Polystyrene is safe for food in solid state, less so otherwise


Hello, dear readers, and welcome to the bonus letters column we promised you. We are delighted that you’re keeping our mailboxes full, and we will continue to do our best to stay abreast of your letters.

-- A reader from Oklahoma had a question regarding a takeout dinner that was delivered in Styrofoam containers stacked one on top of the other. “When we got home, the heat from the food in the top container had burned a hole in the top of the bottom one,” he wrote. “We put that container in the freezer, where it still is. Can we safely eat that food?”

Styrofoam is a trademark name for polystyrene, a petroleum-based chemical compound. It’s manufactured from styrene, a volatile colorless liquid. Studies have linked exposure to styrene to genetic damage to white blood cells and to certain blood cancers. Polystyrene is considered safe for food use when in a solid state. However, heating can cause chemicals to leach from the foam and into the food. Eating the contents of a melted foam container one time is unlikely to cause harm. However, repeated exposure, which can be cumulative, can be a health risk.

Elizabeth Ko, MD and Eve Glazier, MD

-- After a column about plantar fasciitis, which occurs when inflammation causes stabbing and often debilitating pain in the heel, a number of readers shared their experiences with this condition. We also heard from an orthopedic surgeon in Nebraska who suggested some treatments that his own patients have found helpful. One is a wearable device known as an Airheel, which uses interconnected air cells to protect and support the foot. Once the inflammation and pain of plantar fasciitis has eased, which can take up to six months, he recommends the use of a rigid plastic heel cup to prevent a recurrence. “The rigidity of the cup helps the fat pad under the heel to maintain its thickness, and thereby absorb the shock at heel strike,” he wrote. He explained that the cup also helps to spread out the impact of each footfall, which lessens pressure on the vulnerable tissues of the heel. We hope readers find this useful.

-- We recently wrote about a link between the repeated concussions and head strikes that are sustained in football and an increased risk of developing amyotrophic lateral sclerosis, or ALS. A reader near Chicago asked if better helmets could protect players from this neurodegenerative disease. “I wonder what effect improved helmets, with more and better padding, would have on the number of players getting ALS,” she wrote. While this seems like a logical solution, more padding itself won’t actually help with brain injuries. A helmet can be effective in protecting against a skull fracture. However, it cannot prevent the brain from being jostled within the skull upon impact. It is this uncontrolled movement of the brain within the skull -- repeatedly injuring and damaging delicate tissues, blood vessels and neurons -- that leads to concussion and other injuries.

Thank you, as always, to everyone who took the time to write to us. We will be back with our regular letters column in a few weeks.

(Send your questions to [email protected], or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)