Aluminum is not really a heavy metal-that is, it is low (number 13 on the "periodic" table of elements) in molecular weight-so it does behave differently from metals such as lead or mercury. Recent investigations, however, implicate aluminum toxicity in Alzheimer's disease and other brain and senility syndromes. The evidence of aluminum's toxicity or essentiality is not conclusive as yet.

The amount of aluminum in the human body ranges between 50 and 150 mg., with an average of about 65 mg. Most of this mineral is found in the lungs, brain, kidneys, liver, and thyroid. Our daily intake of aluminum may range from 10-110 mg., but the body will eliminate most of this in the feces and urine and some in the sweat. With decreased kidney function, more aluminum will be stored, particularly in the bones.

Sources: For most people, the greatest aluminum intake comes from food additives. Sodium aluminum phosphate is an emulsifier in processed cheese, potassium alum is used to whiten flour, and sodium silicoaluminate and/or aluminum calcium silicate are added to common table salt to help it run freely and not cake. In the average diet, 40-50 mg. a day may come from foods.

With use of aluminum pots and pans and aluminum foil, some aluminum leaches into food, especially with acid foods such as tomatoes or rhubarb. Cooking with fluoridated water in aluminum cookware increases the aluminum in the water and the food; still, the amounts we obtain in this manner are small in comparison with those from additives. Aluminum salts used in antiperspirants are not a major contaminant either, unless these products are overused. (Aerosol sprays, however, should be avoided for environmental toxicity reasons.) Antacids containing aluminum hydroxide can be a big source if they are taken regularly or abused, as antacids sometimes are. Some children's aspirins have been found to contain aluminum as well.

Methods of toxicity: Aluminum is probably the least toxic of the minerals discussed in this section, although the concern is that it has become so pervasive and is now found in higher levels in human tissues. It is not clear how aluminum functions or interferes with activities in the human body, possibly through some magnesium functions. It may reduce vitamin levels or bind to DNA, and it has been correlated with weakened tissue of the gastrointestinal tract. In Alzheimer's disease, there are increased aluminum levels in the brain tissue and an increase in what are called "neurofibrillary tangles," which tend to reduce nerve synapses and conduction.

Oral aluminum, as obtained from antacids, can bind pepsin and weaken protein digestion. It also has astringent qualities, and thus can dry the tissues and mucous linings and contribute to constipation. Regular use of aluminum-containing deodorants may contribute to the clogging of underarm lymphatics and then to breast problems such as cystic disease. Ann Louise Gittleman, a prominent nutritionist, calls aluminum a "detrimental protoplasmic poison."