Aluminum foil is a great tool to use in cooking, baking and food storage. However, there are dangers associated with its use. These dangers include safety and health risks, such as food contamination and the absorption of too much aluminum into the body. There is some controversy as to the extent of aluminum foil's impact in these situations, but scientists continue to investigate its safety in everyday use.
Just like the metal in forks and knives, metal in aluminum foil can cause problems in the microwave. As a microwave emits waves of electromagnetic energy, the surface of aluminum foil can act as a collecting station for that energy. Eventually, if there is too much buildup, the energy discharges into arching sparks. This sort of discharge can damage the microwave. It should be noted, however, that small amounts of aluminum foil are okay to use in a microwave, as long as the foil does not completely cover the food and is more than an inch away from the walls of the microwave.
Although it may be safe to use aluminum foil in the microwave, that doesn't mean it should be done. Research indicates that aluminum leaches out of foil when it is heated for cooking purposes. This is especially true for foods that are high in acid, such as tomato-based foods, as well as foods that are heavy in spices. When using aluminum foil to heat foods, the amount of aluminum that leaches out is higher than the daily recommended intake, which could lead to health risks in the form of Alzheimer's disease and osteoporosis.
One of the health risks associated with aluminum foil is an increased risk of Alzheimer's disease, which is linked to aluminum buildup in the brain. After aluminum leaches off of foil during cooking, the extra aluminum is ingested and can build up in the brain. This aluminum may contribute to the development of amyloid plaques, one of the hallmark causes of Alzheimer's disease. However, this hypothesis is still controversial, with no clear verdict either way in whether leaching of aluminum foil can truly contribute to the development of Alzheimer's disease.
Aluminum can also build up in the body, leading to diseases such as osteoporosis. Along with calcium, the element fluoride is needed to maintain strong bones. However, aluminum can bind to fluoride, causing fluoride to exit the body in stool before it's able to reach the bones. Abundant aluminum also affects how calcium is absorbed in the body, further contributing to bone deficiency.