Hi Ron, I hope this note finds you well and entering a happy and healthy holiday season. I was reviewing ACA CG1 course -stomach function and physiology in particular- and have a question regarding histamine and HCl production. 

1) If someone is told they have low HCl in their stomach, could it be explained by a long history of antihistamine use, due to allergy symptoms.

2) Do antihistamines affect histamine levels in stomach?   

This same person  also has  a history of Melatonin intake ( sometimes unto 5 days per week) as a sleep aid. You mentioned that melatonin can inhibit proton pump function. 

3) Is it fair to suspect a cumulative effect of HCl suppression under these circumstances?     

The person in question also has been found to have low level H Pylori in stool sample. Does H Pylori affect stomach acid production?   Thank you in advance for any clarification on this.   

4) PS. I just started working on the stomach mobility to stimulate parietal cell activity in the hope of encouraging stomach acid production and wondering if it might be helpful to find alternatives to antihistamine and melatonin?   

Warmest regards, Domenic Lopez, LMT VM1-5, LT1 ACA-CG1 virtual only and CG2 virtual only