Well, one adjustment is that it looks like any high temperature process resulting in a maillard-type reaction can elevate these. So I suppose roasted vegetables are going to have elevated levels as well. Darker crusty breads more than lighter breads, etc. Smoking and coffee are higher risk factors than food, although idk if that's accounting for rate/volume of consumption.

A (very) quick look at this says that the compounds are doing the damage, but the real problem is that some people don't metabolize them as quickly as others, and they build up. These are neurotoxic at higher concentrations and cross the blood-brain barrier, so if you aren't clearing them out then I guess you're exposing your cerebellum to more of them for a longer duration.

Studies suggest that people with ET have higher levels of these beta-carbolines in their blood than control patients, in some cases (like familial tremor) even if their diet and lifestyle doesn't look it should be risk.