3 Metals That Might Cause Memory Problems

The exact causes of Alzheimer's disease are still unknown, but experts have identified a host of contributing factors: diabetes, smoking, saturated fats. Now a theory points the finger in a different direction: a variety of metals that can build up in the body over time. Look inside the brains of people with Alzheimer's who have died and you'll find protein clogging the brain's signaling system, along with tiny clusters called beta-amyloid plaques. "When researchers tease those plaques apart, they find metals, including iron, copper, and aluminum," says Neal Barnard, MD, an adjunct associate professor of medicine at the George Washington University School of Medicine. "These metals produce free radicals, which are like little sparks that damage brain cells." And dementia isn't the only risk; metals have been linked to everyday mental fuzziness: A study of roughly 1,450 adults in The Journal of Nutrition, Health & Aging found that women who performed highest on cognition tests had the lowest levels of copper and iron in their blood. But you needn't let metals meddle with your noggin: A few simple swaps can help shield your brain and protect your memory. 

It's the fuel that allows red blood cells to transport oxygen throughout the body. But when it comes to brain health, a 2011 study in the journal Neurology showed that people with high hemoglobin (an indicator of iron levels) were more than three times as likely to develop Alzheimer's as those with levels in a healthy range. 

The aluminum-Alzheimer's link remains hotly contested, but most experts agree that the metal can be a neurotoxin. Although our bodies don't need aluminum to function, it seeps in through antacids ("they can deliver a hundred times more aluminum than you'd get from a day's worth of food," Barnard says); soda cans, which can leach aluminum; and tap water (aluminum can be introduced during purification). In one British study, people with high levels of aluminum in their tap water had a 50 percent increased risk for Alzheimer's compared to those with the least exposure. 

Dietary copper (in foods like shellfish, nuts, and beans) is generally safe. But inorganic copper—the type in multivitamins and tap water—largely bypasses the liver's filtration system and heads directly to the blood and brain. It's especially dangerous when combined with saturated and trans fats: Research has found that individuals whose high-fat diets included 1.6 or more mg of copper a day experienced a loss of mental function equivalent to an extra 19 years of aging, compared with those who took in an average of 0.9 mg a day.