Stella Barbone linked to The A2 milk case: a critical review.
This was refuted by A critique of Truswell's A2 milk review.
That referenced Autism and schizophrenia: Intestinal disorders , Can the pathophysiology of autism be explained by the nature of discovered urine peptides? , Enzymatic release of neocasomorphin and beta-casomorphin from bovine beta-casein. & Opioid activities of human b-casomorphin.
Babies have naturally-high gut permeability, so wrong milk proteins may cause damage. Human breast milk contains only A2 casein.
In older humans, gut permeability is modulated by several factors.
1. Insufficient sun exposure, causing hypovitaminosis D. See http://www.ncbi.nlm.nih.gov/pubmed/?term=%22Vitamin+D%22[All+Fields]+AND+%22tight%20junction%22+AND+hasabstract[text]
2. Excessive consumption of oils high in polyunsaturated fatty acids. See Dietary Fat Can Modulate Intestinal Tight Junction Integrity.
3. Excessive consumption of Wheat. See http://www.ncbi.nlm.nih.gov/pubmed/?term=%22Wheat%22[All+Fields]+AND+%22tight+junction%22+AND+hasabstract[text]
4. Excessive exercise. See Shedding Some Light on the Leaky Gut <> Exercise Connection. Plus: 20+ Things You Should or Shouldn't Do to Protect and Restore the Integrity of Your Intestinal Wall.
5. Lack of dietary Sulphur. See Sulphation and Autism: What are the links? A good source of sulphate is Epsom Salts.
See also Physiology and Immunology of Digestion.
Continued on Wheat, Constipation, Ischaemic Heart Disease, Type 1 Diabetes, Schizophrenia and Autism.