Response: Aluminum, a soft metal, is found nearly everywhere in the environment. Most exposures to aluminum occur through ingestion or eating and drinking, with daily intakes generally low, averaging between 30-50 mg. For the typical person, drinking water, medicines and other pharmaceuticals (such as antacids and antiperspirants) are the biggest contributors to aluminum exposures; however, aluminum cookware is also a potential source. As you note, aluminum exposures have raised some health concerns due to the effects of aluminum on the human nervous system and the much discussed (but inconclusive) linkages between aluminum exposures and Alzheimer's disease.
Aluminum exposures from cookware, of which more than half is made of aluminum, is not well studied, but is thought to be a relatively minor source of aluminum exposures. Exposures to aluminum through food can occur when aluminum leaches or otherwise dissolves from the cookware into the food. Leaching is most likely when the foods being cooked or stored are highly basic (like baking soda) or highly acidic (like tomato sauce, lemon juice, oranges, or vinegar). For example, tomato sauce has been shown to contain 3-6 mg aluminum (per 100 g serving) after cooking in aluminum pans, which translates into about one-tenth of the typical daily intake. This leaching of aluminum with acidic foods does not happen with aluminum cookware that is anodized, or electro-chemically processed to seal the aluminum in the cookware. Clemson University Extension’s Home and Garden Information Center tested different cookware types, and found anodized aluminum cookware to be safe. Regardless, it would probably be wise to store tomato sauce and other acidic foods in something other than an aluminum pot.
As for the juicer that you mention, I did a quick and non-exhaustive check of various websites, none of which said that the juicer is made of anodized aluminum. One site did say that it was made of acid-resistant aluminum and chrome, suggesting that the aluminum is somehow sealed and that leaching of aluminum will not occur during the juicing process. An easy way to check for this is to look at the juicer and see whether the aluminum becomes pitted or pock-marked after several uses. Since leaching takes time and juicing is a relatively quick process, this pitting would not occur immediately but would rather occur over time. As a result, you should probably continue to check your juicer for pitting over time.
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Helen Suh MacIntosh is a professor in environmental health at Harvard University and studies how pollution behaves in the environment and how it affects people's health. Please keep in mind that her answers are just her interpretation of available information and should not be taken as the only viewpoint or solution to a problem. Use this column at your own risk. Having said this, please feel free to post any of your environmental health questions to Helen@TreeHugger.com. (Please use a descriptive email subject line and mention if you want to remain anonymous or not).