For decades, patients undergoing blood cancer treatment have been told to avoid certain foods to reduce infection risk, guidance that some physicians hoped could safely be relaxed.

Now, a University of Florida study offers clear evidence that a diet designed to limit exposure to foodborne microbes results in fewer serious infections, confirming it is still the safest choice.

Published in the Journal of Clinical Oncology, findings from the large phase 3 randomized trial — considered the gold standard for clinical trials — demonstrated that patients hospitalized for blood cancer treatment who followed a diet restricting fresh fruits and vegetables had a lower risk of developing serious infection.

This “neutropenic” [new-tro-pee-nik] diet, gets its name from neutropenia, a condition in which patients have low levels of protective white blood cells called neutrophils. During chemotherapy, these cells are suppressed, increasing infection risk. The most serious infections arise from the intestinal tract and are linked to microbes in uncooked foods.

Fresh fruits and vegetables are important components of a healthy diet once patients’ immune systems have recovered, but during treatment, clinicians prescribe the diet to protect against infection. Researchers emphasized the need to come up with better approaches to improve the nutrition of patients with cancer without compromising their safety.

The study finally answers a decades-old question about the effectiveness of the neutropenic diet at preventing infection, but more work needs to be done to address ongoing nutrition issues, researchers said. A healthy diet remains important not only for the gut, but also for patient outcomes.