If you ask pediatricians who were in practice 20 years ago, they often say constipation was extremely rare back then. Now it is a very common complaint expressed by parents. So why did this become such a huge problem? I suspect it is related to the change in food variety and quality children eat now compared to then as well as a change in their intestinal microbiome.
Bacteria and even yeast are normally found (colonized) in the intestines. Our intestines start to become colonized immediately after birth, with different types of bacteria depending on whether we are born by vaginal delivery or cesarean section, breast-fed or formula-fed. As we eat food, suck on fingers and toes, and bring objects to our mouth, additional microbes are introduced. The types of bacteria in our intestines also change normally as we age.
When the healthy bacteria/yeast are present in sufficient amounts and unhealthy ones are either non-existent or in very low amounts, the intestines perform optimally. This is a healthy microbiome. Changes to this delicate balance (or homeostasis) are associated with certain conditions such as constipation, irritable bowel syndrome (IBS), chronic diarrhea, and irritable bowel diseases such as crohn disease and ulcerative collitis. They are associated with diseases outside the GI tract and especially chronic inflammation conditions such as fibromyalgia, multiple sclerosis, and rheumatoid arthritis.
Many people believe constipation is not possible a child has a bowel movement daily or every other day. This is just not true. When discussing this with parents, I like to have them envision a roll of quarters turned vertical, one end pointed towards the floor and the other up at the sky. If additional quarters are added to the top, and quarters fall out below, there is still a rolled paper that is full of quarters. Other factors I consider is the consistency and amount of stool in each bowel movement. Large, formed stools that clog the toilet are almost certainly constipation.