I had a poor diet (junk food), drank crap beer (tavern keg) and worried about an ulcer. A visit to the doctor confirmed the latter. The ulcer cure then was "the diet": steamed fish, rice pudding and ovaltine biscuits. No beer. "But," I said to my doctor "I need my beer". His reply was, "If you can get ordinary bitter, or preferably mild, from the old-fashioned handpump, the odd pint drunk slowly, shouldn't do you too much harm". "Why?", says I.
"Well, these new keg beers are carbonated; too much fizz will upset you. They are chilled; too cold will upset you. Carbon dioxide and water make carbonic acid and that will upset you".
So my quest was on. In Bristol, mild was out of the question, but fortunately I did not have to look far for bitter. My local, 10 yards away, had Courage ordinary (3%) on handpump. I discovered, and joined CAMRA in 1973, and ever since have drunk and enjoyed mild and light bitters. Occasionally, I treat myself to something stronger, but tend to fall over. But guess what? No more ulcers. A gammy leg, poor sight, a bit deaf but no more ulcers.
So the message is: real ale in moderation definitely is good for you.