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Thursday, November 13, 2014

Tastes like oysters

The other night, over a bowl of menudo, we had a discussion about "shocking" foods. While some immediately drew the line at even trying tripe, at least one person boasted about trying lutefisk, balut, and century eggs. These exotica aren't really all that wild - certainly balut and century eggs are readily available in the Asian megamalls here in Houston. What intrigues me to get is the elusive tamilok or edible shipworm.

Wood ravaged by shipworms, from Wikimedia Commons
Sometimes referred to as the "termites of the sea" - shipworms burrow their way into wood, and are seen as a pest to the shipping industry. Numerous species abound in the oceans, but the edible shipworm, the tamilok, is found in mangrove trees in Palawan, the Philippines (I've seen unsubstantiated references that the name comes from the English "Tommy, look!", but i can't confirm the etymology), and is often served in kilawin ("cooked" in vinegar). It's often described as tasting vaguely of oysters - although the addition of so many strong flavors may mask it. That's not so unusual because, well, the shipworm isn't a worm at all. It's actually a bivalve mollusc, like an oyster or a clam.

Now, how a shipworm lives on wood as its diet actually depends on the microorganisms it harbors in its gills - much like a termite relies upon symbiotic bacteria in its gut to digest the wood it consumes. Wood, believe it or not, is mostly a carbohydrate called cellulose, and unlike starch, isn't so easily digested into sugars. Various types of cellulose, from paper to switch grass, represent stores of locked up energy, and the biofuel industry seeks out cellulases for industrial production of ethanol from cellulose rather than starch. And shipworms carry a different set of bacteria for it's cellulosic diet, representing a potentially valuable trove of tools to fuel the ship, even if the mollusc itself dines on the hull.

Monday, November 3, 2014

Finding a sugar conspiracy

In a recent piece on HBO, humorist John Oliver painted a scare tactic about how the "sugar industry" is ducking their responsibility for injecting so much sugar into the (unwilling?) American public. Though I usually chuckle along with John Oliver's rants, this one fails on the fact scale by sheer poor understanding of what sugar actually is.

So, let's start there - what is sugar? For most people, that term refers to the sweet crystalline stuff that comes from sugar cane or beets, used to cooking applications. But chemically, sugars are a catchall phrase for simple carbohydrates. You can hook sugars up into larger molecules, and when they get big enough, we start referring to them as starches (if digestible), or fiber (if indigestible). But break down this big molecules - and we get sugars again. The sugar most people are accustomed to dealing with directly is chemically called sucrose - we use such terms in science to be precise, and to avoid the confusion that happens when the same word is used to refer to different things.

And that is exactly the kind of confusion that John Oliver falls into when discussing Clamato. The label he points out (around 2:50) indicates Sugars 11g which he gleefully interprets to mean that the makers add 11 g of sucrose per serving. Notice the difference in reference? That plural form means a measurement of simple carbohydrates in the product, which does not necessarily mean it was sugar added to it. Let's look at one of those labels more closely.

This is a label from a popular apple juice brand known to have no added sugar. Notice that the sugars line is under Total Carbohydrates. That's because collectively, sugars are a type of carbohydrate - this section breaks down that out of the 34 g of measurable carbohydrates, 31g are classifiable as simple enough to be sugars. That could of fructose, glucose, maltose - and yes, even sucrose, but does not mean that 31 g of sucrose were mixed in. The underlying assumption with a lot of these politically charged food issues is a naturalistic fallacy that unless one adds sucrose to an item, it's free of sugars. And metabolically speaking, there's no good reason to go further than this - these simple carbohydrates are digested similarly, and this is the most useful measure. It is actually far more accurate - since it reports the total sugars content via direct analysis. Note, complex carbohydrates can break down into sugars during processing. 

The actual boondoggle here is the FDA proposal to require a further breakdown for "added sugar". The only basis for doing this is the naturalistic fallacy again - as if the intrinsic sugars content of the other ingredients (like apples, tomatoes, and yes, even clams) is chemically different from the added sucrose. The number currently reported for sugars already includes any added sugar (sucrose or otherwise). One cannot separate out the added sugar component via chemical analysis of the product - to get this number, the producer has to track the pipeline and account for this. The FDA then has to implement an audit system to ensure that this accounting is accurate and adds up. This does not replace the chemical analysis in the end - which still has to report the total sugars and other components in the food item. Of course the industry is going to fight this; it is a costly requirement that has dubious benefits for either consumer or producer. 

Instead of understanding the science, Oliver simply plays the easy card of big business taking advantage of the hapless American consumer. With a soundbite from Eric Stice, boom - sugar is cocaine. His example of a scientist is one James Rippe - a doctor heavily vested in "lifestyle medicine". At least understand what a scientist does. His staff casually interleaves sugary drinks consumption into the argument - a Gish galloping bouncing of topics to build  an entertaining, but ultimately fallacious case for this labeling initiative. If there is indeed some kind of sugar conspiracy - I see more evidence of an entertainer trying to spin a tale than an investigator uncovering facts. 

So, please stop forwarding this video on as if it validates anything. It simply preys on a basic lack of understanding of chemistry. 

Thursday, July 31, 2014

Will Vegan Cheese Work?

A recently funded Indiegogo campaign to make "Real Vegan Cheese" has been brought to my attention recently. It's quite an impressive project for "biohackers" - a promise to make "real" (we'll come back to that) cheese without involving cows. And the speculation about it is feeding the narrative for the reporters on the science beat.

But this really isn't a science question. It isn't teaching us something about the natural universe - it pokes at our cultural definitions of cheese, veganism, and food in general.

To start with, the campaign makes some scientifically dubious promises and allusions - for example, they prominently claim that the "real vegan cheese" will not contain GMO even though they'll be using genetically modified yeast because they are purifying the casein protein. This shouldn't matter to those who worry about GMO contamination (otherwise, there wouldn't be objections to sugar produced from GMO sugar beets). Or the claim that this method of cheese production will be more sustainable than the status quo - there's no data for this. After all, one should consider the inputs to fabricating all the components. And even more dubious is the promise of lowered allergenicity in the product by modifying the casein produced - hypothetically possible, the process is far more complex than they imply, and could affect the product itself.

The challenges are huge. The prerequisite that isn't discussed is they plan to make a "vegan milk", which is thought to be a simple mixture of protein, fat and sugar - but milk is far more complex than that. Milk is chock full of a structure known as micelles which are serve to hold on high concentrations of calcium for delivery to offspring. In fact, caseins (there are more than one kind) are thought to have evolved as a calcium retention mechanism, and building the milk micelle isn't a matter of mixing things together in a blender - and this type of macromolecular assembly is key to how curds form, and cheese to be made. And leaving out lactose means that the microbes that can be supported would be quite different from the conventional cheese production.

So, will it work? Can they make it?

Does this question matter at all?

They will make a product - but will it be cheese? What is cheese anyway? There is a legal definition of cheese, which is tied to a definition of milk (and there is a biological definition of that - and it's tied to animal production). By this alone, they probably cannot call whatever is made cheese (similar to how a product can be called an ice cream or a mellorine).

Moreover, the quest serves the point of veganism - which is itself not a scientifically defined practice. Evolutionarily speaking, yeast are pretty closely related to mammals relative to flowering plants, but to the vegan demarcation - they're vegetables. This is an arbitrary classification that serves a cultural whim, seeking a food product that is itself a luxury. In short, it's very much a first world problem. While not as much of a publicity stunt as the "cultured meat" project, this project is just as devoid of science all the while dressed up in the robes of scientific practice. But it has carried the imagination of the public enough to get funded. Good luck to them, and to everyone who has invested in it.

Thursday, June 26, 2014

Not all white bread are equal

I respect Scientific American as an science communication institution - over they decades, they've evolved from the classic magazine to the myriad online avenues, from blogs to Twitter and podcasts. But I fear that in the zest to embrace the age of the soundbite, some of the care may be slipping. A recent 60-second podcast by Karen Hopkin reports on the potential "health benefits" of white bread. Most of these snappy one-offs are really a populist summarization of the results of a recent academic publication - in general, I approve of this, as the culture of scientific publication still favors dense writing that requires specialization just to read. However, simplification should not happen at the expense of accuracy.

Yes, this is white bread.
The report is about the unexpected association of Lactobacillus (a "healthy" marker in the microbiome) with the consumption of white bread, so it prominently begins with the mention of Wonder Bread. This, of course, is a byproduct of the America-centric nature of the target audience, to whom white bread is synonymous with Wonder Bread. But the study was conducted in Spain, and white bread in Europe is markedly different from the ubiquitous "glutenous slab".

So, how was the study conducted? The authors selected 27 female and 11 male volunteers, aged 56-67 years old, and asked them about what they recalled eating from a selection of 160 items within the past year. After the interview, they collected one stool sample, and analyzed it for DNA. It isn't just any 38 healthy individuals - the data is based on the recollection of middle-aged to older volunteers (heavily skewed to women) from their diets a full year prior, and the stool sample came from one time point.

Though not explicitly stated, the misled hordes of the internet now parrot the line about how white bread (somehow equivocating to Wonder Bread) can be a healthy item. But it is a correlation, and at best a promising line of research. But I am dismayed that science journalism tends to lean towards this need to sell a particular story frame, toying with the very edges of veracity, often misleading lay readers to the wrong conclusion, by selectively glossing over details, or (as in this case) introducing "facts" that weren't in the original paper to begin with. I cannot call this outright lying, but its effects can be more insidious. In the name of "spicing up" a story, a writer can pretty invert the conclusions of a study or report, manipulating the expectations and emotions of the reader. This is a powerful skill, and should be used judiciously.

Tuesday, June 24, 2014

Environmental Impact of "Cultured Meat"

Frog Legs, A Ly, Houston, TX. I'll bet we'll have better luck mass producing tissue cultured frog meat. 
I have previously described my problems with the mainstream media fascination with the "cultured meat" project. But recently, I've been contacted by journalist asking what my opinion is about the published dramatically lower environmental impact from culturing meat as opposed to conventional animal husbandry.The paper cited was published in 2011 by the American Chemical Society's Environmental Science and Technology, authored by Tuomisto and Mattos, claiming a dramatic 45% lower energy use, 96% lower greenhouse gas emissions, and an amazing 96% lower water use. Indeed, this is the paper cited by among its FAQs as a key advantage for tissue cultured meat.

So, let's see what the paper reports. Since a cultured meat production industry doesn't really exist, the paper is basically a fairly complex thought experiment. It presumes the existence of such an industry, and compares it to current beef, sheep, pork and poultry production. This is a vaporware comparison - the authors could assign all sorts of properties to the hypothetical cultured meat production, and we cannot contest it. But if we assign time to when such a pipeline would exist, the evolution of conventional meat production would have also improved in efficiency. In the end, though, this paper does not such prove anything, nor does it actually lead to testable hypotheses. In a sense, it isn't really falsifiable, and makes for poor science.

But such a thought experiment begins with a number of assumptions - and did the authors make reasonable assumptions? Aside from the laughable comparison of value since a number of products come from whole animals other than mincemeat, while culture vats will only make meat, there's the near magical creation of new technology. From the abstract:

Cyanobacteria hydrolysate was assumed to be used as the nutrient and energy source for muscle cell growth.
This is already a problem. Under no circumstance have we proven that conventional animal meat tissue can be grown using cyanobacteria hydrolysate, that raw proteins can be pumped onto cultured muscle cells and they'll metabolize it. Either the authors are ignorant of basic biology of isolated animal cells, interchanging them with yeast cells, or have conveniently cherry picked past this fundamental point. Moreover, the authors write:

The production of growth factors and vitamins are not included in the study as the quantities needed are small (under 0.1% of the DM weight of the media), and therefore the environmental impacts are negligible.
This is a grossly incorrect assumption to make. Despite the lower per weight composition of these micronutrients and growth factors, they are essential and difficult to isolate and synthesize. We have no substitute at the moment for using fetal bovine serum at the moment specifically because this fact. The cells will not grow without these growth factors, one cannot gloss over the environmental impact of harvesting and isolating this material. It's like ignoring the environmental impact of diamonds because they are so small - when in fact mountains can be destroyed to get them.

So, let's do a little background research. This press release from Oxford University (Hanna Tuomisto, the lead author, was a PhD student there at the time) hides a small note at the end: the research was funded by New Harvest, a nonprofit dedicated to cultured meat production. On the border, I would think of this as a conflict of interest. After all, it's a vaporware review that has been used in the last 3 years to claim advantages with regards to environmental impact, but it stands on fantastical unproven promises.