How can aluminum affect health?
Low level exposure to aluminum from food, air, water or contact with skin is not thought to harm your health. Aluminum however is not necessary substance for our bodies and too much is harmful. People who are exposed to high levels of aluminum in air may have respiratory problems including asthma from dust. Aluminum can cause delays in skeletal and neurologic development.
It is also linked to Alzheimer's disease because of high levels of aluminum in brain.
Some people develop bone diseases and skin rashes due to aluminum exposure. Alumnium exposure is also known to cause degradation of sleep in humans.

How is one exposed to Aluminum?
By eating small amounts of aluminum in food and milk.
By drinking water with high level of aluminum.
Breathing higher level of aluminum dust in air.

Problems of Aluminum Cookware ?
Along with aluminum foil, cookware and vessels made of aluminum are significant source of excess aluminum in the diet. Boiling water in aluminum containers, especially with acidic substances causes aluminum to leech into the water and food. Water containing fluorides also encourages leaching process in aluminum cookware.
Thus water, milk or any kind of food generally is avoided from storing or cooking in aluminum vessels.