The acid gets mixed up with other stomach secretions so it levels out at around pH 1–3, says The Institute Of Human Anatomy.Thankfully, all that mucus we mentioned acts as a physical barrier ...

Over time, this can lead to a condition called “hourglass syndrome” – a detrimental change in the structure of the abdominal wall, which may cause a visible crease to form in the mid-abdomen.

Over time, this can lead to a condition called "hourglass syndrome" — a detrimental change in the structure of the abdominal wall, which may cause a visible crease to form in the mid-abdomen.