Ultra-processed food linked to higher risk of depression, research finds | Hacker News Reader

Ultra-processed food linked to higher risk of depression, research finds

theguardian.com

77 pointsPaulHoule67 comments

From article:

```

Others urged greater caution. Prof David Curtis, an honorary professor at University College London Genetics Institute, said: “The only foodstuffs which [this study] shows are associated with increased risk of depression are artificial sweeteners. Of course, this does not mean that an effect of artificial sweeteners is to increase depression risk – it is just that people with increased risk of developing depression tend to consume larger quantities of artificial sweeteners.”

But the authors disagree. Prof Andrew T Chan, chief of the clinical and translational epidemiology unit at Massachusetts general hospital and co-author of the research, said: “The strength of our study is that we were able to assess diet several years before the onset of depression. This minimises the likelihood that our findings are simply due to individuals with depression being more likely to choose ultra-processed foods.

```

Seems to be a correlation study to me. I also don't see any controls for other circumstances, so it can also be explained that other factors could contribute both to eating processed foods and getting depressed (ex: working long hours, having low income, relationship stress)

The correlation might still be useful as identifying how society is failing both in providing (tasty, easy, cost equivalent or better, healthy) alternative foods and how rampant a problem this is.

Depression impairs motivation, decreases tolerance of physical discomfort, and is also associated with impairment of planning abilities, and also has a correlation with eating disorders.

Occam's razor: the depressed can't plan and then cook a good meal for themselves, and so buy ready-to-eat processed food.

Anecdotally, when I was younger and very poor, I could not eat well unless I did everything from scratch -- several hours of work a day in the kitchen. When I got depressed, I'd try to cook while hungry, and get more and more agitated at my discomfort until I lost emotional control, and nothing got cooked. Cry. Eat instant noodles or crackers. Repeat the next day. When I finally made or got my hands on a proper hot meal with protein, my mood would noticeably improve.

My mood is still very susceptible to my diet, but these days I can afford stop-gap solutions to having no energy to cook, like just getting some reasonably healthy takeout.

Oh well in that case yeah throw out any concerns or criticisms. `retrac`'s anecdote and invocation of the law of Occam's Razor is proof that the study is iron clad.

Or realize that on such a painful and personal subject that some people will share their personal anecdotes—totally unscientific, oh my!

Also impulse control and relationship to instant gratification and addictive behaviors.

Processed foods are formulated to induce addictive behavior.

"We used 2 definitions for depression:

(1) a strict definition requiring self-reported clinician–diagnosed depression and regular antidepressant use and

(2) a broad definition requiring clinical diagnosis and/or antidepressant use.

We estimated hazard ratios (HRs) and 95% CIs for depression according to quintiles of UPF intake using Cox proportional hazards models, with adjustment for known and suspected risk factors for depression, including age, total caloric intake, body mass index (BMI; calculated as weight in kilograms divided by height in meters squared), physical activity, smoking status, menopausal hormone therapy, total energy intake, alcohol, comorbidities (eg, diabetes, hypertension, dyslipidemia), median family income, social network levels, marital status, sleep duration, and pain."

https://jamanetwork.com/journals/jamanetworkopen/fullarticle...

I know that when my mental health starts to become a problem again the first thing that goes is any desire to cook. Which often leads to gettin take out, frozen meals, or just constant snacking.

I have had basically zero desire to cook (or really do much of anything in complete honesty) for the last couple weeks and I am super thankful for "processed" things like Huel.

Edit: Also I am 100% going to reach for that frozen meal from Trader joes that gives me a brief amount of joy and makes me feel good.

Hope you feel better soon :)

But this shows that theres no eating processed food --> get depressed causation, just a correlation. Otherwise a perfectly happy person who eats a lot of tv dinners would inexplicably get sad with nothing else in their life changing.

Thank you!

I have an appointment with my psychiatrist tomorrow! Yay mental health.

Exactly, I don't want to reject the study personally. Mental health is a complex beast and it was worthwhile to look at, but there is also a lot of stigma around processed foods that I think make something like this very complicated and it doesn't address why people may use the processed food in the first place.

> I have had basically zero desire to cook (or really do much of anything in complete honesty) for the last couple weeks and I am super thankful for "processed" things like Huel.

I'd never heard of Huel. Just looking at the info on their bag of pasta bolognese:

* bag size is 721 grams but serving size is 101g!

* they put the "per day" measurement at 505g? But even there, you're be consuming 3200mg of sodium-- 139% of the daily recommended value

Honestly, eating a 101g serving sounds to me like attempting to eat 1/8 of a bag of M&Ms.

If I open that 721g bag for lunch, it's going to be gone by end of day, guaranteed. (Probably with half a baguette for dipping.)

Edit: I forgot it's for lunch and dinner in my example. So make that a whole baguette. :)

Yeah so I don't do the Huel hot meals, I just never liked them.

I do the Huel Black which is a meal replacement shake with extra protein. Which if I did 5 servings of would be about 2,250mg of sodium a day. However personally I do it 3 times a day (the extra protein helps) and then a couple snacks like an apple or something else throughout the day.

However I will say regarding eating the entire bag in a day. It is fairly dense and filling (even though I didn't like the taste). So I would be surprised if you would finish it in a day. (then again it is only 7 meals to a bag compared to the 17 meals in a bag of Huel Black so maybe I am remembering wrong)

I wonder if depression simply starts much earlier than diagnostic controls detect it.

Even though this study started years before these people were diagnosed, they may have already had depression.

Researchers love dunking on artificial sweeteners. It is one of the guaranteed methods of getting loads of press. Press yields prestige. Given that artificial sweeteners often correlate with people with weight / health problems like diabetes for very functional reasons, it's like shooting fish in a barrel.

Paradoxically this same data source (the Nurses' Health study, which is a continuous series of questionnaires) has had a prior paper claiming "sugar-sweetened soft drinks, refined grains, and red meat" led to depression. Now that "ultra-processed foods" and artificial sweeteners are the public demon, they take centre stage for the next round. I suspect with a bit of p-hacking one can contrive whatever aha result they desire out of it.

Their argument regarding eliminating correlation seems suspect. They analyzed diet in period 1 against reported depression in period 1 and found a given correlation. They then analyzed diet in period 1 against reported depression in period 2 (apparently 4 years later) and claim to have found the same correlation, which is what he cites in defence. Yet they never state that depression in period 2 in those cases is worse than period 1, invalidating it.

The Nurses' Health Study is a really fascinating exercise and certainly holds massive use, but it also has been a source of a lot of incredibly dubious nutritional "science".

https://nurseshealthstudy.org/participants/questionnaires

The NHS II surveys were the ones they used for this "get press" study, and looking at the actual surveys it seems doubtful that they yielded the results they did.

Probably could build a lot of fun blog entries p-hacking the data from these surveys.

There is a lot of evidence that artificial^W non-caloric sweeteners are terrible.

There are correlation studies in humans showing many different health issues (weight gain, cancer, mental health issues, among others) that correct for all sorts of confounding factors.

There are experimental studies in rodents that show all of the above across multiple products.

They're known to interact poorly with certain drugs taken for mental illness, and can cause all sorts of brain-related problems in some people (such as migraines).

They're also known to screw up your gut's microbial community, and that's shown to cause depression.

(I'm not commenting on the quality of this particular study, to be clear.)

>There is a lot of evidence that artificial^W non-caloric sweeteners are terrible.

There is shockingly little good evidence showing this, and these are many of the most studied substances in human history. There are a lot of very flawed studies that got enormous press and attention, however, yielding the "overwhelming proof" illusion.

This argument was made (practically verbatim) to defend tobacco, asbestos, and fossil fuels. It's easy to fund and publish a sloppy study that shows no correlation, and then claim the findings in the literature are "contradictory".

The studies I'm referring to go back to the 1970's. I've seen many that show strong negative effects, and some that show no or inconclusive effects. None show positive effects.

At this point, if the negative effect studies are statistical anomalies, then there should also be a roughly equal number of studies showing positive effects too.

>This argument was made (practically verbatim) to defend tobacco, asbestos, and fossil fuels

Sure it was. Indeed, your argument is practically verbatim the rhetoric of antivaxxers, flat Earthers and climate change deniers.

As to your other point, what "positive effect" are you demanding? Controlling blood sugar and controlling calories both have an *enormous*, overwhelming volume of evidence. Sugar substitutes are just tangentially related to that effort.

Sugar substitutes lead to metabolic issues that outweigh the reduction of calories eaten. If you also eat food that contains sugar, then they cravings they cause lead to blood sugar spikes later in the day. This is all settled science.

Anyway, I'd love to get some links to the scientific studies that the flat Earthers have saying the earth might be flat, after all.

Also, I don't think the anti-vaxxer's citation of one retracted study about mercury poisoning is really comparable to the dozens of non-retracted studies showing negative effects of artificial sweeteners across multiple mammals (including humans), or the work showing the chain of causal relationships that lead to metabolic issues.

Similarly, climate change has been scientific consensus since at least 1980, and I'm arguing on the side of scientific consensus, not against it.

The sweeteners cause incorrect hunger satiation signaling (as does HFCS), and also screw up your gut microbiome. The incorrect signaling makes you hungrier after eating the sweetener. If you eat at that point, then there goes the caloric intake benefits.

If you don't eat at that point, your body reacts by slowing down your metabolism, conserving more calories than you saved from avoiding sugar and also discouraging you from exercising. Over time, the lack of exercise and artificially lowered metabolism leads to a lower base metabolism, causing long term weight gain.

This doesn't touch on the problems a disrupted gut microbiome causes, known side-effects / intolerances / drug interactions that various products cause, or that some of them are carcinogens.

Making hugely contentious claims and then stating that it's "settled science" is not a convincing tactic. Again, you are using the anti-science tactic of saying "this one thing kind of said this, and that's what I've selected as my position, ergo it is The Truth". Science doesn't remotely work like that. Claiming you are on the side of "scientific consensus" is so cosmically wrong you're either lying, or staggeringly ill-informed.

There were HCQ and Ivermectin fanatics who were sure it was "settled science" because they read only what they wanted to see, and only accepted results they wanted to be true.

"f you don't eat at that point, your body reacts by slowing down your metabolism, conserving more calories than you saved from avoiding sugar and also discouraging you from exercising."

Ah, the "what's even the point?" tactic, which is the fallback of lazy dieters everywhere. Their metabolism "slowed" and magically the conservation of energy no longer applies.

What if the deep subconscious keeps track of sweetness in the mouth and nutritional requirements (conscience hunger and cravings)? Artificial sweeteners would break the biological programming and cause all sorts of problems including depression and inappropriate hunger.

Edit: I hadn’t fully thought this through, but in my experience sometimes looking at a clock causes the physical hunger sensation. I have also been painfully starving which immediately stopped after the first swallow of a chugging a coke. Artificial sweeteners would have thrown a monkey wrench in my biological machinery.

> I also don't see any controls for other circumstances, so it can also be explained that other factors could contribute both to eating processed foods and getting depressed (ex: working long hours, having low income, relationship stress)

Of course there were controls.

Directly from the article: “Adjusting for other health, lifestyle and socioeconomic risk factors for depression…”

As noted in another comment, the paper goes into further details on the controls they used.

Honestly, this kind of thing is insulting. If you’re going to levy that kind of accusation of incompetence against someone, you at least owe it to them to read the source material before doing so.

It’s good of you make this correction, we need to be accurate when discussing the research at hand.

That said, it’s worth pointing out that “adjusting for” a factor isn’t quite as effective as it sounds: https://dynomight.net/control/

Having built some regression models in my time, throwing a ton of extra variables in doesn’t fill me with confidence that I am “controlling” much of anything.

Following from the above, I'll presume you've got a specific methodological critique based on the process detailed in the paper?

The paper in question: https://jamanetwork.com/journals/jamanetworkopen/fullarticle...

It’s a research letter, which is peer-reviewed by JAMA but shorter than a traditional, full-fledged research article.

The full text of the letter’s description of the adjustments:

> with adjustment for known and suspected risk factors for depression, including

[followed by a list of over a dozen factors]

The data sharing supplement says that the code is on GitHub (hmm!), but doesn’t include a link (oh…).

That’s all I have to work with. I can’t make a specific criticism of the adjustments in this study. I’m left with my preconceived notions of how this kind of research is often done, even with peer-review.

When I read the words “we controlled for X in our population study of Y”, I usually take the lazy shortcut of not updating my internal model of the relationship between X and Y at all, because I’ve fooled myself too many times before. If they mention a natural experiment or instrumental variable I get excited.

The counterargument by Chan misses Curtis' point - people with higher RISK of developing depression. Depression goes hand in hand with high trait neuroticism, and both the internalizing and externalizing branches of neuroticism contain subtraits related to lower self-control (though we're mostly with the internalizing one here, I'd imagine)

My brain now automatically replaces "linked to" with "correlated with, and no evidence of causing" whenever I read a headline. Obviously if they had evidence of causation they would lead with that.

"Linked to" does mean "correlated with" so there's no problem there. "No evidence of causing" is not the right takeaway. A strong correlation does not mean this is the causal link. But it does suggest there is something in that ballpark worth thinking about that is at least a noteworthy cofounder. Causal studies of some things are basically impossible.

Now that I think of it, it reminds of me of the notorious case of Dan White who shot Harvey Milk and George Moscone who invoked

https://en.wikipedia.org/wiki/Twinkie_defense

There was a lot of anger about him getting a relatively short sentence leading to

https://en.wikipedia.org/wiki/White_Night_riots

but his mental health struggle may well have been real because he died by his own hand less than two years after he got out of prison.

To add to the significant caveats already posted by others (correlation<>causation, confounding factors, etc), diary studies of diet are known to have very poor signal to noise.

Also, there's a notable counter-example since diabetics are a large, distinct group which has had substantially higher average artificial sweetener consumption than the general population for many decades.

are you asserting that diabetics have lower depression rates than the general population?

Is this another case where science got the causation and correlation backwards? Is it not more likely that depressed people eat processed food rather then the other way around?

More likely highly processed food has no fiber. That leads to glucose spikes when eating. They release insulin to protect the body from high blood sugar. that leads to glucose stored as fat. Eventually there is a blood sugar crash. the whole process plays havoc with the body and its hormones. depression is probably really easy to create in this environment.

I've recently taken a greater interest in my fibre intake. It is quite shocking to see how little fibre is in most foods on the shelves, even in things that you thought surely had a at least some fibre.

The best thing I've found so far in terms of somewhat "shelf stable" sources of fibre is dried figs (and dates to a lesser degree) and certain brands of high fibre digestive cookies.

Low fibre content in a frozen TV dinner seems obvious, but it seems less obvious when you say "practically anything other than a handful of items outside of the fresh fruits/vegetable section".

I have not eaten fibre for many years. It's one of those overhyped health things. Fibre is not needed at all https://www.youtube.com/watch?v=xqUO4P9ADI0

It does help I guess if you eat so much sugar and fibre helps mop it up and digest it slowly. But the solution isn't to eat more fibre, it's to eat less or no sugar.

A body can survive without glucose and burn fat for energy instead.

They ask you to create an account.

The options are "Sign up" and "I'll sign up later".

How about that distasteful mindfuckery.

Seeing it a lot.

I get annoyed at all the "processed food" studies because when you go to look up the definition of ultraprocessed and processed it's all very hand-wavy "you know it when you see it" kind of thing so there's no way to know what to avoid in your diet.

This makes complete sense when paired with growing body of research [1] [2] on the gut-brain axis and how gut health impacts cognition, mood, and various neurological functions.

We already know that processed foods with low fiber, lots of sugar, and various chemicals can worsen gut biome diversity, increase bad bacteria, cause inflammation and gut permeability ('leaky gut'), etc. It follows that this would have an impact on mood from both depression-as-inflammation and gut-brain axis theories.

From [2]:

> Several studies have shown that fecal transplants rich with bacteria from depressed rats, as well as from depressed humans, can induce depression in recipient rats. In December 2021, a review of 34 human studies showed a similar pattern of bacterial species in the guts of people diagnosed with depression, bipolar disorder and schizophrenia.

I know of at least one microbiome startup staffed by a lot of great researchers that are working on this line of research to treat depression. I'm also personally involved in a study on the gut biome connection to MECFS & long covid [3]. Tests on my gut biome show I have a leaky gut (high gram negative lipopolysaccharides and various imbalances) and after 6 weeks of repairing this with pre & probiotics and a more restrictive diet I'm seeing notable improvement in my energy, cognition, and mood.

[1] https://www.washingtonpost.com/wellness/2023/01/31/gut-micro...

[2] https://www.npr.org/sections/health-shots/2023/07/08/1186092...

[3] https://remissionbiome.org

I think there's probably a decent correlation with people who are depressed going for convenience meals rather than take the time to cook or shop for healthy foods and that type of thing. It sounds like they tried to control for some of this but it's not clear how successful that was (I'm not a statistician so I can't speak to that).

At the same time, I think diet and gut health can have major impacts on physical and mental health as well so it makes some intuitive sense that certain foods might be linked with depression. I've always been suspicious of artificial sweeteners, they just seem a lot more chemical and artificial than the natural ones which we evolved to properly ingest.

Anecdata: during a period of essentially eliminating all added sugar (save for a small piece of dark chocolate a day which amounted to 2-3g of sugar), I never felt better. It was two to three months long. I'm hoping I can repeat that again.

Since we're sharing anecdata: I eliminated all sugar from my diet for a month[1], it didn't change a thing. I didn't feel better or worse. I didn't have more or fewer sugar "cravings". Food didn't taste more or less sweet than before.

[1] This was during the early pandemic so I was staying inside, cooking all my own meals from scratch, and since I was dieting I was strictly controlling what I ate.

Before you changed your diet, did strawberries taste actually sweet to you?

Post diet change, do they taste sweet now?

I don't think I ever ate strawberries pre-diet. After that month I went back to eating sugar like normal (but still successfully dieting to lose weight, just abandoning the sugar experiment). The only strawberries I remember ever eating were on some pancakes and covered in syrup, and they were sweet, but the syrup may have influenced that.

Have you tried supplementing magnesium or zinc or some other minerals? One of the troubles with processed food is that it reduces the minerals you get out of the food. Maybe the grand parent had a positive reaction because their alternate foods with less processing. Eg dark chocolate tends to contain a lot of magnesium.

I personally felt a big difference with magnesium supplementation.

My multivitamin has 11mg/day of zinc but it looks like it doesn't have any magnesium. I'll have to try that, thanks!

Interesting. So my cravings went down significantly, almost to zero. Normally I have such a sweet tooth, that I cannot resist desserts. During my no-sugar period, I was completely indifferent to it.

Food tasted the same, but my sensitivity to sugar was significantly increased. For example, half the usual amount of sugar in my tea would be enough.

I've recently increased the amount of fiber, decreased added sugar and decreased salt. (I check the percent daily value of each on the back of the package. Fiber has to be above the carbs percentage, and the other two have to be below my target calorie percentage.)

I highly, highly recommend doing that. Such a diet has been shown to reduce your risk of heart disease, cancer and diabetes.

As importantly, I feel much better, and am slowly (sustainably?) losing weight and decreasing my body fat percentage, despite eating how much I want, and regularly cheating on the diet.

Following it even half the time is a huge improvement. The only real discipline it requires is at the grocery store, which is easier than when I'm hungry.

am I depressed because I'm eating microwavable pizza pockets at 4am, or the other way round?

First one. I think all brain problems exist because it doesn't get what it needs to get in order to function properly. So it starts to malfunction. The brain illnesses are different because you can't use your ill brain to diagnose your brain. You can use your healthy brain to diagnose any other body part.

That is a big jump to make since you don't know what else they are eating.

This is like assuming that because I may have gone to get a candy bar or desert with dinner it means that I am not getting my proper nutrients in other places. Which is absurd.

Personally I feel like it is likely the other way around (and actually seems to be backed up by part of this artless with some calling question.

Sure, I’ll just take some salads for lunch to cure my traumatic brain injury :)

Injury != illness

But if you have an actual brain injury you are better off if you eat that salad compared with not eating it.

Probably a bit of both.

Depression makes it hard to have executive function. Lack of executive function makes depression worse. It's a vicious self feeding cycle.

The important thing is that you remember to pair your samsung fridge with your samsung tv so that advertisers know that their plan to get you to eat the pizza pockets has succeeded.

Remember, anything short of setting that up is stealing.

In this era of highly processed foods and added sugar, consuming fiber supplement has never been more essential.

Contradiction: your fiber supplement is also probably a highly processed food.

What about seaweed?

That's an interesting way of expressing "eating more salad."

Salad is probably the most acutely dangerous thing you can order in a restaurant or buy in a supermarket. Especially if it contains sprouts.

Something I learned the hard way, especially when traveling (which is most of the time,) is to avoid ordering salad at restaurants.

Cooked veggies are better. But I'll take metamucil over salad, easy.

Right, but you can still eat salad at home no? Where presumably most of your cooking occurs

Of course it is. Consuming a lot of ultra-processed food is one of worst things you can do to yourself. Occasional consumption is perfectly OK, but it doesn't take a rocket scientist to observe some patterns in obesity, well-being and general health, between people (or countries for that matter) consuming a healthy diet vs those consuming mostly ultra-processed garbage.

Correlation vs causation - my understanding is that this is the point of the study - they measured the ultra-processed food consumption patterns way before the onset of depression.

Is tofu unhealthy? I mean that seems pretty processed to me.

There are also things like Huel and Soylent which is probably about as processed as you are going to get and I really don't see any health issues with those (outside of the usual "its not real food" people but I really don't care about them).

It doesn't help that "ultra processed" is such a blanket term that it's basically meaningless.

I mean just because I buy "whole" ingredients doesn't mean that I magically cooked a healthy meal either. It could be just as bad (or worse with a few of the recipes I have made from Julia Child's book... as good as they are) than some of the processed meals I see out there. Maybe just less sodium.

Much of the same correlation you are looking at can also be attributed to the type of active (or less so) style that people have. Less walking, more relying on cars, etc.

I think "ultra-processed" is code for "food with all the fiber ripped out, and lots of added sugar and/or salt".

The latter is more obviously bad, and also very actionable for consumers.

Also, since I left "lots of artificial stuff" out of my definition, I intentionally included a broad range of "healthy organic snacks" that are actually terrible for you. It's probably best to avoid artificial crap in your food, but that should be(?) obvious.

Anyway, regarding tofu, it was hard to find a nutrition label, but this story has a bunch of them in a picture at the top: https://sporked.com/article/best-tofu/

They all have no salt, high fiber (vs. carbs), high protein and no sugar.

Also, they all have one ingredient (fermented soybeans) and a few preservatives(?)

Is "processed" the problem? What's the process that makes you fat and sick? Is it boiling? Stirring? Heating? Freezing?

Or is it the added sugar?

It's the sugar

“Processed” is pretty well-documented at this point. There's a range and ultraprocessed seems to be the highest culmnination.

Highly processed foods eliminate fiber. lack of fiber leads to blood sugar spike and insulin release. insulin stores blood sugar as fat. next is a blood sugar crash which means low energy, depression and cravings. It becomes a cycle.

also, some artificial sweeteners can cause an insulin response, and affect gut health

Everything you said is correct, but too much salt also causes trouble, and processed foods have way more salt than most people use when cooking in the kitchen.

Reply on news.ycombinator.com