Neutropenic Diet: Is It Harmful or Helpful for Reducing Infections?

The neutropenic diet is commonly recommended for people with neutropenia, a condition characterized by low levels of neutrophils, a type of white blood cell.

The diet — also known as the low-bacteria or sterile diet — limits foods that tend to carry harmful amounts of bacteria, which may increase the risk of serious illness in people with neutropenia due to their weakened immune systems.

However, there remains much controversy as to whether the neutropenic diet is truly beneficial for reducing infections and illness in people with neutropenia.

This article explains everything you need to know about the neutropenic diet and whether it’s helpful or harmful for people at risk for or with neutropenia.

What is the neutropenic diet?

The purpose of the neutropenic diet is to reduce the risk of introducing microorganisms like bacteria and fungi into the body from food that can cause infections.

The diet is intended for people with neutropenia, a condition characterized by a low number of neutrophils (1).

Neutrophils are a type of white blood cell that protects the body from infections.

While almost any infection can cause neutropenia, it’s often a side effect from the treatment of cancer with chemotherapy or radiation therapy or the treatment of rheumatoid arthritis with certain medications (2).

Although no standardized definition for the neutropenic diet exists, it generally includes well-cooked foods only and limits fresh foods that tend to carry harmful levels of microorganisms.

Foods to avoid and eat

The neutropenic diet focuses on avoiding specific foods that are more likely to expose you to microorganisms.

Foods to avoid

Restricted foods commonly include (3):

• Produce: fresh fruits, dried fruits, fresh vegetables
• Grains: undercooked or raw brewer’s yeast
• Dairy: unpasteurized milk, yogurt, aged cheeses, soft-serve ice cream
• Meats: deli meats, and raw or undercooked meats, including rare and medium-rare items
• Poultry: raw or undercooked chicken, turkey, or unpasteurized eggs
• Seafood: raw or partially cooked fish and shellfish
• Condiments and miscellaneous: raw herbs, spices, and honey, herbal and nutritional supplements, nuts that are sold open and in bulk, and roasted nuts in the shell
• Beverages: freshly squeezed juices, fountain drinks, wine, beer, and iced or cold-brew coffee or tea from restaurants or coffee shops

Foods to eat

Foods allowed on the neutropenic diet include:

• Produce: cooked, canned, and frozen fruits and vegetables
• Bread and grains: all bread, rolls, and bagels, chips, popcorn, pretzels, rice, pasta, and other cooked grains
• Dairy: pasteurized milk and dairy products like cottage cheese, sour cream, whipped cream, yogurt, and packaged cheese such as American, mozzarella, and Swiss
• Meats: canned meats and well-cooked fresh meat, including pork, beef, and lamb
• Poultry: well-cooked eggs and poultry
• Seafood: canned fish and thoroughly cooked fresh fish
• Beverages: pasteurized juices and frozen concentrates, sports drinks, hot coffee and tea, bottled water, and most tap water provided by local municipalities

Is the neutropenic diet beneficial?

While the neutropenic diet sounds helpful in theory, research has suggested that the diet is no more effective than a regular diet for reducing the risk of infection in people with neutropenia.

Several reviews of randomized controlled trials in children and adults with cancer found no benefit of the neutropenic diet compared with a regular diet for decreasing the risk of infections or improving their quality of life (4, 5, 6, 7).

In fact, one study showed that the neutropenic diet led to a higher rate of infections in patients receiving a bone marrow transplant compared with a general hospital diet (8).

Due to the restrictions of fresh fruits and vegetables, the neutropenic diet lacks fiber and key vitamins and minerals that have anti-cancer effects and other health benefits (9, 10).

Even with the inclusion of cooked fruits and vegetables, overcooking them can diminish their nutrient content, especially potassium, vitamin C, and B vitamins (11, 12).

Some studies have also reported that children have a more difficult time following the neutropenic diet compared with a regular diet (13).

Still, despite there being no evidence to support the neutropenic diet for reducing infections or improving other health outcomes in people with neutropenia, many doctors and websites of top cancer centers still recommend the diet (14, 15, 16).

Food safety tips

Ensuring food safety is the best way to prevent foodborne illness, especially for people with weakened immune systems.

This is because food can serve as a vehicle for harmful bacteria that cause illness.

As such, handling and cooking food safely is far more important for preventing foodborne illnesses than specific avoidance of healthy foods like raw fruits and vegetables.

Here are some tips for safe food handling, preparation, cooking, and storage (17):

• Wash hands in warm, soapy water for at least 20 seconds before and after handling food.
• Thoroughly rinse fresh fruits and vegetables, using a brush to scrub firm produce like melons.
• Clean the lids of canned goods before opening them.
• Use one cutting board for fresh produce and another for meats.
• Cook foods and leftovers to the right temperature — color and texture are unreliable indicators of safety.
• Use a thermometer to be sure the fridge temperature is always 40°F or below and the freezer temperature is 0°F or below.
• Thaw foods in the refrigerator, in cold water, or in the microwave — never thaw food at room temperature, such as on the countertop.
• Divide large amounts of leftovers like soup into shallow containers for quicker cooling in the refrigerator.
• Store raw meats on the bottom shelf and ready-to-eat foods like dairy products, leftovers, and prepared salads on the top and middle shelves of the refrigerator.

The bottom line

The neutropenic diet consists of foods thought to contain low levels of microorganisms to reduce the risk of infections in people with a weakened immune system, including those with neutropenia.

While well-intentioned, there is currently no evidence to support the use of the neutropenic diet for improving health outcomes or reducing the risk of infections in people with neutropenia.

Moreover, compared with a regular, unrestricted diet, the neutropenic diet may be less nutritious and difficult to follow.

Instead, the most effective way to reduce the risk of foodborne illness is by following safe food-handling guidelines.