There is a breaking story about small amounts of Mercury being found in high fructose corn syrup, which is used as a sweetener in a lot of junk food.

The frustrating part of the story is that there has been some “ain’t it awful” type articles, but few that actually give us information about what the finding means–although if you eat a lot of junk food, you might want to check this list (pdf file) and eliminate Hershey’s chocolate syrup (but not their other syrups) from your kids diet.

There has been so much hysteria about the tiny doses of mercury used in vaccines causing autism that one hesitates to believe the “ain’t it awful” articles in the press.  The hysteria was probably a false alarm: after all, the autism rate didn’t stop when the mercury was removed, and of course kids in the third world didn’t get autism from their shots.

But mercury is a bad thing, and to put this latest scare into perspective, one has to realize that it is not a new problem.

From the Social History of Medicine:

pink disease (acrodynia),(is) a serious disease of infants and young children that baffled the medical world during the first half of the twentieth century until it was shown to be caused by mercury poisoning. In the English-speaking world the commonest source of the mercury was teething powders, which were widely available and advertised with increasing sophistication.

That was before my time.

An outbreak in the 1950’s and 1960’s in Minamata Japan, however, horrified the world, and led to many countries regulating toxic waste. Photos of the brain damaged Japanese children horrified mothers, and there was some hysteria about the question if mercury fillings in teeth were poisoning the kids.

A later outbreak was in Iraq, when seed grain coated with a mercury compound to eliminate insects, was eaten by some villagers.

Mercury, of course, also is found in natural rocks, and is part of the environment. There are various forms, including elemental (shiny silver) mercury, organic mercury, and inorganic mercury.

But coal burning power plants are a major source of mercury emissions, that get into the food chain.

From the Cebu Daily news:

The power plants that burn fossil fuel, particularly coal, is the primary source of the mercury. It accumulates in streams, rivers, oceans, and with the aid of bacteria, it is chemically transformed into methyl-mercury, which is highly toxic. As the fish feed on aquatic organisms, it absorbs methyl-mercury from the water. Larger fish eat smaller fish, live longer, and so they contain higher level of methy-mercury.

Ah, but it’s a third world problem, isn’t it?

Wrong.

From Treehugger:

According to the Environmental Protection Agency, coal-fired power plants are the largest industrial source of mercury pollution in the country. Mercury is a neurotoxin that has already contaminated water bodies in all 50 states. Also according to EPA , more than one in six women have already consumed so much mercury-contaminated fish that it threatens any children they may have.

Actually, studies in the MMWR show that the blood mercury levels in women are low, but

 approximately 10% of women have Hg levels within one tenth of potentially hazardous levels indicating a narrow margin of safety for some women and supporting efforts to reduce methylmercury exposure.

When I lived in Minnesota, we had to caution our traditional Objibwe people not to eat locally caught fish more than twice a week, and  less than that if they were pregnant.

Again, from the Cebu Daily:

  The Food and Drug Administration (FDA) has “recommended that pregnant women, breastfeeding mothers, and young children avoid eating fish with a high mercury content (>1 ppm), such as shark, swordfish, tilefish, and king mackerel … This also includes fresh and frozen tuna (mercury content between 0.5 ppm and 1.5 ppm) but not canned tuna, which consists of smaller, shorter-lived species with lower mercury levels.”

In layman’s term, what does that mean?

The above stated recommendation translates into consumption of one can (198 g or 7 oz) of tuna for an adult per week, and not more. For children and women of child-bearing age, only one can per month.

Actually, white tuna, which has little fat, is considered safe, but people were advised not to eat the darker high fat tuna used in pet food.  (here, kitty,kitty, kitty…)

So what is this about mercury in high fructose corn syrup?

Apparantly some older plants use an older caustic soda method to extract the fructose, and sometimes this caustic soda is contaminated with mercury.

The FDA knew about this several years ago, but someone felt the levels were not high enough to worry about, so the news did not become public until one scientist quit, and became a whistleblower.

In the meanwhile, what does all of this mean?

Well, until a wider study is done of consumer products to see how widespread the mercury contamination is, and until someone starts checking if people who eat a lot of junk food have higher levels of mercury in their bodies, there is just not enough information to try to figure out if the contamination is clinically significant (translation: so small an amount that it won’t hurt you).

But if I had small kids, or if I were pregnant, I’d avoid junk food unless I was certain that the company was monitoring their products for mercury contamination.

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Nancy Reyes is a retired physician living in the rural Philippines. Her website is Finest Kind Clinic and Fishmarket, and she writes medical essays at HeyDoc Xanga Blog.