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Fructose and Mercury: Is this the explanation?
Jacob Schor, ND, FABNO
February 22, 2010
Several people responded to our recent newsletter on the link between soda consumption and pancreatic cancer bringing my attention to a recent study that reported that high fructose corn syrups used to sweeten soda may contain high levels of mercury. These writers ask whether this might be a better explanation than the insulin hypothesis being used to explain the link.
Last weeks newsletter on soda consumption and pancreatic cancer risk is at:
I’ve written about fructose in the past and am admittedly not a big fan of the stuff, but this study raises our concern to a new level.
The September 2009 issue of the Environmental Health Journal contained an article suggesting that some of the chemicals used in making high fructose corn syrup may contain mercury and as a result may impart unacceptably high levels of mercury into the corn syrups. The full text of the article is posted at:
High fructose corn syrup (HFCS) over the last thirty years has become a common ingredient in many foods. It is very inexpensive, very sweet tasting and increases shelf life of the food. It is the preferred ingredient for sweetening soft drinks.
HFCS is made from corn. The corn is milled, the corn starch is extracted and enzymatically converted to corn syrup which is almost pure glucose. Most of the glucose syrup is converted through the use of a series of enzymatic reactions into fructose. During the process, the pH of the reaction is carefully controlled through the addition of either acidic hyrdochloride solutions or caustic soda solutions. These solutions used to adjust the pH of the chemical reactions may be the source of the mercury. Both chemicals are known as chlor-alkali products.
Chlor –alkali products are made through two different processes. The older method, known as the the Castner-Kellner process dates back to 1892 and uses mercury to manufacture chlorine and caustic soda. An electric current is run through giant vats filled with concentrated salt water that floats on top of a cathode made of a thin layer of mercury. Chlorine is produced at the anode, and sodium is produced at the mercury cathode where it forms a sodium-mercury amalgam with the mercury. The amalgam is drawn out of the cell and reacted with water that decomposes the amalgam into sodium hydroxide and mercury. The mercury is theoretically recycled into the electrolytic cell. In theory, because some of the mercury is not recovered; it is lost. These mercury cell chemical plants are gradually being phased out. A newer, more energy efficient, mercury free process that uses membrane technology is gradually being phased in
Yet, there are still about fifty of these older mercury cell chlor-alkali plants operating in the world, eight of which are in the United States. Each of these plants operates an average of 56 mercury cells, each cell containing about 8,000 pounds of mercury. The EPA estimates that in 2000, each of these plants ‘lost’ seven tons of mercury.
This mercury ends up in the chemicals produced by the mercury cells. From there it can be incorporated into the food products these chemicals are used to make.
The September study was just a pilot study; high fructose corn syrup samples were collected from just three different manufacturers and analyzed for total mercury. The samples varied depending on their source. Some contained undetectable levels, less than 0.005 micrograms of mercury per gram HFCS. Some samples were quite high, up to 0.570 mcg/gm. Average daily consumption of HFCS in the US is about 50 gm per day. Obviously some people consume even more. This may provide a potentially high mercury burden to consumers.
As mentioned, this was just a pilot study. The FDA does not yet monitor mercury in fructose or soda or other food products made using these chlor-alkali process chemicals. It is not possible to tell from labeling which foods are made using these chemicals and which not.
Using the numbers from this pilot study, we can calculate that average mercury exposure from HFCS may range from zero to 28.4 mcg of mercury per day. For the sake of comparison, total mercury exposure from dental amalgam fillings in children is estimated to range from 0.79 to 1.91 mcg/day.
Mercury is nasty. It is an extremely potent neurotoxin. Organic mercury compounds cross the blood brain barrier damaging developing brain tissue. We clearly do not want pregnant women consuming mercury. But does mercury cause pancreatic cancer?
It doesn’t appear to. While a search of the medical journals using PubMed yields multiple papers linking sugar consumption to pancreatic cancer, a search for articles on mercury and pancreatic cancer yields nothing. If the results of larger studies are consistent with those of this pilot study, fructose will need to be viewed with greater caution. Even if this does turn out to be the case, mercury in fructose, and so in soda, does not explain the link between soda consumption and pancreatic cancer. That doesn't mean that fructose is good for you by any means. It just means it probably doesn't cause pancreatic cancer.
Past articles on fructose: