Updated: Aug 4, 2010
Aluminum is a trivalent cation found in its ionic form in most kinds of animal and plant tissues and in natural waters everywhere.1 It is the third most prevalent element and the most abundant metal in the earth’s crust, representing approximately 8% of total mineral components.2 Due to its reactivity, aluminum in nature is found only in combination with other elements.
Dietary aluminum is ubiquitous but in such small quantities that it is not a significant source of concern in persons with normal elimination capacity. Urban water supplies may contain a greater concentration because water is usually treated with aluminum before becoming part of the supply. Subsequent purification processes that remove organic compounds take away many of the same compounds that bind the element in its free state, further increasing aluminum concentration.
All metals can cause disease through excess. In addition, essential metals can affect the human body in the case of deficiency or imbalance.3 Malabsorption through diarrheal states can result in essential metal and trace element deficiencies. Toxic effects are dependent upon the amount of metal ingested, entry rate, tissue distribution, concentration achieved, and excretion rate. Mechanisms of toxicity include inhibition of enzyme activity and protein synthesis, alterations in nucleic acid function, and changes in cell membrane permeability.
No known physiologic need exists for aluminum; however, because of its atomic size and electric charge (0.051 nm and 3+, respectively), it is sometimes a competitive inhibitor of several essential elements of similar characteristics, such as magnesium (0.066 nm, 2+), calcium (0.099 nm, 2+), and iron (0.064 nm, 3+). At physiological pH, aluminum forms a barely soluble Al(OH)3 that can be easily dissolved by minor changes in the acidity of the media.2