What's Wrong With High Fructose Corn Syrup?

Corn with biohazard sign

Dear Vanessa,

I’ve been told that I should avoid high-fructose corn syrup, and yesterday I read that there is mercury in the syrup. Why would mercury be in a food product, anyway? And what’s the problem with corn syrup in general?

— Feeling Corny in the Heartland

Dear Corny,

There are many issues about high-fructose corn syrup, all of them connected to corn-focused industrial agriculture, a practice that is destroying our health and our environment.

Let's start with corn. How did we transform a native grain that sustained myriad cultures for thousands of years into a symbol of everything that's wrong with our economy, agriculture and health? (This will be an exercise in restraint for me. I will do my best to ignore that high-fructose corn syrup, or HFCS, originates in a simple corn field and focus on the complex problems surrounding this sticky, adulterated version of corn-stuff.)

So what’s the problem with HFCS? It is a highly processed, unnatural product, yet it is often sold under “all natural” labels. It is artificially cheap because of America's massive corn subsidies. And though it's calorie-rich, it's nutritionally impoverished. HFCS is also a significant cause of the obesity pandemic — just look at the way the rapid rise in obesity mirrors the rise in HFCS consumption.

The Corn Refiners Association disagrees, and their pro-HFCS campaign can be found here. Food manufacturers, not growers, are bound to the product. It acts as a preservative, extending the shelf life of foods, yet it's cheaper than sugar and other natural sweeteners.

A bit of history

HFCS was introduced in 1970. By 1990, consumption of it had increased 1000 percent. HFCS is now found in almost all caloric sweeteners which are added to foods and beverages in the U.S. It can be found in soft drinks and fruit drinks, candied and canned fruits, dairy products like ice cream and yogurt, bread and baked goods, cereals, jellies, ketchup, BBQ sauce, salad dressing — even vitamins and supplements — and overwhelmingly in foods marketed to children. In short, HFCS is found in most processed foods, and it is difficult to avoid. Every American consumes an average of 60 pounds of HFCS a year.

HFCS’s connection to obesity, diabetes and heart disease lies in the way our bodies react to the substance. Unlike glucose, fructose does not stimulate insulin secretion or enhance leptin production, both key processes in appetite regulation and fat storage. Instead, fructose forms the backbone for triacylglycerols. Elevated levels of triacylglycerols prevent leptin from reaching the brain and are linked to an increased risk of heart disease. Why does that matter? Without leptin, the brain doesn’t send out the signal to stop eating. There is no caloric difference between the two sugars, but glucose is readily absorbed and allows the brain to signal that we’ve had enough food.

Simply put, fructose leads our bodies to store more calories as fat, and leads us to overeat because we don’t feel full.

A USDA study that compared rats fed a high-fructose diet to those fed glucose found disastrous results from the fructose diet. The male rats did not reach adulthood, had anemia, high cholesterol and heart hypertrophy — which means their hearts enlarged until they exploded — and their testicles didn’t develop properly. Female rats were not as dramatically affected, but they were unable to produce live babies. The results were exacerbated by copper deficiency, a fairly common deficiency in Americans. Dr. Meira Field, who led the study, notes that while "every cell in the body can metabolize glucose ... fructose must be metabolized in the liver. The livers of the rats on the high-fructose diet looked like the livers of alcoholics, plugged with fat and cirrhotic." Yum.

And now, add a bit of mercury

The newest HFCS scandal arose from two recent studies. The first, peer-reviewed and published in Environmental Health — abstract here; PDF here — found detectable levels of mercury in nine of 20 samples of commercial HFCS. The second study by the Institute for Agriculture and Trade Policy (IATP), a nonprofit watchdog group, found that nearly one in three of 55 brand-name foods contained mercury. The chemical was found most commonly in dairy products, dressings and condiments containing HFCS.

This, at least, is an avoidable consequence of HFCS consumption. Of the many chemicals required to make HFCS, caustic soda and hydrochloric acid, can contain traces of mercury. These two chemicals, made the same way as chlorine, can be produced in two ways. One involves pumping saltwater through a vat of mercury; the other does not. AsDr. David Wallinga of the IATP stated, "Mercury is toxic in all its forms. Given how much high-fructose corn syrup is consumed by children, it could be a significant additional source of mercury never before considered. We are calling for immediate changes by industry and the [U.S. Food and Drug Administration] to help stop this avoidable mercury contamination of the food supply." The good news is that the industry is heeding the call and moving away from this “mercury grade” process.

More peeves over HFCS? You bet. I find it ridiculous that the substance can be marketed as “natural.” While the Corn Refiners Association claims high-fructose corn syrup is made from corn, has no artificial ingredients, has the same calories as sugar and is fine to eat in moderation, there is nothing “natural” about it. Does it originate in corn? Absolutely. But HFCS cannot be found in corn or anywhere else in nature.

Manufacturing HFCS requires a long series of mechanical processes and chemical reactions, including the introduction of three different enzymes to incite molecular rearrangements. Genetically modified corn, molecularly altered by genetically engineered enzymes ... how can that be considered natural?

The environmental costs

I know I said I’d refrain from a diatribe on corn, but I must tell you about the environmental costs of HFCS.

"The environmental footprint of HFCS is deep and wide," says Michael Pollan, author and journalist extraordinaire. "Look no farther than the dead zone in the Gulf [of Mexico,] an area the size of New Jersey where virtually nothing will live because it has been starved of oxygen by the fertilizer runoff coming down the Mississippi from the Corn Belt. Then there is the atrazine in the water in farm country — a nasty herbicide that, at concentrations as little as 0.1 part per billion, has been shown to turn male frogs into hermaphrodites."

Industrial agriculture grows only corn, with no crop rotation. This practice depletes soil nutrients, requires more pesticides and fertilizers, and leads to the loss of topsoil. And, of course, milling and chemically altering corn to make high-fructose corn syrup is energy-intensive.