Chances are you're doing everything that you can to eat plenty of "superfoods" blueberries, walnuts and other nutritious and antioxidant-rich wonders–that many scientists believe help reduce risk for a variety of chronic health problems, including Alzheimer's disease.

The missing part of the story: What you may not know is that most people get too much of certain nutrients-even those found in some superfoods that have long been considered an important part of a nutritious diet.

Iron, copper and zinc, which are widely recognized as key nutrients, actually are metallic minerals. They are common in many of the foods you may be eating, the water you drink-and even in some of the supplements you may be taking to improve your health.

What researchers are now discovering: Excessive amounts of iron, copper and zinc can produce free radicals that impair memory.

In fact, scientists have discovered that these metals are more prevalent in the brains of Alzheimer's patients than in people without the disease. Even in healthy adults, high levels appear to interfere with normal brain functions.

Three Newly Discovered Dangers

Your body does need iron, copper and zinc, but only in miniscule amounts. If you exceed these levels, your brain is at risk. What to watch out for…

  • Iron. Unless you have been diagnosed with a condition that requires supplemental iron, such as anemia, you probably don't need more than you're already getting from your diet-and even that might be too much.

Compelling evidence: In a study of 793 adults, those who had the most iron in their blood did worse on cognitive tests than those with normal levels.

In a study of 881 adults, those with high hemoglobin levels (a measure of iron in the blood) were three times more likely to develop Alzlieimer's disease than those with normal levels. Hemoglobin levels above 13.7 g/dL were associated with increased Alzheimer's risk. Those whose iron levels are too low are also at risk for Alzheimer's.

My advice: Emphasize plant-based foods in your diet. These foods contain as much or more iron than what's found in meat-but our bodies are better able to regulate our intake of the type of iron found in plant-based foods, such as spinach, dried apricots, lima beans and wheat germ. Your body absorbs more of this nonheme iron when you need it and absorbs less when you don't.

In contrast, the heme iron in meats, poultry, fish and shellfish (particularly oysters) is absorbed whether you need it or not. Because of this, a high-meat diet is a main cause of iron overload, which potentially damages not only your brain but also your heart.

Other smart steps…

  • Don't use iron cookware. A significant amount of iron leaches from uncoated cast-iron pots, pans and skillets into foods–particularly acidic foods, such as tomatoes.
  • Choose an iron-free product if you take a daily multisupplement.
  • Read cereal labels. Many breakfast cereals are fortified with iron. You don't need it.

What About Aluminum?

This ubiquitous metal has never been considered a nutrient-it plays no role in the body. While questions have persisted for several years about whether aluminum interferes with brain health, recent studies suggest that the risk is real.

In the UK, researchers found that Alzheimer's cases occurred 50% more often in counties with high aluminum levels in the water. Other studies have had similar results.

My advice: While researchers search for definitive findings on aluminum, err on the side of caution…

  • Don't buy foods that contain aluminum. Check food labels. Cheese products (such as the cheese on frozen pizza) often contain aluminum. So do baking powders and the baked goods that include them. You can buy an aluminum-free baking powder, such as the Rumford brand.
  • Don't take aluminum antacids. Use an aluminum-free product, such as Tums. Other druys, such as buffered aspirin, may also contain aluminum. Check the label.
  • Cook with steel-clad or porcelain-coated pots...use wax paper instead of aluminum foil...and don't consume foods or beverages that come in aluminum cans.
  • Check your tap water. If it's high in aluminum or other metals, use bottled water or a reverse osmosis filter. You can use the EPA Web site,, to get information about the water sources in your area.
  • Avoid antiperspirants with aluminum. Labels may say aluminum or alum to indicate an aluminum-containing ingredient.

Amount of iron you need in your diet: 8 mg per day for men age 19 and older and women age 51 and older Women age 19 to 50 need 18 mg per day. (In general, women should get the lower amount of iron when they stop menstruating.)

  • Copper. At proper levels, copper is essential for enzyme function and helps promote heart health and bone strength. At excess levels, copper-like iron--triggers the production of free radicals that can damage brain cells.

Important finding: A study of 1,451 people in southern California found that those who had the least copper in their blood were mentally sharper and had fewer problems with long- and short-term memory than those whose levels were high.

How copper may promote almost 20 years of aging: When high copper levels are combined with excess saturated fat in the diet-another risk factor for brain problems the effect is particularly detrimental. Data from the Chicago Health and Aging Project found that high copper/saturated fat caused a loss of mental function that was the equivalent of 19 years of aging.

My advice: Don't take any supplement that contains copper. If you have copper plumbing, it's fine to use tap water for doing dishes and washing but not for cooking or drinking. It is better to use bottled water or water filtered with an activated carbon filter (such as those found in Brita pitchers).

You are unlikely to get too much copper from plant foods that are rich in the mineral such as whole grains, nuts and beans because they also contain natural compounds called phytates that limit copper absorption.

Amount of copper you need: 09 mg daily.

  • Zinc. Our bodies need adequate zinc levels for key functions such as immunity, skin health and sexual function. Excessive amounts, however, are thought to promote the clumping of beta-amyloid proteins in the brain the hallmark of Alzheimer's disease.

Much of the excess zinc in the American diet comes from supplements. If you take a multivitamin-mineral supplement and also eat fortified cereals or other foods that include zinc, such as oysters, pumpkin seeds or cocoa, you could be getting too much.

Amount of zinc you need: 11 mg daily for men and 8 mg for women.

Takeaway On Minerals

Testing is not needed to check levels of iron, copper and zinc in your blood. It is wise to simply avoid the mineral sources in this article.

If you are getting too much of these minerals, your levels will gradually decline when you avoid excessive intakes.

Important: Avoid multivitamin-mineral supplements.

Better choices: "Vitamin only" supplements such as No Minerals Multi-Vitamin by Nature's Blend or Vitamins Only by Solgar.

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