The Ars reports of an interesting study published in Nature about a possible link between food emulsifiers and inflammatory disorders.
Emulsifiers are used in processed foods, drugs, vitamins, vaccines, soaps, and cosmetics. They hold ingredients that generally don't like to be together, like oil and water, in a stable union. They are found in everyday products ranging from mouthwash to ice cream to salad dressing and barbecue sauce.
When emulsifiers first came into vogue, they were classified by the government as GRAS—"generally regarded as safe"—because in animal studies designed to detect acute toxicity and/or carcinogenic properties, they exhibited neither. But their consumption in the Western world has risen dramatically over the late twentieth century, largely in tandem with inflammatory disorders like colitis and metabolic syndrome, a collective suite of obesity-associated diseases. That connection has prompted more refined safety studies on emulsifiers and other food additives.
Although further work is obviously needed to assess the effects of emulsifiers on human health, the authors suggest that emulsifiers may have contributed to the enormous increase in inflammatory bowel disease and metabolic syndrome that has occurred over the last half century. However, the researchers note that "this hypothesis does not dispute the commonly held assumption that excess caloric consumption is a predominant factor driving the metabolic syndrome epidemic."
Maybe it's not entirely our fault that we've been eating everything in sight; by messing with our microbiome, the emulsifiers made us do it.
Original found in Nature, 2014. DOI: 10.1038/nature14232. Of course, correlation is not causation, but the results do suggest there is link between gut health, inflammatory disorders, and what's in the food we eat.
(Score: 3, Interesting) by buswolley on Monday March 02 2015, @06:38AM
Second, while I have not read the paper's experimental method closely, the admonishment about correlation not being causation is not appropriate. This is an experiment with random assignment to several experimental conditions; the purpose of random assignment is to be able to infer causality.
subicular junctures
(Score: 2, Disagree) by aristarchus on Monday March 02 2015, @06:56AM
But if your purpose is to assign causality, you have committed the fallacy of petitio principii. And after you have done that, how can the rest of the scientific community ever trust you again? It's like Mormon Archeology or Nazi Anthropology. Not science. My pet research project: to prove that I am, the most interesting man in the world! So far all my data points look good!
(Score: 2) by buswolley on Monday March 02 2015, @07:09AM
Not relevant. If science presumed causality there would be no use for a null condition (control), but science does, and thus does not presume the result (when performed competently)
subicular junctures
(Score: 1, Redundant) by aristarchus on Monday March 02 2015, @07:23AM
Exactly my point? What are you disagreeing with? Correlation does not imply causation. Unless you really, really want it to? Science, bro!
(Score: 2) by buswolley on Monday March 02 2015, @08:02AM
I'm not sure of your point exactly. If an effect of a condition above the null is found in a randomized experiment, one can rationally infer that the condition caused the effect (and not that the effect caused the condition). Experiments are tools to inquire about causation.
In any case know that it is equally true that causation does not imply correlation (because of suppression effects by a mediating variable), but I'm sure that isn't relevant to the point you are making, of which I can discern little.
subicular junctures
(Score: 3, Insightful) by aristarchus on Monday March 02 2015, @08:45AM
OK, this is important, so I will do my best to be clear. Correlation does not imply causation. Period. At all! This is sometimes referred to as the "induction problem" as identified by David Hume. We assume that the future will resemble th past, because it always has. But really we have no reason other than our assumption to think so.
I know what you're thinking: but a really strong correlation would imply causation, right? Nope. Let's say we have some phenomena that always, so far as we can tell, follows some other phenomena. We may be able to establish a probability of the second event following the second based on induction, the preponderance of evidence of a correlation in the past. But this is not enough to establish causation. Cause is a law, it has to be 100%, and as Hume pointed out, we never observe cause, only correlation. So once again, correlation does not imply causation.
This does save us from some jumping to conclusions, which humans are prone to do. And things like selection bias and irrefutable hypothesis. The rain dance is an example. In some cultures (California?) a drought calls for active intervention. We dance for rain. Does the dance cause it to rain? Yes, because if it doesn't you're not doing it right. We dance, oh, how long? Until it rains. Post hoc, ergo propter hoc, and what's more, it works every time! With that kind of correlation, there must be a causal relation, right? Um, no. It is kind of like how when you're search for something, it is always in the last place you look.
Hope this helps.
(Score: 3, Informative) by Anonymous Coward on Monday March 02 2015, @10:03AM
No, you thick-skulled windbag. Correlation does not imply causation, but it's about the damn best sign suggesting there MIGHT be something there so worth looking into.
(Score: 3, Insightful) by aristarchus on Monday March 02 2015, @10:09AM
Which, you pneumatically challenged windbag yourself, does not imply causation! There is no "might", not even a "maybe", unless you want to go back to the metaphysics of the past. LaPlace's demons, anyone? (Oh, and less name calling might cause a more successful argument.)
(Score: 0) by Anonymous Coward on Monday March 02 2015, @02:07PM
Correlation between A and B can be due to one of the following possibilities:
So you see, from the four possible reasons of correlation, all but one are eliminated by a properly dome randomized experiment. The one that remains is:
A causes B
So in short, yes, in this case does correlation imply causation.
(Score: 2) by buswolley on Monday March 02 2015, @03:07PM
All you point out is that there is an immutability assumption. Yawn.
Sure. One wonders whether the rules of logic also have assumptions like universality and immutability. Arithmetic also requires first principles. While I suppose these assumptions are profound, they also aren't that important practically. Science is about probability not proof. One might assign a probability to a change in this assumption and incorporate that into statistical models but damn me if that isnt a waste of time.
subicular junctures
(Score: 3, Informative) by GreatAuntAnesthesia on Monday March 02 2015, @08:44AM
A lot of people are quick to shout "Correlation =/= Causation", but they ignore the fact that while this is true, it doesn't mean that correlation has no place in science. I think the mantra should be "Correlation =/= causation (but it's often a good reason to look more closely at something.)"
Not quite as catchy, admittedly.
(Score: 3, Insightful) by aristarchus on Monday March 02 2015, @09:36AM
Exactly! Correlation implies correlation! But more importantly, correlation implies predictability. That is really all we need. Of course, all our theories about why there is correlation could be completely wrong, but as long as they work . . . This is the American school of Philosophy know as Pragmatism. If it works, it's true, because that is what true is.
(Score: 2) by sjames on Monday March 02 2015, @11:35PM
Correlation is not causation but it does waggle it's eyebrows and glance meaningfully at it. It is necessary but not sufficient to show causation. As such, it is a good quick way to determine if further investigation is warranted.
(Score: 2) by Reziac on Tuesday March 03 2015, @05:32PM
I'm not going to dive behind the paywall to read the full article, but I did read the linked part, and my first question (having a biochemistry background myself) was -- which emulsifiers? what is the chemical pathway here? are they over-generalizing?
Cuz, emulsifiers in general? that sounds like biochemical nonsense; your own gut's bile is an emulsifier, without which you can't digest fats. Beating an egg emulsifies it. But soy proteins, when used as an emulsifying agent? that's a known possible, due to how soy increases the production of gut mucus, which in turn changes the microbial and parasite environment. Generally, more mucus makes the gut more-friendly to hostiles, and prevents your immune system from doing its job.
And there is no Alkibiades to come back and save us from ourselves.
(Score: 5, Informative) by SlimmPickens on Monday March 02 2015, @06:38AM
Nice topic, but IMHO the summary should have included this paragraph which tells us we're not talking about lecithin (egg yolk...mayo, hollandaise) and soy lecithin (lot's of things including pharmaceuticals) and also that it's more than just the association of junk food with IBS and metabolic syndrome.
Normally, the bacterial residents of the intestine are separated from the intestinal wall by a layer of mucus. But when mice were given two emulsifiers, polysorbate-80 and carboxymethylcellulose, the distance between the bacteria and the epithelium was reduced by half because the mucus wall was thinner. Some bacteria were pressed right up against the epithelium, and a few even adhered to it. The emulsifiers also changed the composition of the microbiome, reducing levels of Bacteroidales (species generally considered to be good guys in terms of the host's health) and increased levels of species that degrade mucus.
(Score: 4, Interesting) by VLM on Monday March 02 2015, @12:59PM
This is a good point, and another area of interesting further research is emulsified foods themselves not just the emulsifier.
You can buy canned (bottled) real mayo, and it'll be made of soybean oil, eggs, and vinegar, mostly.
Its interesting that before processed mayo and fake mayo, people probably didn't eat as much soybean oil or vinegar. I like a nice vinaigrette dressing on a salad once in a while, or the occasional pickle, but there's people out slathering a quarter cup of mayo or fake mayo every single day on a sandwich, for example. Surely not just the egg is changing their gut biome and digestion etc if you double someones egg intake while hundred-tupling their soybean oil and vinegar intake.
That's before you get into secondary effects, like the presence of mayo making sandwiches taste better resulting in increased intake of sliced mystery meat or whatever.
I would guess they aren't correcting for food intake in the analysis, making test subjects drink a quarter cup of soybean oil and a few teaspoons of vinegar very day would probably drift into cruel and unusual punishment territory.
(Score: 2) by sjames on Monday March 02 2015, @11:49PM
Pickled foods (either vinegar or fermented foods with lactic acid) were probably even more common due to the lack of refrigeration. Likewise, extracting oil is a good way to store nutritional value from a food that might otherwise spoil.
(Score: 0) by Anonymous Coward on Tuesday March 03 2015, @03:57AM
A quarter cup of mayo is hardly enough for "slathering" ... ;)
*burp* ... 'scuse me ...
(Score: 2) by Reziac on Tuesday March 03 2015, @05:46PM
IBS should *always* be investigated as a symptom of acute-phase Hashimoto's thyroiditis. In fact per an article I read in the Journal of Endocrinology, IBS is considered *definitive* for Hashimoto's, even without the initial presence of thyroid antibodies.
From the bit you quoted here, it sounds to me like what's happening in their studies is that the natural mucus is also being emulsified, which obviously is going to mess things up because it's basically the layer of protective goo. I'm guessing this didn't really become a problem until the low-fat craze (given cholesterol's role in cellular structures). I'd like to see their results on a normal-fat vs low-fat/low-cholesterol diet.
BTW, a realworld example of what I mentioned above re soy proteins: Dogs develop natural antibodies to roundworms by the time the dog is about a year old, which then naturally expel any remaining worms. But dogs fed a soy-based diet will still tend to be wormy. Why? Because soy protein stimulates excess gut mucus, which protects the roundworms from antibodies. The same applies to some pathogenic bacteria.
And there is no Alkibiades to come back and save us from ourselves.
(Score: 2) by gringer on Monday March 02 2015, @09:02AM
The Malaghan Institute of Medical Research [malaghan.org.nz] is trying to build up skills in researching the microbiota of the gut, with the aim of improving health and disease outcomes. Part of this research is investigating how different foods can be given to people to change their gut microflora, with a particular interest in the effect on the immune system (i.e. allergy and inflammation).
disclaimer: I'm a bioinformatician working for MIMR, but not in the Gut Immunology branch of the institute
Ask me about Sequencing DNA in front of Linus Torvalds [youtube.com]
(Score: 2) by MichaelDavidCrawford on Monday March 02 2015, @10:46AM
whenever a study is published that finds a correllation between two phenomena, a huge outcry of "CORRELATION IS NOT CAUSATION!" erupts.
Finding correlations is just part of the process. Yes we want to know the causes, but finding the correlations yields clues as to the causes.
Anyone who has the least clue about the scientific method knows very well that correlation is not causation. Isaac Newton, Galileo Galilei, Nicholas Copernicus, Ptolemy, Jesus Christ and Sidarttha Gautama all knew that correlation is not causation.
The vast majority of scientific research is simple grunt work, like digging ditches. The real glory comes when one does determine the cause for something, but really that doesn't occur very often; consider that the Standard Model - all of the physical laws other than general relativity - only has a couple dozen laws in it - the speed of light, the charge of an electron &c. To boil most but not all of physics down to two dozen or so laws, humanity had to puzzle over the mysteries of nature for three million years.
Yes I Have No Bananas. [gofundme.com]
(Score: 0) by Anonymous Coward on Monday March 02 2015, @01:24PM
I am beginning to believe that the outry is from people stating not to outcry that "CORRELATION IS NOT CAUSATION!"
*Except when statistically analyzing comments on articles regarding a study; it seems anecdotally correlated that more comments are made about such comments than otherwise could be inferred via random chance. I thus conclude that !=causation commentary is correlated with correlation is not causation comments.
(Score: 1) by Snort on Monday March 02 2015, @01:57PM
http://dx.doi.org/10.1038/nature14232 [doi.org]
That DOI you posted in the summary is also a permanent linking mechanism in addition to being a reference identifier.
take that DOI and add it the http://dx.doi.org/ [doi.org] and make magic happen!