Also, Levosugars: huh?

[learnedax]

Years ago I heard and for a long time believed that sucralose was the left-handed version of glucose,* rather than the chlorine-doped sucrose it actually is. That explains why it doesn't taste precisely like sugar, though it is a relatively close approximation. It also raises questions about its breakdown producing free chlorine, since it is not clear whether it gets partially metabolized.

But anyway, my real interest is in levorotatory sugars (L sugars bend light left where D sugars bend light right, you see) : is it true that they would react chemically like regular sugars but not lock in with the appropriate enzymes to be metabolized? Gilbert Levin (what an appropriate name) of Spherix seems to strongly argue that this is the case... but, despite their literature mentioning frequently his quest for a usable left-handed sugar, their sweetener product is D-tagatose, which just happens to be chemically similar to L-fructose (i.e. the normal kind). Since levosugars are so expensive to produce, it was much more commercially viable for him to make tagatose, which is similar enough to fructose to fool the body into mostly not digesting it.

But wait, because here's where I get confused. Fructose is already a dead common left-handed sugar, which ought to be metabolized less than tagatose. In fact, high-fructose corn syrup has already replaced regular sucrose in the majority of commercial products (because it's cheaper, but nevermind why). So that's a good thing, right? Except everything I can find on high-fructose corn syrup decries the horrors of fructose, precisely because it's metabolized poorly. So, then... huh?

If it was economically feasible, would L-glucose be the magic bullet, or not?

*Which I thought of as sinistrose, by extension from dextrose. For some unclear reason there are two latinate roots, and the chosen one is laevus, so we get levulose - which is of course actually fructose, not L-glucose. Perfectly clear.**

**Ok, it actually does make a certain sense since sucrose breaks down into dexrose and levulose.

Comments

[patrissimo.livejournal.com]

High-fructose corn syrup is not actually cheaper than sugar, its just that subsidies/tariffs make it that way. ADM, the company that makes most high-fructose corn syrup, essentially makes a living off government tariffs in its favor. (their biggest boondoggle is ethanol for fuel - the govt. pays them about a buck to make every ten cents worth).

also, don't forget as an alternative to your levorotatory search the alternative of pentose sugars like xylitol. we digest them much more poorly than hexase sugars like glucose, so they are lower cal. but if you eat too much you get gas.

http://www.scientificpsychic.com/fitness/carbohydrates.html

[learnedax.livejournal.com]

Xylitol seems comparable to tagatose in how the body reacts to it, but it has 60% of glucose's nutritive content instead of 33%. On the other hand, chewing xylitol-sweetened gum may be very good for your teeth, so start chewing Trident.

There seem to be a lot of better alternatives than what we're using. Sinistrose is the most interesting to me since it should be a one-for-one replacement for dextrose pretty much everywhere, but I am curious whether any undigested sugars would pose the same (in my opinion mild) health concerns as fructose and xylitol, or whether those are due to their specific breakdown properties.

[plymouth.livejournal.com]

sucralose makes me tummy cranky. aspartame tastes like ass. I think the only synthetic sugar I actually like is sorbitol... which isn't as low-cal but IS better for my teeth.

[learnedax.livejournal.com]

The artificial sweeteners seem to pose nasty health problems, as well as tasting nasty. Donald Rumsfeld got aspartame FDA approved for personal profit despite some significant evidence of its dangers; saccharin only recently lost its mandatory warning because it's no longer strongly linked to cancer; it's unclear what the health effects are of acesulfame potassium, though it may be relatively safe; stevia may cause impotence, and metabolizes into a mutagen.

So, yeah, wood sugars like sorbitol seem to be a better bet.

[plymouth.livejournal.com]

I don't think Stevia counts as an artificial sweetener because it comes directly from a plant... but I think it also tastes vile. I really can't imagine putting it in anything other than a strong tea because it has such an intensely herbal flavor.

At least I don't have to worry about impotence :)

[metahacker.livejournal.com]

IIRC, they used to call it sinistrose. For the obvious reason it was changed to levulose...

Remember rape seed oil?

[umbran.livejournal.com]

is it true that they would react chemically like regular sugars but not lock in with the appropriate enzymes to be metabolized?

The answer, as it usually is with chemistry, is that the devil is in the details. Handedness alone is not enough to determine how the thing will react with enzymes. Being of the wrong handedness may be a nice first indicator for things to try, but given that they've typically got structures that are highly symmetric to begin with, changing handedness alone may not do the trick.

[herooftheage.livejournal.com]

Interesting -I had always heard Splenda hyped as using the chlorine trick, with the selling point that it was undigestible.

If it isn't, that's bad news, but I would have thought it would be easy to tell - presumably one of our waste outputs should be Splenda-laden if it is not digestible.

[learnedax.livejournal.com]

Well, some studies say it get partially metabolized, others say it doesn't. It looks like maybe 5% gets broken down, and the metabolites are probably passed without any real effect on the body. Probably.