the same time, so the study cannot show which came first.
Ultra-processed food has been linked to heart disease, diabetes, depression and several cancers. Prostate cancer, one of the commonest cancers in men, has had less attention, and headlines this summer reported a 30% higher risk.
The study behind them, in The American Journal of Medicine, used US national nutrition surveys covering 17,024 men. Those eating more ultra-processed food more often reported having had prostate cancer. The signal is real in the data but the design is weak, and the authors say so.
What prostate cancer is
MedlinePlus explains that prostate cancer begins in the cells of the prostate, a gland in the male reproductive system, and that it is one of the most common types of cancer. Many prostate cancers grow slowly, but some grow quickly and spread.
Its causes are not fully understood. Age, family history and ethnicity matter most, and diet has long been suspected of playing a part. As the authors write, data are sparse about ultra processed foods and prostate cancer.
How the prostate cancer survey analysis worked
The researchers used the National Health and Nutrition Examination Survey, a nationally representative US survey, from 2003 to 2023. Ultra-processed food intake was estimated from two 24-hour dietary recalls, in which participants list everything they ate the previous day, and classified using the widely used NOVA system.
Prostate cancer was defined by self-report: men were asked whether a doctor had ever told them they had it. The researchers then compared men by quarters of ultra-processed food intake, adjusting for age, smoking, ethnicity and poverty.
What the prostate cancer numbers showed
Men beyond the lowest quarter of intake more often reported prostate cancer. Compared with the lowest quarter, the combined top half had a significant 30% higher risk, and the combined top three quarters 29% higher.
The top quarter on its own showed a 31% increase that did not clear the study’s threshold, which the authors attribute to smaller numbers. The study also used a looser threshold for chance than most, because the authors had specified in advance that they were looking for harm. Together, those details make the result a signal rather than a firm finding.
Why an ultra-processed food signal still matters
Prostate cancer is common enough that even a modest dietary influence would affect many men, and ultra-processed food makes up a large share of the typical US diet. A signal in nationally representative data is a reason to look harder.
The authors are direct about what their study can and cannot do. They conclude that people with higher ultra-processed food intake had higher risks of prostate cancer, and that analytic studies are necessary to test this hypothesis, meaning studies that follow men over time and measure cancer independently.
What a survey snapshot cannot show
Diet and cancer were captured at the same moment. Many men in the survey were diagnosed years earlier, and a diagnosis can change how people eat, so the order of events is unknown. Two days of food recall say little about decades of eating.
Self-reported cancer misses men who were never diagnosed and relies on memory. Men who eat more ultra-processed food may also differ in weight, activity, screening and healthcare use in ways the adjustments do not capture, and prostate cancer detection depends heavily on screening.
What this changes for men and diet
Nothing here is strong enough to change prostate cancer advice. Screening decisions still rest on age, family history, ethnicity and a conversation with a doctor about the pros and cons of PSA testing.
Eating less ultra-processed food is reasonable advice for heart and metabolic health regardless. If larger studies that follow men over time confirm this link, prostate cancer may be added to the reasons; for now, it is an open question.
People also ask
What did the study find?
Compared with the lowest quarter of ultra-processed food intake, men in the combined second to fourth quarters had 29% higher risk of prostate cancer (p = 0.031) and those in the combined third and fourth quarters 30% higher (p = 0.035). The fourth quarter alone showed a 31% increase that was not statistically significant (p = 0.079). After adjustment for age, smoking, ethnicity and poverty the figures were 27%, 31% and 34%.
What counts as ultra-processed food?
Under the NOVA system, industrially made products built largely from refined ingredients and additives, such as packaged snacks, sugary drinks, processed meats, instant meals and many breakfast cereals.
Why is the design considered weak?
Diet was measured with two days of recall, prostate cancer was self-reported, and both were measured at the same time. Men diagnosed with cancer may also have changed how they eat.
What about the 90% confidence intervals?
The authors used a less strict statistical threshold than usual because they had specified in advance that they were looking for harm. That makes borderline results easier to call significant.
Does this mean ultra-processed food causes prostate cancer?
No. The authors themselves say analytic studies are needed to test the hypothesis. Larger studies that follow men over time are the next step.
What should men do?
Eating less ultra-processed food is sensible for many reasons. For prostate cancer, talk to a doctor about screening based on age, family history and other risk factors. This is general information rather than medical advice.