A red meat-derived glycan promotes inflammation and cancer progression | Hacker News Reader

A red meat-derived glycan promotes inflammation and cancer progression

pnas.org

46 pointssfilipov43 comments

Previous discussion (shorter than I would expect)

https://news.ycombinator.com/item?id=8819065

An explanation that I could actually understand

https://www.reddit.com/r/science/comments/2qwwr4/red_meat_tr...

I missed the discussion on this last time this came up, but this fits squarely within my area of research, so it would be remiss of me not to pass comment. The Reddit link from Evgeny does a pretty good job of giving the gist of the research.

The big puzzle here is the precise mechanism by which this kind of thing can occur. To some degree, the binding of particular sugar-binding proteins to these newly incorporated sialic acids could perhaps influence cellular processes. What exactly is binding the sugars, and which molecules the sugars are incorporated onto will help with understanding the cellular processes.

The paper linked is an elaboration on Ajit Varki's work - but there's a lot more we don't understand about it than we do understand before we go about making conclusions. For what it's worth, I believe that Varki is not eating red meat [1]. I will try to get a look at his plate at the next conference dinner.

edit: [1] I'm not sure if he previously ate meat, so I removed the "now".

I'm curious about the validity of a mouse model for this subject. I remember early reports that rapeseed oil causes cancer in rats, followed by the discovery that feeding rats large amounts of any oil gives them cancer, because it's a bad model.

I don't think of small rodents as being particularly carnivorous, and as eating bugs and small bites of rotten meat when they do eat animals. Could this be affecting the results of this study?

Red meat gives you cancer, each vegetable has a weird side effect, carbs should be avoided, seafood can poison you, etc. I'm ignorant like the most of the population and I'm scared. We still don't really "know" what's good for us, and that makes me want to return to what kept us going during the 99% of the time-span of our evolution. But then, even that is a topic of discussion, I see[1]. I don't even want to get into the form and frequency of food consumption. Maybe in a few hundred years[2], we'll have enough research to say something like "well, eat X, Y and Z, N times a day and you should be fine with a statistical confidence of 95%".

The biggest problem is, most people just hang on to the first thing that "works" for them, then keep suggesting everyone that they should do exactly as they do.

[1][1]: http://www.huffingtonpost.com/kathy-freston/shattering-the-m...

[1][2]: http://www.peta.org/living/food/natural-human-diet/

[2]: Maybe I'm too optimistic?

Practice common habits from people who carry good health into old age. The science of nutrition is more confusing and contradicting than ever.

Right. My grandmother was tack-sharp into her 90s, and her daily diet was pretty much vodka martinis, steak and eggs, ice cream and cigarettes. I'll just do that ...

Amazingly enough, that may actually be good for you. Why? Most likely, she didn't really care about the health aspects of it, had those in social events (the vodka martinis) and enjoyed more stress-free eating that folks nowadays.

I don't promote unhealthy eating, but between unhealthy eaten care free lifestyle or health obsessed, stressed everything gives you cancer lifestyle, I believe the former will be better.

The vast majority of the vodka martinis were consumed in her kitchen between 10am and 1pm, not at social events =)

You will be surprised, by this will lead you to the plant-based diet. See https://en.wikipedia.org/wiki/Blue_Zone and http://www.bluezones.com/

The oldest living woman smoked daily into her late 90s.

I suspect those links are biased because the people writing them want to believe eating vegetables and not harming animals is not only ethically right, but also biologically right. However, I think mainstream science currently holds that humans evolved as natural omnivores, eating both vegetables and meat.

The problem with that assessment is omnivores don't just eat the meat. They also eat, cartilage, ligaments, organs, skin, etc.

People might love 'Steak and Potatoes' and look down on a hotdog as mystery meat. But chances are the hotdog is closer to what our ancestors were eating. Edit: Ignoring the preservatives etc.

PS: Consider, we acutally need to maintian ligaments etc so not eating such things seems somewhat risky.

They still do, at least in Europe and Asia. I can hardly think of something uneatable except skin and bones. For example, an old national Lithuanian dish is made of pig's intestine stuffed with blood and pearl-barley. And I won't even start what kind of things I've eaten in China..

Oh, no, the skin is quite edible. Fry it until it's suitably hard and crispy, and you have a delicious snack.

Uhhh, if you've had fried chicken you're probably eating the skin. And as you noted about the Chinese eating many things, I believe its pretty common that they eat the bones. I think bone marrow is common in some European dishes. I'd say the big difference between a hotdog and what we ate a long time ago is probably all the hotdog's nitrates.

I've seen enough information that I believe it's worth noting glycine and lysine and tryptophan intake for this reason. The problem with muscle meat, ignoring the claims of the article under discussion, is far too much tryptophan and not enough glycine. This is well demonstrated to be inflammatory. Any historically normal consumption of muscle meat would have been accompanied by large amounts of collagen and organs, which appropriately balances the amino acid ratios.

So I make a point of eating more gelatin and shellfish in preference to isolated servings of muscle meat.

Ah, yes, sorry. I didn't mean meat as in steak and potatoes. What I actually meant was "animals".

(BTW, I love chicken skin, bone and bone marrow. My wife watches in silent horror as I chew that stuff).

Dr. T. Colin Campbell wrote in his book "Whole" (2013) that he was not based on ethics, but on science only. So you assumption is wrong. Btw, he is from the mainstream science.

Forget that, lets do paleo right and go back to eating bugs! The whole "biotruth" "evolution-as-intelligent-design" argument isn't very interesting. Who cares how ancient humans ate? Their lifestyle was completely different. They didn't have access to the resources (both in terms of food and education) we do now, why would their diet necessarily be the best?

I somewhat agree with you, but I think that's going a bit too far. We should care what ancient humans ate because it can give us insights into what is healthy for us now.

The beef (no pun intended) I have with this sort of articles is that I think the authors start from their ethical point of view ("eating animals is wrong") and then they try to find a biological justification, which happens to be a bit flimsy and not what mainstream science currently holds. If they were more honest, they would admit: "I don't care what ancient humans ate, or what we are more biologically suited for. I still think eating animals is wrong, and that today we have the means to adapt to a diet that doesn't involve harming them." (Not that I agree with this position, but it would seem more honest to me).

I prefer no-nonsense diets. Avoid highly processed foods within reason[1], eat what your body tells you it needs. If you're feeling peckish and your mind is filled with steak, eat steak. If it's filled with pasta, eat pasta. If it's filled with lettuce, eat lettuce. And so on.

Avoid snacking if possible. When you notice yourself snacking, just go have a real meal. You're probably hungry.

[1] Processed foods in terms of microwave dinners, crazy super ground-up fastfood meats and so on. For instance, a sausage is better than a wiener. A ready-made salad is better than a ready-made smoothie.

If at all possible, buy straight up ingredients and assemble yourself.

And remember: fat keeps you full the longest, protein keeps you full reasonably long, carbs don't keep you full very long.

I've heard snacking is actually pretty good at maintaining your blood sugar level. Most people just snack on crap food though, and that's obviously bad.

In my personal experience snacking makes you consume a lot of (ie. more than you need) food, but never leaves you feeling full. Which is bad.

If at all possible, it's better to just have a meal which leaves you feeling full for the next 3 hours. It's also easier to focus on work if you aren't constantly thinking about food, which is what happens when you're hungry.

The assumption I'm making is that you're having 5 to 6 meals a day. If you call the meal between lunch and supper a snack, then yes, carry on snacking. But don't do that thing where you get up every 10 minutes to put something little in your mouth for four hours straight.

> We still don't really "know" what's good for us, and that makes me want to return to what kept us going during the 99% of the time-span of our evolution.

I believe we (the general first world population) eat much better than a few hundred years ago.

During our evolution we would starve or get scurvy and if lucky would get a meal a day. We adapted. We can eat pretty much any junk and we will survive. The drawback is if we constantly eat exactly the same thing for months, we die.

Compare with today, we can buy almost any vegetable imaginable, meat, fat, protein, exotic fruit, minerals any time of the year. This is unprecedented in human history.

The problem is the food industry trying to make us crave for the next shit so that we buy more and more of it. Who can blame them?

I guess for now the solution is to use common sense, eat a little bit of everything, "good" or "bad", and exercise. As a friend of mine says: "Try to make your body die equally everywhere."

Try to make your body die equally everywhere.

Like the "One-Hoss Shay": http://rpo.library.utoronto.ca/poems/deacons-masterpiece-or-...

We're getting to the point where it makes sense to take a complete, routine genetic profile of every person enrolled in a study, ever. What you're hoping for will more likely take the form of "given your genetics, we recommend avoiding the following foods, in the following combinations, and eating these things at these times". It is also unlikely to take hundreds of years.

Red meat is linked to a heart disease and some cancers. Comparing that to "each vegetable has a weird side effect" (what?) is intellectually dishonest. Vegetarianism has been given a bad name by "alt medicine" quacks, but reducing red meat consumption is a no brainer.

"Red meat is linked to a heart disease...reducing red meat consumption is a no brainer"

"Linked" doesn't mean much (correlated maybe?). But you believe that red meat statistically causes heart disease. Why do you believe that? Is it generally true, or does it only increase the risk for some people?

"Associated with increased risk" is probably a better way to put it. If you're healthy I don't think anyone is saying "don't eat red meat" but I'd think twice about eating a burger for lunch every day.

Just eat a little bit of everything, lots of colors, each thing in moderation. It's what really old active people tend to do, and it usually gives you complete nutrition.

Diets that omit or focus on one group of edible foods usually turn out to be bad for you in other subtle ways, it's because humans are strongly evolved to be omnivores.

Stephan Guyenet has a 6 part series called "Is Meat Unhealthy?" In his last post a few weeks ago he addressed this study and here is part of the relevant section:

>This study needs to be interpreted in the proper context. First, it was conducted in mice. Second, the amount of Neu5Gc in the diet was equivalent to a diet composed entirely of beef-- and not just any beef, but the highest-Neu5Gc beef measured in the study (beef Neu5Gc ranges 10-fold). The exposure to dietary Neu5Gc was therefore some 40-fold higher than what most red meat eaters would experience. Still, the study outlines a plausible mechanism for a link between red meat and cancer, and that helps increase our confidence in the observational findings.

Part VI: http://wholehealthsource.blogspot.com/2015/01/is-meat-unheal...

Part I: http://wholehealthsource.blogspot.com/2014/10/is-meat-unheal...

I can elaborate a little more, but in short Guyenet is incredibly balanced and professional on this sort of stuff.

Reminds me of this: http://kill-or-cure.herokuapp.com/

In the mean time red meat cures cancer: https://www.youtube.com/watch?v=YJ3C0mrZ3ZY

My transcript from the video, at 4:05

> For some weird reason, the mitochondria in cancer cell are defective.

I never heard this before. Is there an article (published in a peer review journal) that support this?

It's been suspected (and proved in some specific cases) since the 1920's - see e.g. http://en.wikipedia.org/wiki/Warburg_hypothesis

Some skepticism: http://www.sciencebasedmedicine.org/ketogenic-diets-for-canc...

Well, if one is to rely on anecdotal evidence only... there's been no studies to back it up. There's also this:

http://www.naturalhealth365.com/ketogenic_diet/cancer_part_1...

I don't pay attention to such articles anymore. For every "meat is bad" research/article you can find "meat is good" one, usually publicized nearly simultaneously. It's more like politics aimed to confirm someone's (or certain group's, depends on who paid a grant) bias, not science.

Why then is Argentina's cancer rate so low compared to that of Europe and the US?

Ignoring all the other things that affect cancer rates, a difference between Argentinian and American beef does come time mind: I believe that grass fed beef is still the norm in Argentina, whereas most US beef is grain fed.

Don't know if total ignorance is a blessing or not in this case, but....

Perhaps it has to do with how the animal is raised (grain vs grass?), or how the meat is prepared. Maybe there's something else in their diet or culture or even genetics which helps to offset it. Maybe they are dying of something else. Maybe the numbers of under-reported. Maybe cancer rates are more impacted by other factors, like smoking and drinking, and this is, relatively speaking, a drop in the bucket.

If you follow the Reddit comment linked and referenced from this thread that gives the high-level immunological summary of what's supposed to be happening here, it's hard to see how grass vs. corn fed beef could be making that much of a difference.

Grass-fed steak has about twice as many omega-3s as a typical grain-fed steak. And since grass-fed cattle are typically leaner, almost all cuts of grass-fed beef have less total fat than beef from corn-raised cattle.

Of course, Beef Magazine will refute those numbers with industry-sponsored "studies", but I tend to take them with a grain of salt (just like my steak).

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