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Weighing Heavy Metals

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Mercury in fish and dental fillings. Lead in old paint. Cadmium and arsenic in industrial wastes. There’s a lot of talk about heavy-metal toxins these days. But how worried should you be, really? And what can you do to protect yourself?

What would you think if someone asked you to consume a dose of heavy metals every day for the rest of your life? Most likely, you’d be horrified. But truth be told, you’re already doing it. Everyone ingests small amounts of arsenic, cadmium, lead and mercury daily. It’s not an option or an immodest proposal – it’s an environmental mandate.

The environment, unfortunately, is laden with heavy metals, mostly as a result of big-industry waste. But what people may not realize is that many heavy metals get a free pass into the body, day in and day out, through the lungs, digestive tract and skin. We aren’t just talking about the blue-collar worker who toils as a lead smelter, but also the average office worker, adolescent and stay-at-home mom. Anyone who eats a fish sandwich, inhales secondhand smoke, drinks a glass of water or simply breathes air can be exposed.

Heavy-metal toxins is one of those doomsday topics that makes John Q. Public and even some medical experts want to scoff and look away. But the threat is real, and while the extent of the potential damage is still being debated, you don’t have to wait to begin protecting yourself. There are dozens of simple ways to minimize your exposure and curtail potential dangers.

The key is to be proactive about what you can change and mindful about what you can’t. Knowing what you’re up against can help you strike a healthy balance, and may inspire you to learn more about the heated environmental and political debates that surround this important issue.

Metal Detection

Of all the heavy metals in the environment, the most abundant and potentially deadly are arsenic, cadmium, lead and mercury. A metal is considered “heavy” if its gravity is at least five times heavier than water. The density of heavy metals increases the probability that they will end up in soil and water.

Heavy metals are an equal-opportunity offender. Since everyone eats food grown in tainted soil and breathes air contaminated by pollutants, no one gets off entirely toxin-free. The body, though, deserves kudos for doing its best to purge heavy metals. A large percentage of metals are excreted through sweat, urine and the bowels. What the body can’t toss, it socks away in places that aren’t so immediately vital to maintaining life, such as fat, teeth and bones.

When heavy metals build up faster than the body can eliminate them, it’s called bioaccumulation. Scientists are just beginning to understand the seriousness of it. And before they can hope to accurately access the health ramifications of heavy metals, they first must get a better idea of what they are up against. The Centers for Disease Control and Prevention (CDC) is aiming to do just that.

In 2003, the CDC published the second in an ongoing series of reports tracking Americans’ exposure to chemicals in the environment (a third report is due this year). Scientists at the CDC tested approximately 2,500 men, women and children for 116 household chemicals. They looked for everything from the synthetic components found in new carpets to chemicals found in nail polish. What they found was disturbing: Everyone, regardless of age, race or gender, had traceable levels of manmade chemicals in his or her body. “We’ve known that toxins in the environment could wind up in humans, but this is the first time we’ve actually been able to see it,” says Jim Pirkle, PhD, and the study’s lead investigator. “This is not what might have gotten into you, this is what did get into you.”

Alarming as that may sound, many mainstream scientists, including Pirkle, say not to fret. “Just because you can measure something in people doesn’t mean it’s dangerous,” he asserts. Indeed, the CDC report (available at www.cdc.gov/exposure report/2nd) draws few overt conclusions. Instead, it lists raw data and repeatedly notes that “further study is necessary” to determine the concentrations at which various chemicals pose a threat to human health. But in the meantime, should we really be assuming we are safe?

Researchers who conducted another human toxic-burden study released in 2003 think not. The BodyBurden study (www.ewg.org/reports/bodyburden), a joint project by the Environmental Working Group (EWG), the Mt. Sinai School of Medicine, and Commonweal (a nonprofit health and environmental research institute), looked for 167 chemicals in nine volunteers and found an average of 91 industrial compounds, pollutants and other chemicals in their blood and urine. Their general conclusion: That what we don’t know about the effects of all these combined chemicals could be hurting us, and until they are proven safe, we should consider them with caution.

“The CDC studied individual chemicals in a whole lot of people; we studied individual people for a whole lot of chemicals,” says Tim Kropp, PhD, a senior scientist with the EWG. He points out that while the CDC’s research looks at exposure levels across the population, the EWG study is the first to look “at the complex reality of the human body burden – what we call the ‘pollution in people.'”

Both studies, according to Kropp, reveal some disturbing gaps in our scientific understanding of environmental contaminants and point to weakness in our system of regulatory safeguards. “The CDC looks at whether or not a person is over the federal standard for a single chemical, like lead,” explains Kropp. “Our goal is to approximate real life by studying what happens when you add all these chemicals up. What is the effect of a bunch of heavy metals and other chemicals on a woman’s reproductive system? Right now, we don’t know.”

While the researchers are doing the math and debating the precise levels at which heavy metals and other toxins become dangerous to us in theory, some clinicians are taking a more pragmatic approach, trying to help individuals reduce exposure and eliminate the toxins already in their systems.

“Heavy-metal exposure is a serious health problem,” says Walter Crinnion, a naturopathic physician and director of the Environmental Medicine Center at the Southwest College of Naturopathic Medicine in Tempe, Ariz. Over the years, Crinnion has treated hundreds of patients suffering from heavy-metal toxicity. “Do we all have them in our bodies? Absolutely,” he says. “Will they affect your health? It depends.”

Danger? What Danger?

Several factors determine a person’s susceptibility to heavy-metal toxicity. Three of the biggest include diet, exposure to pollution and genetic makeup. The sneaky part about chronic exposure to low levels of heavy metals is that most don’t cause health problems right away. It’s a lifetime of exposure that spells trouble.

Tom McGuire, DDS, a holistic dentist in Santa Rosa, Calif., and an expert on mercury-free dentistry, compares the body’s slow accumulation of heavy metals to the damage done by smoking. A person isn’t going to get lung cancer from the first cigarette, he says, but that doesn’t mean he shouldn’t worry about the long-term health risks of smoking. “Sadly, most people don’t realize they are being poisoned by heavy metals until they have already affected their health.”

To confound matters even further, heavy-metal toxicity can masquerade as a host of other ailments, so it may fly under the radar of conventional healthcare practitioners. “Most physicians don’t think to look at heavy metals as an underlying cause of disease,” says Liz Lipski, PhD, an expert in dietary detox and author of Digestive Wellness (McGraw-Hill, 1999). “It’s just not in their training.”

Symptoms of chronic heavy-metal exposure include depression, irritability, mood swings, tremors, autoimmune diseases, chronic infections and cancer. Skeptics point out that most of these ills can be caused by any number of other factors. Crinnion agrees, but poses the question: “Wouldn’t it be great if everyone who has these health problems were screened to find out if they actually have a heavy-metal burden?”

The trouble is, even if you get screened for heavy-metal exposure, the reliability of such tests (commonly done with hair or urine) is hotly disputed. And the most common interventions involve either oral or intravenous chelation. The intravenous therapy involves receiving a solution infused with a chemical called ethyl-enediaminetetraacetic acid (EDTA). EDTA works by latching onto lead and other unwanted minerals in the bloodstream and escorting them out of the body through the urine.

Unfortunately, few standards or protocols are in place to protect patients against charlatans. Advocates of the therapy often recommend between 20 and 50 treatments, each lasting up to four hours and costing upward of $100. As a result, the field is ripe with unscrupulous practitioners looking to cash in.

Whether we decide to get tested or not, though, it seems that each of us is likely to be saddled with our own heavy-metal baggage. “We are all going to be exposed,” says Elson Haas, MD, author of Staying Healthy with Nutrition (Celestial Arts, summer 2005). “That’s part of living on Earth in this day and age. What we do to the environment, we do to ourselves.”

You can cut down on the amount of heavy metals you imbibe by cleaning up your diet and living space. Here’s a guide to four of the most common heavy metals – arsenic, cadmium, lead and mercury – the effects they have on the body, and the ways you can mitigate your exposure.

Arsenic

What It Is
There are two types: organic and inorganic. Organic arsenic occurs naturally in the earth and small amounts are necessary for the body to function properly. Because the soil contains organic arsenic, many foods have traces of the metal, but it’s not considered toxic. The problem is inorganic arsenic, a known carcinogen. Inorganic arsenic is released into the air by burning fuel oils and coal and also by the widespread use of weed killers and insecticides.

The wood industry is one of the biggest culprits in arsenic pollution. The industry has used arsenic to preserve wood since the 1940s. Arsenic-laced wood has been used to make an estimated 90 percent of wooden play structures, decks and picnic tables. In 2002, the EPA announced the industry decision to phase out arsenic-treated wood, but some consumer advocates assert that the agency hasn’t gone far enough.

Adults and children can absorb arsenic simply by touching wood treated with arsenic. In a study by the Environmental Working Group (EWG), an environmental watchdog organization based in Washington, D.C., researchers found that “the amount of arsenic wiped off a small area of wood about the size of a 4-year-old’s handprint typically far exceeds what EPA allows in a glass of water.”

Other sources of arsenic exposure include herbicides and many foods, including meat, fish, poultry and even wine. (Arsenic-containing pesticides are often sprayed on winemaking grapes.)

What It Does
The average person’s body contains about 10 to 20 milligrams of arsenic. The good news is that the body efficiently rids itself of the metal. Up to 95 percent of the arsenic the body absorbs is excreted by the kidneys and bowels. The bad news is that chronic exposure to low levels of arsenic can create problems for nearly all the organ systems and is strongly linked to lung and skin cancer.

What You Can Do

  • Buy organic, pesticide-free fruits and vegetables.
  • Avoid insecticides and weed killers. If you must spray, avoid products that contain lead arsenate.
  • If your home has arsenic-treated wood, consider replacing it with newer, healthier, arsenic-free alternatives. Keep children away from wood treated with the chemical.
  • Don’t eat food directly off of picnic tables.
  • Add vitamin C to your diet by upping your intake of citrus fruits, strawberries and red peppers. The nutrient can help protect the body from arsenic toxicity.

Cadmium

What It Is
Cadmium is a growing source of environmental toxicity. Found deep below the earth’s surface, cadmium began to contaminate the food and water supply when people began mining for zinc, which is often found mixed with cadmium.

What It Does
Since cadmium is naturally drawn to zinc, it can elbow zinc out of the body, which throws key biological functions out of whack. Without a proper zinc-to-cadmium ratio, the body becomes more vulnerable to cadmium toxicity.

One of the biggest contributors to cadmium toxicity is refined grain. Grains are exposed to cadmium in the soil. The cadmium nestles into the grain’s inner kernel. Zinc, on the other hand, is housed primarily in the outer germ and bran layers. When grains are refined, the outer zinc-rich layers are stripped off and the cadmium-rich kernel is kept. Eventually, too much cadmium can lead to a depressed immune system, kidney damage and cancer.

Cadmium is also found in cigarette smoke. One cigarette contains 1 microgram of cadmium. When smoked, 30 percent of a cigarette’s cadmium is absorbed directly into the smoker’s lungs. The other 70 percent is released into the air.

What You Can Do

  • Don’t smoke and avoid exposure to secondhand smoke.
  • Replace white bread, white rice and white pasta with their whole-grain alternatives. Eat zinc-rich foods, such as whole grains, beans and nuts, wheatgrass and spirulina.
  • Take a daily multivitamin or super-green supplement that includes zinc, calcium and selenium. All three help the body rebuff cadmium deposits.

Lead

What It Is
Lead was discovered as a byproduct of smelting silver and has been used by humans since the beginning of civilization. Unfortunately, lead is a potent neurotoxin that affects brain development and the nervous system. Too much can be deadly. In fact, some historians blame lead for the fall of the Roman Empire. Romans used lead to make water pipes and storage containers for food and water.

In the 20th century, gasoline was single-handedly responsible for most of America’s lead emissions. In the 1920s, oil companies discovered lead was an inexpensive octane booster. Unfortunately, it took several decades for scientists to realize that people were being slowly poisoned, according to Pirkle. Gas makers began phasing lead out of the production process in the 1970s.

Paint is also a significant factor in lead pollution. Before 1955, much of the white house paint used throughout the country contained up to 50 percent lead. It wasn’t until 1971 that the government lowered allowable lead levels in paint to 1 percent. By 1977 that number was reduced to .06 percent. But that doesn’t mean paint no longer poses a threat: 83 to 86 percent of homes built before 1978 still contain lead-based paint.

Today, one of the main sources of lead exposure for adults is drinking water. Lead can seep into water from lead pipes, faucets and solder, found primarily in older buildings. It is also found in lead-wicked candles.

What It Does
Of all the heavy metals in our bodies, lead is the most plentiful. It’s estimated that people have between 125 and 200 milligrams of lead in their bodies, nearly 1,000 times more than our ancestors. Inside the body, high lead levels may cause less pliable arteries, an irregular heartbeat and high blood pressure. The body stores lead in the teeth and bones, both places that welcome minerals. “There is no known minimum level of lead that is safe for humans,” says Lipski.

Authors of a recent study, published in the March 2003 issue of Journal of the American Medical Association (JAMA), found a link between high blood pressure and lead in the blood. The relationship was most pronounced in postmenopausal women, a population already at high risk of heart disease.

Specifically, women with the most lead in their blood had a 3.4-fold increased risk of hypertension compared with those women whose blood contained the least amount of the mineral. Although scientists don’t fully understand the connection between lead and heart disease, they suspect the higher blood levels in postmenopausal women may be related to the fact that the body stores lead in the bones. Therefore, when women begin to lose bone mass during menopause, lead is released into the body.

When a patient with hypertension comes to see him, naturopathic physician Crinnion immediately tests for heavy metals. “We are finding very high heavy-metal burdens in people with hypertension,” he says, “especially those who don’t respond well to medication.”

What You Can Do

  • Consume more vitamin C. The vitamin latches onto lead and ushers it from the body via urine. Eat plenty of citrus fruits and take a daily supplement containing between 250 and 500 milligrams of the vitamin.
  • Keep up your calcium levels. Calcium vies for space with the metal and prevents it from entering bone cells. Stock up on calcium-rich foods, such as low-fat dairy products, broccoli, sardines and collard greens.
  • Do not burn candles unless their labels specify that the wicks are lead-free. Many metal-wicked candles, especially imports, contain lead. When burned, the metal is vaporized (meaning you can breathe it) as well as turned into ash, which can put a fine layer of leaded dust on nearby surfaces.
  • Before you fill up your drinking glass with tap water, flush standing water from the pipes by letting the faucet run for a few minutes. (Better yet, install a water filtration system.) Also, drinking cold water will cut down your exposure, since leaching rates rise when water is heated.
  • If you are renovating an older home, consult a professional or your county lead-abatement program.

Mercury

What It Is
Of all the heavy metals, mercury often gets the greatest spotlight. Coal-burning power plants are the biggest mercury polluters. Each year hundreds of power plants in the United States spew around 98,000 pounds of mercury into the air. From this air and ground contamination, mercury seeps into rivers, lakes and oceans, where small organisms, like algae, absorb it. The toxin makes its way up the food chain to bigger and bigger fish, becoming more concentrated at each level. Mercury levels in fish at the highest levels of the food chain, such as shark, can measure thousands of times higher than the water in which they live. Once it enters the environment, mercury never leaves.

Last year, the EPA said it was considering two plans: requiring utility companies to install maximum achievable control technologies (MACT), which would cut emissions by 30 percent by the end of 2007; or a market-based cap-and-trade program that would reduce mercury emissions by nearly 70 percent by 2018 (go to www.generation green.org/cap-trade.htm for more information on cap-and-trade). The EPA has suggested that MACT rules would be less effective than cap-and-trade, yet a 2001 EPA report indicated that MACT alone could lower emissions by 90 percent by 2008. So far the Bush Administration has ignored the earlier report and the EPA has yet to make a final recommendation. (For more on this story, see The New York Times magazine article, “Changing All the Rules,” [April 4, 2004], available at www.nytimes.com.)

Another use of mercury is in dental amalgam fillings. The controversy is still swirling over whether or not people with amalgam fillings suffer ills because of mercury exposure. (See “Mouthful of Mercury?” below.) Although mercury-free fillings are now available, many dentists swear by conventional amalgam fillings. In 1999, the most recent year for which numbers are obtainable, Americans received about 71 million new amalgam fillings.

What It Does
Mercury competes for space in red blood cells with oxygen. When oxygen can’t get through, the body is deprived of energy. As a result, a common symptom of mercury poisoning is fatigue. Mercury is also a potent neurotoxin. The heavy metal disrupts the development of the central nervous system, therefore mercury is most dangerous for pregnant women, children and teenagers. But scientists are just beginning to understand how chronic, low-level exposure to mercury may contribute to chronic ills most often seen in adults, such as heart disease and cataracts.

What You Can Do

  • Be fastidious about fish. Much of the world’s fish supply is contaminated with methylmercury, a particularly hazardous form of the metal. When shopping for seafood, aim low on the food chain. That means more cod and sardines and less swordfish. If you’re a tuna lover, proceed with caution. The popular fish lands smack in the middle of the mercury scale. Light canned tuna and fresh yellowfin tuna are likely to be less contaminated than white canned tuna and albacore.
  • According to an advisory published last March by the Food and Drug Administration, pregnant women, women who may become pregnant, nursing mothers and young children should avoid shark, swordfish, king mackerel and tilefish, as well as limit their consumption of other fish (shrimp, canned light tuna, salmon, pollack and catfish) to 12 ounces (roughly two meals) a week.
  • Eat seaweed with your fish. “Seaweed is a natural chelator in the gut,” says Haas. “I always make sure I have seaweed when I eat fish.” Seaweed not your thing? Then take a daily selenium supplement of at least 200 micrograms. Selenium helps the body ward off toxicity from heavy metals, including mercury.

Catherine Guthrie is a freelance health writer in Bloomington, Ind. Her work also appears in Alternative Medicine, Yoga Journal and Arthritis Today.

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