There is a difference of opinion today between the food industry and many health conscious people concerning the danger of aluminum in the diet. The official school of thought, backed by the US government, is that aluminum is harmless in our diets as it can't be absorbed through the intestinal tract into our blood stream. You can see an argument for this side of the controversy on the FDA's web site. Interestingly enough, one of the arguments they use in saying cooking with aluminum pots and pans is safe is the fact that the average North American eats many more times the amount of aluminum in their foods than could leach off an aluminum pan from the cooking process. A very large amount of it comes from baking powder.
Antacid pills are another major source, as are other medicines and foods.
On the other side of the discussion are the people who argue that ingestion of aluminum in any amount whatsoever is dangerous to your health. They point out that virtually all Alzheimer patients have abnormally high levels of aluminum in their brain. This fact is one of their main arguments. Studies are not conclusive yet as to why this is. You can see this argument on Healthwell's web site.