Apparently, some people are born with aldolase B defects. Aldolase B is the enzyme necessary for the proper metabolism of fructose (including fructose from fruit). When these people ingest fructose, the metabolic pathway proceeds normally to the conversion of fructose to fructose 1-phosphate, but then no further. Since the phosphate - which came from ATP - is stuck there, it's not returned to the metabolic pathway; and the result is a drop in free phosphate levels and a subsequent loss of ATP, leading to symptoms of hypoglycemia (severe weakness, tremulousness and sweating). The condition can be fatal.

Another genetic disorder is called "essential fructosuria", caused by a deficiency of the fructokinase enzyme, but this is a relatively benign disorder because metabolism of fructose is interrupted before phosphate is removed from ATP. Fructose is then metabolized through an alternative, but slower, pathway.

In my case, I must have aldolase and fructokinase all over the place, because fruit is so easy for me to metabolize! But we're all a little different.

Here's something else I think is interesting: The body synthesizes it's own fructose. Why? Well, fructose is the major fuel source for sperm.

interesting ... id be curious to find out what causes a aldolase B defect in the first place ...

thanks for posting !

...Jodi, the banana eating buddhist

The cause is something to do with missense mutation from what i remember. Really was hard to understand and follow.

There are quite a few conditions which can cause people to not tolerate fruit. Ive came from that background when my digestion was such a mess in that a single piece of fruit could send me to sleep, leave me fatigued, shakey, IBS/weird bowel movements, severe stomach pain, furry white tongue etc.

Pretty much all of the above was due to lack of gut flora and stomach acid. Now a days i can munch all the fruit id like in a sitting and i do, but some cant seem to understand what its like for those who do have trouble.

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Huh, this is interesting. Am likewise wondering about the root cause[powerlifer, gonna look up what you mentioned!]. I wonder if it can be reversed, because I would imagine it would be difficult to get necessary carbs without consuming fructose at all.

I know someone who, for lack of kidneys, has serious phosphate metabolization problems, and as a result must refrain from eating foods containing phosphorous. Cruelly, these are also in so many of the foods that would help his body function without a gallbladder(also gone). He maintains a positive outlook, but I think it must be a misery to live like that

Must be very hard like you say tamukha.

These people likely don't eat raw and get there carbs from other sources obviously non-fructose, it seems they do pretty well on dextrose etc. Also Gluconeogenesis probably helps alot.

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