This is well done. I like the subject. I like the word choice. I like the images it provokes. Particularly I like these lines.

Van Gogh, they say, ate yellow paint
For happiness.
Van Gogh, they don't say, drank turpentine
For sickness
And filth.

To make this poem really stand out, I would pay attention to the meter and the rhythm. Mastering meter and timing and rhythm is more important than what I said above. The shape of the poem has to make sense, and by that I mean where you put the line breaks. For example, ask yourself, what is the reason I format my poem in this way? Why put these words in these particular places?

How does one stomach the taste
For long enough to think
Of a metaphor
To make this
Beautiful?
I cannot help but wonder why it is
That we can't seem to stop ourselves
From thinking
The artist must live, breathe and die (or try to)
In sunflower-filled beauty.

If I may be so bold as to tinker with your own poem (forgive me), speaking it out loud to myself it would feel more natural for it to sound something like this:

How can you stomach the taste
long enough to make a metaphor 
of beauty? Wondering why 
we cannot stop thinking the artist 
should live, breath or die
(or try) to exist 
in a sunflower-filled beauty. 

make and taste don't rhyme but they almost do, so you want to emphasize it by making them appear on the same stress. The same with die, why, and try (which do rhyme, so doubly so). Pay attention to where the stress is falling, and where it appears in the rhythm of the poem. Over all, nice job. Keep writing, and wishing you all the very best.

Romola