According to a study published by the International Journal of Electrochemical Science, you may want to think twice before wrapping your food in aluminum foil to cook it — because some of that foil will leach into your meal.
“Aluminum foil used in cooking provides an easy channel for the metal to enter the human body,” concludes the study, which examined the effect foil has on a variety of different foods when used to prepare them.
The human body is wired to excrete small amounts of aluminum quite efficiently, so minimal exposure to the metal isn’t a concern. The World Health Organization (WHO) has even established daily intake levels of aluminum that have been shown to cause no harm.
“But most people are exposed to and ingest far more than this suggested safe daily intake,” said Ghada Bassioni, one of the study’s researchers, in a recent article.
This is due, in part, to the fact that aluminum — the most abundant metal in the earth’s crust — is found in a wide range of foods and spices. But it’s also used in cooking utensils. Pots and pans, for instance, are lined with aluminum. Most are oxidized to prevent the metal from leaching into food, but, according to Bassioni, this process becomes increasingly negated over time as people scrub their utensils after meals.
Further, aluminum sulfate is used as a coagulant in the process of purifying drinking water — a practice the WHO has found “may lead to increased concentrations of aluminum in finished water.”
This documented overexposure has scientists looking into just how damaging aluminum is to the human body. Bassioni points out that several studies have suggested high aluminum intake can cause significant harm to people with renal impairment and certain bone diseases, and has been shown to reduce the growth rate of brain cells in human beings.
Particularly, researchers are making connections between aluminum and Alzheimer’s disease, leading them to contend that the condition could in fact be a modern illness born out of the industrialization of the planet.
When it comes to cooking, aluminum in pots and pans is far less problematic than foil, Bassioni’s research group found. This is because the de-oxidation process happens gradually and can actually be worked around altogether. Boiling water several times in new pots, for example, creates a matte layer that will prevent leaching.
But aluminum foil is disposable. Single sheets aren’t used repeatedly, so there’s no way to create a protection layer prior to cooking. And due to the volatile nature of aluminum, chemical reactions occur during the cooking process that leads to leaching — particularly with foods that are highly acidic.
“This research suggests that aluminum foil should not be used for cooking,” concludes Bassioni. “Instead, we’d recommend using glassware or porcelain when preparing baked dishes.”