Children’s Health is one of my favourite topics, as so much can happen in such a short time. They are like sponges!
So keep that in mind when they eat sugar, additives, flavour enhancers, or absorb chemicals from skin products and in environments of high toxic loads, as there little bodies absorb twice as much as adults (due to their size, mainly). You may know that nutrition science shows that people with chronic or undiagnosed health conditions routinely suffer with issues relating to: oxalates, salicylates, amines, histamine, glutamate, and FODMAPS, as well as poor mitochondrial function, methylation, transsulfuration, and sulfation. What does all this mean?
Basically they are food chemicals and depending on many factors such as genes, environment, nutritional status, stress will depend on how you metabolise them or in some cases- DON’T metabolise them! You can have many and varied side effects such as:
1. Bloating, wind, gastric upset
2. Constipation, loose stools
3. Anger issues , erratic behaviour
4. Depression, anxiety
5. Learning difficulties, attention issues, OCD
The lists go on!
And these food chemicals can be in many nutritious foods such as spinach, broccoli, cauliflower, bananas. So finding out which food chemicals are not great for you or your child takes time and patience and some help from a qualified practitioner. With support and guidance it can be achieved and when the Gut is absorbing and methylating properly literally I have seen MIRACLES happen (or so it seems like a miracle!) Your child will love you for it and be so much more tolerable to live with 
MINDD Qualified Practitioner/Special areas of study in Nutrition for Children.