Childhood allergies: What can parents do to prevent them?

Dr Breanne Kunstler (BBiomedSci, BHealthSci, MPhysio, PhD).

As parents, when we think ‘solids’ we think 2 things: choking and allergy…oh and a third…copious amounts of mess.

As a mum, I want to do all that I can to prevent my 5-month old daughter, Abby, from developing any allergy, including food allergies and related diseases like asthma, eczema etc. To do this, I have been eating peanuts, fish, shellfish, tree nuts (e.g. almonds), taking probiotics daily and working hard to continue exclusively breastfeeding all because I have heard somewhere or from someone that this can help to prevent Abby from developing allergies. I also jumped at the chance to feed Abby peanut butter, egg, fish and other foods because I also heard that she should eat these as soon as she starts solids to reduce her chance of developing allergies.

Image 1: Abby loves eating solid foods, especially when she can make a mess. I made some love-heart shaped omelette with sesame oil. Allergens galore!

So, I’m going to look at what the research tells us about preventing allergy while I am up at 2am with the possums every morning expressing to “keep my boobs going” and eating peanuts.

Parents have so many questions but so few answers

Here are just some of the questions my friends have asked me or I have asked myself:

1. Isn’t breastfeeding a way to prevent my child from developing allergies?
2. Just feed babies some hydrolysed formula! Isn’t giving that to my baby meant to prevent allergies?
3. I heard that we should avoid giving any allergy inducing foods until after 12 months when my baby’s immune system is more mature, so should I avoid giving my baby certain foods?
4. Should I test peanut butter and other allergens on my baby’s skin before feeding them it to see if they react? Surely this is safer than risking their airway?

I hear you asking these questions too! So, let’s get a better understanding of allergy and its prevention by diving into the recent literature.

What is a food allergy and how is it different to an intolerance?

One is deadly, one isn’t. People with lactose intolerance might fart a lot or even poo themselves, but they’ll only die from embarrassment.

One is driven by an inappropriate and excessive response by the immune system to something that is usually benign (e.g. peanut proteins in peanut allergy), one isn’t.

That’s pretty much it (go here for more info).

Is food allergy permanent?

Some allergies might not last forever. About 50% of babies and young children with either cow’s milk, egg, wheat or soy allergy will see the allergy disappear before they are 10-years old.

Other allergies are more stubborn though. Only 20% of young children with peanut allergy, and 10% with tree nut allergy, will see the back of it by 4-years old. 

Allergies to seeds, fish and shellfish tend to remain for longer or even permanently.

Food allergy is a growing problem in Australia

Prevalence of food allergy in Australia, along with other western nations, is high and has been increasing over recent decades. Food allergy affects 10% of Australian children under 1 year-old and 8% of children under 5 years-old. Hospital admissions for anaphylaxis have increased five-fold for Australian kids 0-4 years old in the past decade! We have a serious problem on our hands here.

Common food allergens of main concern (causing 90% of food-related allergic reactions like anaphylactic shock) include cow’s milk, egg, peanut, tree nuts (e.g. brazil nuts, walnuts, cashews, almonds, hazelnuts, macadamias, pecans, pistachios…basically everything in a ‘mixed nuts’ bag), sesame, soy, fish, shellfish and wheat (Image 2). Food allergy is a serious issue affecting our kids. Other conditions such as asthma, wheeze and eczema also pose a significant problem.

Image 2: The nine main food allergy culprits (credit: National Allergy Strategy)

Naturally, as a parent I am slightly freaked out by the idea of exposing Abby to allergenic foods due to the risk of her experiencing a serious and potentially deadly reaction (Image 3). I often consider having 000 on speed dial and an EpiPen available during mealtimes. This has led me to ask whether or not I can do anything to reduce my anxiety by preventing allergies in the first place.

Image 3: Signs of anaphylaxis (credit: Essential Parent)

What does the evidence say about preventing allergy in babies and young children?

1. Introduce specific allergens early, often and orally

In past years we were told to delay introducing solids and allergens to our babies in the hope that this would prevent allergies. Well, not anymore. It’s all about early exposure now. Start introducing solid foods, including allergenic foods like peanuts, at about 6 months (but not before 4 months) while continuing to breastfeed (if you are).

Image 4: Abby is down for eating peanut butter for brekkie with her mum

Introducing solids is messy! Our babies love covering themselves with their food as they experience the different tastes and textures. We don’t need to add to this mess by choosing to smear allergenic foods on their skin in the hope that this will tell us what bubs will react to. Exposing your baby to allergens via the skin can actually increase their chance of developing an allergy. So, put it in their mouth, not on their skin.

How do you know your baby is ready for solids? Check out this site.

Despite there being a large number of potentially allergenic foods, we only have convincing evidence for peanuts (and maybe egg) when it comes to preventing allergy through exposure (e.g. eating smooth peanut butter or scrambled egg). Be sure to see your doctor before introducing these foods if your child is considered high risk for developing allergy (i.e bubs has a parent or sibling with an allergic condition like food allergy, atopic dermatitis, asthma or allergic rhinitis [hay fever]) to ensure the process is as safe as possible.

Repetition is important! It’s not enough to give your baby peanut butter once and assume they will never become allergic to peanuts if they tolerated it well. It’s important to continue giving bubs allergenic foods regularly (e.g. weekly) to keep reminding the immune system that the food is not a threat. So, get creative! I have mixed smooth peanut butter in rice cereal, spread it on toast and crumpets, and made peanut butter omelettes (literally 3 ingredients: egg [two birds with one stone!], banana and peanut butter. Cook in oven until firm. I got my inspiration from this recipe). Get creative in the kitchen mum and dad! You might even create something that you like to eat too.

Some pregnant and breastfeeding women avoid consuming allergens themselves, assuming that this will help to prevent their child developing allergies. There is no evidence for this, so stop restricting! I’m doing the opposite and eating all the allergens I can get my hands on. However, there’s nothing really in the literature to say that this will reduce Abby’s chance of developing allergies. I’m going to continue to do it anyway because I also can’t find any strong evidence to say that it won’t help or that it’s harmful. I also happen to like peanuts and shellfish.

2. When in Rome (and Australia), do as the Romans do: Eat a Mediterranean diet

Eat like a traditional nonno or yiayia! I’m not talking about stuffing your face with Australian-ised Italian and Greek foods like pizza, kebabs and baklava (Image 5). I mean that we should eat like the traditional Greeks, Italians, French and Spaniards do by following a Mediterranean style of living and eating.

Image 5: We had a delicious Australian-ised Greek spread for lunch the other day. Abby was pretty excited by the chips! This is definitely not an example of following the Mediterranean eating pattern though.

Women consuming a Mediterranean diet, or eating pattern, instead of a traditional western diet (including refined carbs like white bread and processed meats like chicken nuggets) during pregnancy and breastfeeding have children with lower risk of developing several conditions like hay fever, respiratory distress syndrome at birth, asthma and wheeze. Even kids who follow the eating pattern themselves have lower risk of developing allergies in general, as well as wheezing and asthma! Let’s have a look at what this eating pattern involves.

The Mediterranean diet is identified again and again as the best eating pattern or lifestyle to maintain good health and longevity. But what actually is involved in the Mediterranean eating pattern? The Mediterranean Diet Pyramid outlines the foods that primarily make up the eating pattern (Image 6). You can see that fruits, vegetables, healthy fats (e.g. olive oil, nuts), wholegrains (e.g. grainy bread) and proteins (e.g. legumes, fish) make up most of the eating pattern, whereas red meats, dairy and discretionary foods like sweets are consumed much less often. Seafood is promoted as the primary meat to be consumed and red wine is encouraged to be enjoyed while eating and in moderation (up to 175ml a day).

You’ll also see that the pyramid includes participating in physical activity and eating with others, suggesting that adopting the eating pattern becomes more of a lifestyle than a diet.

Image 6: The Mediterranean Diet Pyramid (credit: Oldways Preservation and Exchange Trust)

But you don’t necessarily need to strictly follow the Mediterranean eating pattern to give your bub some protection from allergies. Try simply increasing mum’s and bub’s fruit, vegetable and fish consumption because that can also help to prevent allergy. Don’t like fish? Unfortunately, most of the evidence suggests that you can’t get the same effect from taking a supplement of the fatty acids found in fish instead. Again, get creative in the kitchen and find a way to enjoy your fish (and I don’t mean deep frying it in batter, although there’s nothing wrong with that occasionally. Yum!). Hint: use herbs, especially garlic!

So, I guess the main message is to live a healthy lifestyle! It’s almost like we should follow the advice we have always been given: eat a healthy, balanced diet with plenty of fresh vegetables, fruit and lean meats and consume discretionary foods (e.g. sweets, kebabs, fried fish and chips) in moderation. Oh, and go for a walk occasionally.

3. Protect your gut health

I am currently taking a daily probiotic for a couple of reasons. I heard that Abby can get the probiotics from my skin and breast milk, which can reduce her risk of developing allergies and constipation. I also have irritable bowel syndrome and I find that they help with my symptoms. But can they really reduce Abby’s chance of developing allergies?

Taking probiotics during late pregnancy and breastfeeding might reduce the chance of babies developing eczema. Also, having mum take probiotics prenatally AND exposing bub to them in early life might reduce the chance that bub will become sensitive to allergens in general. So, there might be some benefits to having probiotics in the diet of both mother and baby when it comes to preventing allergy.

It’s not just about taking probiotics but it’s also about the balance of certain bacteria in the gut. Unfortunately, you can’t just take a certain probiotic and expect that they will all have the same effect. Certain mixes of bacteria and other critters like yeasts in the gut have different health effects; the greater variety we have, the greater the chance of preventing allergies and asthma. So, having a healthy gut environment with a variety of bacteria and yeasts is important to have any hope of preventing allergies. But we don’t necessarily need to take probiotics to do this! We can support good gut health by following a healthy eating pattern full of different fruit and vegetables that can give us large amounts of different fibres that various different bacteria enjoy munching on! Possibly another benefit of following the Mediterranean eating pattern perhaps?

Image 7: various small critters live in a healthy gut (credit: Smithsonian Magazine)

4. Get some sun

Vitamin D might have a part to play in reducing the chance of babies developing allergies. Mums who have sufficient vitamin D levels prenatally and antenatally might have kids with less chance of developing recurrent wheeze, asthma and respiratory tract infections. However, the evidence is mixed on this.

How much vitamin D is ‘sufficient’, you ask? A few minutes in the sun on most days of the week usually does it.

The evidence is also mixed on whether or not taking vitamin D supplements antenatally or postnatally can reduce the chance of kids developing dermatitis, hay fever, food allergies and eczema. So, there might not be much point in mums trying to increase their vitamin D levels beyond normal recommended levels prenatally or antenatally to prevent allergies and related conditions in their children.

Vitamin D deficiency, however, can increase the chance of kids developing allergies. Mums who are vitamin D deficient have a greater chance of having children who develop eczema. Additionally, the less vitamin D kids have in their blood, the more likely they are to develop allergies to airborne particles (e.g. pollen) and hay fever.

So, it seems that there’s not much point supplementing our vitamin D intake to get as much as possible, but we should probably avoid becoming deficient. Given all the other benefits of vitamin D intake for good health (e.g. strong bones), I think we should avoid deficiency anyway.

Image 8: Take some time out and put your feet up in the sun (credit: Mother Nature Network)

5. Breastfeed as much as is possible, but not to reduce allergy risk

Breastfeeding has so many benefits for mum and bub that it should be encouraged as a first choice for infant feeding. Breastfeeding can reduce women’s chance of developing breast cancer, type 2 diabetes and osteoporosis. Breast milk is easy to digest and has fats necessary for newborn brain development. When it comes to preventing allergy, breastfeeding might reduce the chance of the child developing respiratory infections, cow’s milk allergy and asthma. But we don’t really know if breastfeeding can protect our little ones from developing other food allergies, hay fever and dermatitis.

6. Don’t bother supplementing breast milk with formula, or choosing special formulas, to prevent allergy

Some parents supplement breastfeeding with formula feeding for many reasons. One of my genius friends found that topping bubs up with formula before bedtime gets her a full night of UNINTERRUPTED sleep! So, formula supplementation can be helpful for some things, but don’t bother using it to prevent allergy.

Hydrolysed (either extensively or partially) formula includes proteins that are broken up (hydrolysed) into smaller bits than what you might find in cow’s milk or soy-based formulas. Some people think that supplementing breastfeeding with hydrolysed formula, or exclusively feeding with it, can reduce the chance of their bub developing allergies. However, there is no evidence to say that using hydrolysed formula instead of breastfeeding (just supplementing or completely replacing) will prevent allergies.

What about for babies who are exclusively formula fed? Using hydrolysed formula instead of cow’s milk formula might reduce the chance of these babies developing allergies, including cow’s milk allergy. However, the available evidence in this area is scarce and of poor quality, so don’t go running to your local Woolies to change up your formula any time soon.

7. Keep the stress levels low

Expecting mums should keep their stress levels low due to the detrimental effects it can have on themselves (e.g. increased susceptibility to post-natal depression) and their future bub (e.g. higher rates of hospitalisation for infectious diseases).

Being stressed (e.g. as a result of job strain, anxiety, depression or bereavement) prenatally or antenatally might also increase the risk of bubs developing asthma and wheeze, and possibly even eczema and dermatitis. More high-quality research is needed before we can say that maternal stress actually causes these conditions though.

In summary, what can we do to prevent allergy?

The only thing we can be sure of when it comes to preventing allergy is that there’s a lot of high-quality evidence saying that we need more high-quality evidence in this area. Seriously. We know very little right now when it comes to preventing allergies even with the explosion of research in recent years.

Despite there being so much uncertainty in the literature, there are some guidelines that we can follow to try and prevent allergies:

1. Start to introduce a variety of solid foods when bubs is ready (at about 6 months but not before 4 months), starting with iron rich foods, while continuing breastfeeding;
2. All babies (those at low and high risk of allergy) should be given allergenic solid foods including peanut butter, cooked egg, dairy (cow's milk should not form a large part of bubs' diet though, especially before 12 months) and wheat products in the first year of life; and
3. Hydrolysed (partially or extensively) infant formula is not recommended for the prevention of allergies and related diseases like asthma.

I would argue, based on the evidence that I have come across, that we can also do some other things to help prevent allergies:

1. Introduce foods orally and don’t test them on skin first;
2. Give a variety of foods regularly, covering all potential allergenic foods, as not giving regularly can result in food allergy development;
3. Monitor and address mum’s stress levels before and during pregnancy;
4. Avoid vitamin D deficiency; and
5. Enjoy a healthy lifestyle, such as the Mediterranean lifestyle, which involves eating a well-balanced diet and getting some exercise during and after pregnancy.

Interested in where I got my info?

You can view my notes here, complete with hyperlinks to sources.

Resources

Want more information on allergy prevention and management? Check out these resources:

1. Resources on allergy prevention from the Australasian Society of Clinical Immunology and Allergy
2. Parent information sheet from the Australasian Society of Clinical Immunology and Allergy: How to introduce allergy foods, which ones to introduce, how you know it’s time, choking prevention and what to do if bub has an allergic reaction
3. How to identify and act on an allergic reaction
4. Fast Facts: Australasian Society of Clinical Immunology and Allergy have a great page of bite sized, easy to read and trustworthy information on allergy and other immune diseases
5. What is an allergy? Information about identifying allergies and anaphylaxis from the Royal Children’s Hospital, Australia
6. Allergy and Anaphylaxis Australia website: Plenty of tips on living with allergies
7. Raising Children Network: Healthy eating for children (First 1000 Days)
8. Professor Dianne Campbell writes for ABC Online: Food allergies are all too common in Australia, but there are ways to help avoid them
9. Nip allergies in the bub: A great website on everything you need to know about introducing allergenic foods to your baby