Mercury and HFCS
Mon, Feb 16, 2009
Mercury drop on paper
Editor’s note: The author of this post, Amy Proulx, is our blog’s Science & Technology Editor. She looks forward to tackling more science, technology, nutrition and policy questions through a question and answer forum and says, “Bring it on! There are lots of scientists and regulators who came to the profession as hard-core foodies. I would love to provide answers for your questions, and have some fun with food.”
So don’t be shy. Post a response. We really do want to hear from you.
To worry, or not?
Mercury in the headlines, and in our food
A lot of recent, somewhat anxious press has been made over the Institute for Agriculture and Trade Policy (IATP) reports on mercury in high fructose corn syrup (HFCS). The two part study showed the presence of mercury in 9 out of 20 samples of the industrial ingredient, and mercury in a variety of consumer goods.
Let’s start with the question as it is: Should we be worried about mercury in HFCS? The reports from the IATP are very interesting, and do raise a legitimate concern. Mercury in any form within the diet may have negative consequences on health, especially in infants, children, and women. The levels found in the consumer products, however must be taken into a real context.
For example, a high-risk preschool child weighing 12kg, let’s say about 18 months old, would have to eat their own body weight per day in granola bars to consume the provisional tolerable intake for mercury. Looked at another way, the same child would need to drink 250 L of soft drinks or 200kg of ketchup each week to consume enough mercury to be of concern.
Should we be worried about mercury in HFCS? In general, the risk of toxic exposure from mercury is extremely unlikely. The processed food industry can take the lead by demanding mercury levels now be part of their “Certificates of Analysis” from their ingredient suppliers, to ensure their products fall well within safe limits. Ingredient suppliers listen to their customers. With proper public outcry, consumers will demand accountability.
That said, to address this issue more accurately, this question should actually be broken down into more basic questions.
Should we be worried about HFCS? A recent review by Kim Stanhope and Peter Havel (American Journal of Clinical Nutrition, 2008 ) shows evidence that high levels of fructose consumption correlate to biomarkers for diabetes, obesity and other adverse metabolic effects. Diets high in HFCS are diets full of processed foods. Fructose does occur naturally in many foods, but not in the levels found in some processed foods, the same processed foods which tend to be low in other beneficial, health promoting nutrients.
Should we be worried about mercury? Yes, indeed, mercury can cause major neurological problems and kidney dysfunction. The major source of mercury in our diet, by far, comes from large fish, especially tuna, but also shark, marlin and orange roughy, and not from HFCS.
Mercury in fish can be up to 1 part per million, over 1000-fold more mercury than found in the suspect foods. Health Canada has set recommendations that balance the health benefit of fish consumption against the mercury risk. These guidelines are valuable, especially since tuna is one of the most popular fish products, and rich in heart healthy omega-3 fatty acids. Many provinces also have regional guidelines for sport fishing.
A paper based on the Canadian Total Diet Study (Dabeka et al., Food Additives and Contaminants, 2003) shows that the levels of mercury found in many meat, fruit and vegetables common in the Canadian diet are comparable or higher than those found in the products flagged by the IATP. Rather, the fact that many animals are being fed fish meal has raised more recent concerns about mercury bioaccumulation in meat, eggs and dairy (Dorea, Journal of Food Protection, 2006).
Other prime sources of mercury in our environment come from mining, waste fluorescent light bulbs, batteries and coal fired energy plants. And the most likely exposure from mercury comes from dental fillings. Mercury is hard to avoid, but fortunately Canadian regulators have taken a lead in setting highly cautious environmental and dietary limits.
The final question is, should we worry? If the primary worry is mercury poisoning from HFCS, I would worry far more over the other detrimental metabolic effects which would most definitely occur long before mercury poisoning. But we should have a healthy concern for contaminants in our food supply, and advocate for a safe, healthy food supply. We just have to balance our level of concern within the framework of reality.
Posted by Dr. Amy Proulx.
Dr. Proulx (or Amy, as all her friends call her) is a research fellow in natural products chemistry and cellular biology at Agriculture Canada’s Guelph Food Research Centre.
Photo © lulazzo. Published under a Creative Commons License.
Tags: food safety, HFCS, mercury
My main concern is with the average North American diet, which is full of processed and packaged foods. We eat too much HFCS because we eat too much junk. That HFSC has mercury in it is just more evidence we need to return to more natural, less processed foods.
Mercury in fish is a much bigger concern for me and I’ve stopped eating it regularly. Thanks for the link to Health Canada’s recommendations. I’ll try to eat lower down on the fish food chain — if my grocery store stocks such items.
I agree, a diet rich in junk food is going to be the highest risk for disease of some sort, but likely not mercury poisoning.
The average grocery store stocks lots of fish that are lower in mercury. The fish with consumption warnings are either very large in size, (tuna, shark or marlin), or grow very slowly (orange roughy), so have eaten more than their fair share of mercury contaminated food, and accumulated it in their muscles and fat.
Salmon, sea bass, fresh water trout, perch, pollock, tilapia, virtually all shellfish, herring, flounder, sole, catfish, sardines, whitefish, all are excellent low mercury choices.
Halibut, bluefish and snapper are larger fish, but tend to be in the medium range for mercury. Lobster and crabs, because of their slower growth are in the medium range as well. Plenty of healthier options available.