Post Tagged with: "monosaccharide"

Why is High Fructose Corn Syrup so bad for you?

Is high fructose good for you or bad for you?

How many of you said bad?  Leads to obesity, right?  Gotta stay away from HFCS, right? That’s what ‘everyone’ says, right?

Consider: The sugar we call ‘table sugar’ is sucrose: a disaccharide: a molecule of glucose and a molecule of fructose (two monosaccharides) covalently bonded to each other.  Sucrose is broken into fructose and glucose by enzymes within living organisms (like humans).  Humans don’t use sucrose for energy, first we break it into glucose and fructose and metabolize the monosaccharides for energy.  So we ingest sucrose, digest it to glucose and fructose, then use the monosaccharides for energy.

One molecule of sucrose becomes 1 molecule of glucose and 1 molecule of fructose.  That means that sucrose is digested to a 50/50 mixture of fructose and glucose.

Consider: High fructose corn syrup is a straight mixture of unbonded glucose and fructose.  There are two common types of HFCS: HFCS 55 and HFCS 42.  HFCS 55 is ~55% fructose and ~42% glucose.  HFCS 42 is ~42% fructose and ~53% glucose.

So what’s the difference?

Sucrose becomes a 50/50 mixture of fructose and glucose.  HFCS 55 is a 55/42 mixture of fructose and glucose.  Chemically, there’s no difference between fructose from sucrose and fructose from HFCS.  Our bodies can’t tell the difference between fructose from sucrose or fructose from HFCS.  We’ve been fretting so much about a 5% difference between the fructose content in the two sweeteners.

If our body can’t tell the difference, and the percent content of fructose is essentially the same, why is HFCS so much worse for us than ‘natural,’ or ‘organic’ sugar?

It’s not.

HFCS is no worse for us, and causes no more obesity than table sugar.  Once ingested, table sugar and HFCS are metabolized by our bodies in exactly the same way.

So what’s the problem?  Well, the problem is sugars (both sucrose and HFCS) are in EVERYTHING.  Too much sugar (again, either from sucrose or from HFCS) IS bad for us, and will lead to higher caloric intake, and eventually weight gain.  So the problem is too much sugar – not too much HFCS, and the solution is to eat less sugars overall – not to ban HFCS from everything.

But that’s not what ‘everyone’ is saying.  And the court of public opinion can be quite harsh.  So harsh, in fact, that the HFCS manufacturers are attempting to rebrand.  No longer will we find HFCS on the ingredient list.  Now, we will see ‘Corn Sugar.’  This means the same thing.  It’s the same 55/43 mixture of fructose to glucose, but they’re rebranding to move away from the negative associations.

What do you think?  Good idea or bad idea?  Should we just ban HFCS/Corn Sugar?  Should we regulate the amount of sweetener that’s allowed to be in a Suggested Serving Size?  Do you agree with the decision by the HFCS manufacturers?


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By September 14, 2010 39 comments in vivo chemistry, science news