Food protein intolerance in children

Overview

Food protein intolerance is a condition where a child's body has trouble digesting or reacting to certain proteins in food. It is different from a food allergy, which involves the immune system in a more immediate and severe way. With intolerance, symptoms are usually delayed and affect the digestive system.

Yes, it is fairly common in infants. Cow's milk protein intolerance affects about 2 to 5 percent of babies. It is less common in older children and adults.

Food protein intolerance typically affects infants and young children, often starting in the first few months of life. It can also occur in older children, but it becomes less common as the child grows. It is slightly more common in children with a family history of allergies or intolerances.

Symptoms

Common symptoms

• Stomach pain or cramps
• Vomiting or spitting up more than usual
• Diarrhoea, sometimes with blood or mucus
• Fussiness, crying, or refusing to feed
• Poor weight gain or weight loss
• Eczema or skin rashes

Symptoms in children

• Irritability and trouble sleeping
• Reflux (bringing up stomach contents) that doesn't improve with usual care
• Blood in the stool (often seen as red flecks)
• Swelling of the lips, tongue, or face (though this is more common with allergies)

Symptoms in older adults

• Food protein intolerance is rare in older adults. If it does appear, symptoms may include ongoing bloating, stomach discomfort, or diarrhoea after eating trigger foods like dairy or eggs.

Causes

Main causes

• The immune system overreacts to certain proteins in food, most often cow's milk protein, but also soy, eggs, wheat, or other foods.
• The reaction is delayed, unlike a food allergy which happens quickly, and it mainly affects the digestive system.

Risk factors

• Family history of allergies, asthma, eczema, or food intolerances
• Being introduced to cow's milk formula before 6 months of age
• Having a weak or immature digestive system, more common in premature babies

When to see a doctor

See a doctor urgently if:

• If your child has any of the emergency symptoms listed above, call your local emergency number or go to the nearest emergency department right away.
• If your child has blood in their stool, even a small amount, see a doctor urgently.

Book a routine appointment if:

• If your baby is fussy after feeding, has chronic diarrhoea, or is not gaining weight as expected, make an appointment with your doctor.
• If you suspect a specific food is causing symptoms, discuss it with your doctor before cutting that food out completely.

Diagnosis

There is no single test for food protein intolerance. Diagnosis is usually made by taking a detailed history of symptoms and diet, then removing the suspected food (elimination diet) to see if symptoms improve. If they do, and then come back when the food is given again (food challenge), the diagnosis is confirmed.

Tests that may be done

• Skin prick test or blood test to rule out a food allergy, but these are not diagnostic for intolerance.
• Stool test to check for blood or inflammation.
• An elimination diet followed by a supervised food challenge. This is the most reliable way to diagnose.

What to expect at your appointment

Your doctor will ask about feeding and symptoms and may suggest removing cow's milk or other triggers from your child's diet for 2 to 4 weeks. If symptoms improve, the food may be slowly reintroduced under medical guidance. This process can take several weeks, but it provides clear answers. A dietitian can help make sure your child still gets all the nutrients they need during the elimination phase.

Treatment

The main treatment is to avoid the specific food protein causing the intolerance. In infants, this often means switching to a special hypoallergenic formula that the body can tolerate. Breastfeeding mothers may need to cut the trigger food from their own diet. Most children outgrow the intolerance, so periodic rechecks are done to see if the food can be tolerated again.

Self-care at home

• Read food labels carefully to avoid hidden sources of the trigger protein.
• Keep a symptom diary to track which foods cause problems.
• Work with a dietitian to ensure your child's diet is balanced and meeting growth needs.
• For babies, consider exclusive breastfeeding for the first 6 months if possible, as this may lower the risk.

Medical treatments

Medical treatment focuses on dietary management. For infants with cow's milk protein intolerance, doctors may recommend an extensively hydrolysed formula (where the milk proteins are broken down into very small pieces) or an amino acid-based formula (which contains no whole proteins). These formulas are available on prescription. For older children, avoidance of the trigger food is the main approach. No medications are used specifically to treat the intolerance, but medicines may be given for related problems like reflux or eczema if needed. Always follow the doctor's guidance on formula selection.

When is surgery considered?

Surgery is not needed for food protein intolerance.

Living with this condition

Living with food protein intolerance means being careful about what your child eats, but it is very manageable. With help from your doctor and dietitian, you can plan meals that are safe and nutritious. Many families find that symptoms improve quickly once the trigger food is removed, and children can eat normally as they grow.

Lifestyle tips

• Learn to read food labels for hidden sources of trigger proteins (like 'casein' or 'whey' in milk).
• When eating out, ask about ingredients and choose simple dishes.
• Carry safe snacks for your child when you are away from home.
• Connect with other families who are managing food intolerances for tips and support.

Diet and exercise

Your child's diet should be balanced with fruits, vegetables, whole grains, and healthy fats, while avoiding the trigger food. A paediatric dietitian can help you find alternatives to ensure enough protein, calcium, and vitamins. For infants, the special formula provides complete nutrition. Exercise is not affected, and your child should be encouraged to be active as normal.

Mental health and emotional wellbeing

Caring for a child with a food intolerance can be stressful. You may feel anxious about feeding, especially early on. It is important to talk to your doctor about these feelings. Remember that the condition is temporary for most children, and you are not alone. If you are feeling overwhelmed, reach out to a mental health professional or a support group.

Prevention

It is not always possible to prevent food protein intolerance, but some studies suggest that exclusive breastfeeding for the first 6 months may lower the risk. There is no strong evidence that avoiding certain foods during pregnancy or while breastfeeding prevents the condition. If your family has a history of allergies, talk to your doctor about what may be best for your baby.

Complications

If left untreated

• Poor growth or failure to thrive from not absorbing enough nutrients
• Anaemia (low iron levels) if the intolerance causes blood loss in the stool
• Persistent diarrhoea leading to dehydration
• Reflux or other digestive problems that can be uncomfortable and affect sleep and feeding

Long-term outlook

The outlook for children with food protein intolerance is excellent. Most children outgrow the condition by age 3 to 5, sometimes earlier. With proper dietary management, children grow and develop normally. Even if the intolerance lasts longer, it is very treatable with the right support. You and your healthcare team can help your child live a healthy, happy life.

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