Ultra-processed food tied to breast cancer deaths

Black women who ate the most ultra-processed food before a breast cancer diagnosis were 40 per cent more likely to die from the disease, a study has found.

The research analysed the diets of more than 1,730 Black women in New Jersey who were diagnosed with breast cancer between 2005 and 2019. About 10 months after diagnosis, participants were interviewed at home and completed questionnaires about what they ate in the year before their cancer was detected. They were then followed for around nine years.

Ultra-processed food is commonly defined as products made with ingredients not typically used in home cooking, such as chemical preservatives, high-fructose corn syrup and artificial colours or flavours. Examples include sugary drinks, biscuits, white bread, deli meats and confectionery.

Women who consumed more than eight servings of ultra-processed food a day were 40 per cent more likely to die from breast cancer and 36 per cent more likely to die from any cause than those who ate fewer than three servings daily.

Processed meats, including bacon and hot dogs, showed the strongest association with death from breast cancer among all categories of ultra-processed food.

Tengteng Wang, assistant professor of medicine at Rutgers Robert Wood Johnson Medical School and lead author of the study, said: “Black women have the highest mortality rate from breast cancer compared with other racial or ethnic groups in the US. We wanted to see what factors might contribute to these differences.”

Wang added: “We found that processed meats were the top-worst foods among all ultra-processed food subgroups. So maybe the takeaway is to avoid this one thing: Limit how much processed meat you eat.”

The findings mirror those of a 2023 study of cancer survivors in the United Kingdom, which found a 22 per cent higher risk of cancer-related death among those who ate the most ultra-processed food. However, 95 per cent of participants in that study were white and 45 per cent were men.

More than 73 per cent of women in the current study were diagnosed with hormone receptor-positive breast cancer, meaning the cancer was driven by oestrogen or progesterone. This made it difficult to determine whether ultra-processed food intake had different effects across specific subtypes, such as triple-negative breast cancer, which does not respond to hormone therapies.

Tracy Crane, associate professor of medical oncology at the Sylvester Comprehensive Cancer Center at the University of Miami, who was not involved in the study, said: “Studies like this make it clear that diet doesn’t stop mattering once breast cancer is diagnosed and may directly shape survivorship.”

According to Crane, ultra-processed foods add inflammation and additional stress to the body at a time when it is already under strain. She said diets focused on minimally processed foods, lean protein and healthy fats can help the body tolerate treatment.

“These are actionable, evidence-based choices that can meaningfully improve long-term outcomes and quality of life for survivors of breast cancer,” she added.

Wang acknowledged that making major dietary changes during treatment and recovery can be daunting. She suggested practical options such as pre-cut vegetables, particularly dark green and dark orange varieties, pre-cut fruit, and simple proteins including ground beef or turkey without additives, chicken pieces or fish.

“You just want to avoid bacon and hot dogs and highly processed meats, things with nitrates and preservatives,” she said.