Can anyone provide any information (or point me to a site that has information) on sugars such as Dextrose, Maltodextrin, Dextrose Monohydrate, Glucose, Fructose etc?
What I want to know is how (and how fast) they are absorbed by the body, and if they do anything different physiologically.
At different health food stores, they always have labelling slightly different from each other (or directly contradictory), and the staff either can’t tell me the difference, or just tell me that theirs is the best (of course).
I assume they are all fairly similar, but being a pedantic sort, I want to know the details.
First off: Dextrose is your basic in-your-bloodstream sugar; it’s the “left-handed” version of glucose, and when you buy glucose it’s almost always dextrose. Dextrose monohydrate is basically wet dextrose; the water is incorporated into the crystal structure, so it’s still a powder; I think it dissolves a little faster than anhydrous dextrose, but it can’t be much. Maltodextrin is a short chain of dextrose molecules, and it’s more or less equivalent to dextrose, except that I think it’s not as sweet and doesn’t cause cavities. Malto dextrin is technically not a “sugar,” but a partially hydrolysed starch
Fructose is a similar molecule; sucrose contains one glucose and one fructose, and I believe glucose eventually becomes fructose during metabolism (man, it’s been a long time), but I don’t know if that’s the most efficient pathway.
Basically, the different sugars are extremely similar, and handled the same way, and I doubt the utility of choosing one or the other for exercise, but I suppose elite athletes may need the few seconds gained by bypassing a single enzyme in the pathway
This site appears to have a fairly decent overview of sugars and nutrition. This site covers the chemical differences between the various sugars and carbohydrates in great detail -just skip the parts where it gets overly involved.
Dextrose polarizes light to the right, hence the name. Levulose polarizes light to the left, and is also called invert sugar. They are the two isomeric forms of glucose. Dextrose accounts for greater than 99% of the glucose out there.
In the strict chemical sense, no, fructose is not an isomer of glucose. But depending on who’s doing the teaching, and what the subject is, the term isomer is sometimes used more loosely, in order to emphasize the similarities between two compounds.
Biochemically, fructose bypasses one of the regulated steps in glucose metabolism. Different sugars get metabolized in different ways. This is not necessarily bad, and certainly not uncontrolled, but it does have biochemical and physiological consequences.
I’m not sure how much detail you’re after. Basically:
Sugars are like beads. Starches are like strings of beads (ie, many sugars linked together).
Your body can only absorb sugars in the bead-like form.
When you eat starch, the individual sugars get chopped off the string one by one and absorbed.
This takes time.
That’s why when you eat, say, a Lickem-Stickem (remember those!) you get a big so-called “sugar hit”-- the sugar is already in bead-like form and so aborbed very quickly.
When you eat a piece of Wonder bread, you still get kind of a hit, because the sugar is in the form of a more highly processed starch, and so the string is smaller and is chopped up and absorbed fairly quickly.
When you eat some whole wheat bread (the real kind, not the white bread with a fashionable tan) the starch is in a little processed, long chain form, so it takes longer to be chopped up and the sugar is absorbed over a longer period of time (no hit).
Any sugar with -ose at the end is either a bead or a very, very short chain. It will be absorbed quickly.
Fructose is one of the most common of these sugars. It’s the kind in, as the name implies, fruit.
Glucose is the other very common bead-like sugar.
Common table sugar is called sucrose, which is a very short chain consisting of one fructose and one glucose.
