A Story of Whales, Mercury & Controversy


Mercury is a toxic substance that can evoke a wide range of symptoms up to and including brain damage. In Merry Olde England, mercury was used in the manufacture of hats causing many workers to become ill and giving rise to tales of "Mad Hatter's Disease." Due to the threat of mercury poisoning, the EPA ( Environmental Protection Agency ) has put limits on the seafood consumed by children and pregnant women. Over time, fish accumulate mercury from contaminated water and older, larger fish accumulate the most. The chart below presents the recommendations of the EPA. If you assume 100 gram serving sizes, these recommendations would limit mercury intake to 96 micrograms per month. If you are an adult and are not pregnant, the EPA has not issued warning limits.

EPA Recommendations for Children and Pregnant Women

Serving Limits
(meals per month)

Mercury
(concentration ppm)

Type of Fish

Don't eat ever

0.97-1.90 ppm

Tilefish
1 per month

0.48-0.96 ppm

Swordfish, mackerel, shark,
red snapper, orange roughy,
saltwater bass, moonfish
2 per month

0.24-0.48 ppm

Marlin, trout, fresh tuna,
frozen tuna, lobster, grouper,
and bluefish
4 per month

0.12-0.24 ppm

Canned tuna, halibut, pollock,
crab, cod, mahi-mahi, haddock,
whitefish, herring
8-16 per month

less than 0.12 ppm

Perch, salmon, shrimp, clams,
oyster, tilapia, scallops, catfish,
flounder, sole


Fish are not the only sources of mercury we have to worry about. Most of us have fillings in our teeth made from an amalgam of mercury and silver. The American Dental Association claims that mercury in fillings stays put even though they are bathed in saliva year after year. The Swedish government has a different view and has banned dental mercury. According to Swedish studies, the average Swede with amalgam fillings is exposed to 48 micrograms of dental mercury every day, of which a fourth is absorbed into body tissue. Such continuous exposure would amount to 1440 micrograms per month, about 15 times the EPA limit for fish mercury. How reasonable are these numbers? At the Swedish rate of mercury loss, would there be any left after 50 years? Let's do a calculation based on 8 fillings, each with 1/2 gram of mercury. The total mercury available would be 4 grams. After 50 years, the loss would be 0.86 grams or 22% of the total. That sounds believable to me considering many fillings have to be replaced. I guess we have to be concerned about mercury in teeth, although the American Dental Association disputes the Swedish numbers. It is also claimed that the mercury in fish is an organic form called methyl-mercury that is more toxic than the elemental form in dental mercury. You have to be an organic chemist to decide whether to be afraid.

Why am I so concerned about mercury? It is thought that mercury can interfere with sulfite oxidase enzyme production and be at the root of some forms of sulfite sensitivity. To better judge my risk, I had my hair analyzed for toxic mineral imbalances and my mercury levels were twice the recommended maximum. It will come as no surprise that I used to have 6 amalgam fillings. Based on the excessive mercury in my hair, I tried supplementing with chlorella algae, cilantro and alpha lipoic acid which are reputed to help cleanse the body of heavy metals. It helped me somewhat. Since that time, I have had my amalgam fillings replaced with acrylic material. That has also helped me a little.

So, do I recommend that you stop eating fish and have your amalgam fillings replaced? Mercury is a danger and methyl-mercury is even worse. But here is where the story gets really interesting. The study used by the EPA in designing limits on fish consumption may have been interpreted improperly. In other words, sloppy science. They looked at a study of a fish eating population on the Faroe Islands which showed a strong correlation between mercury levels in the diet and health problems. Based entirely on the Faroe study, they applied a safety margin and established the above table of limits for children and pregnant women. Unfortunately, they ignored a similar study in progress on the Seychelles Islands. On the Seychelles, the population seemed to have no symptoms of mercury poisoning although they ate just as much seafood. What's the difference in the two studies? According to Dr. Nicholas Ralston of the Energy & Environmental Research Center of the University of North Dakota, the big difference was the mineral selenium. Selenium is widely known to counter the effects of mercury, binding with and inactivating mercury's mischief. In most ocean species, selenium occurs in greater concentration than mercury. The pilot whale is a rare exception to this rule, having low levels of selenium along with high levels of mercury. Unfortunately for those on Faroe, they eat pilot whales resulting in lots of mercury with very little selenium. The people of the Seychelles have a more normal fish diet, get plenty of selenium and have no mercury problems. Who are you going to believe, Dr. Ralston or the EPA? The EPA is not willing to change its stance, claiming the issue needs more study. Dr. Ralston thinks most fish are not only safe but of tremendous nutritional benefit. Below are some of his selenium to mercury ratios for fish of interest. For most fish, the ratio is greater than one, meaning those fish contain more selenium than mercury. The blue part of the graph represents excess selenium and might be interpreted as a safety margin.

Selenium Relative to Mercury

Using both the EPA mercury table and Dr. Ralston's selenium chart, it would seem you shouldn't eat pilot whales or most sharks. I suppose you could also avoid tarpon and tilefish, although I don't think I've ever seen either one. The fish most people prefer are pollock, tuna, flounder and salmon.  In those fish, the selenium out numbers the mercury better than 10 to 1. And you know what, selenium is a part of most daily vitamin mixtures or is available as a supplement on its own. Because of Dr. Ralston's work, I routinely take selenium whenever I am concerned about mercury. For instance, before having the amalgams removed from my teeth, I took selenium supplements and continued them for several weeks thereafter. Even a careful dentist will contaminate you with mercury gas and particles during the removal process. Being chock full of selenium minimizes the harm during your transition to a mercury free mouth. On the other hand, if you want to keep your amalgam fillings, perhaps it would be a good idea to take 50 micrograms of selenium every day to counter the 48 micrograms of mercury that leaches from all those Swedish teeth.

Mercury in fish is not the only controversy concerning human health. Sulfite discussions contribute their own controversies which I am sure you will encounter as you surf the web. Countless questions arise over bottled water, sulfates, canned goods, dangerous food, test strips and medical proclamations. Here is my take on a few of these issues.

Does Bottled Water Contain Sulfites? Several websites claim bottled water contains sulfites. They are wrong. Bottled water contains no sulfite but it does contain sulfate. The confusion arises over a misunderstanding of the difference between sulfites and sulfates. Sulfites contain a sulfur atom bonded to 3 oxygen atoms ( SO3 ). Sulfates have one more oxygen ( SO4 ). Most people with a sulfite sensitivity must avoid sulfites, sulfur dioxide and sulfa drugs, but not sulfates. An unlucky few people do have problems with sulfates. These folks usually have skin reactions to soap and shampoo that contain sodium lauryl sulfate. If you don't get skin rashes or hives from soap and shampoo, most likely you don't have to worry about sulfates. Of course, if you are troubled by rashes, then avoiding bottled water high in sulfates may be prudent. Mineral waters like Pelligrino contain the most sulfate, as high as 500 ppm. Spring waters like Poland Spring and Volvic contain very low levels of sulfate, less than 7 ppm. None of them contain sulfite.

CandyAre Canned Goods Dangerous? Many websites list general categories of food that contain sulfites. Such warnings include bakery and canned goods, candy, cereal, condiments, soups and sauces, crackers and chips, packaged products, salad bars, seafood and spices to name a few. Such lists are meaningless because they are too broad. Sure, there are sulfited items in every category of food. But there are good choices in every category, too. You just have to read the food labels and know what ingredients are taboo. In particular, canned goods are no more dangerous than any other food group. Yes, canned garbanzo beans, sauerkraut, hominy and marinated beans are usually preserved with sulfite. Also, canned fruits can be packed in heavy corn syrup, baked beans may contain molasses and chili usually has caramel color added. So, you have to watch out and read labels. But canned peas, green beans, lima beans, pinto beans, tomatoes, tomato paste, beets, corn, carrots, asparagus, artichokes, mushrooms, olives and potatoes are typically OK. And, if you look really hard, you can even find canned fruit packed in pear juice instead of corn syrup.

Is Pectin ( in Jelly and Jam ) Sulfited? Some foods have a historical overhang, but are safe today. Pectin used to be preserved with sulfite when Lassie was America's favorite dog. Currently, pectin is a safe ingredient. The same is true of clams. They were preserved with sulfite, but today, triphosphate preservatives are used. This makes clams ( and some clam chowders ) perfectly safe. Hooray! Apple cider vinegar is another case in point. Sulfites were added in the past. Today, apple cider vinegar has been transformed into a health food item and the sulfites are typically gone. We cannot forget about canned tuna. Many years ago, a canner accidentally added sulfites to the tuna, resulting in a recall with lots of media attention. The bad image has stuck and many people will still tell you to avoid canned tuna. You don't have to avoid it, as canned tuna is a safe bet. Finally, we must discuss the salad bar in your favorite restaurant. All of the current laws regarding sulfite labeling are the result of deaths in the 1980's, many due to sulfites on the lettuce in salad bars. Today, if lettuce is treated with sulfite, there must be a warning sign. I have eaten at hundreds of salad bars in recent years and never seen such a sign. Salad bar lettuce is safe in my experience. Of course, you have to be careful what you put on top of the lettuce. Avoid pickled peppers, raisins, banana chips, shredded coconut and sausage. And, the dressing can be a problem, too. It is safest to bring your own from home, perhaps seasoned rice vinegar. If you are willing to gamble, I have had pretty good luck with blue cheese dressing.

Sulfite TestingCan Sulfite Test Strips Help? Test strips are available that turn pink when dipped into a solution containing sulfite at 10 ppm or greater. The ones I am most familiar with are made by Merck Company and marketed under the EM-Quant brand. The good news is they work pretty much as advertised. The bad news is there are a few catches. For instance, if the solution is strongly colored, especially red, the pink indicator is difficult to discern. Secondly, the strips are sensitive only to the sulfite ion and not to sulfur dioxide locked inside a molecule. This means a strong sulfa drug ( which contains sulfur dioxide in every molecule ) will not turn the strips pink. And finally, the 10 ppm test limit is not sensitive enough to detect a wide range of dangerous foods. Consider an 8 ounce glass of juice, weighing about 240 grams. The 10 ppm threshold would be 10x240=2400 micrograms of sulfite. That means a glass of juice containing less than 2400 micrograms would test clean. Compare that to my threshold of a few hundred micrograms and you can see why I don't think much of sulfite test strips. That being said, if your personal tolerance to sulfites is ten times higher than mine, then maybe the strips could be beneficial. This would be especially true if your tolerance was high and your reaction was dangerous.

It has also been suggested that sulfite strips are capable of diagnosing an intolerance by simply testing urine. As I understand this argument, if your urine turns the strips pink, your body does not properly process sulfite and it winds up in the toilet. Unfortunately, the numbers don't add up. A typical human body weighs about 70 kg and is 2/3 water. This amounts to about 40 kg of water. If all the water in your body contained the same level of sulfite in urine, it would take 400 mg or 400,000 micrograms of sulfite to reach the 10 ppm threshold of the test strips. I don't know but that sounds like a lethal amount of sulfite, at least for me. I supose you could argue that concentrations differ between urine and the bulk of body water, but I must give you one more piece of information. I have tried this test and the strips do not detect sulfite even when I have a monster headache.

If You Don't Have Asthma, Are Sulfites Safe?
Some impressive medical websites make strong statements about sulfites. For instance, consider the following claims. Are they true?

"Sulfite sensitivity is unusual if you are not asthmatic."
"An allergy to sulfa drugs does not imply an allergy to sulfite."
"The typical symptoms are breathing problems, hives and allergic shock."
"Foods with under 10 ppm sulfite have not been shown to cause trouble."

Well, all I can say is I am the exception to every one of those statements. And so are the thousands of people that have written to my website over the past ten years. Most doctors care about their patients, are pretty smart and are well educated. Unfortunately, they weren't taught much about sulfites in medical school. And most of what they were taught revolves around the subset of asthma patients that react to sulfites. If you are shopping for a doctor to help with your sulfite sensitivity, you probably won't find one that knows much about it. But you can find doctors that are sensitive to your needs and willing to work with you. Perhaps, you can avoid the allergy specialist that I consulted about my sulfite headaches who told me, " I never heard of headaches caused by sulfites and there's nothing I can do for sulfites, anyway. By the way, stay away from salad bars." That's when I decided to write a book and put it on the web.

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