Most vinegar is filtered and pasteurized.

In the context of the relation with gastric cancer, pickling is about fermentation, not acidity. The studies suggesting a relationship are all epidemiological and suggest a weak link at best [1].

The stomach is already very acidic; much more acidic than vinegar, which makes both gastric cancer and any potential benefits unlikely.

[1] https://www.spokesman.com/stories/2017/oct/05/ask-the-doctor...