Mar
30
2010

Sugar or corn syrup? Well, obese rats would recommend…

Are you into the white stuff? Or are you a corn man?: Don't answer that.
Are you into the white stuff? Or are you a corn man?: Don't answer that.Courtesy Andrew_B
About a month ago I fell off my bicycle and got a brain injury. Can you imagine? The doctor called it a “corncussion.” I was thinking I would do a Science Buzz post on corncussions, but I couldn’t find any information on the condition. What gives, Google? Did I invent the corncussion? I don’t think so.

What I did find, however, was also pretty interesting: this new research on corn syrup.

Don’t run off! Corn syrup is interesting! And it’s relevant! On my desk, for instance, I see three food-related items: a half-full pack of m&m’s, a Tootsie Roll Pop wrapper, and an apple. Of these items, only the apple doesn’t have any “high-fructose corn syrup” in it. High fructose corn syrup is the sweetener of choice for lots and lots of food in this country (check your kitchen), and it has been for decades. It’s cheap, it’s really sweet, and it’s made from corn (we like making things from corn in these parts), so what’s not to like?

Lots of things, according to some people, and nothing, according to other people. The problem is that the above disagreement usually goes something like this when it is discussed:

“Corn syrup is horrible! Why? Because, like, it’s not like regular sugar, and your body doesn’t… your body treats it, like… it’s different and bad! Chemistry! Biology!”
-or-
“Corn syrup isn’t bad, it’s awesome! It’s made from corn, and corn is natural, and when has anything natural been bad for you?”

And both sides, frankly, are pretty dumb. Because in the former’s case, people usually aren’t really saying anything. What you sort of heard from a friend who might have read something about how the body treats corn syrup differently or something doesn’t count as solid scientific backing for your position. Be honest—it’s just your way of saying that you shop at Whole Foods.

On the other hand, it’s not like we’re sprinkling kernels of fresh corn on our food when we’re using high-fructose corn syrup—lots of fancy refining goes into making that sweetener, which may or may not be a good thing. And, in any case, being “natural” doesn’t make something healthy. You know what else is natural? Syphilis, arsenic, and getting punched in the face.

The thing is, there seems to be an association between the rise in obesity rates (and related diseases) and the introduction of high-fructose corn syrup (let’s call it “HFCS” from here on) to American diets about 40 years ago. But that doesn’t mean that there really is a link between the two—we don’t know exactly how HFCS would cause obesity, and we don’t know if it was for sure HFCS that made us all fatter, or if it was some other widespread lifestyle change. Or if it was a combination of things.

The issue is complicated by stuff like research that indicates that drinking too much pop can raise your risk of cancer. Is that because too much of a sweet drink is bad for you? Or is it because lots of soft drinks use HFCS as their sweetener?

It’s confusing, and we’ve never really been able to definitively say, “HFCS is/is not bad for you.”

And we still can’t.

However, yesterday I read an interesting article about a study that seems to reinforce the connection between HFCS and obesity, even if it doesn’t show a causal relationship. (That is, it seems to show that something really is happening, but it can’t say why.)

Researchers at Princeton studied two groups of rats. One group got regular rat-chow, and water sweetened with HFCS. The other group got the same amount of rat-chow, and water sweetened with regular sugar from sugar cane or beets (this sugar is called sucrose). All the rats consumed the same amount of calories each day, no matter what their beverage was.

The researchers found that some of the rats eating regular sugar gained weight, and that some of them gained no weight. However, all of the rats eating HFCS gained weight (from body fat), and showed an increase in blood fats called “triglycerides.” The researchers pointed out that even rats given a high-fat diet don’t show such consistent weight gain.

The next part of their experiment tracked the long-term effects of a high HFCS diet on the rats. These rats all showed signs of a condition known (in humans) as metabolic syndrome. They had lots of blood fat, and gained lots of weight, especially around the belly. In fact, they gained 48% more weight than rats eating a normal diet.

What about that?

Well, the Corn Refiners Association has something to say about it: They think it was a misleading study. In their response to the research the CFA points out that there was no regular sugar control for the second part of the study—HFCS-eating rats were only compared to rat-chow-eating rats, not to rats eating regular sugar. So it would be like comparing weight gain between someone who just ate candy bars, and someone who just ate granola, instead of between a candy bar-eater and an ice-cream eater. (Does that sentence make any sense?) I don’t know if the original study really did lack that control, or if there was a reason they felt it wasn’t necessary. The CFA calls it a “gross error,” but it could be that it was just outside the intended scope of the research.

The CFA also thinks that the portions of HFCS given to the rats constitute a “gross error.” According to them, a proportional amount given to a human would be about 3000 calories from HFCS a day. They point out that adults eat only 2000 calories a day, from a variety of sources. It’s a good point, but not a great one, I think. That 2000 calorie figure is based on the Food and Drug Administration’s recommended diet (you know, the label you see on the back of everything you eat), and how many people stick exactly to the recommended diet? A 3000-calorie/day diet would definitely not be out of the question for lots and lots of people. And, sure, those calories are supposed to come from many food sources, but, again, go check your kitchen, and see how many items in there us HFCS. (Lots do.)

Keep in mind, though, that just because the people that make HFCS are arguing that it’s safe doesn’t necessarily mean that it’s not safe. Of course they want to defend their product. Not everything is a global corporate conspiracy.

But the Princeton study sure does make it look like there’s something about HFCS that causes it to contribute to obesity more than regular sugar. The study just doesn’t show how it might do that. That’s the causal relationship we talked about earlier. They have some ideas, though.

The CFA claims that “a sugar is a sugar, whether it comes from cane, corn or beets. Both sugar and HFCS are handled the same way by the body. Maybe, but sugar and HFCS aren’t totally identical. Both sweeteners are made up of two kinds of sugar molecules, called glucose and fructose. Regular sugar is about 50% glucose and 50% fructose. HFCS, on the other hand, has more fructose (about 55%), less glucose (about 42%), and a small amount of larger sugar molecules called saccharides (3%). The way these molecules are put together in the difference sweeteners differs too: in regular sugar, each fructose molecule is bound to a glucose molecule, but the process of making HFCS causes its fructose molecules to all be “free and unbound.”

Some scientists think that because the fructose in HFCS is free, it is more easily metabolized (used by your body) and is more quickly turned into fat. The extra step needed to separate the fructose from the glucose in regular sugar might cause it to be metabolized differently, with more of it being stored in the liver or muscles as carbohydrates.

But, once more, that part is what people are uncertain about.

It’s a tricky issue, because there are a lot of dogs in the fight—I’m sure the manufacturers of regular sugar are just as defensive about their product (and just as likely to be very selective about which studies the promote) as the corn refiners are. But what about us poor norms? All we want is to sit and eat sweet things all day, while gaining as little weight as possible. I mean, we could just consume sweeteners in moderation until science proves who’s really right, but… where’s the fun in that?

It’s something to consider. Choose wisely, and stuff.

Your Comments, Thoughts, Questions, Ideas

KelsiDayle's picture
KelsiDayle says:

The whole HFCS and obesity debate was a bit of a pet project for one of my undergraduate professors and I remember a little history lesson he gave us:

HFCS is relatively new to our diets. It's proliferation in processed foods and drinks can be traced to the Cuban Embargo of the 70s. At that time, the U.S. got much of our sugar from Cuba and the embargo put a cramp in our sweet tooth consumptive habits.

posted on Thu, 04/01/2010 - 1:41pm
JGordon's picture
JGordon says:

I read something about that too. Maybe the connection requires too many tenuous leaps, but it's interesting to think that mid-Cold War politics might be affecting present day obesity rates. The world is a cooomplicated place.

posted on Thu, 04/01/2010 - 5:17pm

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