Preventing Allergies: 4 Keys To Building A Healthy Immune System

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Something interesting happens at the clinic when one of our patients has a baby – more often than you’d think, we hear about babe’s arrival (yay!) and shortly after, life changes so drastically that we don’t often hear from them again for a little while.  And for good reason!  We helped them achieve their goal of ‘healthy baby,’ and now life revolves around caring for this beautiful little human. 


Often, the next time I’ll hear from a new Mum or Dad, is when it comes time to consider introducing solid food – and how to do so properly to prevent reactions and maximize current and future health.  I thought I’d share some thoughts today on how to build a healthy immune system with the goal of preventing allergies, eczema, and other long-term chronic diseases.


One of the key windows of opportunity to set up the foundation for future long-term vitality and health is in the first few years of development.  From conception onward through childhood, the immune system of your little human is very impressionable, and rapidly developing.  As we learn more and more about the microbiome (the ecosystem of microbes that inhabit our intestinal tract) and the immune system, we realize that setting up a healthy digestive tract is key #1 to building a healthy immune defense.


Long-term health relies heavily on a robust immune system, which relies heavily on a healthy gut.  So how do we set that up?


One of my colleagues (Dr. Melina Roberts ND) has written an entire book on this subject, so if you’d like any more information on setting up your child’s immune system for success be sure to check it out.  I’ll summarize some of her ideas below to get you thinking, and refer to her literature for more.


The development of the organ systems in the human body, starting in utero, is an incredibly interesting story.  All of our organs begin to develop while in the womb, and as we grow from birth onward, each organ system reaches its full development at different times.  By keeping this system of development in mind, we can support our childrens’ development as best as possible, setting them up for success in the long-term.


For example:

-the pancreas (which releases digestive enzymes) isn’t fully functional until 24 or 25 months

-the liver reaches full maturation around 4-5 years of age

-lungs are not fully developed until age 18-20


Here are four keys to developing a healthy immune system.



Key #1: breastfeed exclusively for ideally 6 months


At birth, the digestive tract of an infant is termed ‘hyperpermeable’ or ‘leaky.’  This means that whatever they ingest easily moves through the wall of the intestinal tract and into the bloodstream.  This is important, because directly behind the wall of the intestinal tract is the developing immune system – and the process for preventing food reactions (allergies and intolerances) is not fully developed. 


Thus, whatever we feed to our children when their guts are hyperpermeable has a strong impact on the likelihood that they’ll develop allergies or eczema.  This is partly why children who breastfed have lower rates of allergies, eczema and autoimmune reactions – breastmilk is the perfect food for a developing human.  The makeup of breastmilk changes as your baby develops, adapting to his/her needs and supporting organ system development.  Further, breastmilk contains antibodies and other immune system components that protect babe from infections and help develop a robust immune system.


Key #2: be healthy while breastfeeding


It is important to remember that whatever mom is eating (or putting on her skin, for that matter) may be passed through breastmilk and turned into what baby’s eating.  There are certain foods that should certainly not be staples in the diet of a breastfeeding mom, in the best interest of her baby’s health.  Antigens of the foods she eats, if they’re hyper-allergic, can be passed through the breast milk and cause an allergic reaction. 

Some foods to limit or avoid (on recommendation from your doc) include:


            -alcohol (avoid 100%)



            -cow’s dairy


            -refined sugar




These highly allergenic foods can aggravate the delicate immune system of a growing babe.  While not all breastfeeding mothers have to avoid this list 100% (except alcohol, as it can cause fetal alcohol syndrome), they should especially be investigated if the child is experiencing rashes, wheezing, eczema, colic, digestive pain or other issues (constipation, diarrhea, vomiting), or spitting up after feedings.


Moms and Dads should also be very careful about what chemicals are being used in the home – from cleaning products, to mom’s personal care products and makeup, the immature liver of a growing babe can be easily overwhelmed by toxic products in his/her environment and breastmilk.  Using glass bottles over plastic is one such consideration.


Key #3: if formula is the only option, make your own


Some mothers don’t have the capability of breastfeeding – either due to having adopted a child, a physical concern, low breastmilk production, or baby not being able to latch properly.  While breastfeeding troubleshooting should be another whole blog post (or course!) on its own, if you’re unable to breastfeed, the next best option is a homemade formula.  I have yet to find a commercially produced formula that looks like a good idea.  Sometimes with patients, I’ll help them decide between some commercial formulas to choose the best option and then tailor it with specific supplements to make it more closely mimic breastmilk.  But by far the best option is to make your own. 

A homemade formula with a goat’s milk base is my favourite, because the casein molecules (casein is a protein in dairy) in goat’s milk are much smaller and easier to handle with an immature digestive tract than those in cow’s milk.  Dr. Roberts has an easy, 4 ingredient, homemade formula recipe in her book.  It’s an excellent start! And again, can be tailored by your ND to suit your individual babe’s needs.



Key #4: introduce solid foods at the right times


Once you’ve reached the 6 month mark of either exclusively breastfeeding or using a homemade formula, you’ve reached a crucial period of immune system development – the introduction of solid foods.  This is one of the subjects I’m asked about time and time again by new parents, because the information out there on food introduction is so contradictory.  When we look at the developmental stages, however, it gives us some guidance on what foods to give when – or how to optimally support each organ system as it develops, and not cause an aggravation of the immune system as it develops.


As Dr. Roberts says, “solid foods should be delayed as long as possible.  The more mature the infant’s digestive tract is at the time of solid food introduction, the more likely he or she will be able to tolerate the food.  The longer you can wait to introduce foods, the more time you give the digestive tract to fully develop.  This reduces the development of allergies, eczema, and chronic disease.”


New solid foods should always be introduced one at a time (every 4 days), and in small quantities in the mornings so you can watch during the day to see if a food reaction occurs.  First foods should be organic, and non-GMO, as the child’s liver will not fully function until 4-5 years of age to detoxify contaminants like pesticides.  And starting with easily digested cooked veggies, move on to sweeter fruits, and saving cereals and other highly allergenic foods until the immune system is more fully developed is the best plan.


A full food introduction plan can be found in Dr. Roberts’ book.  But here are her general recommendations:


Six months: steamed and pureed hypoallergenic vegetables

Eight months: cooked fruits

Ten months: proteins and harder to digest veggies

Twelve months: more acidic fruits and veggies, goat’s milk if weaning from breastmilk

Eighteen months: easy to digest complex carbohydrates

Twenty-four months: grains


There are other considerations to building a healthy immune system, such as environmental contaminants, hygeine practices, and timing of new foods that your ND can help you with as your healthy babe grows.  But start with the above, and you'll be ahead of the races. 




In health,



Dr. Kali MacIsaac HBSc, ND

Naturopathic Doctor