I see that your question was submitted some hours ago. I am a double board certified clinical doctor and was just alerted to your question.
Welcome to just answer.
I am sorry to here about your problem.
If it is not from the mouth, then it is from the digestive track.
Esophagus, stomach or small bowel.
Or digestion in general.
Of course we do not diagnose or treat online, but my first piece of advice is to see a GI specialist.
You certainly need to be tested for H pylori, the bacterial that causes gastritis and stomach ulcers as well as duodenal ulcers.
Acid reflux can have bad breath as its only symptom and this needs to be ruled out as well.
Ironically, not enough stomach acid can do this, and this condition is often missed by doctors.
As you are gearing up to see the specialist, I would start a very powerful pro biotic, not just an over the counter typical product, but 50 billion mixed flora twice a day.
You also should rule out small bowel overgrowth, which is also often missed, and this can be done with a hydrogen breath test and exam.
If probiotics make you feel worse, small bowel overgrowth is likely and would first need a course of
rifaxamin before the probiotics will help.
The diet itself should be addressed. A mediterranean type of diet, modified to be nutrient dense and anti inflammatory.
So, I know that is a lot. Let me know if you have more information you want me to consider, or further questions.
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