>> Monday, April 20, 2009
A few weeks back I got an e-mail from a reader asking about the additive TBHQ. Cindy wrote, "I have wondered what TBHQ for freshness is and is this bad?" Great question! I had to a little research because I didn't know what this ingredient was either.
TBHQ is the short name for tert-butylhydroquinone. TBHQ is a synthetic antioxidant added to oils and fats to retard spoilage. Vegetable oils contain a natural antioxidant called tocopherol (aka vitamin E); however, the amount present in oils is often not enough for oxidative stability. Adding extra tocopherol doesn't really help, and so a synthetic antioxidant such as TBHQ is often added.
It doesn't take much of any of these compounds to provide oxidative stability, and they are all considered safe in the amounts used. However, they are all also suspected carcinogens. Studies in animals have shown that consumption of BHA and BHT may increase the risk of cancer and that these compounds may accumulate in body tissue (though they've also been shown to be rapidly excreted in urine). TBHQ is also a suspected carcinogen; however, one study suggests that it does not accumulate in body tissue.
Before freaking out too much over these studies, remember that most of these studies involve animals - not humans - consuming enormous amounts of the compound in question. They are in many ways necessarily unrealistic. A good quote from a commentor of a blog that I like, Molecule of the Day, "How about a general rule: You don't get to call something "poisonous" if the "hazardous dose" would hurt when thrown at your head?" There is some truth in that quote.
On the flip side, there are possible good effects from these synthetic antioxidants. A 1994 study suggests that BHA and BHT may actually retard cancer development. And BHA and BHT are being studied for their antiviral and antimicrobial activities. Researchers are looking at ways to use BHT to treat herpes simplex and even AIDS. BHT is actually sold as a health food supplement in capsule form, particularly as a treatment for herpes family viruses.
Where do you find these additives? Well, everywhere. Since getting this question via e-mail, I've seen TBHQ and BHT in many different food products in our household. BHT is commonly added to petroleum products to slow oxidation. You'll also find them in cosmetics, pharmaceuticals, fuels, and even embalming fluid.
Should you be concerned about consuming these additives? That's a trickier question. While these additives serve a useful purpose, they clearly have a darker side. What is unclear is whether that darker side exists in the very small quantities that they're consumed in. There is considerable uncertainty in the literature concerning the safety of BHT, BHA, and TBHQ. BHT and BHA may accumulate in tissue (maybe), which presents a greater long term concern to me - especially as a mother.
My bottom line is that I personally am not going to give up foods containing these additives. But, I will be more aware of our consumption of these additives after this. If anything, it increases my resolve to be more aware of what we consume and makes me happy that we have significantly decreased the amount of processed foods that we consume.