German nutritional expert Uwe Knop said the smell of fermentation from the mouth indicates lactose intolerance (milk sugar).
He explained that the lack of the enzyme lactase leads to the lactose reaching the stomach without being digested and exposed to fermentation due to intestinal bacteria. During this process, gases arise that lead to the emission of fermenting odor from the mouth, in addition to the unpleasant smell of feces.
A doctor should be consulted to check for lactose intolerance through a breath test. In the event of verification of the infection, the patient should resort to foods without lactose, which are now widely available in the market.
Symptoms of lactose intolerance also include bloating, nausea, severe stomach cramps and diarrhea, especially after eating dairy products, knowing that lactose is hidden in other foods such as baked goods and ice cream.