Mercury

Your amalgam or metal fillings will make you sick

Mercury has gotten such a bad rap in recent years that it’s hard to remember why it was ever considered good in the first place. Though there’s no real evidence showing it’s a problem, people don’t like the mercury in vaccines. There’s the mercury in fish, which no one likes. And there’s plain old mercury in a number of work sources that causes neurotoxicity, and absolutely no one likes that. So it’s no wonder that we finally got around to being upset about the mercury in our dental fillings.

Why is it there in the first place? Well, dentists use it because it works. A dental amalgam filling is 52 percent mercury and 48 percent copper, zinc, and silver. Mercury, an odd metal that is in liquid form at room temperature, binds the other particles together into a tough, long-lasting compound.

So what’s the problem? Well, the reason that so many people are concerned about mercury is that there is a fairly large amount of research that shows it’s terrible for you. Mercury toxicity has been linked to fatigue, memory loss, and depression. It’s also bad for the immune system, and has been shown to interfere with the production of immunoglobulins and antibodies in animal studies. And the fact that mercury got tied into the whole vaccine mess didn’t help.

But what makes this a myth is the fact that, while mercury is bad for you, it is much harder to say that the mercury in your fillings is bad for you. For one thing, it is a different kind of mercury. For instance, the mercury in fish is methylmercury, which is an organic mercury. Methylmercury is mostly absorbed in the digestive system and is much more toxic than, for instance, mercury vapor. Mercury vapor is absorbed mostly in the lungs. The mercury in amalgam fillings is elemental mercury, and—you guessed it—it’s released as mercury vapor.

Moreover, there are simply no good studies proving that people with mercury amalgam fillings have worse health outcomes, like those above, than those without. And it’s not as though those studies would be difficult to do. There are many millions of people with amalgam fillings in their mouths right now. Aaron’s got one. Rachel’s got many. And any proof of Aaron’s superiority cannot be blamed on Rachel having more amalgam fillings.

In fact, such a study has been performed. Scientists looked at two different databases: (1) ninety patients who were part of a clinical trial that removed amalgam fillings in people who thought their health complaints were due to the fillings, and (2) 116 patients from an environmental medicine clinic who thought their symptoms were due to environmental sources, and not the fillings. They found that the amalgam-blaming group more frequently reported mental symptoms while the environment-blaming group had more physical symptoms. Overall, there was no proof of an amalgam-specific syndrome.

Nonamalgam fillings are much more expensive. Many patients simply can’t afford them. And fillings are really important to dental health. There are lots of studies that show that having good teeth is a very important part of being healthy overall. People are much better off getting amalgam fillings than nothing, and amalgam fillings are not proven to be bad for your health.

Eating fish while you are pregnant will give your baby birth defects

Most pregnant women want to do whatever it takes to have the healthiest baby possible. Many women quit smoking and avoid drinking alcohol. (And, as pediatricians, we should quickly note that not smoking and not drinking alcohol are proven to be very good ideas for your growing baby!) Pregnant women also try to choose foods that will be safe and healthy for their developing baby. They are instructed to avoid deli meats, sushi, and soft cheeses because of the potential for these foods to harbor dangerous bacteria. They are also told to avoid eating fish because it can contain too much mercury and other toxins.

Whether or not pregnant women should eat fish is a dilemma. Exposure to too much mercury can cause problems for the development of a baby’s brain. Too much mercury is not good for any human being, but it is especially problematic when a baby is in the womb and their brains are still developing. Many people have been worried about a connection between being exposed to mercury and developmental delays. While the science on this connection is not conclusive, the concerns make people understandably eager to avoid taking in too much mercury. Fish and shellfish can contain mercury, and so many pregnant women are told to avoid eating them. Even if the risks are relatively small, it makes sense to be extra careful to protect a developing baby.

Eating fish may also impact how big the baby grows. Eating lean fish is also associated with a lower risk of having a baby that is smaller than they should be (this is a good thing). In contrast, eating more servings of canned tuna and shellfish have been associated with a higher risk of having babies that are smaller than they should be. Whether this is related to the amount of mercury in canned tuna or shellfish or whether it is related to something else about these types of fish has not yet been figured out.

Eating fish can be beneficial for both pregnant women and their developing babies. Fish is a good source of protein and contains lots of omega-3 fatty acids, which are considered healthy for our hearts and brains. A review of the research about fish and shellfish that was published in 2006 in the Journal of the American Medical Association found that eating more fish was associated with many good things for your body; eating more fish was connected with having less heart disease, fewer deaths from heart disease, and fewer deaths overall. (Perhaps we should recommend a fish a day instead of an apple!) In contrast, the risks from mercury and the other toxins in fish were found to be very low in the studies that were identified. Given the strong benefits from fish and the low risks, this review recommends that even pregnant women should eat fish.

Recent studies have gone even further. They not only find no increase in birth defects among the children of mothers who ate fish, but also that the children of pregnant women who ate fish actually have better scores on tests of their brain development when they are four years old. Even if too much mercury has a potential to cause problems for developing babies, the benefits of fish for the brain may outweigh the risks!

If you want to get the benefits from fish while keeping your risk of mercury poisoning as low as possible, you can eat fish that are extra safe. Some fish contain a lot more mercury than other types of fish. This can also vary from one region to another, so you might want to check what fish are available and recommended where you live. The general recommendations from the United States Department of Health and Human Services state that pregnant women should avoid the fish that have the highest levels of mercury. This means avoiding shark, swordfish, mackerel, and tilefish. The department also recommends that you should not eat more than six ounces of white tuna, albacore tuna, or tuna steak per week. In one week, a pregnant woman should not eat more than two servings or twelve ounces of fish. In general, good fish choices for pregnant women are shrimp, salmon, pollock, catfish, and light tuna, and there may be other fish in your area that are recommended.