Martin noticed the Brain-gut connection in the little girl in The Magic Pill. Her chronic constipation reversed after being on the Diet for a few weeks. It was in the long list of her symptoms and then the improvements, but definitely not a focus for the parents. Although odd, the older sister has celiac and you would think the household wouldn’t have grain products, but that was the foundation for the younger one's diet. Perfect gut health wasn’t a goal, but the change in foods quickly changed digestion for a few of the subjects. No reflux, stomach aches, normal bowel habits, standard signs of a digestion in working order....there was no testing the microbiome or taking any supplements, not even yogurt since no dairy.