Heavy metal? Exploring the aluminum/Alzheimer's link.
But other agencies, including the National Institute of Environmental Health Sciences (NIEHS), continue to look into it because aluminum is so ubiquitous in our daily lives. We swallow it in foods like processed cheese and baked goods. Babies encounter it in formula, breast milk and vaccines. Since aluminum is both strong and lightweight, more auto manufacturers are relying on it to boost fuel efficiency. That means more aluminum byproducts will enter the air, water and, ultimately, the landfills.
"The Alzheimer's risk with aluminum hasn't been well defined," says Robert Yokel, a University of Kentucky pharmacy professor who is studying aluminum for the NIEHS. "You have to weigh risks and benefits. My personal opinion is if you can make simple choices to avoid it until we sort this thing out, why not?"
One certainty is that Alzheimer's disease is not going away. As the baby boom generation ages and more Americans live longer, this devastating illness is affecting more patients and their families. Currently, about five percent of people over age 60 will develop Alzheimer's disease. Some research shows a relationship between aluminum and other nervous-system disorders, such as Lou Gehrig's disease and Parkinson's Disease.
Pros and Cons
Scientists first became aware of aluminum's potential health risks 20 years ago, when a group of kidney patients came down with a similar form of dementia after being exposed to aluminum through dialysis. Another study found aluminum inside the plaques and tangles that appear in Alzheimer's patients' brains.
Meanwhile, a few epidemiological studies found that people with a high level of aluminum in their drinking water had a higher incidence of Alzheimer's. Other studies that followed, however, did not show the same correlation. Studies of cultures that drink large amounts of tea (which leaches a lot of aluminum) also did not show a link. After several decades, scientists have been unable to replicate the original studies showing aluminum deposits in a brain affected by Alzheimer's. "There was an aluminum scare 20 years ago, but it now looks like there is no connection," says Harvard Alzheimer's researcher Dr. Ashley Bush.
New research, by Bush and others, shows Alzheimer's to be a much more complex illness than anyone had imagined. Bush's laboratory is developing a promising new drug that prevents zinc from reacting with the proteins that form the abnormal deposits in brains attacked by Alzheimer's. Phase III clinical trials of the drug, developed by Prana Biotech (www.pranabio.com), will begin next year.
Experts now believe if aluminum does appear in an Alzheimer's brain, it's simply because it is so common in our environment. "It's a major component of the Earth's crust, so it shows up everywhere" Bush says. As for food and water contamination, aluminum probably isn't much of a threat because most of it passes right through the intestines without being absorbed.
Some natural health advocates disagree with this position. Suzan Walter is president of the American Holistic Health Association, and her mother died of Alzheimer's. She says many natural health experts advise patients to avoid aluminum based on the precautionary principle, and she takes steps to avoid it in her personal life. "We don't know what causes Alzheimer's, but why not stay away from aluminum just in case?" Walter asks. "It doesn't compromise my life to avoid it and it can't hurt."
Paul Schwartz, national policy coordinator for Clean Water Action, adds, "There is a valid concern to be raised about aluminum and health effects, but the science is not definitive."
Aluminum in Food and Medicine
While the metal is not easily absorbed, the government is still paying scientists like Yokel to make sure we are safe when it comes to dietary sources of aluminum. Currently, the U.S. Food and Drug Administration does not limit aluminum in food because it is "generally recognized as safe." At the same time, no one knows the exact rate the body absorbs aluminum from food. Since food accounts for 95 percent of our aluminum intake, it's worth examining, Yokel says. "We're looking into whether this constant exposure in our diet is causing a problem," Yokel says.
Yokel is also studying the rate of absorption for aluminum in drinking water. For years, municipal water treatment operators have added aluminum to their tanks to make bacteria settle out of the final product, If Yokel's ongoing experiments show our bodies absorb too much aluminum from tap water, the EPA may adopt stricter regulations.
Aluminum is so common that all of us have some background level in our bodies. For example, all mothers have traces of aluminum in their breast milk (about 40 micrograms per liter). Infant formula has about five times as much aluminum as breast milk (soy formula has the most). And the load just builds from there as a person ages.
"If aluminum does cause Alzheimer's, it's possible that lifelong exposure could contribute," Yokel says. "Sometime later in life, you could hit that threshold and develop a problem--but it's all speculation at this point."
Certain over-the-counter medicines are loaded with aluminum. For example, the World Health Organization estimates antacid users swallow as much as five grams of aluminum per day. Buffered aspirin also has aluminum.
Vaccines are another little-known source of aluminum in our lives. The media has focused a great deal on mercury in childhood vaccines. But many vaccines also contain aluminum as an additive. That may be a concern because the body absorbs injected aluminum more easily. Vaccine critics also question whether mercury and aluminum might have a synergistic effect on the developing nervous system.
Aluminum is an important part of vaccines, however, because it makes them work better, says Dr. Paul Offit, chief of infectious diseases at the Children's Hospital of Philadelphia. "It's used when you want to enhance the immune response," Offit says. The Hepatitis B, tetanus and DPT vaccines contain aluminum, as do some batches of the flu shot.
Some parent groups, such as the Virginia-based National Vaccine Information Center, have been critical of the government's childhood vaccine policies. They argue medical policy makers and drug companies should offer vaccines without additives like mercury and aluminum.
While most childhood vaccines no longer contain mercury, aluminum might be harder to replace, says FDA spokesperson Lenore Gelb. So far, no one has identified a safe alternative that can perform the same way. Even if researchers find a new substance, the testing and approval process would take years, she adds.
In pockets of the country, fears about these additives are causing an anti-vaccine backlash. Some parents are home schooling their kids to avoid government-mandated vaccines. And what about elderly patients who might skip their flu shot because they don't want an extra load of aluminum in their brains?
Offit believes the immediate benefits of vaccines outweigh any future risks. Right now, we have no definite proof that aluminum causes Alzheimer's, Offit argues. But each year, thousands of children and elderly people die of flu complications. "There is nothing theoretical about the flu," he says.
What About Antiperspirants?
Adults and teens who use antiperspirant every morning get another daily dose of aluminum. While the skin absorbs a very small percentage of the aluminum in antiperspirants, studies show, natural health advocates raise questions about the effects of constant exposure. Antiperspirants work by plugging sweat glands with aluminum salts.
Plenty of herbal alternatives are on the market at health food stores. But Yokel encourages shoppers to do their homework. A check of the label on one brand of crystal deodorant stone showed "alum" in the ingredients. That, Yokel advises, is simply a natural form of aluminum. Another option is to buy conventional deodorant, which should be aluminum-free as long as it doesn't say "antiperspirant" on the label. CONTACT: Mzheimer's Association, (800) 272-3900, www.alz.org; Environmental Working Group, (202) 667-6982, www.ewg.org; National Vaccine Information Center, (703)938DPT3, www.909shot.com; Immunization Action Coalition, (651)647-9009, www.vaccineinformation.org.
RELATED ARTICLE: Avoiding aluminum.
To cut your aluminum intake, follow these steps:
* Switch to stainless steel cookware (nonstick types have other toxins);
* Try aluminum-free deodorant;
* Reduce your consumption of tea, processed cheese, and aluminum-containing baking powder;
* When possible, breastfeed. Soy formula has the most aluminum.
* Invest in a water filter.
Dr. Robert Griffith, editor of the Santa Fe-based web journal Health and Age (www.HealthandAge.com), shares a few of the latest ideas in Alzheimer's prevention:
* Anything that is good for the heart is good for Alzheimer's, Griffith says, so keep your cholesterol low and cut calories, especially those that come from fat;
* A recent study showed walking every day cuts Alzheimer's risk;
* Take antioxidants and Vitamin C and E together. Studies show these supplements appear to have a protective effect for those at risk for Alzheimer's disease;
* Consider the herb curcumin, which may help prevent Alzheimer's;
* Eat more fruits and vegetables: they are full of antioxidants.
MELISSA KNOPPER is a Colorado-based science writer.
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|Title Annotation:||Your Health|
|Date:||Jan 1, 2005|
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