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Nutrition and daily life

Food safety when immunity is low

When leukemia and its treatment weaken immunity, germs in food can be more dangerous than usual. That does not mean food should be frightening. This topic explains which foods carry more risk, four simple rules, the current view of the “neutropenic diet”, and when to call your doctor.

Last updated: ~5 min read
On a dark navy background, a freshly cooked meal with rising steam on a table: a bowl of soup, cooked chicken, rice and steamed vegetables in warm light.
Figure 1.Hot, freshly cooked food is the basis of safe eating when immunity is low.

01Short answer

When immunity is weak (especially when neutrophils are low), food-borne infections can be more serious. The main protection is four steps: keep hands and surfaces clean, keep raw meat, fish and eggs away from ready-to-eat food, cook food thoroughly, and refrigerate it promptly. The riskiest foods are raw or undercooked meat, poultry, fish, shellfish and eggs; unpasteurized milk, cheese and juices; raw sprouts; unwashed fruit and vegetables; and unheated deli meats. Research has not shown that a strict “neutropenic diet” reduces infections; most centres now recommend safe food handling instead. After a transplant the rules may be stricter — follow your team’s instructions.

02Simple explanation

Neutrophils are the cells that fight germs entering through the gut and mouth first. When they drop after chemotherapy, even a food germ that would not bother a healthy person can cause an infection.

Most food infections are caused by bacteria such as Salmonella, Listeria, Campylobacter and E. coli. They are found most often in raw meat, eggs, unpasteurized dairy and unwashed vegetables. Thorough cooking kills them.

The good news: simple habits cut the risk a lot — washing hands, keeping raw and cooked food apart, cooking food all the way through, and cooling leftovers quickly. This applies to the patient and to family members who cook.

Many hospitals used to apply a strict “neutropenic diet” with no raw fruit or vegetables at all. Research showed that it did not reduce infections but made eating harder. The focus is now on preparing food safely.

Each centre may have its own rules, especially after an allogeneic transplant. If you see conflicting advice, follow your own team’s recommendations.

03Scientific explanation

Riskier foods: according to the CDC, people with weakened immune systems are more vulnerable to food poisoning. Riskier foods include raw or undercooked poultry, meat, seafood and eggs; raw sprouts; unwashed produce; cut melon; unpasteurized milk, juice and soft cheese; and raw dough.

Listeria: the CDC advises people with weakened immunity to avoid unheated deli meats and sausages, refrigerated smoked fish, premade deli salads and unpasteurized dairy, and instead to reheat such foods until steaming hot (74 °C).

The neutropenic diet: a 2019 systematic review and meta-analysis (BMJ Supportive & Palliative Care) found that a strict neutropenic diet does not lower infection risk. The 2022 ASCO guideline also does not recommend a neutropenic diet to prevent infection during treatment, and the Leukemia & Lymphoma Society considers safe food handling more important.

Four steps: the WHO “Five keys to safer food” and the CDC principle “clean, separate, cook, chill” rest on the same basis: clean hands and surfaces, separating raw from ready-to-eat food, cooking at a high enough temperature, cooling promptly, and safe water and ingredients.

04What happens in the body?

Who needs this most?

People with low neutrophils after chemotherapy or targeted therapy, people having a stem cell transplant, and people on high-dose steroids. Ask your team about your neutrophil count and when you need to be most careful — often the riskiest period is 1–2 weeks after a course.

The four main steps

Clean: wash hands with soap for 20 seconds before eating and cooking, and keep surfaces clean. Separate: use a separate board and knife for raw meat, fish and eggs. Cook: cook meat, poultry, fish and eggs thoroughly. Chill: refrigerate cooked food within 2 hours; keep the fridge at 4–5 °C or colder.

On a dark navy background, four translucent scenes in a row: water droplets with soap foam, two separate cutting boards, a steaming pan, and a frosty fridge shelf.
Figure 2.Four steps: clean, separate, cook, chill.

Riskier foods

Raw or rare meat, undercooked kebabs and burgers, raw fish (sushi, lightly salted raw fish), raw or runny eggs (including eggnog and homemade mayonnaise), unpasteurized milk, homemade cheese and yogurt, soft mould-ripened cheeses, raw sprouts, unheated sausages and deli meats, unpasteurized juices. Avoid them, or eat them only when thoroughly cooked.

Safer choices

Well-cooked meat, chicken and fish, hard-boiled eggs, pasteurized milk, yogurt and hard cheese, boiled or cooked vegetables, well-washed or peeled fruit, packaged bread and grains, canned foods, and tea or stewed fruit drinks made with boiled water. Hot dishes such as pilaf, stuffed vine leaves, soups and stews are good choices.

On a dark navy background, toast, cooked lentils and a baked potato glow in warm light on the left, while dimmed raw fish and a raw egg sit behind a soft curtain of light on the right.
Figure 3.Well-cooked food is safer; risky raw and undercooked foods are best avoided.

Fruit and vegetables

Most centres now allow well-washed fresh fruit and vegetables. Wash under running water, scrub thick-skinned produce with a brush, and discard damaged or mouldy parts. Do not use soap or bleach. Wash berries and leafy greens especially carefully. After a transplant your team may set stricter rules.

Signs of food poisoning

Nausea, vomiting, diarrhea, stomach pain, fever, chills. During neutropenia a fever is an emergency — do not try to treat it at home; call your team straight away. Talk to a doctor before replacing lost fluids on your own or taking anti-diarrhea medicine.

05Safe food in four steps

Clean, separate, cook, chill.

Clean — Hands, surfaces, fruit and vegetables.1CleanHands, surfaces, fruit and vegetables.
Separate — Raw meat, fish and eggs kept apart.2SeparateRaw meat, fish and eggs kept apart.
Cook — All the way through, steaming hot.3CookAll the way through, steaming hot.
Chill — Into the fridge within 2 hours.4ChillInto the fridge within 2 hours.
Lower infection riskMost germs are destroyed.
Varied foodWithout harsh bans.
With the familyFor everyone who cooks.

06Riskier and safer choices (simplified)

Food groupRiskierSafer
Meat and poultryRare, undercooked, raw minceFully cooked, no pink inside
FishSushi, raw or lightly salted fishWell-cooked fish, canned fish
EggsRunny eggs, eggnog, homemade mayonnaiseHard-boiled eggs, pasteurized products
DairyRaw milk, homemade cheese, soft mould-ripened cheesePasteurized milk, yogurt, hard cheese
Deli foodsUnheated sausages, pâté, premade saladsReheated until steaming
Fruit and vegetablesUnwashed, damaged, raw sproutsWell washed, peeled or cooked

* The table is general information. After a transplant or with very low counts the rules may be stricter — follow your team’s advice.

07Key terms

Neutropenia
A low level of neutrophils, the cells that fight infection.
Food poisoning
Illness caused by germs or toxins in food.
Listeria
A bacterium that can grow even in the fridge; dangerous when immunity is weak.
Salmonella
A bacterium found in raw eggs and poultry.
Pasteurization
Heating milk and juices to kill germs.
Cross-contamination
Germs passing from raw food to ready-to-eat food.
Neutropenic diet
An older approach banning all raw foods; no proven benefit.
Danger zone
Roughly 5–60 °C, where bacteria multiply quickly.

08Key points

  • Food infections are more dangerous when neutrophils are low.
  • Clean, separate, cook, chill.
  • Avoid raw or undercooked meat, fish and eggs.
  • Pasteurized dairy only.
  • Wash fruit and vegetables well.
  • A strict “sterile diet” is usually not needed.
  • Rules may be stricter after a transplant.
  • Call straight away with fever or diarrhea.

09Frequently asked questions

Can I eat fresh fruit and vegetables?

Most centres allow well-washed fresh fruit and vegetables. Throw away damaged parts and avoid raw sprouts. After a transplant, or if you have special instructions, follow your team’s rules.

What is a “neutropenic diet”, and do I need one?

It is an older approach that bans all raw foods. Research has shown it does not reduce infections. Safe food handling is recommended now, although some centres still use their own rules.

Can I eat at restaurants?

When counts are very low, fresh home-cooked food is safer. At a restaurant choose freshly cooked hot dishes and avoid buffets and salad bars. A separate topic covers this in detail.

Can I have probiotic yogurt?

Commercial yogurt made from pasteurized milk is safe in most cases. Supplements with live bacteria (capsules) may carry risk for some patients — talk to your team before taking them.

I have pets — does that affect food safety?

Wash your hands after touching your pet or its bowl, and keep pets off kitchen surfaces. Do not prepare pet food where you prepare your own.

Should family members follow these rules too?

Everyone who cooks — yes. A family member with diarrhea or vomiting should not cook for you until they have recovered.

10Questions for your doctor

Take these questions to your appointment. The ones you save are collected on the “My questions” page and stay on this device only.

  1. Can I eat fresh fruit and vegetables?

  2. What is a “neutropenic diet”, and do I need one?

  3. Can I eat at restaurants?

  4. Can I have probiotic yogurt?

  5. I have pets — does that affect food safety?

  6. Should family members follow these rules too?

My questions

12Sources

  1. CDC. Safer Food Choices for People With Weakened Immune Systems
  2. CDC. Preventing Food Poisoning
  3. CDC. Preventing Listeria Infection
  4. U.S. Food and Drug Administration (FDA). Food Safety for Older Adults and People with Cancer, Diabetes, HIV/AIDS, Organ Transplants, and Autoimmune Diseases
  5. American Cancer Society. Food Safety During Cancer Treatment
  6. Memorial Sloan Kettering Cancer Center. Food Safety During Cancer Treatment
  7. Leukemia & Lymphoma Society. Diet Guidelines for Immunosuppressed Patients
  8. World Health Organization (WHO). Five keys to safer food manual
  9. World Health Organization (WHO). Food safety — fact sheet
  10. National Cancer Institute (NCI). Infection and Neutropenia during Cancer Treatment
  11. BMJ Supportive & Palliative Care, 2019. Neutropenic diets to prevent cancer infections: updated systematic review and meta-analysis
  12. Journal of Clinical Oncology, 2022. Exercise, Diet, and Weight Management During Cancer Treatment: ASCO Guideline
Medical disclaimerThis information is for educational purposes only and does not replace medical advice.
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