Healthy Eating With Primary Immunodeficiency

Primary immunodeficiency (PI) is a group of disorders in which the immune system doesn’t work as well as it should, causing infections to be more frequent, more severe, and harder to recover from. That can affect many parts of daily life, including which foods and supplements you should include in your diet and which to avoid.

The good news: For most people with PI, it’s not complicated. Healthy eating starts with the same foundation as it does for anyone else. However, some eating patterns need adjusting because of the risk of infections, digestive symptoms, poor appetite, and foodborne illness.

Benefits of Healthy Eating for Primary Immunodeficiency

While no special diet is needed for most people with PI, the ideal eating pattern is nutrient dense and provides enough protein, carbohydrates, fats, fiber, vitamins, and minerals to meet the body’s needs, says Julia Zumpano, RD, of Cleveland Clinic in Ohio.

These are the key dietary components and their roles in the body, according to Zumpano:

• Fiber, essential for fostering healthy gut microbiota, which is often compromised in people with PI
• Protein, an essential macronutrient for tissue repair
• Nutrients that support immune cell signaling, including protein, fats, and carbohydrates, as well as micronutrients such as zinc, selenium, and iron

Zumpano confirms that malnutrition is an issue for some of her clients with PI. Other concerns include poor appetite, weight loss, malnutrition, vitamin and mineral deficiencies, dehydration, and digestive symptoms such as diarrhea, constipation, nausea, gas, indigestion, cramping, and abdominal pain.

For most people with PI, a balanced diet that focuses on lean proteins, whole grains, and plenty of fruits and vegetables will check all the recommended boxes. Unless a person with a PI has another condition, like diabetes, food allergies, or a gluten sensitivity, special diets aren’t necessary.

Foods to Avoid — and Why

Because people with PI may be more vulnerable to infections, food safety is a bigger part of healthy eating. The main concern is food that may carry bacteria such as listeria or salmonella, says Zumpano.

Undercooked Meats Raw or undercooked meat, poultry, and seafood are among the higher-risk foods for people with weakened immune systems. That includes rare steak, undercooked chicken and turkey, sushi, sashimi, ceviche, and raw oysters.

“Eggs should be cooked until the yolks and whites are firm,” says Zumpano. For foods that will not be cooked to a safe temperature — such as mousse, homemade dressing, or other recipes using raw eggs — pasteurized eggs are the safer choice.

Raw Cheese and Other Dairy Products Unpasteurized milk and dairy products made from raw milk should be avoided. Soft cheeses made from unpasteurized milk — such as queso fresco, Brie, Camembert, and blue-veined cheeses — can be risky.

Fruits and Vegetables Food safety precautions apply to produce as well, says Zumpano. “Wash fruits and vegetables thoroughly under running water, and avoid precut and packaged salads,” she says.

Safe Drinking Water

Water can carry germs, especially when it comes from an unknown or untreated source.

Zumpano recommends the following practices for people with PI:

• Avoid well water unless it’s tested and found safe.
• Boil water at least one minute if you are unsure of its source.
• Choose distilled or reverse osmosis water as often as possible.

Spring water and mineral water are not guaranteed safe, she says.

Supplements

There are no specific vitamin or mineral supplements routinely recommended for everyone with PI, says Zumpano.

“But that doesn’t mean supplements are never useful: If bloodwork shows a deficiency, a doctor or dietitian may recommend a targeted supplement,” she says.

According to Zumpano, nutrients that may be considered include zinc, selenium, iron, and vitamins A, D, and C — but never take these without checking with your doctor first.

For people with PI, that language can be especially misleading. A supplement that claims to support immunity may not be helpful, and it could interfere with medications or treatments, says Zumpano.

If you’re curious about a supplement, the safest move is to bring the bottle or a photo of the full label to your next appointment so your care team can check the ingredients, dose, and possible interactions.

The Takeaway

• Most people with primary immunodeficiency do not need a special diet, but they do need a consistent healthy and balanced diet.
• Because PI can make infections harder to fight, food safety matters — especially avoiding raw or undercooked foods, unpasteurized dairy products, and water from unsafe sources.
• Supplements that claim to be “immune-boosting” are not a shortcut and may cause problems, so check with your doctor or dietitian before taking them.
• Your care team can help you decide how cautious you need to be about food choices based on your diagnosis, treatment plan, infection history, and nutrition needs.