Gluten and casein are famous for being addictive because they form opiod-like substances. Stomach acid is necessary to prevent them from becoming opiods.
Histamine helps trigger the release of stomach acid. Histamine is found in several foods, especially ferments, so pile on another reason to eat ferments with every meal. Adequate zinc is also necessary to produce stomach acid (remember what's not absorbed well without it?).
Source: HealThyself