Study: Fructose Is A Cortisol Booster

[berk]

Biochemists at the University of Belgrade published in the Journal of Nutritional Biochemistry the results of a study in which they examined another potentially fattening aspect of fructose: the effect of cortisol in fat cells.
Throughout the world there are a couple of dozen laboratories that are working on developing slimming aids that deactivate this hormone in fat deposits by blocking the enzyme 11-beta-HSD-1. This is the enzyme that converts the inactive hormone cortisone into the active hormone cortisol. Cortisol is a stress hormone that inhibits muscle growth but stimulates the growth of fat cells.

Study
The Serbian researchers studied two groups of male lab rats. One group was given ordinary drinking water [Control]; the other was given drinking water that contained 10 percent fructose [Fructose].

Results
After nine weeks the rats in the fructose group ate more than the animals in the control group. The fructose rats had slightly more abdominal fat than the control rats, but the difference was not statistically significant.

The amount of free fatty acids [NEFA] in the blood of the fructose rats was significantly higher than the amount in the control rats. If you burn the free fatty acids there's no problem. If you don't, a high concentration of free fatty acids in your blood spells disaster in the long term. The fatty acids build up in your muscles and organs and end up sabotaging their functioning.

The fructose diet didn't increase the number of cortisol receptors [GR] in the fat cells, but the researchers did find considerably higher numbers of cortisol receptors in the cell nuclei. These were probably receptors activated by cortisol, which then pass on instructions to the DNA in the fat cells.

In the fat cells the researchers found more 11-beta-HSD-1 and more H6PDH. H6PDH is an enzyme that provides energy to 11-beta-HSD-1, so it can carry out its work.

Conclusion
The researchers were not able to confirm the theory that 11-beta-HSD-1 and H6PDH blockers are slimming aids. They didn't observe a significant increase in the abdominal fat of their lab animals, but their study does suggest that a low-fructose diet is interesting for anyone wanting to reduce their cortisol levels.

Source:
J Nutr Biochem. 2013 Jun;24(6):1166-72.

 

[Gone Peating]

It’s kind of an unrealistic study since fructose alone doesn’t occur in any food in nature. It’s always paired with glucose or some other carbohydrate

 

[Kvothe]

Biochemists at the University of Belgrade published in the Journal of Nutritional Biochemistry the results of a study in which they examined another potentially fattening aspect of fructose: the effect of cortisol in fat cells.
Throughout the world there are a couple of dozen laboratories that are working on developing slimming aids that deactivate this hormone in fat deposits by blocking the enzyme 11-beta-HSD-1. This is the enzyme that converts the inactive hormone cortisone into the active hormone cortisol. Cortisol is a stress hormone that inhibits muscle growth but stimulates the growth of fat cells.

Study
The Serbian researchers studied two groups of male lab rats. One group was given ordinary drinking water [Control]; the other was given drinking water that contained 10 percent fructose [Fructose].

Results
After nine weeks the rats in the fructose group ate more than the animals in the control group. The fructose rats had slightly more abdominal fat than the control rats, but the difference was not statistically significant.

The amount of free fatty acids [NEFA] in the blood of the fructose rats was significantly higher than the amount in the control rats. If you burn the free fatty acids there's no problem. If you don't, a high concentration of free fatty acids in your blood spells disaster in the long term. The fatty acids build up in your muscles and organs and end up sabotaging their functioning.

The fructose diet didn't increase the number of cortisol receptors [GR] in the fat cells, but the researchers did find considerably higher numbers of cortisol receptors in the cell nuclei. These were probably receptors activated by cortisol, which then pass on instructions to the DNA in the fat cells.

In the fat cells the researchers found more 11-beta-HSD-1 and more H6PDH. H6PDH is an enzyme that provides energy to 11-beta-HSD-1, so it can carry out its work.

Conclusion
The researchers were not able to confirm the theory that 11-beta-HSD-1 and H6PDH blockers are slimming aids. They didn't observe a significant increase in the abdominal fat of their lab animals, but their study does suggest that a low-fructose diet is interesting for anyone wanting to reduce their cortisol levels.

Source:
J Nutr Biochem. 2013 Jun;24(6):1166-72.

I agree with the first reply, feeding pure fructose seems unphysiological, as it doesn't really happen in nature. Some of the effects might be explained by fructose malabsorption and dysbiosis. What is curious, though, is that the fructose animals ate 25% more calories, yet weighed significantly less. Sounds like what Peat is always saying about the metabolic advantages of fructose.

 

[scoobydoo]

I agree with the first reply, feeding pure fructose seems unphysiological, as it doesn't really happen in nature. Some of the effects might be explained by fructose malabsorption and dysbiosis. What is curious, though, is that the fructose animals ate 25% more calories, yet weighed significantly less. Sounds like what Peat is always saying about the metabolic advantages of fructose.

yes, but this same physiological affect (high cortisol and weight reduction) is why many say keto is bad. Just because someone loses weight does not automatically equate to healthier metabolism

I personally have noticed an increase in cortisol when adding carbs and fruit (tested via Dutch test) vs a lower carb diet

 

[tankasnowgod]

The fructose fed rats ate more, weighed less, and didn't have any significant differences in visceral fat. Why wasn't that the headline of the study?

Seems to go well with this study Haidut posted a while ago-

Drinking Coke Freely Quadruples Calorie Intake WITHOUT Weight Gain

Also, one other note..... the researchers didn't test Cortisol, they tested Corticosterone, so the title of this thread is inaccurate.

 

[tankasnowgod]

I personally have noticed an increase in cortisol when adding carbs and fruit (tested via Dutch test) vs a lower carb diet

You mean an increase in cortisol ELIMINATION.

 

[scoobydoo]

You mean an increase in cortisol ELIMINATION.

I’m not sure I understand the difference
Can you explain? I thought the Dutch test was a good indicator for cortisol levels

 

[methylenewhite]

Fructose fed mice have higher fat, lower muscle mass and higher cortisol.

Same study with sucrose needed

 

[tankasnowgod]

I’m not sure I understand the difference
Can you explain? I thought the Dutch test was a good indicator for cortisol levels

It might be, but it's testing cortisol levels in urine. What you eliminated. If you had just switched from low carb to higher carb, your body may have been eliminating excess cortisol. I've seen this in studies before.

The plasma range for cortisol even varies from morning to evening. I don't know how reliable the DUTCH test is. I imagine it could be useful for trends over time.

 

[tankasnowgod]

Fructose fed mice have higher fat, lower muscle mass and higher cortisol.

Same study with sucrose needed

The difference in visceral fat was insignificant, (about 0.5 grams in a 311 gram animal), and the researchers didn't even test cortisol.

 

[Hans]

I’m not sure I understand the difference
Can you explain? I thought the Dutch test was a good indicator for cortisol levels

Salivary or blood? Salivary only shows the free fraction which doesn't show total cortisol at all.
Urinary cortisol shows the elimination of cortisol, so the total blood cortisol.

 

[Hans]

I'd also like to add, from my article: Why the side effects of sugar are based on flawed research and how to make sugar work for you instead of against you » MenElite

"However, sugar actually decreases 11β-HSD1 mRNA (R), the enzyme that activates cortisol and sugar also increases the NAD:NADH ratio (R), which is needed to deactivate cortisol; both of which will lead to less cortisol production, keeping stress under control. This study also shows that sugar was just as effective as bananas at lowering cortisol (R).

In short, sugar doesn’t increase cortisol, but can actually help make you more stress resilient."

 

[scoobydoo]

Salivary or blood? Salivary only shows the free fraction which doesn't show total cortisol at all.
Urinary cortisol shows the elimination of cortisol, so the total blood cortisol.

Mine was urinary test
Low carb it was low and raised throughout the day
Higher carb raised cortisol levels overall

 

[methylenewhite]

The difference in visceral fat was insignificant, (about 0.5 grams in a 311 gram animal), and the researchers didn't even test cortisol.

Corticosterone. Pardon.

 

[methylenewhite]

But corticosterone=cortisol in case of rodents.

 

[Kvothe]

Fructose fed mice have higher fat, lower muscle mass and higher cortisol.

Same study with sucrose needed

Why do you purposely make false claims? The study neither says that the fructose mice had higher body fat, nor that they had less muscle mass.

Urinary cortisol shows the elimination of cortisol, so the total blood cortisol.

That's false and misleading.

 

[Hans]

Why do you purposely make false claims? The study neither says that the fructose mice had higher body fat, nor that they had less muscle mass.



That's false and misleading.

Grammer mistake, I meant it doesn't accurately show total blood cortisol. How is that misleading?

 

[Hans]

Mine was urinary test
Low carb it was low and raised throughout the day
Higher carb raised cortisol levels overall

Thyroid hormones increase cortisol excretion and a low carb diet can lower thyroid hormones.
It's common for a low carb diet to lower urinary cortisol and for a high carb diet to increase it. But that doesn't show that carbs increase cortisol. Carbs increase insulin which suppresses cortisol.

 

[methylenewhite]

Why do you purposely make false claims? The study neither says that the fructose mice had higher body fat, nor that they had less muscle mass.

Don't you see the table?

 

[tankasnowgod]

Don't you see the table?

Yes, and there is no body fat percentage on the table, nor a measurement of lean mass. Only a measurement of visceral fat mass, which showed an insignificant difference (both statistically and clinically).