IgG antibodies at high levels combine with the protein in the food to form an ‘antigen-antibody complex’. These complexes are usually eliminated by other cells in the immune system. However, if the immune system is overloaded, these molecules can become deposited in various body parts such as the head, lung tissue, gastro-intestinal tract, skin and joints where they produce symptoms such as headaches, asthma, irritable bowel syndrome, eczema and rashes, and arthritis.