At a minimum, there's a connection between gut health and insulin resistance - which seems to lead to systemic inflammation.

Both liver and gut are involved in lipid production and disposal. For instance, providing delayed release niacinamide (a form of B3) to the gut has been shown to reduce insulin resistance in pre-diabetics. See https://www.gertitashkomd.com/blog/2018/3/5/niacin-improvesmicrobiome-and-insulin-resistance

And there's a correlation between metabolic syndrome and systemic inflammation, which is probably a result of high insulin levels, often associated with high lipid particle count and elevated cancer risk.

So even without direct gut leakage, there's already systemic inflammation.

Disclaimer: not a bio guy, just a digital native trying to make sense of things.