Is regular sugar greener than high-fructose corn syrup?

Illuminating answers to environmental questions.
May 19 2009 11:59 AM

May Cause Earth Decay

Is regular sugar greener than high-fructose corn syrup?

A can of soda.
Is high-fructose corn syrup bad for the planet?

A colleague of yours recently debunked the idea that regular sugar is necessarily healthier than high-fructose corn syrup. But what about the health of the planet? Corn needs a lot of processing before it can sweeten my soda, but then again, sugar doesn't exactly sprinkle down from the skies. So which one is more environmentally friendly?

It's true: King Corn is as much a bogeyman for the eco-conscious as the health-conscious. The crop gets a bad rap because it's so ubiquitous—thanks to aggressive farm subsidies, 27 percent of America's farm acres (PDF) are currently devoted to corn, with soybeans and wheat running a close second and third. According to anti-corn crusader Michael Pollan, modern corn hybrids require more pesticides and more fertilizers than any other food crop; this not only requires major inputs of fossil fuels but also causes significant groundwater pollution.

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But it's not entirely fair to lay all of that at the sticky feet of high-fructose corn syrup, as the maligned sweetener accounts for only about 5 percent of America's total grain corn production. (That figure rises to about 7 percent when you count other corn sweeteners.) We use a whole lot more corn for fuel alcohol (36 percent in 2008) and animal feed (roughly 50 percent), so if you're concerned about the impact the metastasizing industry is having on the planet, HFCS in your soft drinks and cupcakes may not be the most effective target.

Of course, even at just 5 percent of the overall crop, we're still talking about a lot of farmland: Nearly 4 million acres' worth of grain corn became HFCS in 2008. Compare that with the 1 million acres planted with sugar beets and 872,000 with sugar cane, the two crops that produce the sucrose we generically refer to as "sugar."

Thanks to protectionist trade policies, most of the table sugar we eat in the United States is domestically produced. Organic sugar is an exception—most of that comes from Brazil, Argentina, or Paraguay. Depending on where you live, that could mean a significantly longer farm-to-table journey, even compared with domestic, Hawaiian-grown sugar cane.

Even local cane and beet productions don't have great reputations with environmentalists. First of all, like rice and cotton, sugar cane is a very thirsty crop; according to the World Wildlife Fund, it takes 750 to 5,000 gallons of water (PDF) to grow a single acre of sugar cane. The WWF also blames both beets and cane for significant soil erosion (PDF) problems.

In 2007, an Australian sugar cane industry group compared the environmental impacts of growing Australian cane, U.K. beets, and American corn. The study was designed to assess the crops' viability as ethanol feedstocks, but the findings shed some light on our sweetener quandary. The products analyzed were 1 kilogram of sugar, in clarified juice form, from both cane and beets, and 1 kilogram of simple sugar syrup from cornstarch.

The researchers found that, on average, fossil fuel use, greenhouse gas emissions, and the release of acidifying substances seemed highest with corn sugar, while water usage was highest for cane sugar. The differences arose, in large part, because each crop has very different yields. While individual corn kernels are more densely packed with sugar than beets or cane (producing about four times as much by weight), cornfields themselves are relatively sparse. One U.S. acre produces about 4tons of corn, while an acre of Australian sugar cane field produces 38tons of cane and a U.K. beet field 22 tons of beets. As a result, a single acre can produce about 5.4 tons of sugar from sugar cane versus 3.4 tons from sugar beets and only 2.5 tons from corn.

A big wild card here is that making sweetener from any of these crops returns some useful byproducts that can offset some of the environmental burdens. Beet pulp, for example, can be used as animal feed, as can the corn protein and gluten meal that get separated out during the corn wet-milling process. Sugar cane probably gets the biggest plus in this category, as its waste fiber, known as bagasse, makes an efficient fuel source: Many sugar mills—where cane stalks from the field are converted into raw sugar—run entirely on bagasse, cutting out the need for additional fossil fuels.

So sugar cane seems to be the most efficient producer of sugar and potentially the lightest user of fossil fuels, even though its significant water requirements can't be ignored.

But to truly compare table sugar with HFCS, we need to look at the later stages of processing. We do know that evaporating cane and beet juice into dry, raw sugar—the least-processed variety—requires significant amounts of energy. A report from 1985 estimates that it takes 3,380 kilocalories and 5,660 kilocalories, respectively, to process a kilogram of crystalline sugar from cane and beets—quite a bit, considering that kilogram of sugar provides 3,850 kilocalories of food energy. It's unclear whether that figure pertains to raw or refined sugar, however. Producing the finer stuff not only requires several more steps—evaporating, spinning, melting, chemical decolorizing treatments—it also means more food miles, since these steps occur in a separate facility.

Meanwhile, to turn simple corn syrup into high-fructose corn syrup, enzymes are used to convert 90 percent of the glucose molecules into supersweet fructose before the resulting solution gets blended back with simple glucose syrup. It's unclear just what kind of additional burden these final steps account for, but we do know that the entire corn wet-milling process takes a whole lot of energy—according to the consulting firm FTI, it's the most energy-intensive food-manufacturing industry in America, meaning it spent the most on electricity and fuel per dollar-value of shipments made. Sugar beet processing comes in at No. 2; sugar cane mills and refiners, collectively, are No. 3.

As your mom, your dentist, and the Lantern has told you time and time again, take all things in moderation and you'll probably be fine—that goes for sugar and high-fructose corn syrup, as well. And cutting down on our overall sweetener intake makes a lot more sense than simply switching one for the other. After all, if we all boycotted HFCS and instead ramped up our consumption of cane sugar, where would we find enough hot, humid land to put all those additional cane fields? Are you willing to gobble up the rest of Florida, Louisiana, Hawaii, and Texas just to avoid corn in your Coke?

Is there an environmental quandary that's been keeping you up at night? Send it to ask.the.lantern@gmail.com, and check this space every Tuesday.

Nina Shen Rastogi is a writer and editor, and is also the vice president for content at Figment.

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