Thursday, April 10, 2008

Avoid fructose to avoid diabetes?

For a while now Barry Groves has had an article on his site about the dangers of fructose

There are many good reasons to avoid the fruit sugar, fructose, but all you need is one: type 2 diabetes. And even worse that fruit itself that ubiquitous additive to many processed foods — high fructose corn syrup.

A recent study highlighted diabetes and all the other key reasons why it's a healthy idea to avoid this truly awful component of processed foods and soft drinks.

I thought of his article when I saw this abstract that noted that:

Long-term exposure of normal rats to a fructose-enriched diet or drinking water is currently used as an animal model for experimental insulin resistance.

When scientists want to induce insulin resistance - a precursor to diabetes - they give rats lots of fructose. Scary. Barry Groves states: "Eat 5 portions of fruti and veg? Not if you want to avoid diabetes"


Scott Kustes said...

The funny thing is that sugar is 50/50 glucose and fructose, while HFCS is 45/55, respectively. Honey usually has a similar ratio to HFCS and agave nectar can be as much as 90% fructose. Yet so many of us get up in arms over HFCS. It's the overall sugar load that's killing us, not just the HFCS. HFCS has just made sugar so cheap that it's added to everything.

I think it's rather absurd to think that normal portions of fruits and vegetables are going to induce Type 2 Diabetes in people with normal biological functions. If people just avoid the added sweeteners and stick with the natural sweetness of apples, peaches, blueberries, canteloupes, carrots, and such, there'd be little to be concerned with, even though our modern fruits are sweeter and higher sugar than those of our ancestral past.

Scott Kustes
Modern Forager

Chris said...

Hi Scott

I suppose that post was a bit over the top!

I have been reading through some of Peter's old posts on the Hyperlipid bloag and he had a really good post on fructose:

Fructose is an unusual sugar for humans to eat. We have no system to break down fructose polymers. The only sources of fructose we can use are the simple sugar in fruit or honey and as the molecule combined with glucose as sucrose, ie table sugar. Drenching your metabolism with fructose is a recent innovation for humans. The current preferred sweetener for soft drinks is "high fructose corn syrup", a product of our dearly beloved food industry in the last thirty years or less.

What happens when you drench you metabolism with fructose? It enters the metabolic pathway of carbohydrate below its main control step and is immediately converted to fructose-1-phosphate. Quite why evolution has arranged things this way is a mystery, but my suspicion is that evolution does not like free fructose in human metabolism. So drinking a small bucket of cola will put 100gm of fructose in to your liver. This will require a large input of phosphate to for the fructose-1-phosphate, leaving very little for the generation of adenosine tri phosphate (ATP), the primary energy currency of our cells. A lack of ATP triggers activity of the degradation system for adenine and the production of, guess what, uric acid! Gout, and not a serving of kidneys in sight. Until 100 years ago only the rich could afford enough sugar to get gout, now it is a feature of metabolic syndrome and available to all.

Incidentally the fructose has to be "put" somewhere, and that is in to fat for storage, via elevated triglyceride levels in the blood. It causes insulin resistance too. Even the full metabolic syndrome!

In fact, probably the truth is that fructose causes insulin resistance, which causes gout. The hyper uricaemia and the fact that the joints produce uric acid crystals do not have to be causally related. I'd say they're not.

Incidentally, these bright researchers are looking for ways to minimise the self poisoning caused by fructose. They are actually suggesting looking for a drug to allow you to drink high fructose corn syrup without the rise in uric acid.

A drug for life to enjoy your cola. But of course that won't stop the insulin resistance from fructose, so......