Fructose and monosaccharides

August 5, 2004

This has been bugging me lately ... partly because of the

discussion about birch sugar, partly because of the whole fructose

issue as it relates to someone I know. It seems that pure fructose

causes problems for about 1/3 of humans generally, and 80% of people

with gut distress. Since it is in EVERYTHING nowadays (particularly

candy and pop) it would then seem that pop today would be a whole

lot worse for your gut than pop 50 years ago. And it might account for

the high levels of IBS today!

But ... as and others have pointed out on numerous occasions,

sucrose is really one fructose and one glucose, so why would fructose

be worse? I don't know the answer to that, but I found an interesting

abstract:

439534 & dopt=Abstract

there is no evidence of active intestinal fructose transport in the human

intestine. By means of hydrogen breath tests, a very low absorption capacity for

fructose given as the free monosaccharide has been found in humans. Fructose

given as sucrose or in equimolar combinations with glucose is well absorbed, and

only fructose in excess of glucose is malabsorbed. On this basis it is

hypothesized that two different uptake mechanisms for fructose are present in

the human intestine. One of these may be a disaccharidase-related uptake system.

Sorbitol ingestion may aggravate malabsorption of fructose given as the

monosaccharide; it is not known whether a specific mechanism is involved. In

children and adults with functional bowel distress the absorption capacities for

fructose may not differ from those of healthy individuals, but malabsorption of

fructose and/or sorbitol may be the cause of or aggravate abdominal symptoms.

Fructose polymers (fructans) are also subject to increasing nutritional

interest. Fructans are not absorbed in the small intestine but are strongly

fermented in the large bowel. Fructans may be of potential benefit for

large-bowel function and blood glucose regulation.

Which seems to say that fructose by itself ... read " high fructose corn syrup "

really is more of a problem for digestion. More and more products have switched

from cane sugar to corn sugar, esp. sodas and candies, so that might be causing

a lot of the digestive problems that one might think would be caused by hidden

gluten or bad food. Fructose malabsorption might not be rare ... it seems to be

the norm according to the above article. Beware of soda!

I'm not sure what this means for plain ol' fruit though. Is " real " fruit high in

fructose or is it a mix of sugars?

-- Heidi

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