Corn Syrup vs. Cane/Beet Sugar

[shadron]

Bottom line: if you have to drink soda (and I'm not recommending that you do), drink the diet, caffeine-free variety. This substance, in my very humble and not-fully-able-to-be-substantiated opinion, is likely one of the primary causes of the current obesity and diabetes epidemic.

~Dr. Imago

Let me see if I understand this: HFCS 55 only differs from sucrose by having the fructose and glucose molecules held together by a weak bond which the human enzyme sucrose is designed to undo, and by being pre-dissolved in water. Is this the significant difference that allows it to more readily be metabolized into fat? Or is there a different imbalance here you are referring to, between table sugar and HFCS?

Would you be less upset by soda if they used sucrose? Why should soda be a problem (you seem to indicate it is with the "if you must" attitude) with artificial sweeteners, where there is no chance for either tooth decay enhancement or for fructose metabolism?

The fact that we have enzymes that break down fructose, some of which are absent in certain disease states, is further illustrative of the fact that fructose is tolerable in the diet for most individuals, and that we evolved to be able to process the disaccharide, sucrose. The problem arises, though, with the extraordinarily high levels of fructose in certain "fortified" foods, such as in sweetened soft-drinks, and this causes the issue of "shunting" into fat anabolism. Generally, fructose itself is not problematic provided this doesn't become a primary dietary source of carbohydrate.

OK, does that refer to HFCS specifically, or use of table sugar in general, or what? Stop eating grapes? Remember, the "level" of fructose in that table sugar that we evolved to digest is itself 50% fructose. Do not any other sugars lend themselves to fat metabolism?

 

[lomiller]

Of course, the simple solution here would be to consume sweet foods and drinks in moderation and exercise more, but this seems to be a task far beyond the means of many people.

even the exercise may not be an absolute necessity. Apparently food intake alone is sufficient to explain the current obesity epidemic.

http://www.sciencedaily.com/releases/2009/05/090508045321.htm

 

[casebro]

But I don't believe that we can make fructose. And we do need it, to make membranes and also add to semen to fuel those little wigglers. Hence my earlier statement that "fructose is the only know essential carbohydrate". Since the liver does make glucose out of fat.

And I THINK grapes are glucose, not sucrose? so no fructose?
I only know that LoQuats make awesome white wine.

 

[ponderingturtle]

HFCS is used only because the US sugar market is highly regulated and restricted (to enrich sugar cane growers in Florida and Louisiana).

I thought it was to make sugar beets a viable crop.

 

[Dr. Imago]

I had to re-check my biochemistry knowledge, but some sugars can be oxidized into fructose (e.g., sorbitol).

The issue, again, is not with fructose itself. It is with fortified sweeteners and the excessive amount of fructose they contain.

Generally speaking, I don't think soft drinks are a wise dietary choice. However, most people drink them (myself included), but I think people should try to limit the amount of fortified sweetener by, at the very least, limiting their intake. Personally, when I drink soft drinks I drink the diet variety. When I switched (years ago) from regular, non-diet soft drinks to diet I lost about 10 lbs. over the course of a year just with this one change.

~Dr. Imago

 

[JJM]

{snip} The issue, again, is not with fructose itself. It is with fortified sweeteners and the excessive amount of fructose they contain. {snip}
~Dr. Imago

I cited the ADA summary that excessive amounts of fructose are not present in foodstuffs. That is, the studies showing problems from excessive fructose are purely experimental. HFCS, used in commerce, is sweeter than sucrose; thus the sweetness can be achieved with less carbohydrate.

On the other hand, HFCS and sucrose provide different sensations (apart from sweetness), often called "mouth-feel," such that equally sweet formulas give a different experience. Some people may prefer one over the other on that basis; but the nutrition and physiology is the same.

 

[drkitten]

I cited the ADA summary that excessive amounts of fructose are not present in foodstuffs.

Yeah. The problem is that summary is almost laughingly misleading. It's so misleading that I suspect a deliberate and politically-motivated attempt at deception.

"Both sweeteners [...] consist of about equal parts of fructose and glucose."

The only issue is that "about equal parts" is not especially meaningful in chemistry. As a simple example, if I were to mix "about equal parts of" metallic sodium and gaseous chlorine and expose you to that mixture, you'd respond completely differently than you would to sodium chloride, which of course is simple table salt.

Similarly, despite the fact that carbonated water is "just" carbon, hydrogen, and oxygen, the same ingredients you get in an appropriately proportioned glucose solution, you'll respond completely differently if I try to keep you alive on IV seltzer.

Or even seltzer by mouth.

but the nutrition and physiology is the same.

Wrong. There's a reason that the concept of the glycemic index was invented. Because not all combinations of carbon, hydrogen, and oxygen are equivalent.

 

[JJM]

{snipped embarrassing, to you, part} "Both sweeteners [...] consist of about equal parts of fructose and glucose."

The only issue is that "about equal parts" is not especially meaningful in chemistry. As a simple example, if I were to mix "about equal parts of" metallic sodium and gaseous chlorine and expose you to that mixture, you'd respond completely differently than you would to sodium chloride, which of course is simple table salt.

Similarly, despite the fact that carbonated water is "just" carbon, hydrogen, and oxygen, the same ingredients you get in an appropriately proportioned glucose solution, you'll respond completely differently if I try to keep you alive on IV seltzer. {snipped more embarrassing nonsense}

Your analogies are so far from correct, they are not even wrong! Physiologically, fructose and glucose are readily-interconverted isomers. Your faux comparisons involve synthesis of new compounds from unrelated starting materials.

If you took intro, and organic chem in my classes, I can only hope you would understand that. Many youngsters graduate without comprehension; albeit, without outstanding grades. (I never subscribed to the grade inflation of the last half-century.)

Wrong. There's a reason that the concept of the glycemic index was invented. {snipped even more, embarrassing nonsense}

The item I cited addressed the question of the glycemic index, did you read it? If so, can you provide evidence that you understood it and that the document is wrong?

 

[Dr. Imago]

Your analogies are so far from correct, they are not even wrong! Physiologically, fructose and glucose are readily-interconverted isomers.

Ummm... you might want to re-check your source. Fructose is a 5-atom-ring molecule, and glucose is a 6-atom-ring molecule. They are not "readily-interconverted."

~Dr. Imago

 

[drkitten]

Your analogies are so far from correct, they are not even wrong! Physiologically, fructose and glucose are readily-interconverted isomers.

Exactly. They are isomers, which is not the same as being chemically or physiologically the same. I'd like to point out that 2-methyl-butane and 2,2-dimethyl-propane are also isomers, but one is a gas at room temperature, the other a liquid.

If you took intro, and organic chem in my classes, I can only hope you would understand that.

If I took organic from you and I understood you to say that isomers were biochemically interchangeable, I'd have words with the department chair about your competence to teach.

Many youngsters graduate without comprehension;

And apparently many oldsters teach without it, too.

 

[JJM]

Ummm... you might want to re-check your source. Fructose is a 5-atom-ring molecule, and glucose is a 6-atom-ring molecule. They are not "readily-interconverted."

~Dr. Imago

They are readily, enzymically=physiologically, interconverted.

Fructose is a 2-keto form of the (1, by definition) aldo-sugar glucose. The five vs. six ring depends on the location of the carbonyl in the chain.

The 2-keto form has one fewer carbon in the ring (as opposed to the ring that includes (1) aldehyde carbonyl).

One of my colleagues studied the mechanism of this reaction 20 years ago (she was applying modern techniques to this very old reaction) and I am embarrassed to say, offhand, I cannot remember the name of the enzyme. Fructose and glucose are C6 sugars that differ at C2 vs C1.

 

[pgwenthold]

I've lost the focus of the discussion. Why is it about glucose/fructose? I thought the question was about sucrose vs HFCS?

This isn't so much of a question about carbs, but more about mixtures vs compounds. In that respect, DrKitten is right, that mixtures are not the same as compounds. For example, methyl ethyl ether (or whatever the IUPAC name is) is nothing like a mixture of methanol and ethanol. OTOH, this is a little simplistic, because while the properties of methanol and ethanol are dictated by the presence of the OH groups, it is not obvious that the properties of glucose or fructose are so dependant on the presence of an OH at the joining positions.

More important is the question of hydrolysis. If sucrose is readily hydrolyzed back into glucose and fructose under the acidic conditions of the stomach, then from a digestive standpoint, there really isn't any difference between ingesting sucrose or a 50/50 mixture of glucose and fructose (there would be a difference in taste, however, because of the difference in activity with taste buds).

Now, I don't know enough about carbohydrate chemistry to know the rates of hydrolysis of sucrose under physiological conditions, but if they are fast compared to digestive absorption, then physiologically there won't be much difference (it's basically a Curtin-Hammett application). It's going to reach equilibrium, regardless of which direction you start from, and that equilibrium mixture is the active agent. However, if those rates are slow, then you certainly need to consider the differences in chemistry between the mono- and disaccharides.

 

[JJM]

Exactly. They are isomers, which is not the same as being chemically or physiologically the same. I'd like to point out that 2-methyl-butane and 2,2-dimethyl-propane are also isomers, but one is a gas at room temperature, the other a liquid.

Again, I am sorry; but you are ignorant on this topic to the point that you are beyond wrong. How can I say this in Politically Correct science? ... You have an excellent misunderstanding! How is that? For that, of course, you expect an "A" in your science course. After all, how could anyone achieve better than an excellent misundestanding?

If I took organic from you and I understood you to say that isomers were biochemically interchangeable, I'd have words with the department chair about your competence to teach.

Or, if you understood that certain isomers were biochemically intercahangeable you might almost be qualified as "educated." I always liked Lubert Stryer's text; but you could also learn from Abeles, Frey and Jencks.

Among the many lessons I learned in grad school was not to expound on any subject in which I was ignorant, maybe they do not teach that these days.

 

[dakotajudo]

They are readily, enzymically=physiologically, interconverted.

Not necessarily.

The primary physiological difference comes not from the metabolism of the two sugars, but the recognition of the sugars. Fructose doesn't seem to trigger an insulin response to the same extent that glucose does. There have been many nutritional studies on this.

However, these same studies probably overstate the impact of HFCS. Most of the studies with fructose use pure fructose, but HFCS is (as noted above) only 55% fructose. This difference does not seem to be physiologically important - at least, not as important as the overall effect of increased sugar in the diet, be it sucrose or HFCS.

For a general overview of the current science of fructose, see http://jn.nutrition.org/cgi/content/abstract/jn.108.097972v1 (and related articles).

 

[JJM]

Not necessarily. {snip}

AS far as I can tell, this is an un-peer-reviewed-symposium that came to ... "what Conclusion"?

No, they came to no conclusion. They need to submit their data to per-review, for starts.

If you read the article I cited, you will see the physiology (in practice) is the same, as log as the commercial doses are used.

 

[drkitten]

Again, I am sorry; but you are ignorant on this topic to the point that you are beyond wrong.

Really? Enlighten me, then.

What are the differences in composition between the two chemicals I have named (2-methyl-butane and 2,2-dimethyl-propane)? Since they're both alkanes, you can even use ASCII art to show their structures, if necessary.

What are their respective boiling and melting points?

I could also add n-pentane into the list as well.

Really, JJM. It really says something pathetic when I, a complete non-specialist, have a better understanding of isomers than you do.

 

[JJM]

Really? Enlighten me, then.

If you insist; but is difficult to do without a chalkboard and/or an educated person. I seem to lack both. Not to say you are a know-nothing, just that you are out of your depth.

What are the differences in composition between the two chemicals I have named (2-methyl-butane and 2,2-dimethyl-propane)? {snip embarrassing staement}

I cannot deny your cleverness in noting that those are isomers. There are many kinds of isomers, perhaps you can entertain us by specifying the various types that exist ... On the other hand, you can go to your local highschool and borrow a text and look at the structures of glucose and fructose. Then, with practice, you can see the trivial difference between the two that allows them to be readily interconverted.

 

[dakotajudo]

AS far as I can tell, this is an un-peer-reviewed-symposium that came to ... "what Conclusion"?

I'm sorry if I confused you. The link I cited is only intended to provide a general overview of the current science of fructose.

Had I intended to directly address you misunderstanding of the physiology of glucose vs fructose, I would have provided, for example, http://www.ajcn.org/cgi/content/abstract/88/6/1733S or http://www.ajcn.org/cgi/content/abstract/85/6/1511.

No, they came to no conclusion. They need to submit their data to per-review, for starts.

If you read the article I cited, you will see the physiology (in practice) is the same, as log as the commercial doses are used.

The peer-reviewed article you cited?

Did you even read it, yourself? They state that sucrose and HFCS are physiologically equivalent. I did not disagree with that statement, per se - the difference between sucrose and HFCS is not physiologically significant.

I do disagree with your statement that glucose and fructose are physiologically equivalent. Go back and re-read what I quoted, and where it is from.

Dr Imago has already touched on one aspect of differences between glucose and fructose metabolism; you might want to review the enzymology of hepatic glucokinase.

 

[JJM]

I'm sorry if I confused you. The link I cited is only intended to provide a general overview of the current science of fructose. {snip}

I do disagree with your statement that glucose and fructose are physiologically equivalent. Go back and re-read what I quoted, and where it is from.

Dr Imago has already touched on one aspect of differences between glucose and fructose metabolism; you might want to review the enzymology of hepatic glucokinase.

Are you nitpicking, or just ignorant? Or was I that unclear about referring to those sugars as nutrients (which is relevant to the topic here), as opposed to substrates in an enzymic reaction. Also, the subject is sucrose vs HFCS; fructose, alone, is not pertinent. Sucrose and HFCS are nutritionally equivalent.

 

[dropzone]

Bottom line: if you have to drink soda (and I'm not recommending that you do), drink the diet, caffeine-free variety.

So, what you are saying is that caffeine has no daily adult requirement? (snort!) Next thing you will say is that there isn't one for nicotine, either, which goes completely against what my pediatrician (RIP) said.

For me, corn syrup has a heavy, "warm" taste that sugar lacks. OTOH, I cannot tell, in a blind taste test, between cane sugar and beet sugar, though my wife can. (She was a professional taster for a junk food flavor manufacturer and can, with a taste, tell you which chemicals in Sunny-D will give you cancer.)