Think of all the things in your life that contain the soft, silvery metal aluminum. The thirteenth element on the periodic table is a light, durable material that has plenty of commercial applications, and you can find it in everything from that roll of aluminum foil in the kitchen and cooking pots to antacid tablets and personal products such as deodorant.
Though it's one of the most widely distributed metals in the environment, it's not a nutritive mineral, meaning that unlike calcium or sodium, our bodies don't need aluminum to survive. In fact, in very large doses aluminum can become toxic, and therein lies a concern about how it may have a negative effect on the brain. For years, aluminum has been suspected as potentially playing a role in the development of Alzheimer's disease and other dementias, but conclusive evidence has been difficult to find.
What Is Alzheimer's Disease?
Alzheimer's disease is the most common form of dementia -- disruptive changes in perception and cognitive performance that tend to develop later in life. The Alzheimer's Association reports that more than 5.8 million adults in the United States have Alzheimer's. It's a terrible disease that robs people of their independence and identity, and it's deadly. The AA reports that Alzheimer's is the sixth leading cause of death in the U.S., and 1 in 3 seniors dies with Alzheimer's or another dementia.
Alzheimer's features specific changes in the brain that alter how cells communicate with each other. These communication disruptions, caused in part by the build-up of certain proteins where they don't belong, lead to the symptoms of Alzheimer's:
-- Forgetfulness and memory loss.
-- Loss of ability to problem-solve or multitask.
-- Difficulty performing familiar tasks.
-- Confusion or disorientation, particularly around time and place.
-- Difficulty interpreting visual information.
-- Decline in judgment skills.
-- Mood disturbances, such as depression or increased irritability.
What Causes Alzheimer's Disease?
Alzheimer's is considered a multifactorial disease -- many causes may contribute to its development -- and there's no one thing that you should or shouldn't do that can specifically change the likelihood that you'll develop it. The AA reports that known risk factors for Alzheimer's include:
-- Age. This is the No. 1 risk factor for Alzheimer's. The majority of people who have Alzheimer's are in their 70s and 80s, and while it's possible to develop it at a younger age, a condition called early-onset Alzheimer's, it becomes much more common as we age.
-- Genetics. A family history of Alzheimer's and dementia is a major risk factor for whether you'll develop it.
-- Lifestyle factors. How much you exercise, how well you sleep, what environmental hazards you're exposed to and what you eat may all play a role in whether or not you develop Alzheimer's.
The Aluminum and Alzheimer's Connection
So does exposure to or ingestion of aluminum contribute to your chances of developing Alzheimer's? It's a tricky question that researchers have been investigating for decades, says Dr. Alex Mroszczyk-McDonald, a practicing family physician with Kaiser Permanente Fontana Medical Center in Fontana, California. "There is no clear answer whether aluminum exposure directly causes Alzheimer's disease, and there is no scientific explanation for this controversial theory which dates back to the 1960s."
So where did the idea of a connection originate? Dr. Douglas Scharre, a neurologist at the Ohio State University Wexner Medical Center, says, "I think that what is pretty well established is that if you have too much aluminum in your brain, that's not healthy. Aluminum can be a neurotoxin, and if you ingest it or get it into your brain, it can cause a dementia-like condition."
In looking at the brains of people who had this sort of aluminum toxicity, researchers noted abnormal structures in the brain that looked quite similar to the neurofibrillary tangles of tau proteins that are a hallmark sign of Alzheimer's in the brain. But Scharre says that the aluminum tangles are somewhat different from those seen in Alzheimer's.
Alzheimer's patients also usually have a build-up of another type of protein, called beta-amyloid, that clumps into structures called plaques that interfere with brain cell signaling. "These are sticky proteins," Scharre says, and "metals like aluminum get caught up in this sticky junk." If aluminum finds its way into the brain and gets stuck in an amyloid plaque, it's harder for the brain's cleaning mechanisms to remove it as it normally would remove a toxin. "You've got mechanisms in the brain to clean out the brain and remove toxins. But if they're stuck there and the normal mechanisms can't remove them," that can lead to a build-up of these metals. Scharre says this is probably at least part of the reason why when looking at the brains of Alzheimer's patients post-mortem, they often contain higher levels of heavy metals and other toxins.
But just because there's more of these substances in the brain doesn't necessarily mean they're causing symptoms or worsening the disease. But because aluminum toxicity is associated with a dementia-like condition, it's easy to see why it's fallen under suspicion as a potential contributing cause of Alzheimer's disease.
Plus, Scharre says that if toxin exposure were the cause of Alzheimer's, there would likely be hot-spot areas of higher incidence of Alzheimer's disease in locations across the country where aluminum levels are higher. "It doesn't make sense that a toxin is the cause of Alzheimer's because it runs more in families than in local areas where there's higher exposure to aluminum or other toxins." He says family history and genetics are a much more likely cause of Alzheimer's than any specific toxin you might encounter.
Mroszczyk-McDonald agrees that the available evidence does not indicate that aluminum exposure is a direct cause of Alzheimer's. "There have been some large studies which show individuals with higher and chronic aluminum exposure in drinking water and especially occupational exposure were more likely to develop Alzheimer's. However, there are other studies which show no association and further, it is unclear exactly how this research translates into risk for the average person." It's not clear whether higher levels of aluminum exposure over the course of a lifetime raises risk, nor is it clear what level of exposure to aluminum is unsafe.
Nevertheless, it's probably not a bad idea to limit your exposure to aluminum, and indeed any other potential toxin in the environment. "In general people who are worried or have a family history of Alzheimer's should probably try to limit their aluminum exposure," Mroszczyk-McDonald says. "In general, as a family physician, I recommend my patients avoid as many chemicals as possible both in terms of cosmetics as well as food products." So while low-level aluminum exposure from food and drinking water, cookware or cosmetics are believed to be unlikely to increase your risk of Alzheimer's, aiming to remove unnecessary chemicals from your life can't hurt. "My quick rule of thumb is, if you cannot pronounce an ingredient in your food or cosmetic products, you probably shouldn't put it in or on your body," Mroszczyk-McDonald says.
Focus on Factors You Can Control
Rather than tossing out all your aluminum pans and avoiding deodorants, perhaps the more reasonable approach is to try to limit the known risk factors over which you have some measure of control. Age and genetics are the two biggest factors in whether someone develops Alzheimer's and, alas, there's nothing you can do about them. But you can improve certain lifestyle factors, such as getting better sleep, eating right and moving more, all of which have been associated with lower risk for not just Alzheimer's, but a variety of other diseases including cancer, diabetes and heart disease.
-- Increase physical activity. Aim for 150 minutes of moderate to vigorous physical activity each week. That's just 2.5 hours in total, or a little more than 20 minutes a day. Brisk walking, vigorous gardening, dancing, cycling, yoga and swimming are all good ways to become more active.
-- Opt for more cognitive training. Use your mind to keep it sharper. "Memory training, memory cues and organizational aids have been shown to have a positive effect on cognition," though the long-term benefits of these interventions are less clear and still being studied, Mroszczyk-McDonald says. In addition, "those who have higher levels of education" seem to be better protected against Alzheimer's and dementia and additionally, those with more education have shown "a more gradual decline in cognition over time," he says. In this sense, the brain is a muscle that needs exercise to stay in shape, just like any other. Use it and you may be able to avoid or delay the onset of dementia.
-- Control blood pressure and blood sugar. Those with elevated blood sugar and diabetes "have demonstrated increased inflammation throughout the body," Mroszczyk-McDonald says, so controlling these levels can help improve your overall health. Inflammation is associated with a host of diseases and conditions, and reducing inflammation is thought to be protective of not just the brain, but also your heart, other internal organs and vascular system. "Making sure blood pressure is well controlled, especially in middle age, may help protect against Alzheimer's dementia, as well as protect against a host of other health problems, most notably stroke and heart attacks," he notes.