Cancer patients with neutropenia or low neutrophil counts are prone to infections and are often recommended to take many precautions and follow a very restricted neutropenic diet which even omits all fresh raw vegetables, many fresh fruits, nuts, raw oats, unpasteurized fruit juices, milk and yogurt. However, different studies and meta-analyses did not find any solid evidence to support that the neutropenic diet prevents infection in cancer patients. The patients who received neutropenic diet also reported that adhering to this diet required more effort. Hence, researchers have raised concerns on recommending neutropenic diet to cancer patients, in the absence of strong evidence on benefits related to reduced infection rates.
What is Neutropenia?
Neutropenia is a health condition associated with a very low count of a type of white blood cells called neutrophils. These white blood cells protect our body from various infections. Any health condition with low white blood cells can increase the risk of infections. In people with neutropenia, a minor infection can end up being life-threatening. Hence, neutropenic patients need to take many precautions to avoid infections.
Neutropenia is mostly triggered :
- By certain chemotherapy
- By radiation therapy given to different parts of the body
- In metastatic cancers that has spread to different parts of the body
- By bone-marrow associated diseases and cancers such as leukemia, lymphoma, and multiple myeloma which can affect the white blood cells
- By other diseases such as autoimmune disorders including aplastic anemia and rheumatoid arthritis
Apart from these, those who have a lowered immune system due to an HIV infection or an organ transplant or those who are aged 70 years and above, are more prone to neutropenia.
A blood test can tell us whether our white blood cell count is low.
What is Neutropenic Diet?
Neutropenic diet is a diet used in people with a suppressed immune system who are at an increased risk of infections from microbes present in our food. The neutropenic diet was initially used in the 1970s, in a study that included diet as a way to support the quality of life of patients who had undergone stem cell transplantation.
The basic idea of a neutropenic diet is to avoid certain foods that can expose us to bacteria and other microbes, take necessary precautions and practice proper food safety and handling.
Foods to Choose and Avoid in Neutropenic Diet
There are a lot of precautions to be taken by patients with neutropenia and many dietary restrictions to be followed in a neutropenic diet. Following are the list of foods to choose and avoid in a neutropenic diet, as available in the public domain.
Foods to Avoid
- Unpasteurized milk and yogurt
- Yogurt made with live or active cultures
- Yogurt or soft ice cream from a machine
- Milkshakes made in a blender
- Soft cheeses (Brie, feta, sharp Cheddar)
- Unpasteurized and raw milk cheese
- Cheese with mould (Gorgonzola, blue cheese)
- Aged cheese
- Cheese with uncooked vegetables
- Mexican-style cheese like queso
Foods to Choose
- Pasteurized milk and yogurt
- Other pasteurized dairy products including cheese, ice cream and sour cream
Foods to Avoid
- Breads and rolls with raw nuts
- Cereals containing raw nuts
- Uncooked pasta
- Pasta salad or potato salad with raw vegetables or eggs
- Raw oats
- Raw grains
Foods to Choose
- All types of breads
- Cooked pastas
- Cooked cereals and grains
- Cooked sweet potatoes
- Cooked beans and peas
- Cooked corn
Foods to Avoid
- Raw vegetables
- Fresh Salads
- Stir-fried vegetables
- Uncooked herbs and spices
- Fresh sauerkraut
Foods to Choose
- All well-cooked frozen or fresh vegetables
- Canned vegetable juices
Foods to Avoid
- Unwashed raw fruits
- Unpasteurized fruit juices
- Dried fruits
- All fresh fruits except those listed below in the “Foods to Choose”
Foods to Choose
- Canned fruits and fruit juices
- Frozen fruits
- Pasteurized frozen juices
- Pasteurized apple juice
- Thoroughly washed and peeled thick-skinned fruits such as bananas, oranges and grapefruits
Foods to Avoid
- Raw or undercooked meat, fish and poultry
- Stir fried foods
- Deli meats
- Old soups
- Fast foods
- Miso products
- Cold meat or poultry
- Raw or Undercooked eggs with runny yolk or sunny side up
Foods to Choose
- Well cooked meats, fish and poultry
- Canned tuna or chicken
- Well heated canned and homemade soups
- Hard-cooked or boiled eggs
- Pasteurized egg substitutes
- Powdered eggs
Foods to Avoid
- Cold brewed tea
- Eggnog made with raw eggs
- Sun tea
- Homemade lemonade
- Fresh apple cider
Foods to Choose
- Instant and brewed coffee and tea
- Bottled (filtered or distilled or undergone reverse osmosis) or distilled water
- Canned or bottled drinks
- Individual cans or bottles of sodas
- Brewed herbal teas
Studies Associated with the Impact of Neutropenic Diet in Cancer Patients
After undergoing chemotherapy or radiotherapy, there is an increased risk of infection in cancer patients from microbes such as bacteria and fungus present in foods. This is because the counts of white blood cells which can fight the bacteria in food is low and also because the gut lining that normally acts as a barrier between bacteria and the bloodstream is damaged by chemotherapy and radiotherapy. Keeping this condition in mind, patients are asked to take many precautions and a special neutropenic diet with many dietary restrictions was introduced for many cancer patients with suppressed immune systems.
Neutropenic diets are often prescribed to cancer patients with the aim of reducing infections by avoiding specific foods and by the use of safe food handling and storage. However, these dietary restrictions to reduce the risk of infection need to be balanced by ensuring that the patients receive adequate nutrition, especially to handle the side-effects of treatments as well as for improving the treatment responses.
Since neutropenic cancer patients have to take many precautions and the recommended neutropenic diet is also a diet with many dietary restrictions which even omits all fresh raw vegetables, many fresh fruits, nuts, raw oats, unpasteurized fruit juices, milk and yogurt and many more, several studies have been carried out by various researchers to study whether introducing a neutropenic diet is actually beneficial in reducing the infection rates in cancer patients. Some of the recent studies and their findings are collated below. Let us have a look!
Systematic Review by the Researchers of the United States and India
Recently, the researchers from the United States and India did a systematic review to study whether there is solid scientific evidence that can support the effectiveness of the neutropenic diet in decreasing infection and mortality among cancer patients. They extracted 11 studies for analysis through literature search in MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials and Scopus databases until March 2019. The study did not find any decrease in infection rates or mortality among cancer patients who followed a neutropenic diet. (Venkataraghavan Ramamoorthy et al, Nutr Cancer., 2020)
The researchers also mentioned that while some institutions followed general food safety practices alone in a neutropenic diet, others avoided foods that increase exposure to microbes, and a third group of institutions followed both. Hence, they suggested precautions and safe food handling and preparation practices recommended by the Food and Drug Administration, to be uniformly followed for neutropenic patients.
Flinders Medical Centre Study in Australia
In a study published in 2020, the researchers from Flinders University and Flinders Medical Centre in Australia put an effort to compare the clinical outcomes of chemotherapy patients who received either a neutropenic diet or a more liberalised diet and also investigated the associations between neutropenic diet and infectious outcomes. For the study, they used data from neutropenic patients aged 18 years and above who were admitted to Flinders Medical Centre between 2013 and 2017 and had previously received chemotherapy. Out of these 79 patients received a neutropenic diet and 75 patients received a liberalised diet. (Mei Shan Heng et al, Eur J Cancer Care (Engl)., 2020)
The study found that the incidence of neutropenia with high fever, bacteraemia and number of days with high fever was still high in the group who received the neutropenic diet. A further analysis of 20 pairs of patients who were matched based on age, sex and cancer diagnosis also didn’t find any significant differences in the clinical outcomes between the patients who received a neutropenic diet and those received a liberalized diet. The researchers hence concluded that neutropenic diet may not help in preventing adverse outcomes in chemotherapy patients.
Combined Research Study by different Universities in the United States
The researchers from the Johns Hopkins University, Mayo Clinic, Massachusetts General Hospital, University of Texas Southwestern Medical Center and Texas Tech University Health Sciences Center in the United states did a meta-analysis on the rates of infections reported in 5 different trials involving 388 patients, comparing the neutropenic diet to unrestricted diets in acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), or sarcoma cancer patients with neutropenia.The trials used for the study were obtained from a comprehensive database search till September 12, 2017. (Somedeb Ball et al, Am J Clin Oncol., 2019)
The study found infection in 53.7% patients who followed a neutropenic diet and 50% patients who followed an unrestricted diet. Hence, the researchers concluded that the use of neutropenic diet may not be associated with a decreased risk of infection in neutropenic cancer patients.
Study by Mayo Clinic, Adult Bone Marrow Transplant Service in Manhattan and Missouri Baptist Medical Center – United States
In a study published in 2018, the researchers evaluated the effectiveness of neutropenic diet in decreasing infection and mortality in cancer patients with neutropenia. 6 studies obtained through database search, were used for the analysis, involving 1116 patients out of which 772 patients had previously undergone a haematopoietic cell transplant. (Mohamad Bassam Sonbol et al, BMJ Support Palliat Care. 2019)
The study found that there was no significant difference in the mortality rates or rates of major infections, bacteremia or fungemia, between those who followed a neutropenic diet and those who took a regular diet. The study also found that neutropenic diet was associated with a slightly higher risk of infections in patients who had undergone a haematopoietic cell transplant.
The researchers didn’t find any evidence to support the use of neutropenic diet in cancer patients with neutropenia. Instead of following a neutropenic diet, they suggested that cancer patients and clinicians should continue to follow the safe food-handling guidelines and take precautions, as recommended by the U.S. Food and Drug Administration.
Study of the Impact of Neutropenic Diet on Pediatric Acute Lymphoblastic Leukemia (ALL) and Sarcoma Patients
A study published by the researchers from different pediatric and oncology hospitals in the United States, compared the neutropenic infection rates in 73 pediatric cancer patients who followed Food and Drug Administration approved food safety guidelines with 77 paediatric cancer cases who followed a neutropenic diet along with Food and Drug Administration approved food safety guidelines, during one cycle of chemotherapy. The patients were mostly diagnosed with ALL or sarcoma. (Karen M Moody et al, Pediatr Blood Cancer., 2018)
The study found infection in 35% patients who followed a neutropenic diet along with Food and Drug Administration approved food safety guidelines and 33% patients who followed Food and Drug Administration approved food safety guidelines alone. The patients who received neutropenia diet also reported that adhering to the neutropenic diet required more effort.
Analysis of the Impact of Neutropenic Diet in AML-BFM 2004 Trial
Researchers from the Johann Wolfgang Goethe-University in Frankfurt, Hannover Medical School in Germany and the Hospital for Sick Children in Toronto, Canada analyzed the impact of neutropenic diet and social restrictions used as anti-infective measures in children with Acute Myeloid Leukemia. The study used information from 339 patients treated in 37 institutions. The study didn’t find any significant benefit of following dietary restrictions in the neutropenic diet in these paediatric cancer patients. (Lars Tramsen et al, J Clin Oncol., 2016)
Should Cancer Patients Follow a Neutropenic Diet?
The above studies suggest that there isn’t solid evidence to support that the neutropenic diet prevents infection in cancer patients. These restrictive diets are also associated with low patient satisfaction and may also result in malnutrition. Even though there is no proper scientific evidence that neutropenic diet reduces the risk of infections in cancer patients or improves white blood cell counts in cancer patients, it is still being recommended on many websites of top US cancer centers, as pointed out in a study published in the Nutrition and Cancer Journal in 2019 (Timothy J Brown et al, Nutr Cancer., 2019).
So far, the National Comprehensive Cancer Network (NCCN) or the Oncology Nursing Society Cancer Chemotherapy guidelines also haven’t recommended the use of neutropenic diet in cancer patients. Some studies also found that taking necessary precautions and adherence to the Safe Food-Handling guidelines issued by the Food and Drug Administration as a mandate for all hospital kitchens, may provide adequate protection against food-borne infection, thereby excluding the need for a neutropenic diet(Heather R Wolfe et al, J Hosp Med., 2018). A study also found that a strict neutropenic diet contained less fiber and vitamin C content (Juliana Elert Maia et al, Pediatr Blood Cancer., 2018). Hence, recommending cancer patients with neutropenia to follow a highly restricted neutropenic diet, with no strong evidence on reduced infection rates, may be questionable.
Cancer patients often have to deal with different chemotherapy side effects which affect their quality of life and look out for alternative therapies for cancer.Taking the right nutrition and supplements based on scientific considerations (avoiding guesswork and random selection) is the best natural remedy for cancer and treatment related side-effects.