Is Guinness good for your health?

It doesn't really work that way.

It's all down to the amounts, and what you're comparing it to.

Beers do contain some important nutrients, which are "healthy" - but it also contains alcohol, which isn't. And those healthy nutrients are easily available in other foodstuffs, often together with even more healthy nutrients.

So, you're very unlikely to gain any health by drinking Guinness, but you're also unlikely to lose any health by having the occasional Guinness.

Have them too often though, and the detrimental effect of the alcohol will quickly become overwhelming.