Quotulatiousness

August 18, 2014

Salt studies and health outcomes – “all models need to be taken with a pinch of salt”

Filed under: Health, Science — Tags: , , , — Nicholas Russon @ 08:41

Colby Cosh linked to this rather interesting BMJ blog post by Richard Lehman, looking at studies of the impact of dietary salt reduction:

601 The usual wisdom about sodium chloride is that the more you take, the higher your blood pressure and hence your cardiovascular risk. We’ll begin, like the NEJM, with the PURE study. This was a massive undertaking. They recruited 102 216 adults from 18 countries and measured their 24 hour sodium and potassium excretion, using a single fasting morning urine specimen, and their blood pressure by using an automated device. In an ideal world, they would have carried on doing this every week for a month or two, but hey, this is still better than anyone has managed before now. Using these single point in time measurements, they found that people with elevated blood pressure seemed to be more sensitive to the effects of the cations sodium and potassium. Higher sodium raised their blood pressure more, and higher potassium lowered it more, than in individuals with normal blood pressure. In fact, if sodium is a cation, potassium should be called a dogion. And what I have described as effects are in fact associations: we cannot really know if they are causal.

612 But now comes the bombshell. In the PURE study, there was no simple linear relationship between sodium intake and the composite outcome of death and major cardiovascular events, over a mean follow-up period of 3.7 years. Quite the contrary, there was a sort of elongated U-shape distribution. The U begins high and is then splayed out: people who excreted less than 3 grams of salt daily were at much the highest risk of death and cardiovascular events. The lowest risk lay between 3 g and 5 g, with a slow and rather flat rise thereafter. On this evidence, trying to achieve a salt intake under 3 g is a bad idea, which will do you more harm than eating as much salt as you like. Moreover, if you eat plenty of potassium as well, you will have plenty of dogion to counter the cation. The true Mediterranean diet wins again. Eat salad and tomatoes with your anchovies, drink wine with your briny olives, sprinkle coarse salt on your grilled fish, lay it on a bed of cucumber, and follow it with ripe figs and apricots. Live long and live happily.

624 It was rather witty, if slightly unkind, of the NEJM to follow these PURE papers with a massive modelling study built on the assumption that sodium increases cardiovascular risk in linear fashion, mediated by blood pressure. Dariush Mozaffarian and his immensely hardworking team must be biting their lips, having trawled through all the data they could find about sodium excretion in 66 countries. They used a reference standard of 2 g sodium a day, assuming this was the point of optimal consumption and lowest risk. But from PURE, we now know it is associated with a higher cardiovascular risk than 13 grams a day. So they should now go through all their data again, having adjusted their statistical software to the observational curves of the PURE study. Even so, I would question the value of modelling studies on this scale: the human race is a complex thing to study, and all models need to be taken with a pinch of salt.

Update: Colby Cosh followed up the original link with this tweet. Ouch!

August 11, 2014

The science of “wine fingerprints”

Filed under: Science, Wine — Tags: , , — Nicholas Russon @ 12:27

Okay, the title of this post is a bit ahead of the facts: scientists are still developing ways to detect the differences in wine from various regions, but they think they’re on the right track.

Malbecs from Argentina and California made by the same winemaker and using the same protocol had distinct molecular signatures and flavours.

But the delicate aroma of a rare vintage can quickly be eroded by poor storage after bottling, the team said.

Details were reported at the American Chemical Society meeting.

Despite the cynicism over wine critique — and the rather grandiose adjectives lavished upon certain appellations — it really does matter where your plonk comes from, according to the researchers from the University of California Davis.

They are attempting to fingerprint “terroir” — the unique characteristics that the geography, geology and climate of a certain place bestows upon a wine.

Subjective regional character is based on the appearance, aroma, taste and mouthfeel (texture) of the wine — all of which combine to create its flavour.

But demand is growing for a more objective test — to help consumers bypass woolly terminology, protect artisan producers’ intellectual property, and help auction houses detect fraud — a growing problem.

July 8, 2014

The wine trade, legal “adjuncts”, and honest labelling

Filed under: Law, Technology, USA, Wine — Tags: , — Nicholas Russon @ 14:47

In Wired, Christopher Null talks to Californian winemaker Paul Draper about what’s actually in the wine that you buy:

Unlike most food and drink, wine and other alcoholic beverages are governed not by the Food and Drug Administration (part of Health and Human Services) but by the Alcohol and Tobacco Tax and Trade Bureau (part of the U.S. Treasury). As the name suggests, the TTB’s primary goal is to collect taxes on booze and cigarettes, a longstanding vestige of Prohibition. Consumers have largely been left in the dark about what’s really inside the bottle.

Not everyone is thrilled about this, and as with many secrecy-laden industries, transparency is a buzzword that has a few wine industry leaders twittering. Their savior is Paul Draper, who has been lambasting adjuncts for years and who eschews their use at Ridge, where he’s been the chief winemaker since 1969. A legend in the business, his Cabernet placed fifth in the famous Judgment of Paris in 1976. His newest, somewhat Quixotic quest: to introduce full and truthful labeling to wine bottles. Ridge has published real ingredients labels on its bottles since 2012.

While Draper dislikes adjuncts, the enemy, he says, isn’t just cheap wine: It’s also winemakers’ increasing thirst for wines that are ready to drink without significant aging. This not only drives consumer sales, it also helps to drive higher scores from wine critics, as even professionals can struggle to rate a wine based on its future potential.

That in turn has led to a more nefarious way in which adjuncts are being deployed. While they are often used as an easy way to make cheap wine more palatable, adjuncts are increasingly being applied to high-end wines to eke another couple of points out of the critics. “You have that machine. It costs a half a million or a million dollars and it’s sitting in your winery,” Draper says. “The temptation to use it in years when you don’t need to use it is immense.” But ultimately, he complains, “If you use these techniques, you aren’t making fine wine.”

You’d think the various adjuncts wouldn’t make it past the sommeliers, high-end buyers, and big-name critics of the wine world, that such chemical or mechanical shortcuts would be picked up by their well-trained palates. But the truth is that these things can’t be sniffed, tasted, or spotted unless they are overused.

June 21, 2014

The science of booze

Filed under: History, Science, Technology, Wine — Tags: , , — Nicholas Russon @ 09:18

Mankind has been making alcoholic beverages for thousands of years, yet there are still some pretty basic things we don’t know about alcohol:

Consider the number of things we still don’t know: Yeast, the single-celled fungus responsible for fermentation (the conversion of sugar into alcohol), seems to have been domesticated about 12,000 years ago, but we don’t know for sure where it came from, why it makes ethanol, or why some strains do it better than others.

The physics of distillation are well established, but nobody knows who invented it — an alchemist in ancient Alexandria called Maria the Jewess? — and getting a consistent taste from the finicky process is more an art than a science.

Aging in toasted barrels clearly does hooch good, as the wood breaks down and the liquid penetrates its pores to mix with tannins and other molecules. But the final flavor of a spirit depends on everything from the temperature in the warehouse where it is aged to the climate where the trees are grown, and attempts to create synthetic processes to season liquor quicker (read: more profitably) have come mostly to naught.

Even at the most basic level, scientists don’t yet understand why booze makes us feel the way it does. Alcohol’s mode of action in the brain is much more complicated and elusive than that of a drug such as heroin, which locks into specific, identified receptors meant for natural neurotransmitters. “The truth is, we don’t know at the molecular level what alcohol is binding to,” Rogers quotes the director of the National Institute on Alcohol Abuse and Alcoholism as saying. “It’s never been resolved.”

March 21, 2014

Byzantium’s secret weapon

Filed under: Europe, History — Tags: , , , — Nicholas Russon @ 07:50

Military History Now had a guest post from Κonstantinos Karatolios talking about the Byzantine secret weapon known as “Greek Fire”:

The thousand-year Byzantine Empire could not have survived through the centuries without its powerful military. But Constantinople’s mighty army and navy didn’t just keep enemies at bay, they also helped it to expand into new territories and ultimately dominate the whole of the Mediterranean for hundreds of years. Of course, while the Byzantines’ stunning battlefield success was in part a by-product of military knowledge inherited from the old Roman Empire, it was also born out of new tactics and weaponry. One example of this is Greek fire. Also known as thalassion pyr, skeyaston pyr and medikon elaion, this incendiary liquid, which could be squirted or hurled into the ranks of an enemy, was perhaps the most fearsome of all of the empire’s armaments. Its use, whether on land or sea, verges on legend and yet almost all we know about Greek fire remains clouded in mystery. We are sure of one thing however — it was used with devastating effect throughout the whole course of the Byzantine Empire.

Here are nine little known facts about Greek fire.

I think there’s a typo in the list, as it mentions the first recorded use of the weapon by Anastasios I in 541, which was actually the middle of the reign of Justinian I. Anastasios I reigned from 491 to 518.

November 27, 2013

OMG! There are scary-sounding chemicals in your Thanksgiving Dinner!

Filed under: Environment, Health, Media — Tags: , , — Nicholas Russon @ 09:23

Our American friends are about to celebrate their (weirdly late) Thanksgiving this week, so junk science food scares are also making another annual appearance. Angela Logomasini explains why you can safely ignore most of the advice you may receive about food safety this Thanksgiving:

Toxic chemicals lurk in the “typical” Thanksgiving meal, warns a green activist website. Eat organic, avoid canned food, and you might be okay, according to their advice. Fortunately, there’s no need to buy this line. In fact, the trace levels of man-made chemicals found in these foods warrant no concern and are no different from trace chemicals that appear in food naturally.

The American Council on Science and Health (ACSH) illustrates this reality best with their Holiday Dinner Menu, which outlines all the “toxic” chemicals found naturally in food. The point is, at such low levels, both the man-made and naturally occurring chemicals pose little risk. This year the ACSH puts the issue in perspective explaining:

    Toxicologists have confirmed that food naturally contains a myriad of chemicals traditionally thought of as “poisons.” Potatoes contain solanine, arsenic, and chaconine. Lima beans contain hydrogen cyanide, a classic suicide substance. Carrots contain carototoxin, a nerve poison. And nutmeg, black pepper, and carrots all contain the hallucinogenic compound myristicin. Moreover, all chemicals, whether natural or synthetic, are potential toxicants at high doses but are perfectly safe when consumed in low doses.”

Typically, these kinds of food safety scares depend on using unfamiliar scientific names of various chemicals, knowing that most peoples’ memories of high school science have long since faded away. Anything “safe” has an ordinary name, while anything “toxic” goes by a tongue-twisting science-y name that conceals far more than it reveals to non-scientists. Remember how many times the dangers of dihydrogen monoxide (DHMO) have been used to whip up support for petitions to ban the stuff (see the Material Safety Data Sheet (pdf) for it). Dihydrogen monoxide is a science-y way of describing a molecule with two hydrogen atoms and one oxygen atom … it’s another name for water, but it sounds so much more ominous that way, doesn’t it?

June 21, 2013

The healing powers of silver

Filed under: Health, Science — Tags: , , , — Nicholas Russon @ 09:01

In The Economist, some new ideas about silver:

Silver has long been known as more than bling. In the fifth century BC Hippocrates noted its ability to preserve food and water. In the late 19th century silver-nitrate eye drops were administered to newborns to prevent conjunctivitis (though this remedy has since been replaced with an antibiotic). Today silver is routinely found in wound dressings and catheters to treat or prevent infections. Yet, despite its widespread use, the source of silver’s antibacterial properties has remained shrouded in mystery.

Now Jose Morones-Ramirez, from Boston University, and colleagues think they may have cracked it. As they report in Science Translational Medicine, silver fights bacteria in a number of ways.

First, silver ions (as atoms stripped of some of their electrons are known) help, through a process known as the Fenton reaction, to convert hydrogen peroxide into molecules called hydroxyl radicals. Radicals are unstable and readily react with cellular components, damaging them. Indeed, an excess is thought to contribute to ageing-related illnesses in humans. However, the researchers found, concentrations of silver ions low enough to leave human cells unscathed nonetheless appear to wreak havoc on bacterial ones.

Using a dye that glows in the presence of hydroxyl radical, Dr Morones-Ramirez treated the bacterium Escherichia coli with silver nitrate (a source of silver ions). The E. coli glowed, and then promptly bit the dust. But when the bacteria were first bathed in a chemical which mops up the hydroxyl radicals, they survived. This points to silver’s effect on the production of hydroxide radicals as the explanation.

April 4, 2013

April 1st meets scientific illiteracy in Florida

Filed under: Humour, Media, USA — Tags: , , , — Nicholas Russon @ 00:01

Did you know that there is dihydrogen monoxide streaming out of the water taps in Fort Myers, Florida? Apparently a lot of radio listeners thought this was a very bad thing:

Florida country radio morning-show hosts Val St. John and Scott Fish are currently serving indefinite suspensions and possibly worse over a successful April Fools’ Day prank. They told their listeners that “dihydrogen monoxide” was coming out of the taps throughout the Fort Myers area. Dihydrogen monoxide is water.

The popular deejays are mainly in all this trouble (potentially of a felony level) because their listeners panicked so much — about the molecular makeup of their drinking water, however unwittingly — that Lee County utility officials had to issue a county-wide statement calming the fears of chemistry challenged Floridians.

February 15, 2013

A useful bit of perspective over Whinnygate

Filed under: Europe, Health — Tags: , , — Nicholas Russon @ 11:35

It’s reasonable to be concerned that your hamburger may once have raced in the Grand National, but worries about chemical contamination from the horse meat are almost certainly overblown. In fact, your health might be more at risk from the burger itself:

There is reasonable public outrage at possible criminal conspiracies to adulterate meat products with horsemeat, and additional concerns raised about the presence of the anti-inflammatory known as bute.

While not in any way questioning this concern about adulteration with a chemical compound, it is helpful to get a sense of magnitude. When bute was given as a human medicine, it was reported to be associated with a serious adverse reaction in 1 in 30,000 (over a whole course of treatment), but at a dose giving concentrations at least 4,000 times that arising from eating a diet of horse meat – see the excellent information from the Science Media Centre

So making all sorts of heroic assumptions about there being a linear-no-threshold response, we might very roughly assign a pro-rata risk of a serious event as 1 in 100,000,000 per burger.

January 10, 2013

QotD: The mild, quiet, unassuming world of high-nitrogen compounds

Filed under: Humour, Quotations, Science — Tags: , — Nicholas Russon @ 00:02

When we last checked in with the Klapötke lab at Münich, it was to highlight their accomplishments in the field of nitrotetrazole oxides. Never forget, the biggest accomplishment in such work is not blowing out the lab windows. We’re talking high-nitrogen compounds here (a specialty of Klapötke’s group), and the question is not whether such things are going to be explosive hazards. (That’s been settled by their empirical formulas, which generally look like typographical errors). The question is whether you’re going to be able to get a long enough look at the material before it realizes its dream of turning into an expanding cloud of hot nitrogen gas.

It’s time for another dispatch from the land of spiderweb-cracked blast shields and “Oh well, I never liked that fume hood, anyway”. Today we have a fine compound from this line of work, part of a series derived from N-amino azidotetrazole. The reasonable response to that statement is “Now hold it right there”, because most chemists will take one look at that name and start making get-it-away-from-me gestures. I’m one of them. To me, that structure is a flashing red warning sign on a dead-end road, but then, I suffer from a lack of vision in these matters.

But remember, N-amino azidotetrazole (I can’t even type that name without wincing) is the starting material for the work I’m talking about today. It’s a base camp, familiar territory, merely a jumping-off point in the quest for still more energetic compounds. The most alarming of them has two carbons, fourteen nitrogens, and no hydrogens at all, a formula that even Klapötke himself, who clearly has refined sensibilities when it comes to hellishly unstable chemicals, calls “exciting”. Trust me, you don’t want to be around when someone who works with azidotetrazoles comes across something “exciting”.

Derek Lowe, “Things I Won’t Work With: Azidoazide Azides, More Or Less”, In the Pipeline, 2013-01-09

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