Sometimes additives have unexpected side effects.

I thought this study was particularly interesting:

Rats dosed with the dye — known as brilliant blue G — after injury showed greater improvement in motor skills than rats not receiving the dye. And assuming the food colorant’s low toxicity holds true for brilliant blue, the research suggests a new approach for treating spinal cord trauma in humans, injuries for which there are few therapies.

Source: ScienceNews.org, Brilliant Blue For The Spine, August 2009; Vol. 176 #5

According to information we've been able to find, Brilliant Blue (E133) currently has no known adverse reactions. Common uses are as a colourant in dairy products, sweets, processed peas, ice-cream, and sport drinks. It is also used in hygiene, and cosmetics applications.

The article mentions "temporary changes to eye and skin color appear to be the only side effect" in the doses used while testing laboratory rats. I can imagine marketing catchphrases like "it's great to feel blue" :).

Obviously this is still very preliminary research, but it's great to see potential for medical benefits.