Quotulatiousness

June 30, 2024

The medieval salt trade in the Baltic

Filed under: Economics, Europe, Food, History — Tags: , , , , , , — Nicholas @ 03:00

In the long-awaited third part of his series on salt, Anton Howes discusses how the extremely low salt level of water in the Baltic Sea helped create a vast salt trade dominated by the merchant cities of the Hanseatic League:

The extent of the Hanseatic League in 1400.
Plate 28 of Professor G. Droysen’s Allgemeiner Historischer Handatlas, published by R. Andrée, 1886, via Wikimedia Commons.

It’s difficult to appreciate salt’s historical significance because it’s now so abundant. Societies used to worry about salt supplies — for preparing and preserving food — as a matter of basic survival. Now we use the vast majority of it for making chemicals or chucking on our roads to keep them from getting icy, while many salt-making plants don’t even operate at full capacity. Yet the story of how we came to achieve salt superabundance is a long and complicated one.

In Part I of this series we looked at salt as a kind of general-purpose technology for the improvement of food, as well as a major revenue-raiser for empires — especially when salt-producing coastal areas could dominate salt-less places inland. In Part II we then looked at a couple of places that were all the more interesting for being both coastal and remarkably salt-less: the coast of Bengal and the Baltic Sea. One was to be exploited by the English East India Company, which needlessly propped up a Bengalese salt industry at great human cost. The other, however, was to prove a more contested prize — and ultimately the place that catalysed the emergence of salt superabundance.

It’s worth a brief recap of where we left the Baltic. Whereas the ocean is on average 3.5% salt, along the Baltic coast it’s at just 0.3% or lower, which would require about twelve times as much time and fuel to produce a given quantity of salt. Although there are a few salt springs near the coast, they were nowhere near large enough to supply the whole region. So from the thirteenth century the Baltic’s salt largely came from the inland salt springs at Lüneburg, supplied via the cities of Lübeck and Hamburg downstream. These two cities had a common interest against the kingdom of Denmark, which controlled the straits between the North and Baltic seas, and created a coalition of trading cities that came to be known as the Hanseatic League. The League resoundingly defeated the Danes in the 1360s and 1430s so that their trade in salt — and the fish they preserved with it — could remain free.

But Lüneburg salt — and by extension the League itself — was soon to face competition.

Lüneburg could simply not keep up with the growth of Baltic demand, as the region’s population became larger and wealthier. And so more and more salt had to come from farther afield, from the Bay of Biscay off France’s western coast, as well as from Setúbal in Portugal and from southern Spain.1 This “bay salt” — originally referring to just the Bay of Bourgneuf, but then extended to the entire Bay of Biscay, and often to all Atlantic solar-evaporated salt — was made by the sun and the wind slowly evaporated the seawater from a series of shallow coastal pools, with the salt forming in coarse, large-grained pieces that were skimmed off the top. Bay salt, however, inevitably ended up mixed with some of the sand and dirt from the bottoms of the pools in which it was held, while the seawater was never filtered, meaning that the salt was often brown, green, grey or black depending on the skill of the person doing the skimming — only the most skilled could create a bay salt that was white. And it often still contained lots of other chemicals found in seawater, like magnesium chloride and sulphate, calcium carbonate and sulphate, potassium chloride and so on, known as bitterns.2

Bay or “black” salt, made with the heat of the sun, was thus of a lower quality than the white salt boiled and refined from inland salt springs or mined as rock. Its dirt discoloured and adulterated food. Its large grains meant it dissolved slowly and unevenly, slowing the rate at which it started to penetrate and preserve the meat and fish — an especially big problem in warmer climates where flesh spoiled quickly. And its bitterns gave it a bitter, gall taste, affecting the texture of the flesh too. Bay salt, thanks to the bitterns, would “draw forth oil and moisture, leading to dryness and hardness”, as well as consuming “the goodness or nutrimental part of the meat, as moisture, gravy, etc.”3 The resulting meat or fish was often left shrunken and tough, while bitterns also slowed the rate at which salt penetrated them too. Bay-salted meat or fish could often end up rotten inside.

But for all these downsides, bay salt required little labour and no fuel. Its main advantage was that it was extremely cheap — as little as half the price of white Lüneburg salt in the Baltic, despite having to be brought from so much farther away.4 Its taste and colour made it unsuitable for use in butter, cheese, or on the table, which was largely reserved for the more expensive white salts. But bay salt’s downsides in terms of preserving meat and fish could be partially offset by simply applying it in excessive quantities — every three barrels of herring, for example, required about a barrel of bay salt to be properly preserved.5

By 1400, Hanseatic merchants were importing bay salt to the Baltic in large and growing quantities, quickly outgrowing the traditional supplies. No other commodity was as necessary or popular: over 70% of the ships arriving to Reval (modern-day Tallinn in Estonia) in the late fifteenth century carried salt, most of it from France. But Hanseatic ships alone proved insufficient to meet the demand. The Danes, Swedes, and even the Hanseatic towns of the eastern Baltic, having so long been under the thumb of Lübeck’s monopoly over salt from Lüneburg, were increasingly happy to accept bay salt brought by ships from the Low Countries — modern-day Belgium and the Netherlands. Indeed, when these interloping Dutch ships were attacked by Lübeck in 1438, most of the rest of the Hanseatic League refused Lübeck’s call to arms. When even the Hanseatic-installed king of Denmark sided with the Dutch as well, Lübeck decided to back down and save face. The 1441 peace treaty allowed the Dutch into the Baltic on equal terms.6 Hanseatic hegemony in the Baltic was officially over.

The Dutch, by the 1440s, had thus gained a share of the carrying trade, exchanging Atlantic bay salt for the Baltic’s grain, timber, and various naval stores like hemp for rope and pitch for caulking. But this was just the beginning.

    1. Philippe Dollinger, The German Hansa, trans. D. S. Ault and S. H. Steinberg, The Emergence of International Business, 1200-1800 (Macmillan and Co Ltd, 1970), pp.219-220, 253-4.

    2. L. Gittins, “Salt, Salt Making, and the Rise of Cheshire”, Transactions of the Newcomen Society 75, no. 1 (January 2005), pp.139–59; L. G. M. Bass-Becking, “Historical Notes on Salt and Salt-Manufacture”, The Scientific Monthly 32, no. 5 (1931), pp.434–46; A. R. Bridbury, England and the Salt Trade in the Later Middle Ages (Clarendon Press, 1955), pp.46-52. Incidentally, some historians, like Jonathan I. Israel, Dutch Primacy in World Trade, 1585-1740 (Clarendon Press, 1989) p.223, note occasional reports of French bay salt having been worse than the Portuguese or Spanish due to its high magnesium content, “which imparted an unattractive, blackish colour”. This must be based on a misunderstanding, however, as the salts would have been identical other than in terms of the amount of dirt taken up with the salt from the pans. At certain points in the seventeenth century the French workers skimming the salt must simply have been relatively careless compared to those of Iberia.

    3. John Collins, Salt and fishery a discourse thereof (1682), pp.17, 54-5, 66-8.

    4. Bridbury, pp.94-7 for estimates.

    5. Karl-Gustaf Hildebrand, “Salt and Cloth in Swedish Economic History”, Scandinavian Economic History Review 2, no. 2 (1 July 1954), pp.81, 86, 91.

    6. For this section see: Dollinger, pp.194-5, 201, 236, 254, 300.

June 9, 2024

QotD: The biological importance of salt to humans

Filed under: Britain, Food, History, Quotations — Tags: , , , — Nicholas @ 01:00

… regardless of whether it was used in agriculture, for preservation, or for cooking, salt was also essential. The human body is constantly losing salt through sweat, and to a certain extent urine, but it tries to keep the blood’s salt concentrations maintained at a certain level. So as the blood loses salt, the body also ejects water to adjust. Ironically, as you lose salt your body responds by drying you out. Without constantly replacing the salt in your body — which is only ever stored for a couple of days at a time — you will at first feel fatigued and a little breathless, but increasingly weak and debilitated, as though sapped of all energy. The slightest exertion would start to bring on cramps, then problems with your heart and lungs, as your body continually shed water. If these did not kill you — and they probably would — you would essentially die through desiccation. The process would be all the faster if you became ill, rendering even the slightest dehydrating fever or bout of diarrhoea utterly lethal.1

A population deprived of salt was thus one that was weaker and more prone to disease — and at a time when the vast majority of the economy’s energy supply came from the straining of muscle, both human and animal, that weakness in effect meant a severe energy shortage. Although the main fuels for muscle power were carb-heavy grains like wheat, rye, oats, and rice, the indispensable ingredient to getting the most out of these grains was salt — just as how nuclear power uses uranium as its fuel, but also requires a suitable neutron moderator. A population deprived of salt would quite literally be more lethargic and sluggish, making it less productive and poorer too.

Salt’s unique properties made it a serious tool of state. In 1633 king Charles I’s newly-appointed Lord Deputy for Ireland, Baron Wentworth, advised controlling its salt supply as a way to make the Irish utterly economically dependent on England. Given salt was “that which preserves and gives value to all their native staple commodities” — herrings, butter and beef — then “how can they depart from us without nakedness and beggary?” Salt would be a method of control, and a profitable one too, being “of so absolute necessity” that it could be sold to the Irish at inflated prices without much dampening demand: salt “must be had whether they will or no, and may at all times be raised in price”.2 Much like economists today, Wentworth saw revenue-raising potential in taxing goods with such unresponsive or “inelastic” demand.

Wentworth’s scheme to control the Irish never came to be. But a great many other countries did choose to tax it. Given a minimum amount of salt had to be consumed by absolutely everyone, monopolising its sale — and levying what was effectively a tax by inflating the price well above the costs of importing or producing it — could function as kind of indirect poll tax, levied more or less per head of both people and livestock, but without any of the administrative hassle of taking and maintaining an accurate census in order to impose such a tax directly.

When compared to other necessities like grain, salt did not need to be traded in especially large quantities either, meaning that its supply could be monopolised with relative ease. And it could not be produced everywhere. Salt tended to be lacking the further you got from the sea coast, unless there happened to be some relatively rare inland sources like salt lakes, brine springs, or rock salt mines. And it could even be lacking on the sea coast where it was either too humid or too cold to get salt cheaply by evaporating seawater using the sun, or where there was insufficient fuel for boiling the brine. These places were thus prone to being charged inflated prices, while the states that controlled places where the costs of production were low — in warmer and drier climes where the salty water of coastal marshes could cheaply be evaporated using only the heat of the summer sun — could extract especially large monopoly profits from the difference. The revenue from controlling solar salt thus became the basis of many kingdoms, some unusually powerful republics, and even empires.

Anton Howes, “The Second Soul”, Age of Invention, 2024-03-08.

    1. Roy Moxham, “Salt Starvation in British India: Consequences of High Salt Taxation in Bengal Presidency, 1765 to 1878”, Economic and Political Weekly 36, no. 25 (2001): p.2270–74.

    2. George O’Brien, The Economic History of Ireland in the Seventeenth Century (Maunsel and Company Limited, 1919), p.244, which has the transcription of Wentworth’s proposal

March 9, 2024

Salt – mundane, boring … and utterly essential

Filed under: Books, Economics, Food, Health, History — Tags: , , , , , , — Nicholas @ 05:00

In the latest Age of Invention newsletter, Anton Howes looks at the importance of salt in history:

There was a product in the seventeenth century that was universally considered a necessity as important as grain and fuel. Controlling the source of this product was one of the first priorities for many a military campaign, and sometimes even a motivation for starting a war. Improvements to the preparation and uses of this product would have increased population size and would have had a general and noticeable impact on people’s living standards. And this product underwent dramatic changes in the seventeenth and eighteenth centuries, becoming an obsession for many inventors and industrialists, while seemingly not featuring in many estimates of historical economic output or growth at all.

The product is salt.

Making salt does not seem, at first glance, all that interesting as an industry. Even ninety years ago, when salt was proportionately a much larger industry in terms of employment, consumption, and economic output, the author of a book on the history salt-making noted how a friend had advised keeping the word salt out of the title, “for people won’t believe it can ever have been important”.1 The bestselling Salt: A World History by Mark Kurlansky, published over twenty years ago, actively leaned into the idea that salt was boring, becoming so popular because it created such a surprisingly compelling narrative around an article that most people consider commonplace. (Kurlansky, it turns out, is behind essentially all of those one-word titles on the seemingly prosaic: cod, milk, paper, and even oysters).

But salt used to be important in a way that’s almost impossible to fully appreciate today.

Try to consider what life was like just a few hundred years ago, when food and drink alone accounted for 75-85% of the typical household’s spending — compared to just 10-15%, in much of the developed world today, and under 50% in all but a handful of even the very poorest countries. Anything that improved food and drink, even a little bit, was thus a very big deal. This might be said for all sorts of things — sugar, spices, herbs, new cooking methods — but salt was more like a general-purpose technology: something that enhances the natural flavours of all and any foods. Using salt, and using it well, is what makes all the difference to cooking, whether that’s judging the perfect amount for pasta water, or remembering to massage it into the turkey the night before Christmas. As chef Samin Nosrat puts it, “salt has a greater impact on flavour than any other ingredient. Learn to use it well, and food will taste good”. Or to quote the anonymous 1612 author of A Theological and Philosophical Treatise of the Nature and Goodness of Salt, salt is that which “gives all things their own true taste and perfect relish”. Salt is not just salty, like sugar is sweet or lemon is sour. Salt is the universal flavour enhancer, or as our 1612 author put it, “the seasoner of all things”.

Making food taste better was thus an especially big deal for people’s living standards, but I’ve never seen any attempt to chart salt’s historical effects on them. To put it in unsentimental economic terms, better access to salt effectively increased the productivity of agriculture — adding salt improved the eventual value of farmers’ and fishers’ produce — at a time when agriculture made up the vast majority of economic activity and employment. Before 1600, agriculture alone employed about two thirds of the English workforce, not to mention the millers, butchers, bakers, brewers and assorted others who transformed seeds into sustenance. Any improvements to the treatment or processing of food and drink would have been hugely significant — something difficult to fathom when agriculture accounts for barely 1% of economic activity in most developed economies today. (Where are all the innovative bakers in our history books?! They existed, but have been largely forgotten.)

And so far we’ve only mentioned salt’s direct effects on the tongue. It also increased the efficiency of agriculture by making food last longer. Properly salted flesh and fish could last for many months, sometimes even years. Salting reduced food waste — again consider just how much bigger a deal this used to be — and extended the range at which food could be transported, providing a whole host of other advantages. Salted provisions allowed sailors to cross oceans, cities to outlast sieges, and armies to go on longer campaigns. Salt’s preservative properties bordered on the necromantic: “it delivers dead bodies from corruption, and as a second soul enters into them and preserves them … from putrefaction, as the soul did when they were alive”.2

Because of salt’s preservative properties, many believed that salt had a crucial connection with life itself. The fluids associated with life — blood, sweat and tears — are all salty. And nowhere seemed to be more teeming with life as the open ocean. At a time when many believed in the spontaneous generation of many animals from inanimate matter, like mice from wheat or maggots from meat, this seemed a more convincing point. No house was said to generate as many rats as a ship passing over the salty sea, while no ship was said to have more rats than one whose cargo was salt.3 Salt seemed to have a kind of multiplying effect on life: something that could be applied not only to seasoning and preserving food, but to growing it.

Livestock, for example, were often fed salt: in Poland, thanks to the Wieliczka salt mines, great stones of salt lay all through the streets of Krakow and the surrounding villages so that “the cattle, passing to and fro, lick of those salt-stones”.4 Cheshire in north-west England, with salt springs at Nantwich, Middlewich and Northwich, has been known for at least half a millennium for its cheese: salt was an essential dietary supplement for the milch cows, also making it (less famously) one of the major production centres for England’s butter, too. In 1790s Bengal, where the East India Company monopolised salt and thereby suppressed its supply, one of the company’s own officials commented on the major effect this had on the region’s agricultural output: “I know nothing in which the rural economy of this country appears more defective than in the care and breed of cattle destined for tillage. Were the people able to give them a proper quantity of salt, they would … probably acquire greater strength and a larger size.”5 And to anyone keeping pigeons, great lumps of baked salt were placed in dovecotes to attract them and keep them coming back, while the dung of salt-eating pigeons, chickens, and other kept birds were considered excellent fertilisers.6

    1. Edward Hughes, Studies in Administration and Finance 1558 – 1825, with Special Reference to the History of Salt Taxation in England (Manchester University Press, 1934), p.2

    2. Anon., Theological and philosophical treatise of the nature and goodness of salt (1612), p.12

    3. Blaise de Vigenère (trans. Edward Stephens), A Discovrse of Fire and Salt, discovering many secret mysteries, as well philosophical, as theological (1649), p.161

    4. “A relation, concerning the Sal-Gemme-Mines in Poland”, Philosophical Transactions of the Royal Society of London 5, 61 (July 1670), p.2001

    5. Quoted in H. R. C. Wright, “Reforms in the Bengal Salt Monopoly, 1786-95”, Studies in Romanticism 1, no. 3 (1962), p.151

    6. Gervase Markam, Markhams farwell to husbandry or, The inriching of all sorts of barren and sterill grounds in our kingdome (1620), p.22

August 16, 2019

Rule Britannia, Britannia Rules the Salt | BETWEEN 2 WARS I 1930 Part 1 of 1

Filed under: Britain, History, India — Tags: , , , , , , , — Nicholas @ 06:00

TimeGhost History
Published on 15 Aug 2019

After the Great War, the British empire is at its peak in terms of population and size. However, resistance against colonialism is starting to brew in the British colonies and dominions.

Join us on Patreon: https://www.patreon.com/TimeGhostHistory

Hosted by: Indy Neidell
Written by: Spartacus Olsson and Francis van Berkel
Directed by: Spartacus Olsson and Astrid Deinhard
Executive Producers: Bodo Rittenauer, Astrid Deinhard, Indy Neidell, Spartacus Olsson
Creative Producer: Joram Appel
Post-Production Director: Wieke Kapteijns
Research by: Francis van Berkel
Edited by: Wieke Kapteijns
Sound design: Iryna Dulka

Portrait Colorizations by Daniel Weiss.

Sources: National Portrait Gallery, Library and Archives Canada, Jenny Scott

A TimeGhost chronological documentary produced by OnLion Entertainment GmbH.

March 26, 2019

QotD: Salt

Filed under: Food, Health, Quotations — Tags: , — Nicholas @ 01:00

My grandfather used to say this all the time, and it’s true. Salt brings out the flavor of the food, full stop. There are a great variety of salts, but the reality is they’re all the same mineral. Coloration in salt comes from the minerals near the salt as it forms. There’s nothing inherently better about colored salts, but the marketers selling you that stuff will try to convince you otherwise. I’ve seen pink salt promoted as an “alternative” salt that doesn’t cause blood pressure issues. That’s a lie. My advice is to buy kosher salt or the chunkier white salt if you like the crunchiness. If you really like the mild flavoring of gray salt, that’s fine, just know that it’s sold at a higher cost for what comes down to the same thing as my box of salt I can get for a couple bucks. And one more thing: All salt is sea salt.

Salt grinders are bullshit

I’m not done with salt yet: Don’t put your salt in a grinder. All you’re doing is making your salt smaller than it was before. Unlike pepper, which is actually processed in the grinder, salt does not need to be ground and is not fresher after coming out of a grinder. It’s just smaller. Use a shaker.

Caitlin PenzeyMoog, “Salt grinders are bullshit, and other lessons from growing up in the spice trade”, The A.V. Club, 2017-04-06.

April 16, 2017

The tale of unsalted butter in French cuisine

Filed under: Bureaucracy, Business, Food, France, History — Tags: , , , — Nicholas @ 05:00

At his new blog, Splendid Isolation, Kim du Toit explains the historical roots of a French culinary oddity:

One of the quirks of French cuisine is that most often the butter is unsalted, and at a French dinner table you will usually find a tiny cruet of salt with a microscopic spoon inside, so that you can salt your butter (or not) according to taste. To someone like myself, accustomed only to salted butter, this seemed like an affectation, but it wasn’t that at all: it was the result of taxation, and this is one of the things changed forever by Napoleon’s administrative reforms.

One of the best parts of our U.S. Constitution is the “interstate commerce” clause, which forbids states from levying taxes on goods and services passing from one state to another, and through another in transit. This was not the case in pre-Napoleonic France. Goods manufactured in, say, Gascony or Provence would pass through a series of customs posts en route to Paris, and at each point the various localities would levy excise taxes on the goods, driving up the final price at its eventual destination.

Which brings us to salt. French salt, you see, was produced mainly on the Atlantic coastline, and was a major “export” of Brittany to the rest of France. Butter, of course, was produced universally — in and outside Paris and ditto for every major city — but the salt for the butter came almost exclusively from Brittany, and having been taxed multiple times by the time it reached points east like Paris or Lyons, it was expensive. So the cuisine and eating habits in those parts developed without the use of salt — or, if salt was requested, at an added cost. It’s why, to this day, many French recipes use unsalted butter as an ingredient. (In contrast, butter for local consumption in western France was [and still is] almost always salted, because salt was dirt cheap there.)

Napoleon’s reforms did away with all that; he saw to it that the douane locale checkpoints and toll booths along the main roads were abolished (causing salt prices in eastern France to plummet and become a mainstay of French cuisine at last). And when the towns and villages protested about the loss of tax revenue, Napoleon made up the shortfall with “federal” funds out of the national treasury.

Of course, the French treasury had in the meantime been emptied out by, amongst other things, the statist welfare policies of the Revolutionary government (stop me if this is starting to sound familiar). Which is why, to raise money, Napoleon invaded wealthy northern Italy and western Germany (as it is now), pillaged their rich cities’ treasuries and garnered revenue from the wealthy aristocracy, who paid bribes to avoid having their palaces sacked and their wealth confiscated.

May 6, 2015

The “salted caramel inquisition”

Filed under: Business, Food, USA — Tags: , — Nicholas @ 03:00

Food fashions and the current tyranny of the salted caramel inquisition, by Megan McArdle:

I don’t need to tell you that food has fashions. Remember when every restaurant with any ambition had a spinach salad with pecans, goat cheese and some sort of onion shaving? That’s now passé even in its last refuge, the twee cafes of Rust Belt suburbs. Or when truffles seemed to sprout from menus like, er, mushrooms, only to disappear almost as quickly, presumably off to hibernate in some subterranean darkness?

We are currently living through what I like to call the salted caramel inquisition, with every perfectly law-abiding caramelized dish in the land, however perfect in its simple sweetness, assaulted and forcibly converted to its more aggressive modern version.

For the last 5 to 10 years, the most notable fashion has been for the complex, spicy and exotic. Foodies exchange worried tips for storing the “basic” spices now grown too numerous for any sort of conventional cupboard. Bitter supertasters exchange angry polemics on the snobs who don’t seem to realize that those of us with less blunted palates might not want every alcoholic beverage well fortified with hops, Campari and an extra-strong helping of Angosturas. Those whose sensitive or aging gastrointestinal tracts cannot cope with all that glorious capsaicin sigh, and order the roasted chicken. Again.

History is reaction and counterreaction. The pendulum is swinging back, as gravity says it must, and I detect a new movement afoot: KISS. Which means, yes: Keep it simple, stupid. And I have to say, I like it.

December 20, 2014

Build a Wooden Salt Cellar

Filed under: Food, Randomness, Woodworking — Tags: , — Nicholas @ 10:38

Published on 14 Dec 2014

Plans and project resources: http://www.thewoodwhisperer.com/videos/salt-cellar/

The Wood Whisperer is education and entertainment for the modern woodworker! Find more at http://thewoodwhisperer.com & don’t forget to subscribe to our YouTube channel!

October 19, 2014

Developing salt-tolerant vegetables

Filed under: Environment, Food, Science — Tags: , , , — Nicholas @ 12:22

Tracy McVeigh on a Dutch experiment to develop food crops that can be irrigated with salt water:

Here, on one of the Netherlands’ northernmost islands, windswept Texel (pronounced Tessel) surrounded by encroaching ocean and salt marshes that seep sea water under its dykes and into ditches and canals, an enterprising farmer has taken the radical step of embracing salt water instead of fighting to keep it out. And now he thinks he might just help feed the world.

Inspired by sea cabbage, 59-year-old Marc van Rijsselberghe set up Salt Farm Texel and teamed up with the Free University in Amsterdam, which sent him [researcher Dr Arjen] de Vos to look at the possibility of growing food using non-fresh water. Their non-GM, non-laboratory-based experiments had help from an elderly Dutch farmer who has a geekish knowledge of thousands of different potato varieties.

“The world’s water is 89% salinated, 50% of agricultural land is threatened by salt water, and there are millions of people living in salt-contaminated areas. So it’s not hard to see we have a slight problem,” said van Rijsselberghe. “Up until now everyone has been concentrating on how to turn the salt water into fresh water; we are looking at what nature has already provided us with.”

August 18, 2014

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

Filed under: Food, Health, Science — Tags: , , , — Nicholas @ 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!

May 3, 2014

Take every salt report with a pinch of salt

Filed under: Food, Health, Science — Tags: — Nicholas @ 09:11

Salt is bad for you, as we’ve been told for years and years. It raises your blood pressure and makes you more prone to strokes and other nasty health issues. Except … perhaps not:

The more salt we eat, the more water our body retains. This increases blood pressure, at least until our kidneys flush out the salt and water. Those who see salt as a problem believe that the effect on blood pressure is more lasting, and that if too much salt is ingested over a long period of time it will cause hypertension and perhaps death. A much-cited study carried out by America’s National Institutes of Health in 2001, called the DASH-sodium study, found that participants put on diets that were lower in sodium than the control group ended up with significantly lower blood pressure. This study forms the basis for many of the public-health pronouncements that demonise salt. America’s dietary guidelines, based on “a strong body of evidence”, put salt at the top of the list of things to avoid.

The body of evidence, though, is rather weaker than the American government lets on. The DASH study is one of many that have looked at the effects of salt intake on health. Others have failed to produce similar results. The English study mentioned above finds a correlation, but other factors — such as a simultaneous decline in smoking — seem more likely to account for the improved health outcomes. In 2011 two meta-analyses, which look at the results from many different studies, were published by the Cochrane Collaboration, a non-profit that reviews medical evidence. The first found that reducing salt intake leads to lower blood pressure, but concluded that there is “insufficient evidence” that this will lead to fewer premature deaths or a lower incidence of heart disease. The second concluded, rather simply, that “we do not know if low salt diets improve or worsen health outcomes.” The authors went on to say that “after more than 150 [randomised controlled trials] and 13 population studies without an obvious signal in favour of sodium reduction, another position could be to accept that such a signal may not exist.”

Some researchers go a step further, claiming that reducing salt intake actually increases a person’s risk of dying. The body needs some amount of sodium; if it gets too little the kidney secretes an enzyme called renin that can lead to hypertension. Some studies have found that low sodium levels were associated with increased risk of heart failure. Others suggest that a low sodium-to-potassium ratio may be the key to heart health. Much depends on the individual. The evidence is inconclusive, yet public-health officials have long presented the link between salt and heart disease as if it were fact. Such confidence is not warranted. There are plenty of reasons to avoid a full English breakfast, but salt may not be one of them.

June 5, 2012

“We do not know if low salt diets improve or worsen health outcomes”

Filed under: Food, Government, Health, USA — Tags: , , , — Nicholas @ 00:14

You’ve undoubtedly heard lots of recommendations to reduce the salt in your diet, right? The western diet — especially the North American variant — has “too much salt”, and it’s killing us. At least, that’s what has been drummed into our heads for the last twenty years or more. The problem is that is may not actually be true, and in fact may create other health issues:

Although researchers quietly acknowledged that the data were “inconclusive and contradictory” or “inconsistent and contradictory” — two quotes from the cardiologist Jeremiah Stamler, a leading proponent of the eat-less-salt campaign, in 1967 and 1981 — publicly, the link between salt and blood pressure was upgraded from hypothesis to fact.

[. . .]

When researchers have looked at all the relevant trials and tried to make sense of them, they’ve continued to support Dr. Stamler’s “inconsistent and contradictory” assessment. Last year, two such “meta-analyses” were published by the Cochrane Collaboration, an international nonprofit organization founded to conduct unbiased reviews of medical evidence. The first of the two reviews concluded that cutting back “the amount of salt eaten reduces blood pressure, but there is insufficient evidence to confirm the predicted reductions in people dying prematurely or suffering cardiovascular disease.” The second concluded that “we do not know if low salt diets improve or worsen health outcomes.”

The idea that eating less salt can worsen health outcomes may sound bizarre, but it also has biological plausibility and is celebrating its 40th anniversary this year, too. A 1972 paper in The New England Journal of Medicine reported that the less salt people ate, the higher their levels of a substance secreted by the kidneys, called renin, which set off a physiological cascade of events that seemed to end with an increased risk of heart disease. In this scenario: eat less salt, secrete more renin, get heart disease, die prematurely.

With nearly everyone focused on the supposed benefits of salt restriction, little research was done to look at the potential dangers. But four years ago, Italian researchers began publishing the results from a series of clinical trials, all of which reported that, among patients with heart failure, reducing salt consumption increased the risk of death.

July 6, 2011

Restricting your salt intake? It may not help you

Filed under: Food, Government, Health, Media — Tags: — Nicholas @ 12:36

Rob Lyons recommends you take the constant barrage of advice about lowering your salt intake a bit less seriously:

The advice to reduce our salt intake has been so ubiquitous for so long that it simply must be correct, right? Those white crystals may make our food taste better, but it’s a Scientific Fact that salt increases blood pressure and, therefore, cutting back on it will reduce blood pressure and we’ll live longer. Trouble is, while this seems to make sense, the evidence keeps failing to back it up — and a study published today raises further questions about this simplistic advice.

The new study is the latest Cochrane Review, an effort to revisit the evidence on a wide variety of healthcare interventions to provide clearer guidance to medical practitioners and patients. The review took in seven studies involving 6,489 patients. ‘Intensive support and encouragement to reduce salt intake did lead to a reduction in salt eaten and a small reduction in blood pressure after more than six months’, according to the article’s lead author, Professor Rod Taylor of the University of Exeter. But the real question was ‘whether this dietary change also reduced a person’s risk of dying or suffering from cardiovascular events’.

And the answer was ‘not really’. That shouldn’t be a surprise. Previous studies have come to a similar conclusion: reducing salt does seem to reduce blood pressure a little, but the effect on cardiovascular disease is so small as to be hardly worth bothering with. If your blood pressure is high enough that you’ve been prescribed drugs to reduce it, then there may be some benefit in also reducing how much salt you eat. But that’s about it.

July 31, 2010

QotD: Take experts’ advice with a pinch of salt

Filed under: Bureaucracy, Food, Health, Media, Quotations — Tags: , , , — Nicholas @ 11:41

More and more, the history of dietary guidelines that our public-health authorities promulgate resembles the Woody Allen comedy Sleeper, in which the main character, awaking from a centuries-long slumber, learns that every food we once thought bad for us is actually good, starting with steak and chocolate. But you wouldn’t know that from government experts’ increasing efforts to nudge us into their approved diets. In 2006, New York City passed the nation’s first ban on the use of trans fats by restaurants, and other cities followed suit, though trans fats constitute just 2 percent of Americans’ caloric intake. Now the Bloomberg administration is trying to push food manufacturers nationwide to reduce their use of salt — and the nutrition panel advising the FDA on the new guidelines similarly recommends reducing salt intake to a maximum of 1,500 milligrams daily (down from 2,300 a day previously). Yet Dr. Michael Alderman, a hypertension specialist at Albert Einstein College of Medicine, observed in the New York Times that because sodium is an essential component of our diets, the city’s effort amounts to a giant uncontrolled experiment with the public’s health that could have unintended consequences. And in 2006, Harvard Medical School professor Norman Hollenberg concluded that while some people benefit from reduced salt intake, the evidence “is too inconsistent and generally too small to mandate policy decisions at the community level.”

Steven Malanga, “Egg on Their Faces: Government dietary advice often proves disastrous”, City Journal, 2010-07

Powered by WordPress