TD queried, "If fermented food is all it takes, then why not beer?"
There are different kinds of fermentation.
Beer is made by the action of yeast, converting sugar in ethanol. Then it is usually pasteurized to kill the yeast.
REAL fermented pickles and sauerkraut and kim-chi for example, are made by the action of bacteria converting sugar to lactic acid. The LIVING bacteria contribute to your gut health.
"Quick" pickles and sauerkraut, etc. made with vinegar are not fermented and do not offer the health benefits of real unpasteurized fermented vegetables.