Nut allergies and children - when to introduce nuts.

Summary of key points:

• Mothers who consume nuts while pregnant and while breastfeeding are associated with a reduced risk of nut allergy in the child
• Delaying the introduction of nuts after the first year of life is an ineffective method in preventing food allergy
• No evidence exists to support the intake of allergenic foods, including nuts before four months of age to prevent food allergies
• Regular peanut intake between four and 12 months of age can reduce the risk of developing peanut allergy
• Top allergenic foods include cows milk, wheat, soy, sesame, fish & shellfish, eggs, peanuts and tree nuts.

What causes nut allergies?

Since the 1980’s, and likely earlier, we’ve seen an emergence of childhood nut allergies. In some circumstances, these allergies can be life threatening. Rates as high as 10% have been reported among preschool children.

There are various theories to explain the potential reasons for this increased prevalence. These include changes in living environments, stress and lifestyle factors. There are also possible genetic and epigenetic changes at play. Recent evidence underscores the importance of the microbiome and its influence on infant immune function. Over-sanitising and nutrient-poor diets are also to be considered as potential causes of nut allergies.

The truth is, the pathogenesis of nut allergies is unclear. It is likely to be a constellation of many factors. Despite not understanding the mechanisms behind nut allergies, nuts should still be included in a healthy diet. Some of this research is outlined below.

Should I eat nuts while pregnant? 

The short answer is yes. Whether you have a family history of allergies or not, the overwhelming consensus amongst the experts is - yes, you can eat nuts while you’re pregnant. 

Maternal diets including nuts may be protective against allergy expression

Netting et al. (2014) conducted a systematic review on maternal nut consumption and health outcomes in babies. This study examined eczema, asthma and allergies and their correlation to nut consumption. There were 42 studies with approximately 40000 children included. The results suggest that maternal diets of whole foods, fruits, vegetables, fish and nuts had a lower risk associated with allergies. Processed and nutrient-devoid foods increased the risk of these conditions.

A Spanish study from 2019 analyzed the association of nut intake during pregnancy with child brain development. This study assessed 2208 mother-child pairs. Children were assessed at birth, and ages 1.5, 5 and 8. Nuts have a protective effect on brain health and improve cognitive scores, according to the research. These results were measurable over the entire 8 year span of the study.

Exposure via breast milk: the protective effects

The World Health Organisation currently recommends exclusive breastfeeding for the first 6 months and continued breastfeeding until 2 years of age. This includes during allergenic and solid food introduction. Breastmilk has incredible immunological functions. It acts as the ‘perpetual gardener’ of your babies' developing microbiome. Key vitamins, anti-inflammatory nutrients and immune cells all feature in breastmilk. Research suggests these  have a role in reducing the risk of allergic disorders. 

When to introduce nuts into my baby’s diet?

In 2016, the Australasian Society of Allergy and Clinical Immunology updated their guidelines for food allergy prevention. They recommend the introduction of solids at ‘around 6 months, but not before 4 months’ irrespective of any family history of allergies. Ideally, breastfeeding should continue throughout and beyond this age into toddlerhood. 

What’s the recommendation for introducing peanuts?

In babies with a high risk of developing peanut allergy, it’s recommended to introduce peanut products between 4 and 11 months of age. A study known as the Learning Early About Peanut Allergy (LEAP), demonstrated that the early introduction of peanuts was effective in reducing peanut allergy compared to avoiding them altogether. This study assessed 640 babies and was later followed up at five years, with a continued result at this age.

What’s the best way to introduce nuts? 

Small amounts of smooth peanut butter can be introduced, at around 6 months of age.

Things to consider:

• Try mixing a small amount (pea size) of peanut butter into your baby’s usual food (such as puree) or try peanut butter alone.
• Gradually increase the amount if your baby is not having any allergic reactions. For example ½ teaspoon the next time.
• Don't rub the food on your baby’s skin. This may increase the risk of the baby developing an allergy to that food.
• Go slowly, introduce one allergenic food or nut at a time and observe your baby.
• Continue to breastfeed or formula feed throughout.

Are nut allergies the same as intolerance?

Different parts of the immune system are involved in an allergy versus intolerance. 

The skin and airways are classically involved in a food allergy. Allergy symptoms occur rapidly, often within an hour of food consumption. This is classed as an IgE-mediated immune response. Food allergy responses can lead to anaphylaxis and requires medical attention. 

The digestive system is involved in a food intolerance and may occur over hours or days following food consumption. It is usually classed as an IgG or IgM-mediated immune response. Symptoms of food intolerance may include gas, bloating, constipation, nausea, irritability, hyer-actiity and frequent night waking, nasal congestion and eczema.

It’s important to be aware of signs of anaphylaxis in children and babies. 

These may include:

• Swelling of the lips, tongue, throat, eyes and ears

• Skin flushing

• Wheezing or breathing difficulty

• Irregular heart rate

• Pale skin, sweating

• Nausea, vomiting, diarrhoea
• Confusion, unusual tiredness, fussing or extreme crying

Seek immediate medical advice if these symptoms are present.

If your baby already has a confirmed allergic disease, it’s important to work with your health provider to find a tailored approach best suited to your situation.

Above all, always follow your mother’s intuition, it’s a real thing.