Food allergies in pregnancy and childhood: how to approach eating safely

When the word allergy shows up next to food, it's easy to start looking at every plate with suspicion.

Can I have dairy during pregnancy? What about peanuts? Eggs? If I avoid certain foods, will my baby be less likely to develop an allergy? And when it's time to start solids, how do I offer these foods safely?

These are very common questions — and there's an important point to start with:

there is no list of allergenic foods that every pregnant or breastfeeding woman needs to cut out of her diet as a precaution.

Food restrictions should have a concrete reason and, when they involve allergies, they need individualized guidance so that both mother and child keep getting the nutrients they need.

What is a food allergy?

A food allergy happens when the immune system reacts to a certain food, or a component of it, as if it were a threat.

This is different from simply feeling uncomfortable after eating something.

ANVISA (Brazil's health regulatory agency) defines food allergy as an adverse reaction caused by a specific immune response after eating a certain food. Symptoms may involve the skin, digestive system, respiratory system or cardiovascular system and can vary widely in intensity.

Any food can cause a reaction in a sensitive person, but some appear more often among allergy cases.

These include:

• milk;
• eggs;
• peanuts;
• soy;
• wheat;
• fish;
• shellfish;
• tree nuts and other nuts.

Brazil's Ministry of Health also recognizes these foods as among the main ones involved in food allergies.

This does not mean, however, that they are "bad" foods or that they should be preventively removed from every family's diet.

Are food allergy and intolerance the same thing?

No.

This confusion is very common.

In a food allergy, the immune system is involved.

A food intolerance, on the other hand, is usually related to the body's difficulty digesting or metabolizing a certain component of the food and does not occur through the same immune mechanism.

The Ministry of Health uses precisely this difference to separate allergies from intolerances in its guidance on infant feeding.

A well-known example is lactose.

Being lactose intolerant and being allergic to cow's milk protein are different situations — and the dietary care may also be different.

That's why it's not a good idea to cut out entire food groups based only on symptoms noticed at home.

Do I need to avoid allergenic foods during pregnancy?

In general, no.

Brazil's Ministry of Health states that restricting the mother's diet during pregnancy is not recommended as a strategy to prevent food allergies in the child.

So there's no need to cut out milk, eggs, fish, peanuts or other potentially allergenic foods just because you're pregnant.

Things are different, of course, when the pregnant woman herself has a diagnosed allergy.

In that case, the food that causes the reaction must still be avoided, following the guidance of the team caring for you during pregnancy.

And here another important point comes in: removing a food can also mean removing a significant source of protein, calcium, vitamins or other nutrients.

That's why, depending on the restriction, your obstetrician and a nutritionist can help you find suitable substitutes.

What if I already have a food allergy?

If you have a known allergy, pregnancy is not the time to "try just a little to see if it's gone".

Keep following medical advice to avoid the food that causes the reaction and let your prenatal care team know about the allergy.

It's also worth paying extra attention to labels.

In Brazil, ANVISA requires packaged foods to carry specific warnings when they contain or may contain certain allergens.

**ALLERGY WARNING: MAY CONTAIN PEANUTS**

The phrase "may contain" can appear when there's a possibility of cross-contamination during production.

For someone with a diagnosed allergy, this information isn't a minor label detail. It's an important part of food safety.

Does cutting foods while breastfeeding prevent allergies?

There is also no recommendation for all breastfeeding women to follow restrictive diets to try to prevent allergies in their children.

Brazil's Dietary Guidelines for Brazilian Children Under 2 Years Old ("Guia Alimentar para Crianças Brasileiras Menores de 2 Anos") advise that, as a general practice, foods should not be removed from a woman's diet during breastfeeding without a specific reason.

So there's no need to give up milk, eggs, chocolate, beans and half the kitchen because someone said it "will give the baby an allergy or colic".

If there are symptoms that raise suspicion of an allergy, the situation needs to be investigated.

Can an exclusively breastfed baby have a food allergy?

Yes.

Some proteins from the mother's diet can reach the baby through breast milk.

The Ministry of Health's Dietary Guidelines explain that this can happen and mention signs such as blood in the stool, reflux and irritability among symptoms that deserve medical evaluation.

But note: these symptoms do not automatically mean a food allergy.

Reflux, crying and intestinal discomfort, for example, can also happen for many other reasons during the first months of life.

That's why starting an elimination diet on your own can end up creating a nutritional problem without resolving the cause of the symptoms.

If the baby has an allergy, do I need to stop breastfeeding?

Not necessarily — and, in many cases, no.

Brazil's Ministry of Health advises that, when a food allergy is confirmed in a breastfed child, breastfeeding can continue.

Depending on the food involved and the medical evaluation, it may be necessary to remove that food from the mother's diet.

This elimination needs to be well planned.

If milk and dairy products need to be removed, for example, it's important to work out how the nutrients that came from these foods will be obtained from other sources.

That's very different from simply opening the fridge and declaring:

When can potentially allergenic foods be introduced into the baby's diet?

Complementary feeding is recommended from 6 months of age, alongside continued breastfeeding.

And potentially allergenic foods generally don't need to wait until the child turns one or two.

Brazil's Ministry of Health states that foods such as eggs and fish can be offered from 6 months, like other complementary foods. Nuts, such as peanuts and tree nuts, can also be part of the diet, as long as they are offered in a form that is safe for the child's age, such as ground or finely chopped.

The old strategy of delaying the introduction of these foods for a long time to try to prevent allergies is no longer the general guidance adopted by Brazil's Dietary Guidelines.

But how do I offer peanuts and nuts without a choking risk?

There are two different issues here: allergy and choking.

A child may have no allergy to peanuts at all and still be at risk of choking on a whole peanut.

That's why hard, small foods need to be offered in a texture that matches the child's abilities.

The Dietary Guidelines recommend that peanuts, tree nuts and walnuts be offered ground or finely chopped, according to the stage of feeding development.

A suitable nut butter can also be an option depending on its consistency and the child's diet, but the format must be safe and appropriate for the child's age.

My child has a family history of allergy. Should I do anything differently?

A family history of allergies is worth discussing during pediatric checkups, especially when there's a significant history of allergic diseases.

This doesn't automatically mean the child will have a food allergy or that all potentially allergenic foods should be delayed.

Brazil's Ministry of Health advises that children at higher risk or with a family history be followed closely and that the introduction of foods can be organized gradually and individually.

The pediatrician or a pediatric nutritionist can guide the best strategy for that child.

What symptoms can appear with a food allergy?

The signs vary a lot.

Symptoms may affect the skin, the digestive system or the airways, or even cause cardiovascular changes.

Signs described by health authorities include:

• hives;
• itching;
• swelling of the lips or tongue;
• nausea;
• vomiting;
• abdominal pain;
• diarrhea;
• cough;
• wheezing;
• difficulty breathing;
• dizziness.

Not every reaction happens immediately, and not every allergy produces exactly the same symptoms.

That's why a diagnosis shouldn't be made just by comparing symptoms with a list on the internet.

When is an allergic reaction an emergency?

Some food allergies can cause anaphylaxis, a severe reaction that needs immediate care.

Warning signs include:

• difficulty breathing;
• severe wheezing;
• significant swelling of the tongue or throat;
• a feeling that the throat is closing;
• severe dizziness;
• fainting;
• a significant drop in blood pressure;
• symptoms quickly appearing together in different parts of the body.

The Ministry of Health's Virtual Health Library highlights that anaphylaxis can progress quickly and that immediate evaluation and treatment are essential.

In this situation, don't wait to see whether the symptoms will improve on their own. Seek emergency care.

I suspect an allergy. Should I remove the food?

If there was a significant reaction right after a certain food, it may be necessary to stop further exposure until you receive medical guidance.

What is not recommended is starting one elimination diet after another on your own because of vague symptoms.

"now there was reflux, so I'll cut out eggs and wheat too."

Before you know it, the child or the mother is on an extremely restricted diet without a clear diagnosis.

Brazil's Ministry of Health warns of the risk of nutritional deficits in children with allergies or intolerances and advises professional follow-up to properly replace any food that needs to be excluded.

How is a food allergy diagnosed?

There's no single test that can answer every situation on its own.

The investigation may involve:

• a detailed medical history;
• the relationship between the food and the symptoms;
• a physical exam;
• specific tests when indicated;
• elimination and reintroduction strategies guided by a professional;
• food challenge tests in appropriate situations and under specialist supervision.

That's why isolated test results shouldn't be used to build huge lists of "forbidden" foods without clinical interpretation.

If a food allergy is suspected in your child, talk to the pediatrician. Depending on the case, follow-up with an allergist and a nutritionist may be needed.

Learning to read labels becomes part of the routine

When there's a confirmed allergy, reading labels is no longer optional.

Besides looking for the name of the food, watch for specific allergen warnings.

Brazilian regulations require information on ingredients and allergens precisely to help people with food allergies make safer choices.

Even products that apparently wouldn't contain a certain ingredient may carry a "may contain" warning when there's a possibility of cross-contamination.

It's also worth getting into the habit of rereading the packaging of products you already know, because formulas can change.

Safe eating doesn't have to become fearful eating

The idea isn't to see milk, eggs, wheat, fish or peanuts as enemies.

For most people, they can be a normal part of a varied diet.

In pregnancy, there's no general recommendation to eliminate allergenic foods just to try to prevent allergies in the baby. During breastfeeding, starting restrictive diets as a preventive measure is not recommended either. And when starting solids, potentially allergenic foods can be part of the diet from the appropriate time and in a safe consistency.

When there's a true allergy, that's when the care changes.

The goal becomes avoiding the food that causes the reaction without letting the restriction compromise the quality of the diet.

And that's exactly why diagnosis and follow-up make such a difference.

Not every red patch is an allergy.

Not every discomfort is an intolerance.

In summary

During pregnancy: don't remove allergenic foods as a precaution without professional advice.

During breastfeeding: elimination diets are not routinely recommended either. If an allergy is confirmed in the baby, breastfeeding can usually continue and the mother's diet can be adjusted with guidance.

When starting solids: potentially allergenic foods can be offered from 6 months, in an age-appropriate way and without indiscriminately delaying their introduction.

If an allergy is suspected: seek an evaluation before starting major dietary restrictions.

If there is difficulty breathing, significant swelling of the tongue or throat, fainting or other signs of a severe reaction: seek emergency care immediately.

Sources consulted

• Brazil's Ministry of Health — Dietary Guidelines for Brazilian Children Under 2 Years Old ("Guia Alimentar para Crianças Brasileiras Menores de 2 Anos").
• Brazil's Ministry of Health — Foundations for the guidelines and recommendations of the Dietary Guidelines for Brazilian Children Under 2 Years Old.
• Brazil's Ministry of Health — Child Health: breastfeeding and complementary feeding.
• Brazil's Ministry of Health — Healthy eating in early childhood.
• ANVISA — Clarifications on food allergies and other adverse reactions to food.
• ANVISA — Labeling of allergenic foods.
• Virtual Health Library / Brazil's Ministry of Health — Anaphylaxis and food allergy.

Informational and educational content. Elimination diets during pregnancy, breastfeeding or childhood should be followed with professional guidance when indicated. Reactions involving difficulty breathing, swelling of the tongue or throat, severe dizziness or fainting need immediate care.