What is that?
I found it in the ingredients list for Ramen Noodles (which is debatable as a valid food item, anyway!).
TBHQ is a preservative for oils. Wikipedia (http://en.wikipedia.org/wiki/Tert-Butylhydroquinone) says that it is used to prevent evaporation in perfume and is found in varnishes, laquers, and resins, too.
It also potentially causes cancer: "In high doses, it has some negative health effects on lab animals, such as precursors to stomach tumors and damage to DNA. A number of studies have shown that prolonged exposure to TBHQ may induce carcinogenity."
In really really large doses (like if you could stand to eat over 1500 chicken nuggets in one sitting). it's deadly.
TBHQ is widely used (http://www.shreeadditives.com/htmlsite/5e.htm).
"There has been some anecdotal evidence that TBHQ can cause anxiety, restlessness, and aggravation of ADHD symptoms, although there have been no clinical studies that show any link between food additives and behavioral disorders in children." http://www.ehow.com/facts_5594973_tbhq-side-effects.html
Judging by my own behavior today, and my kids', after eating a lot of ramen noodles for lunch, I'd go with the anecdotal evidence on that one. I am usually unbelievably calm and patient in the face of disasters, but today, after lunch, when Benjamin poured a whole pitcher of water on the table (which normally I wouldn't consider anywhere near a disaster--it's just water!), I LOST it. I was throwing dishes, shouting, stomping around. The only thing that stopped me from overturning the table and smashing plates against the wall was the little voice inside me that was analyzing everything from a non-emotive standpoint, giving me a running commentary, like, "What an odd thing to do. Do you realize you just made three of your children cry because they're scared. You don't have enough dishes to be breaking them. You realize you don't usually respond like this. Have you considered what triggered this?" I stormed out and ate chocolate until I calmed down.
Then I read the ingredients list on the package.
TBHQ was the only thing that I don't eat regularly.
So I blame it.
Here is an interesting web page on the subject: