Apple a Day

Most everyone knows the old adage, an apple a day keeps the doctor away, and now scientists have shown that there's more truth to the statement than you might think. I just read an interesting article that reported on a recent study published in the journal Thorax that show that the children of women who ate apples frequently during pregnancy had fewer asthma-related wheezing incidents, and that the children of women who ate plenty of fish during pregnancy had less trouble with eczema.

One thing about the article that stuck with me was a quote attributed to the scientists who did the study: "The advantages of studying foods are that they contain a mixture of micronutrients that may contribute more than the sum of their parts, and that associations with micronutrients that may be currently unrecognised or not easily quantifiable can be examined." Real foods do contain micronutrients that are simply missing from the processed products that line store shelves.

Eat Your Fish

Fish can be dangerous, with mercury and PCBs accumulating in their tissue, yet fish is also a truly remarkable health food. Fish are the best source of those wonderful omega-3 fatty acids, which are associated with all kinds of health benefits ranging from improved cardiac health to improved mood and behavior, and reductions in cancer risk and arthritis symptoms.

Our bodies can't produce these beneficial omega-3 fatty acids; they have to come through our diet, and cold water fish are by far the best source of omega-3 fatty acids. (Other sources include grassfed meat and milk.)

These fish are your best choices for both environmental sustainability and health reasons, and are safe to eat at least once per week:

anchovies,

clams,

Dungeness crab,

king crab (US),

snow crab,

Pacific cod,

crawfish,

Atlantic herring (US/Canada),

lobster (US/Baja/Cananda/Australia),

Atlantic mackerel,

blue mussels,

farmed oysters,

wild Alaskan salmon,

sardines,

farmed scallops,

shrimp (US/Canada),

squid,

tilapia (US/Central America),

farmed rainbow trout,

canned tuna (light/skipjack).

The fish you should absolutely avoid include:

bluefish,

striped bass,

American eel,

weakfish,

king mackerel,

bluefin tuna,

swordfish,

shark,

croaker,

Atlantic salmon.

If you forget the list, this list, and other tips on healthy living are available on the Toxic Burden Living Clean Tips page for easy access.

Mercury levels in fish eaters

This week the New York Department of Health and Mental Hygiene issued a report on mercury levels in the city's population. Taken from the city's Health and Nutrition Examination Survey (HANES), the report found that "among women 20-49 years old in New York City, the average blood mercury level is 2.64 µg/L (micrograms per liter), three times that of similarly-aged women nationally (0.83 µg/L)," and "approximately one quarter of New York City women in this age group have a blood mercury level at or above 5 µg/L."

Another interesting fact from the HANES study: "Higher-income New Yorkers have higher mercury levels; New Yorkers in the highest income bracket average 3.6 µg/L, compared to 2.4 µg/L among the lowest income group."

We usually think that high-income people are healthier because they have access to better food and better health care. So why do high income New Yorkers have higher mercury levels? Because... they have access to better food. High-income people tend to eat more fish, and more expensive fish (can you say sushi?) and it is this fish that is contributing to higher levels of mercury in these women's blood.

I met Dr. Jane Hightower earlier this year at a conference. In the mid-to-late 1990s, Hightower, a thin, dark-haired woman with the intensity of a bloodhound following a choice scent, had dozens of patients being referred to her who had similar yet indistinct symptoms. Other doctors may have finally given these patients a diagnosis of something—Lyme’s disease, chronic fatique, fibromyalgia—but the patient’s tests didn’t quite fit the normal profile for the diagnosis that they had received; nor had treatment seemed to make them any better. Desperate for help, and often years into their hunt for an answer, they’d show up in Hightower’s office.

“I enjoy problem solving,” Hightower, an internist at San Francisco’s California Pacific Medical Center, explains, “so I get a lot of patients that have been through numerous doctors, and through even more numerous tests. These patients were coming in and saying to me, ‘I just don’t feel well. I have a headache all the time, and always feel like I have a hangover. My stomach’s upset. I have muscle and body and joint pains, and I have trouble thinking.’

These patients were a mixed lot: they spanned all age groups, from young kids to the elderly, included both men and women, and represented various ethnic groups. There were CEOs and physicians, secretaries and soccer moms. Many mentioned loss of motor control, and a number added hair loss to their complaints.

“All these patients had one thing in common—they had a laundry list of non-specific symptoms,” Hightower says.

For a long time, her patients’ symptoms had Hightower stymied, but one day in 1999 one of her colleagues, dermatologist Kathy Fields, mentioned that on a recent trip to Idaho she’d heard a call-in radio program about people with high mercury levels in their hair and blood. The common denominator among the callers was that they fished in Idaho lakes, and ate the fish. One symptom really piqued Fields’ attention: hair loss. Dermatologists frequently deal with hair-loss patients, and Fields knew that at least some of Hightower’s mystery patients reported hair loss.

The two doctors teamed up, arranging to test just one of Hightower’s patients who was suffering from hair loss. “We didn’t even really know what test to ask for,” Hightower says. “But we checked her blood, and it came back with what seemed like a high organic mercury level.”

With the results in hand, Hightower had to figure out what they actually meant. She tried to search the medical literature, but there was a paucity of information on mercury in the common texts that doctors refer to. Next, she checked with the California Department of Health; they said organic mercury could go up to 200 µg/L in blood, so mercury wasn’t the patient’s problem. But Hightower did a little more research, and found that the Environmental Protection Agency put the safe level for blood at less than 5 µg/L. The lab, which typically tested occupational exposures, told Hightower they use 13 µg/L ‘at the end of the work week,’ as the safe figure. Hightower pauses in telling her tale: “I scratched my head, and said, ‘Houston, we have a problem. No one is on the same page.’

Hightower reported the patient’s results to the regional poison control center. They put together a team, and went to the patient’s home and place of business. They searched for a source—and didn’t find one. But they tested all the employees at the business, and found two that also had high levels of mercury. The common denominator seemed to be the same one the Idaho callers had talked about on the radio program: high-mercury results corresponded to frequent fish consumption. Hightower tested a few more patients from the laundry-list group; they too had high levels of mercury.

Knowing that a few of her patients indeed had high mercury—which appeared to be associated with their fish consumption—Hightower decided to look more closely at mercury across the spectrum of patients coming into her practice. She designed an experimental program that involved all 720 patients who came to her office for a one-year period. Each patient was asked to complete a survey that asked questions about fish consumption, vaccination history, and about the number of amalgam, or silver fillings the patient had in their teeth because amalgam is another source of mercury. Her findings: patients who ate a lot of fish had significantly higher mercury levels than patients who consumed little or no fish, frequently exceeding the mercury levels EPA reported to be safe.

Mercury releases from chlorine production

This week, Oceana, a nonprofit that works to protect the world's oceans, released a new report, Cleaning UP: Taking mercury-free chlorine production to the bank. Their report outlines how a handful of producers are still releasing large amounts of mercury when there are cost-effective alternatives. According to their report, "Globally, the chlorine industry had largely moved to mercury-free technology by the turn of the 21st century. In the United States, the industry reported that by 2004, 90 percent of its chlorine was produced using mercury-free technology and no new mercury-cell plant has been built since 1970. Oceana’s Campaign to Stop Seafood Contamination targets the plants responsible for the remaining 10 percent."

Why does this matter? Because mercury is a known toxic, and persistent chemical: once it is released into the global mercury pool, it doesn't go away. Mercury is then deposited in the oceans, where it is taken up at first in microorganisms. These are eaten by higher organisms, which are eaten by higher organisms, which in turn are eaten by even higher organisms. The mercury eventually finds its way into the fish we eat. The predator species in the oceans, such as tuna, shark, and swordfish, have some of the highest levels of mercury in their flesh.

In 2004, the Food and Drug Administration and the Environmental Protection Agency jointly issued an advisory on fish consumption to begin addressing mercury concerns. The mercury in fish can be dangerous to anyone, but babies in the womb and small children are particularly vulnerable, so the federal advisory recommends that women who may become pregnant, pregnant women, nursing mothers, and young children avoid some types of fish and eat fish and shellfish that are lower in mercury.

By following these 3 recommendations for selecting and eating fish or shellfish, women and young children will receive the benefits of eating fish and shellfish and be confident that they have reduced their exposure to the harmful effects of mercury.

1. Do not eat Shark, Swordfish, King Mackerel, or Tilefish because they contain high levels of mercury.

2. Eat up to 12 ounces (2 average meals) a week of a variety of fish and shellfish that are lower in mercury.

   • Five of the most commonly eaten fish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish.

   • Another commonly eaten fish, albacore ("white") tuna has more mercury than canned light tuna. So, when choosing your two meals of fish and shellfish, you may eat up to 6 ounces (one average meal) of albacore tuna per week.

3. Check local advisories about the safety of fish caught by family and friends in your local lakes, rivers, and coastal areas. If no advice is available, eat up to 6 ounces (one average meal) per week of fish you catch from local waters, but don't consume any other fish during that week.

The Environmental Defense Fund has a great site on fish consumption recommendations at their Oceans Alive website.

Fish advisories may help reduce problems, but reducing mercury emissions from sources such as the chlorine-production industry is a real key to long-term environmental health--for us and the fish!