When it comes to building a strong and healthy immune system, the first three years of life are critical.
And so, as parents, we begin the long and arduous journey that is protecting our kids as they begin to traipse through the bumps and bruises of daily life.
But are we approaching this in the right way?
Our dirt is not the same as the dirt we had one hundred years ago.
As Professor Mimi Tang, an allergist and immunologist at the Royal Children's Hospital in Melbourne explains, the conversation must move beyond dirt rolling and incessant cleaning.
Early immune development
The human immune system is inseparably bonded to the development of our 'microbiota'.
"The microbiota refers to the micro organisms that live together with us. We have trillions of different bacteria in our gut and these are our greatest burden," Professor Tang told the Huffington Post Australia.
"There are ten times more bacteria than there are human cells in the body, so we depend on them as much as they depend on us to be healthy."
So, why are those first three years critical?
The microbiota in the intestine plays a very critical role in determining healthy immune responses. Disruption of this in early life can lead to long-lasting risks later.
"If you have optimal microbial exposure, you will develop a healthy microbiota which has been shown to interact with the immune system and support healthy immune responses in later life."
And disruption of this can have significant implications down the track.
"We call this disruption 'dysbiosis' and it has been associated with an increased risk of all the chronic illnesses associated with modern society -- from allergy problems to auto-immune disorders and metabolic conditions," Professor Tang said.
"What goes on in those first one thousand days can really determine your long-term risk to all of these illnesses. And once your microbiota is established, it is difficult to shift."
Developing a health microbiota
Since the days of traditional farming societies that engaged in a subsistent life, this part of the conversation has evolved as our microbial exposure, too, has shifted.
At the end of the day, it is likely that other things have changed in our lives. It is not just a matter of over protectiveness.
"Our dirt is not the same dirt as we had one hundred years ago," Professor Tang said.
"Just saying 'allow your children to roll around in the dirt' may not actually revert back to or give them the optimal environment that they need," Professor Tang said.
"At the end of the day, it is likely that other things have changed in our lives. It is not just a matter of over protectiveness."
1. Avoid long-term antibiotics
When it comes to administering antibacterials or antibiotics -- those antimicrobial drugs that are used in the treatment and prevention of bacterial infections -- Professor Tang recommends veering on the side of less is more.
"We know that products will kill bacteria and taking an oral antibiotic is going to alter your intestinal microbiota," Professor Tang said.
But she said incessant antibiotic use can be an issue -- particularly in early life.
"Taking stable courses of antibiotics is insignificant, but if you have repeated insults -- or rounds of antibiotics over an extended period -- that can lead to a degraded microbiota."
2. Promote a healthy diet
For a healthy microbiota to survive, we need soluble fibres that support the growth of good bacteria in our gut.
And so again, we return to the subsistent, grain-heavy diets that once were.
We need to let the children roll but also we need to give them a healthy diet.
"Farming societies that lived in a traditional way -- with a more subsistent diet -- had a much healthier microbiota than those associated with western diets," Professor Tang said.
"Our diets today are pure vegetable and fruit-heavy, and are not supporting a healthy intestinal microbiata."
Professor Tang recommends plenty of grains, less meat and saturated fats as well as a sufficient dose of prebiotics.
"These contain those soluble fibres that are not digested by humans and promote the growth of microorganisms in the intestines.
"They have been associated with a healthier microbiota and, by extension, a healthy immune response."
3. Maximise your child's chances of 'optimal microbial exposure'.
As we mentioned, it's not all about dirt rolling.
According to Professor Tang, other determinants include a mother's microbiota, her mode of delivery, feeding choice and the diet her child is weened on to.
Indirect evidence also points to having pets in the home as being tied to a lower risk of developing these chronic disorders -- and is certainly food for thought.
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