Mechanism of Food Intolerance

The sequence of events is as follows:

• Partially digested foods pass between gut cells into the blood
• These proteins are recognised as ‘foreign’ and food specific IgG are produced in response
•  Antigen/ antibody complexes form between the partially digested foods and the IgG antibodies. The symptoms of food  intolerance tend to be delayed because this formation of complexes is a gradual process – it does not happen immediately
• Complement and macrophages stimulate inflammation, although complement helps to prevent smaller complexes going on to form larger complexes
• Complement is activated which causes respiratory burst in neutrophils, release of proteolytic enzymes, mast cell         mediators and vasoactive peptides, and aggregation of platelets
• The complexes are deposited in tissues (could be anywhere in body such as gut, head, skin etc)
• C2 and C5 (part of the enzyme cascade) can release histamine too
• Macrophages release inflammatory mediators such as interleukin-1, tumour necrosis factor, reactive oxygen species and nitric oxide

(NB  The complement system is an enzyme cascade that helps defend against infection)