MANY BLOOD CANCER PATIENTS receive intensive chemotherapy, in some cases followed by a stem cell transplant, to treat their cancer. The chemotherapy can damage the protective lining of the GI tract and reduce the number of disease-fighting immune cells called neutrophils in the blood. These changes leave patients vulnerable to infections, including from a source people don’t often think about: the food they eat.

For many years, doctors have worked to minimize this risk by recommending that blood cancer patients with compromised immune systems follow a neutropenic diet that limits exposure to microbes that could increase the chance of infection. The diet emphasizes processed or thoroughly cooked foods and close attention to safety practices like thoroughly washing your hands before handling food. Patients on this diet also need to avoid undercooked meats and seafood, unpasteurized dairy and raw fruits and vegetables. That means no sushi, raw snap peas, or strawberries, but cooked carrots, sauteed spinach and well-done burgers can be on the menu.

Yet, more recently, some doctors have moved away from recommending the neutropenic diet over concerns that the restrictions may interfere with a person’s ability to get nutrients at a time when they need them most. Patients with blood cancer who have poor nutritional status and undergo stem cell transplants are at increased risk of complications and reduced survival compared with those who have a higher nutritional status. Because of this, some doctors recommend modifications to the diet that allow a greater variety of foods, such as fresh fruits and vegetables, but prohibit undercooked fish and meat and unpasteurized dairy, to get adequate nutrition without jeopardizing their risk of getting sick.

Some research has supported this change in focus: In one 2023 phase III Italian study in Blood Advances involving 222 people receiving stem cell transplantation for blood cancer, people who followed a strict neutropenic diet were just as likely to get infection as those who followed a modified neutropenic diet that included fresh fruits and vegetables.

However, a phase III clinical trial, published Dec. 17, 2025, in the Journal of Clinical Oncology, has found people with blood cancer who received intensive chemotherapy had a significantly higher risk of infection if they were allowed a liberalized diet—which permitted a daily serving of fresh fruits or vegetables, along with pasteurized yogurt—compared with those on a neutropenic diet.

The recent trial looked at 214 blood cancer patients treated at the University of Florida Health Cancer Institute in Gainesville. Half were assigned a neutropenic diet, while the other half were assigned a liberalized diet that allowed fresh fruits and vegetables, along with pasteurized yogurt. In fact, researchers stopped the trial early because of the marked difference in the major infection rate. The analysis found 31.4% of patients in the liberalized diet group had experienced major infections, compared with 20% of those in the neutropenic diet group, says John Wingard, a medical oncologist and emeritus faculty at the University of Floridain Gainesville, who was the study’s lead author. When the researchers looked at patients who closely followed the liberalized diet, Wingard says, “the infection rate was even higher.”

“We hoped to find that the liberalized diet was safe,” Wingard says. “I personally emphasize fruits and vegetables in my own diet, and I think in non-immunocompromised patients, a plant-based diet is the best thing.” But for patients in this study, who were profoundly immunocompromised during the short window of intensive cancer treatment, he says, “it turned out that there were more infections in the folks that were assigned to the liberalized diet.”

The conflicting results between the two clinical studies present a challenge for both doctors and patients, says Jonathan Peled, a medical oncologist at Memorial Sloan Kettering Cancer Center in New York City. During this critical immunosuppressed period—typically for the 10 to 20 days following chemotherapy infusion or stem cell transplants—patients need food to heal, but they may not feel well enough to eat. “They have disturbances in their taste, they’re nauseated, and they have painful mouth sores,” he says. When it’s already hard to eat, adding additional restrictions around food “can be a wicked combination.”

Yet based on the increased rate of infections reported in the Journal of Clinical Oncology trial, Peled says, “I would continue to recommend the neutropenic diet,” particularly as the patient population in the study may be more similar, in terms of their location and their cancer type, than those in the earlier trial, which was conducted in Italy.

The 2023 study conducted in Italy found that patients reported greater satisfaction with more liberalized diets. But the U.S.-based study didn’t find better quality of life or higher caloric intake among participants who followed the liberalized diet. Most patients in the U.S. study, assigned to either diet, consumed an average of fewer than 750 calories a day, while an average adult needs between 1,600 and 3,000 calories a day. “There was no nutritional benefit to this,” Wingard says, “but there was a higher risk.” Two-thirds of the infections found in patients’ bloodstreams, he notes, came from organisms that live in the intestines, which suggests the infections came from food.

In the past, anything entering an immunosuppressed patient’s environment, including food, had to be boiled or otherwise sterilized to minimize the patient’s infection risk. Now, the neutropenic diet typically allows meats, eggs and vegetables cooked thoroughly, along with instruction on safe food handling practices, such as handwashing. Patients can cook food at home or eat out at restaurants, as long as what they’re eating aligns with the guidance, says Peled.

“The truth is that people who are well often follow diet precautions like this in different periods of life,” says Peled. A pregnant person or someone concerned about infection might follow similar restrictions while traveling abroad, he adds. “Heat kills bacteria and viruses,” he says, so if you’re being careful to avoid bacteria, regardless of your health status, “you might avoid fresh foods that aren’t cooked.”

Cameron Walker is a writer based in California and the author of the children's book National Monuments of the U.S.A.