Questions & Answers about Vezelrijk voedsel is erg gezond, of niet?
How exactly does the suffix -rijk change the meaning of vezel here, and is it a common pattern?
The suffix -rijk means 'rich in' or 'high in'. Added to vezel (fiber), it means 'high-fiber'. This is a very common (productive) pattern in Dutch. You can easily add it to other nouns, like suikerrijk (high-sugar), eiwitrijk (high-protein), or energierijk (high-energy).
Why is there no -e at the end of vezelrijk? Shouldn't adjectives usually get an -e before a noun?
Normally, yes. But voedsel is a neuter (het) word. When a het word is used without an article—such as here, where it functions as a general, uncountable mass noun—the adjective in front of it does not get the -e ending.
Why does the word use the singular vezel instead of the plural vezels before -rijk?
When forming compound adjectives with suffixes like -rijk, -arm (low in), or -vrij (free from), Dutch almost always uses the singular root of the noun. This is why you see vezelrijk instead of vezelsrijk, just like suikervrij instead of suikersvrij.
Is of niet the standard way to form a tag question like 'isn't it?' in Dutch?