Dear Dr. Roach: For about 30 years, I have heard I should avoid contact with aluminum for sustained good health.

Is there science or proven studies about instances of adverse health effects behind these recommendations? Or is avoiding contact with aluminum in deodorant or cookware an incorrect or unsupported assertion that someone once made and that has taken on momentum, periodically resurfacing in articles and in emails?

I am aware that exposure to some heavy metals is bad for us and must be avoided — for example, lead from paint chips could be eaten by children or pets, or lead dust when sanding can be inhaled. But what is known about aluminum?

G.O.

Dear G.O.: Aluminum is a light metal, not heavy, and it rarely builds up to toxic levels in the body. In the vast majority of cases where it does, it is in people with abnormal kidney function.

This is because aluminum is very poorly absorbed, and when it is absorbed, the body has an effective way of getting rid of aluminum — through the kidneys, where 95 percent of aluminum is excreted.

Even in the case of injected aluminum, such as in some vaccines, the amounts are minute and the body is able to rapidly excrete it, provided a person’s kidney function is adequate.

In people on hemodialysis, aluminum from diet, medication and in dialysis fluid can build up in bones. Once this is recognized (usually via a blood test, before and after a chelating agent), aluminum can be removed through chelation therapy.

True aluminum overload occurs almost exclusively in dialysis patients and is increasingly uncommon due to better purification of dialysis fluid. There is no need to avoid aluminum pans or foil, as these do not raise blood aluminum levels. They don’t give off aluminum to food readily nor are any particles well-absorbed.

As far as deodorant use, the preponderance of current evidence states that there is not a risk of breast cancer from aluminum-containing antiperspirants.

For people who want to be as cautious as possible, there are aluminum-free antiperspirants, such as Tom’s products.

Dear Dr. Roach: When I visit people in the hospital, I see many nurses and doctors hanging around the doors, smoking. What kind of example does this give us?

L.H.

Dear L.H.: How do you know they’re nurses and doctors? Most I know don’t smoke. At one time, it was hard to see a speaker at medical meetings because of the smoke-filled air. That is no longer the case.

Just about all hospitals do not allow smoking within the building, and just about all have banned smoking on the premises outside the building.

Where do you live?