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Comment by scavenger5 | Hacker News Reader

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.

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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?

While I agree that these theory based papers are useful, and are often the precursor to experiments, I believe the general understanding of "study has found X" in pop culture is that there is "hard evidence" of the finding being tauted. Theories are risky to place too much credence in without being steeped in the field yourself (is this a theory that most people in the field agree with, or is the one suggesting it an outlier?).

As usual science communication is never done as well as we could all hope, but I personally like this "hierarchy of evidence" approach in understanding if something is ready to be consumed by the general public, rather than requiring further discussion with the scientific community.

I wish sci comms practice would have a standard set of terms for stages of development/belief. Here the headline should be something like “theory proposed that …”

We have that term already. Hypothesis.

Agreed. At this point I am also not willing to just let science off the hook and blame it all on the press: If our smartest people can not find ways to differentiate between ideating and good results in a way that a sensationalist press can't simply ignore, then just maybe they are not trying all that hard.

There's nothing wrong with research like this per se. I think the way it's publicised is the main issue. Broadly I think there are two types of papers: those who are only relevant to other researchers, and those who are interesting to the public as a whole. This is very much in the former category.

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.

This is the case in physics and astronomy. People make predictions that are not only untested, but we have to invent equipment to test them.

One of the great early accomplishments in science was when astronomers, observing our Sun, noted an unknown yellow spectral line signature. In 1868, Norman Lockyer predicted that it must be created by a hitherto unknown element, which he named “Helium” after the Greek Titan of the Sun, Helios.

In 1895, two Swedish chemists detected helium in ore samples here on Earth, and in the great tradition of the scientific method, we had a theory, a prediction, and a confirmation of the theory by test.

http://braythwayt.com/2017/12/29/crown.html

I'm not sure it's always the case that theory precedes evidence, even in physics. We still have loads of evidence that theory does not explain, dark matter, dark energy and superconductivity being the most well known. Theory is often devised to explain something weird or unexpected that experimentalists observe.

Upon reflection, you’re making an excellent point!

Einstein predicted things we’re still confirming empirically, but then again, he started by asking himself how the speed of light could be constant for every observer, which was the result of an experiment that failed to confirm a different theory.

Science is an ouroboros of experiment and theory!

Theory is good. Not sure calling it a study in a headline is a good idea though.

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

We won't. That's why nutrition epidemiology studies are so bad and mostly useless. It's ok to simply say "let's not do this study which we know won't add anything to our knowledge of how nutrition affects health outcomes in real people". See David Chapman for an entertaining review: https://metarationality.com/nutrition

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.

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.

True, it's the headline that's junk. It calls it a "study" which implies running an experiment and observing the results.

A review article is a review article. It isn't a study.

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.

Let's hope the poster isn't lying or wrong

We can always have Bing read the study for us and ask what it thinks.

It thinks that we're bad users :(

But it’s such a good Bing :)

You probably still want to at least look at the research yourself, trusting other "off-hand" comments is, uh, ironically, akin to the moral from the "off-hand" parent comment in this case

Trusting a random commenter to dismiss the contents of an article for you seems almost as bad as only reading the headline. In both cases you're putting full faith in someone else to summarize the article in a way that serves their interests more than yours.

Sometimes it's just the way they do it, that counts.

I skimmed the abstract and would say the comment isn't quite fair to the study. I'm glad I spent the time checking it out myself.

I personally find the parent comment to be way too dismissive. Throwing the baby out with the bathwater.

hummm, many Alzheimer patients are insulin resistant...

https://pubmed.ncbi.nlm.nih.gov/34576151/

"This is a junk study"

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

Fruit contains fiber, and vitamins whereas fruit juice and other sugary foods often don't.

Right, I never drink straight fruit juice. Those large bottles of orange or apple juice commonly seen in supermarkets I consider dangerous, everyone ought to avoid them.

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.

Thanks for the DD, I spent 30 secs scanning the article before thinking "this sounds like drivel, I'm going to check the comments"

Well, at least something is in order :)

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