Translation:Egg is a very important source of protein.
"very important" for the dairy companies to monetize on our dietary ignorance. Vegetables have been proven to have all the protein your body needs. Food for thought.
How do you know which noun the adjectives apply to, ie how do you tell between "Egg is a very important source of protein" and "Egg is a source of very important protein"?
In this case, "source of protein" is a noun phrase, so you apply the adverb and the adjective to the noun phrase without splitting it.
Thanks for that! Do you know how I would write it if I wanted to say "Egg is a very important source of protein"?
That is the same sentence Duo proposed. If you wanted to say: "egg is a source of protein very important" that would be the same. To clarify if "muito importante" is related to the egg, you could say: "ovo é muito importante como fonte de proteína" or "ovo, como fonte de pronteína, é muito importante"
You would write it just like that. For the other sentence you were asking about above, "Egg is a source of very important protein", you would need to quantify the word "protein" to indicate whether it's a source of one very important protein or many. So you could write "Egg is a source of a very important protein" or "Egg is a source of very important proteins".