Questions for Andrew T. Weil, MD

Mercury in fish
I just read about high mercury levels found in fish being sold at supermarkets all over the country. This is so discouraging. What should consumers do to protect themselves?

The latest look at mercury in fish did show that fish from supermarkets in 22 states had levels higher than we should be consuming. The University of North Carolina’s Environmental Quality Institute tested swordfish and tuna sold at Whole Foods, Safeway, Albertsons and other big supermarkets between July 7 and August 11, 2005. The researchers found mercury levels higher than the legal limit in 24 swordfish samples. The tuna tested had mercury levels that averaged as high as those found in canned albacore tuna, a fish that the Food and Drug Agency (F.D.A.) and the Environmental Protection Agency (E.P.A.) have advised children and women of childbearing age to avoid.

Unfortunately, the results are not surprising. Mercury levels have been a problem for years, particularly in such species as shark, swordfish, king mackerel and tilefish. As you may know, in 2004, the F.D.A. and E.P.A. warned women of reproductive age to limit their consumption of some varieties of freshwater fish and some types of ocean fish.

The mercury comes from natural sources as well as emissions from coal-fueled power plants that pollute the air and end up in the water – and in the fish. During pregnancy, mercury from fish the mother has eaten can get into the bloodstream of the fetus and harm the developing nervous system, which can lead to learning disabilities, developmental delays and other serious health problems.

For years, I’ve been recommending that everyone avoid species of fish known to contain high levels of mercury and opt instead for wild Alaskan salmon (especially sockeye), sardines, herring and black cod (sablefish), which generally have lower levels.

In California, supermarkets are required to post signs notifying consumers that certain fish have high levels of mercury. The advocacy group Oceana has been campaigning to have supermarkets and groceries nationwide post the F.D.A. advisory about which fish are particularly high in mercury at seafood counters and in the tuna aisles. Some supermarkets may be trying to educate consumers by making available a brochure produced by the Food Marketing Institute, illustrating 20 types of fish and seafood that are low in mercury. I’ll continue to follow this story and update you as new information comes to light. In the meantime, you may want to keep up yourself via Oceana (www.oceana.org) or the Environmental Working Group (www.ewg.org).

Farmed Salmon
What can you tell me about the new sustainable, farmed salmon? Is it really a safe alternative to ordinary farmed salmon?

You’re referring to a specific method for farming Pacific Coho salmon that was approved in January 2010 by the Monterey Bay Aquarium’s Seafood WATCH program. (Seafood WATCH is the aquarium’s effort to raise awareness of the link between the seafood we eat and the health of the oceans.)

A little background on farmed salmon: Almost all salmon served today is farmed (“Atlantic salmon”), which has less flavor, less protein and more fat than wild salmon, and its health promoting ratio of omega-6 to omega-3 fatty acids may not be as favorable as in wild fish. It likely also contains residues of pesticides, antibiotics and other drugs used to control diseases that occur when fish are crowded together in the open-net pens of fish farms.

Those diseases may escape and decimate wild populations of salmon. Moreover, it takes several pounds of feed fish to produce one pound of salmon. The net result is greatly accelerated depletion of the numbers of fish in the oceans. That is why I have recommended choosing wild Alaskan salmon. It tastes better, is more nutritious than farmed Atlantic salmon, and eating it does not have the environmental impact or health consequences of relying on farmed salmon.

The news that Seafood WATCH has approved the new salmon farming technique is certainly welcome. I understand that this action followed several months of investigation by scientists who inspected the production facilities and reviewed feed ratios, fish contaminant and pollution discharge levels at the salmon farms. Seafood WATCH explained that the new farming methods contain the fish and water in closed systems, such as tanks, rather than releasing them into the environment. In addition, the use of disease-free source water and strict security protocols “minimize the spread of disease to the wild” and “impact the environment less than open net pens.” Its approval of the farming method means that the salmon from these new farms will be assigned a green “Best Choice” rating on the Seafood WATCH website and “Pocket Guide to Ocean-Friendly Seafood.”

In order to be accorded the “Best Choice” designation, the salmon itself must provide the daily minimum of omega-3 fatty acids (at least 250 milligrams per day) based on 28 grams of fish and have levels of polychlorinated biphenyl (PCB) levels under 11 parts per billion. Limited supplies of the new farmed salmon are scheduled to be introduced in the Pacific Northwest this year. Although my personal favorite is still wild Alaskan salmon, I checked to see how the new tank farmed salmon will be priced and found that this has not yet been determined.

Mad cow disease
What is your take on mad cow disease?

As almost everyone knows by now, mad cow disease (bovine spongiform encephalopathy or BSE) has appeared in the United States, raising the remote possibility that eating beef could lead to the human form of the disease, which resembles Creutzfeldt-Jakob disease. This is a complicated issue that raises important questions about the safety of our food supply and the way cattle are fed and slaughtered.

From a food-safety point of view, the odds of developing the human form of mad cow disease are pretty low. Worldwide, only 153 human cases of the disease related to eating beef have been reported, none in the United States. Odds are that if you continue eating beef you’ll be perfectly safe from this disease. But you should be aware that there is no test for mad cow disease that can be done on live cattle – the available tests are done after the cows have been killed. Of the 35 million cattle slaughtered in this country every year, only 20,000 are tested for mad cow disease, so there’s no guarantee that the disease will be caught before it shows up in your hamburger meat.

BSE is caused by a protein called a “prion” that can’t be destroyed by cooking, freezing, irradiation or the usual methods of chemical disinfection. The highest concentrations of infectious prions are found in the spinal column and brain of sick animals. Some experts think that it might be best to avoid meat that comes in contact with these tissues. This would include beef cheeks, tongue, other head meat and bone marrow. Meat cut from spinal bone, such as porterhouse or T-bone steaks, are more likely to come in contact with spinal cord tissue than cuts such as brisket or shanks.

As for hamburgers, you’re better off grinding it yourself from a chuck roast. Reportedly, prepackaged ground meat can come from as many as 400 different animals and often contains meat scraps. There’s also evidence that meat in hot dogs and sausages as well as hamburger meat comes from a process called “advanced meat recovery” in which meat is extruded from carcasses under pressure. A U.S. Agriculture Department study in 2002 found that this type of meat from three quarters of plants tested contained central nervous system tissue.

I’m very concerned about how cattle are fed these days on the big industrial farms where they’re raised. Instead of grazing and eating grass as the animals do naturally, they’re fed diets that include products made from the blood of their own species as well as “protein” in the form of “chicken litter” – the dirt (including feathers and feces) swept out of chicken houses. A recent article in the New York Times noted that some of this feed may contain bovine meat and bone meal, which F.D.A. rules prohibit in cattle feed. In short, we’ve turned vegetarian animals into carnivores and cannibals, a gross violation of the order of nature. The root problem here is the greed that motivates big factory-farming and the disappearance of family farms. I would like to see more public outrage over these changes.

If you want to continue eating beef, I recommend buying only certified-organic meat. The cattle grown on these farms have not been raised on feed that may carry spinal column and brain tissue, and are much less likely to be spreading mad cow disease.

Irradiated food
Our local school board is considering whether to purchase irradiated meat for school lunches. I think this is scary. What is your view?

This issue came up two years ago when Congress reversed an earlier ban on the use of irradiated food in school lunches, via language inserted in the 2002 Farm Bill. Last year, the U.S. Department of Agriculture, which runs the National School Lunch Program, notified schools that they could purchase irradiated ground beef after the first of this year. There’s no requirement to use the irradiated meat – local school officials must decide whether or not to buy it for their school lunches.

Consumers in general have been leery about the use of irradiated food since it first became available, and so far, there has been no big rush to serve irradiated meat in our nation’s schools. The Los Angeles School Board has banned its use in that city’s schools, and The New York Times reported this past October (2003) that few schools nationwide have plans to use irradiated meat. Apart from the health controversy, which I’ll describe below, irradiated beef costs 13 to 20 cents more per pound than regular beef, a big consideration in some school districts, according to the Times article.

Food is irradiated to reduce the danger of contamination with bacteria such as E. coli 0157:H7 and listeria, a legitimate concern because this kind of food poisoning can be very serious, even fatal. According to the U.S. General Accounting Office there were 195 outbreaks of food poisoning in schools during the 1990s. However, opponents of food irradiation aren’t satisfied that the technique is safe, and question whether long-term effects might include genetic damage and cancer, as some data from animal studies have suggested. There is also evidence that irradiation destroys some vitamins in food and creates dangerous trans-fatty acids in meat.

If you oppose purchasing irradiated meat for use in lunches served in your children’s schools, make your voice heard at school board discussions of the issue or contact Public Citizen (www.citizen.org), the national non-profit public interest organization for information about its “Stop Food Irradiation” campaign.

Artificial flavors
I have read online about what artificial flavors are, but I would like to know if these chemicals are harmful in any way.

Artificial flavors are typically not harmful. However, I’m not crazy about them, because they don’t usually reproduce the natural taste of foods and are often markers for low-quality foods. Whether natural or artificial, food flavors are made up of molecules that occur naturally and can be synthesized. In general, natural flavors are much more complex than artificial ones, which have far fewer component molecules.

Artificial flavors may be more stable than natural ones and certainly are less expensive, so manufacturers prefer them, and many consumers are satisfied with them. There is even a weak case to be made that artificial flavors are safer for consumption because they omit components of natural flavors that may be slightly toxic.

If a food product contains artificial flavors, you should check to make sure that it doesn’t also contain less desirable additives. Read labels carefully to check for high fructose corn syrup (HFCS) used to sweeten soft drinks and juices. HFCS contributes to obesity in many people.

Also, watch out for artificial colorings and dyes (look for the terms “artificial color added,” “U.S. certified color added,” “FD & C red no. 3″ (or “green” or “blue” or “yellow” followed by any number) as well as artificial sweeteners and monosodium glutamate (MSG). I’m suspicious of chemicals used to dye foods. They are a group of highly reactive molecules that may interact with DNA and increase mutation or cell transformation. Read labels and avoid them.

“Questions for Andrew Weil, MD” were previously published at www.drweil.com and have been posted on this blog with permission by the author.

Andrew T. Weil, MD is an internationally acknowledged physician and author best known for his work in the field of integrative medicine. He is the founder and Director of the Center for Integrative Medicine at the University of Arizona. For more information, please visit http://www.drweil.com

The articles written by guest contributors are the sole responsibility of the individual writers in terms of factual accuracy and opinion and do not necessarily reflect the views of the publisher of this blog.

Connect with us on FacebookTwitterGoogle+PinterestLinked InYouTubeRSS