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Study Suggests Fructose Could Drive Alzheimer's Disease

197 points| elorant | 3 years ago |news.cuanschutz.edu

103 comments

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[+] scavenger5|3 years ago|reply
This is a junk study. Here is the link: https://www.sciencedirect.com/science/article/pii/S000291652...

If you look at the evidence hierarchy, this study is at the lowest form of evidence (it's a narrative review -i.e expert opinion), they didn't even run a study.

The ultimate study would multiple randomized controlled trials showing sugar/fructose when controlled for calories, causes increased Alheimer's disease. Since we haven't seen that, we should not draw conclusions.

As the saying goes 'correlation does not imply causation'. We don't even have correlation yet, the headline is an overreach.

[+] XFrequentist|3 years ago|reply
Agree that it's a poor headline and that the fructose/Alzheimer's hypothesis is quite speculative, but I don't think calling it a "junk study" or gesturing at evidence hierarchies is particularly helpful.

Theory (almost) always precedes evidence, and coming up with a novel, biologically-plausible explanation for a common ailment is absolutely a valid, useful scientific contribution.

Your general point, that drawing firm conclusions would be radically premature, is spot on. I just stiffen up a bit when I encounter "RCT or GTFO" type arguments; where in the world do you think the ideas for which RCT to run come from?

[+] profstasiak|3 years ago|reply
how do you expect we will ever get a randomized control trial controlling for fructose in diet?

Your right, but RCT would take how long? 50 years? How can you make people not eat fructose or limit that for 50 years?

Wouldnt call the article junk sciensce. We also need hypothesis builing articles. I think they are proposing a specific mechanism of action about how fructose might cause Alzheimers.

I believe there are other clues also pointing in this direction, which I wont bore you with.

Just want to note, that I think everyone would prefer high powered RCTs, but I dont believe they are feasible to fund and run

[+] exfatloss|3 years ago|reply
I would say this comment is a bit unfavorable. The study details some metabolic pathways that were recently discovered and are activated by fructose intake. They then explore a hypothesis as to why this could lead to certain outcomes like Alzheimer's.

Not exactly a "junk study." It's step 1 in a chain of studies that could validate this hypothesis.

[+] ProjectArcturis|3 years ago|reply
A review article is not necessarily junk science. This sort of paper is the first step in allowing us to conduct the more interventional studies you recommend.
[+] MarkMarine|3 years ago|reply
Comments like this are why I love hacker news. Thank you for saving me the minutes I would spend trying to wade through this stuff myself.
[+] hilbert42|3 years ago|reply
"This is a junk study"

I hope you're damn-well right. I love fruit and eat lots of it!

[+] AnIdiotOnTheNet|3 years ago|reply
I predict HN will look on this favorably anyway, because my experience is that a rather large number of them are practitioners of ketogenic or other high-fat low-carb diets and 'fructose bad' may as well be part of their religion.
[+] craigyk|3 years ago|reply
Thanks for the DD, I spent 30 secs scanning the article before thinking "this sounds like drivel, I'm going to check the comments"
[+] azubinski|3 years ago|reply
Well, at least something is in order :)
[+] Baloo|3 years ago|reply
"...other foods can also stimulate fructose production in the body and induce features of metabolic syndrome. These include foods that provide the glucose substrate for the polyol pathway, such as high glycemic carbohydrates, and foods that stimulate aldose reductase, such as *salty foods and alcohol*. Umami foods (especially processed *red meats, organ meats, shellfish, and beer* that is rich in yeast extracts) also engage the purine degradation pathway leading to uric acid.

The second more proximate factor has been the dramatic rise in the intake of added sugars that contain fructose and glucose, such as *table sugar (sucrose) and high-fructose corn syrup (HFCS)*."

And...

"Interestingly, *whole fruits tend not to activate this pathway* owing to a relatively low fructose content in individual fruits and the presence of neutralizing factors (such as fiber, vitamin C, potassium, and flavanols) and because the small intestine metabolizes some fructose before it reaches the liver and brain."

So basically processed meats, table sugar & high-fructose corn syrup are bad for you. I'm shocked /s

[+] unglaublich|3 years ago|reply
> So basically processed meats, table sugar & high-fructose corn syrup are bad for you. I'm shocked /s

The interesting part of the research is that the authors identified a common player that might progress the development of chronic diseases: high uric acid levels.

Uric acid has historically been associated with gout. But more recently, there has been growing interest in the role of uric acid on the development of chronic diseases like metabolic disease, cardiovascular disease and Alzheimer.

An interesting (imo) pop-medscience video by Dr. David Perlmutter - Uric Acid: A KEY Cause of Weight Gain, Diabetes, Heart Disease & Dementia https://www.youtube.com/watch?v=QZ6jPCcFNa8

[+] sys32768|3 years ago|reply
My mom got Alzheimer's at age 58. She was trim, ate organic, exercised daily, never smoked or drank, and had a happy social life.

She was always a super light sleeper though, and had her own room because dad would wake her up at night. I wonder whether her brain's lymphatic system was working.

Only other thing that stuck in my mind is not long before her symptoms, she had like six metal fillings removed and replaced with porcelain all at the same time.

Her aunt got it early too and was a health nut juicer for years who lived a healthy lifestyle.

[+] alfor|3 years ago|reply
Did she spend a lot of time outside?

Lack of infrared exposition is linked to inflammation and Alzheimer.

https://youtu.be/wadKIiGsDTw links to medical papers in the video description.

[+] sdwr|3 years ago|reply
Scary stuff! Thanks for the story.
[+] ProjectArcturis|3 years ago|reply
Have you ever been checked for familial early-onset Alzheimer's genes?
[+] thebigspacefuck|3 years ago|reply
Health nut juicer sounds like she would be taking in a lot of fructose? Did your mom eat a lot of fruit?
[+] ProjectArcturis|3 years ago|reply
I've spent about 10 years doing research into brain metabolism and Alzheimer's. This is an interesting paper! It explains a lot of observed phenomena in the novel context of fructose metabolism. I certainly am convinced that fructose has short-term effects on regional brain activity and whole-body metabolism.

However they don't make great links between fructose and known AD pathology. Beta-amyloid buildup is now pretty convincingly a critical step in the progression of AD. They link a few low-quality papers claiming fructose increases amyloid, but the evidence is pretty weak. Similarly, APOE genotypes are well documented AD risk factors. The authors aren't really able to explain APOE's role in the context of fructose.

Fun read (for me, anyway), but not particularly convincing. Hopefully it provokes some more research to try to fill in some of the missing links.

[+] giantg2|3 years ago|reply
Just another theory. I swear this domain is mostly people throwing shit at the wall to see what sticks.

I wouldn't be surprised if diet is one of many factors involved. But I really don't see much value by most of the studies at this point. Maybe we'll get to see who's right in a decade or two.

[+] yieldcrv|3 years ago|reply
So many ailments rely on multiple states occurring at the same time, and yet our way of studying seemingly has no way to factor this in.

Kind of sad. But we got a lot of lower hanging fruit plucked by figuring out cures and preventative measures for single state ailments.

[+] tomrod|3 years ago|reply
This is why the scientific method exists, thankfully!
[+] tsol|3 years ago|reply
Basically anyone can conduct a study, does not mean it's significant.
[+] ralala|3 years ago|reply
I have fructose malabsorption and when I eat or drink too much of it, I get brain fog (slow reaction, dizziness etc.) for one or two days. Would be interesting to see if fructose malabsorption and Alzheimer's correlate.
[+] alfor|3 years ago|reply
Lack of infrared exposition

Each of our mitochondria need infrared to remove oxidative stress.(inflammation)

They use infrared to do that but we now live inside more and more (especially elderly and sick) and thus we are in a constant crisis of chronic inflammation.

I know it sound new age, but the research is there, like Vit-D with the sun must have sounded ridicule at the time, the need for infrared was not apparent when most people worked outside.

https://youtu.be/wadKIiGsDTw (medical papers in the video description)

[+] hcarvalhoalves|3 years ago|reply
I recently learned about the infrared interaction w/ mitochondria, currently undergoing near-red/low-power laser therapy to recover numbness after fracturing the face.
[+] tsol|3 years ago|reply
This is interesting, but I don't know if there's much to say it causes Alzheimers specifically
[+] unglaublich|3 years ago|reply
You confuse IR with UV light.
[+] tonis2|3 years ago|reply
From my own experience, all the syrups that lots of modern food include cause me massive memory and sleep problems.

I do have some gut bacteria imbalances, that might increase the bad effects of sugar, but still, I could not function if I wont avoid added sugars, which is pretty hard task today.

So I'm not surpised by this study, cause I feel it immediatley how the sugar disables my brain.

[+] msie|3 years ago|reply
"The study said more research is needed on the role of fructose and uric acid metabolism in AD." - we need more money.
[+] M95D|3 years ago|reply
> Metabolizing fructose and its byproduct, intracellular uric acid [...]

Fructose DOES NOT metabolise to uric acid. This means the whole article is fake/scam.

[+] spacephysics|3 years ago|reply
Someone with more domain knowledge, does this study hold water? Even perhaps as a reason to look further into the relationship between diet and Alzheimer’s?
[+] snshn|3 years ago|reply
I am convinced that boredom is the main cause of Alzheimer's and many other neurological ailments.
[+] msie|3 years ago|reply
A theory easy enough to test.
[+] manmal|3 years ago|reply
Unfortunately not, because fructose is also produced endogenously. As mentioned in other comments here, whole fruit consumption seems to not even be the real issue.
[+] m3kw9|3 years ago|reply
Maybe treating AD as a singular disease is confusing researchers into thinking there is a single factor causing this. It’s a spectrum disease, damn do we have to remind them this?
[+] ProjectArcturis|3 years ago|reply
This is an area of active research and it's misleading to claim that there is any kind of consensus that AD is a spectrum disease. If anything, the recent success of anti-amyloid drugs has pushed the consensus the other way.