Thursday, December 17, 2009

Fructose makes bellies fat

Thanks to Eric for alerting me to this article.

Consuming fructose-sweetened, not glucose-sweetened, beverages increases visceral adiposity and lipids and decreases insulin sensitivity in overweight/obese humans

Not much time to comment on it, so a quick look. The research team fed people diets in which 25% of calories came from either a glucose- or a fructose- sweetened beverage.

The results: "Consumption of fructose-sweetened but not glucose-sweetened beverages for 10 weeks increased DNL [denovolipogenesis], promoted dyslipidemia, decreased insulin sensitivity, and increased visceral adiposity in overweight/obese adults."

Small dense LDL results: The glucose-consumers had no net increase in the apparently harmfull small-dense LDL. "In contrast, fasting sdLDL concentrations increased progressively in subjects consuming fructose."

Mean 24 hour triglycerides increased 2.5% in glucose-consumers, 18.2% in fructose-consumers.

For glucose consumers, 23 hour triglyceride area under curve decreased by 32%, whereas for fructose consumers it increased by 99%.

Fasting oxidized LDL increased by 0.7% in glucose consumers, but 12.8% in fructose-consumers.

Cane sugar (white or brown) and high fructose corn syrup both provide about 50% of their carbohydrate as fructose. Honey consumed occasionally by hunter-gatherers has less fructose, at about 39%.

This study gives some indication why diets based on starch (primarily glucose) but containing little fructose do less health damage than diets containing plenty of sugars.

9 comments:

Greg said...

Interesting study. What foods are low in fructose, particularly those in a paleo diet? It seems every time I look at a carbohydrate source it is about half glucose, half fructose

Greg said...

http://en.wikipedia.org/wiki/Fructose#Fructose_and_starch_functionality_in_food_systems

Greg said...

Is it possible that fructose by itself causes problems, but fructose with glucose doesn't? Also I am thinking back to rat studies (were those posted on Hyperlipid?) showing saturated fat having a protective effect with glucose and polyunsaturated a damaging one. Any idea on the type of fat intake here?

Don said...

Greg,

The table you refer to shows no food with more than 8 g total fructose per 100 g serving. All the vegetables show no more than 2.3 g/100 g, and most show less than 1.0 g/100 g.

In this study, they fed people 25% of total calories as fructose. Difficult to get that throught the small amounts of fructose in whole foods. It is concentrated fructose sources like pure sucrose, HFCS, and the like that present the hazard.

Greg said...

Don, I have been thinking the same thing with regards to total caloric intake of fructose. Another data point to consider, however, is the Kitavans, who appeared to be in good health and would have been eating 25% of their calories as fructose.

idblog said...

Don, have you watched Lustig's Sugar: The Bitter Truth?

http://www.youtube.com/watch?v=dBnniua6-oM

He's very down on sugar in general and fructose in particular. Well worth the watch if you haven't seen it.

BTW, the researchers of this study are doing a new study comparing the effects of consuming HFCS and fructose at 0, 10, 17.5 and 25% of energy requirement in young, normal or overweight adults. Should be very interesting!

Beth

Don said...

Greg,

What kind of math do you use to get that figure for Kitavans?

Sweet potatoes, their main food, have only 4.2 g total sugar per 100 g (see your wikipedia reference). At most 1/2 of that is fructose, i.e. 2.1 g, or less than 10% of total CHO in sweet potato (20.1 g/100 g). So if they get 70% of calories from CHO, and only 10% of CHO as fructose, then they get less than 7% of calories from fructose.

Greg said...

Hey Don,

Thanks for the correction, your math seems good.

Richard Nikoley said...

I think this may be one I saw some months back and Stephan blogged. Metabolic shift was amazingly pronounced in the fructose only group.

At any rate, it's primarily what convinced me that starches aren't so bad and I have since incorporated back some potato of various varieties from time to time.