>>How could something as simple as salt stymie scientists for so long?
The human body has numerous overlapping pathways for salt regulation. Salt (sodium chloride) plays a major role in the osmolality (electrolyte concentration) of blood. A drop in the sodium concentration results in the release of renin, which causes changes in vascular constriction, sympathetic activity, and sodium reabsorption itself.
This seems like a great research question for systems biology, although it would require some detailed modeling.
Electrolyte balance in general seems like a good research question. We load our food with sodium chloride, but natural diets are far higher in potassium chloride. The relationship between the various electrolytes is something about which we know very little.
The function of the various proteins used in the sodium-potassium pump, which transports Na+ out of cells and K+ into cells, against their natural diffusion gradient, suggests that the ratio between Na+ ions and K+ ions in the diet, and their relative concentrations in intercellular fluid is far more important than the absolute quantity you consume.
If your Na+ to K+ balance is healthy, consuming too much of both could be solved as easily as drinking more water.
But consuming too little of either one will cause the sodium-potassium pumps to function poorly.
My hypothesis is that there is an optimal ratio of Na+ to K+ such that the saltiest water (containing only NaCl and KCl) that a human could drink for prolonged periods without observable ill effects has that ratio. A different ratio would require more water for the kidneys to clear the ions present in excess, and that would lower the total concentration of dissolved salts.
Learning that value could possibly enable the production of drinkable water by partial desalination with potassium supplementation rather than complete desalination. I have heard that water that is 40% seawater and 60% freshwater can sustain someone in a survival emergency. Perhaps 50% seawater and 50% dilute potassium chloride solution could extend the water supply on a life raft by another 20%? You could hardly do the experiment if an ethical monitor for human experimentation thinks that supplying that much of an absolute quantity of dietary sodium is dangerous, independent of relative concentrations.
Instinctually, I'd be a little wary of that, because Na+ and Ka+ do more than act as ions within the neurological system. I'm not sure a higher concentration, even at the right relative concentrations, wouldn't have adverse effects.
Indeed there are many feedback loops that regulate various things in the body, so I think the general idea is that anything within the range the regulator can compensate for won't cause any immediately harmful effects. On the other hand, making these regulators work constantly near one end of their input range could have long-term effects.
Ben Goldacre, who does a lot for public understanding of health and science, among other things including being a GP for the NHS, is often asked for some positive health advice after he warns about the worthless-at-best value of most health advice. If I recall correctly, his response is always "Try to increase the amount of fresh fruit and veg in your diet, try to reduce alcohol and cigarettes, do some exercise.".
Also, this comedy sketch from Fry & Laurie is relevant, especially the "too much is bad for you" rant at 2m00s.
> especially the "too much is bad for you" rant at 2m00s.
It's also pretty futile. The point is not that a theoretical excessive quantity of something does you significant damage, the point is whether or not you are exposing yourself to that amount now, and/or enough people are for it to be a public health problem. You could make the same rant about being obese, or about hardly moving throughout the day.
That is especially relevant when you have food companies engineering their products to be as pleasurable as possible, without reference to the health consequences - see the enormous amount of sugar in ready meals, or the introduction of trans fats previously.
Of course, that doesn't mean we actually can tell what is good and what is bad for you, or what doesn't matter either way, which is the point of Goldacre's statement.
Fruit might be good for it's vitamins, but in moderation. Increasing fructose consumption after a certain threshold - which could be easily crossed when increasing it's consumption - would not necessarily be a good thing.
That's not really a concern as long as it's just fruit, not juice or processed fruit. There's so much fiber and water in fresh fruit, it's difficult to consume enough at a fast enough rate for the sugar intake to be problematic.
Do you have a reputable source for that? Fruit is definitely good for more than its vitamins.
Also, we are not monkeys anymore, but monkeys eat a lot of fresh raw fruit. Arguably they climb trees while doing so but eating like a monkey seems like a relatively safe thing to do to me.
Elephants and manatees are closely related, as well, but I would not recommend that they look to one another for dietary recommendations.
Speciation can occur when different populations fill different niches. Human physiology (along with still extant hunter-gatherer cultures) indicates that we are opportunistically omnivorous cursorial hunters. The species closest to us genetically are opportunistically omnivorous frugivores. Chimps and bonobos eat fruits and nuts most of the time, and eat monkeys maybe once a month. If you want to consult the animal kingdom for dietary advice, look to wolves for the meat and bears for everything else.
Eat like a bear until you see a potential prey animal, then run it down and eat it like a wolf. When you finish, switch back to bear mode. That seems like a relatively safe diet to me.
This is just one source, of course, but is not the only one in that direction. Carbohydrates in excess - specially sugars like fructose - are being linked to increase of fat accumulation on the body and much of the modern day metabolic diseases - Google scholar should give you a bunch of results in this one too.
The article covers its chosen areas pretty well. Additionally, there are aspects missed in the article.
The Puritan angle is important. If you're not making people feel guilty about enjoying something, its hard to control them, and any attack on any form of Puritanism is fundamentally an attack on all forms of Puritanism. So "salt is OK" is going to fundamentally offend innumerable superficially unrelated individuals who rely on guilt as social control in entirely non-food related areas.
Tied in with the above, bland tasteless food isn't in as much demand as flavorful tasty food. If the average American were dangerously anorexic then a viable public health strategy would be to encourage salty food because it'll taste somewhat better than bland salt free food and optimistically people will eat more preventing anorexia. Obviously a visit to walmart will cure any inaccurate belief about the average American being too skinny to be healthy. So anti-salt is at least somewhat anti-obesity. Making stuff taste bad, is good, if people are fat.
Finally (insert small percentage) of people are salt sensitive and it raises their blood pressure. The other (vast majority percentage) just sweat or pee out excess salt with no effect on their blood pressure. This results in two interesting political issues. One is that financially we're better off telling everyone to eat bland food so we don't have to spend money figuring out who's in the susceptible minority or provide parallel logistical tracks of food. The other is that the mere existence of differences offends certain political beliefs about equality of outcome.
It's sad that we've known this for many years http://www.sciencemag.org/content/281/5379/898.summary but still incredible amounts of effort have been utterly wasted on pushing low salt diets. And as the article describes, this will continue. Truly the study of salt is political science.
Looks like the dietary "guidelines" of the past decades are essentially BS. Especially the "low-fat" wave that came as a consequence.
At least low salt consumption has no consequences (of course if you abstain completely from salt it will have, I'm talking about "normal" low consumption here, however salt replacements, high in potassium, may have)
Then, this past August, the New England Journal of Medicine published the results of a massive research effort known as the PURE study. It indicated that people who conform to the U.S. recommended limits actually have more heart trouble.
[...]
Under the current dietary guidelines, too much is more than 2,300 milligrams of sodium per day - the amount of sodium in a teaspoon of salt. (For people over 50, and for African-Americans, the current recommended intake is even lower - 1,500 milligrams per day.)
If the U.S. salt warnings are correct, Americans are indeed endangering themselves on a massive scale. Americans typically go way over the limit, ingesting about 3,500 milligrams per day.
If the skeptics are correct, on the other hand, most Americans are fine. In their view, a typical healthy person can consume as much as 6,000 milligrams per day without significantly raising health risks. But consuming too little - somewhere below 3,000 milligrams - also raises health risks, they say.
Are those people who actively conform to the recommendation (looking to say healthy) or passively conform somehow (via malnutrition or whatever)?
Another possible question: of those who conform, could many of them be conforming because they were told to do so by their doctor due to some condition, like hypertension? I.e. could it be that health problems cause conformance to sodium intake recommendations, rather than adherence to low sodium intake causing health problems?
I have to watch my salt intake and my specialist NHS dietician commented that the "lo" salt versions of foods have "worse crap in them" than the salt they are replacing
My understand has been that it's likely that problems from "excess" sodium actually stem from an excess in relation to potassium levels, and so ensuring that you've got sufficient potassium is the way to avoid the kinds of things that have been classically associated with high-sodium diets.
So my strategy has been primarily to keep my potassium level up, mostly by ensuring that I'm getting K in addition to just Na when I'm sweating alot. Has this been a bad strategy?
I wonder when they will stop with this one-size-fits all advice? I guess it's because of this ideal that all humans are equal that pervades our culture, which causes many to assume that all people are fundamentally the same. However, every human is biochemically unique. A diet that works well for one person doesn't necessarily work well for another.
I also think it's a mistake to look at any single nutrient or food in isolation, and ask, is this healthy? It's impossible to answer that, because whether or not something is healthy depends on the rest of the diet. For example, is broccoli healthy? If the rest of your diet consists of fast food, then clearly adding some broccoli would be a good idea. But if the rest of your diet already contains tons and tons of vegetables, then perhaps you have a serious gas problem, and you would be better off avoiding adding broccoli to your diet.
EDIT: I remembered that I read somewhere that sodium "competes" with potassium in the body. Apparently, if you consume a lot of potassium, then you can tolerate more sodium.
The headline and some commenters are misrepresenting the debate. From the article:
Both sides agree that eating too much salt, especially for people with high blood pressure, can be dangerous.
The critical disagreement concerns how to define "too much."
Under the current dietary guidelines, too much is more than 2,300 milligrams of sodium per day
... If the skeptics are correct ... a typical healthy person can consume as much as 6,000 milligrams per day without significantly raising health risks.
It's an epidemiological observation that the socially defined "African-American" (also known as "black") racial group in the United States has higher rates of high blood pressure than other officially reported groups. Interestingly, west African people in west Africa do not appear to have higher rates of blood pressure, according to a scientist who studies comparative epidemiology.[1] That's always the trick in group comparisons: to find out if a group difference has a genetic or environmental cause.[2]
Do you know how this plays out in mixed race people? This is a question that no doctor has ever given me a straight answer for. If I have an african-american father and a european mother, do I need to worry about this?
Also, what about people who have a single grandparent who is African-American. Does this kind of thing apply to them?
This indeed is one of the problems with "race" classification. As the Census Bureau itself says, "The U.S. Census Bureau collects race data in accordance with guidelines provided by the U.S. Office of Management and Budget (OMB), and these data are based on self-identification. The racial categories included in the census questionnaire generally reflect a social definition of race recognized in this country and not an attempt to define race biologically, anthropologically, or genetically. In addition, it is recognized that the categories of the race item include racial and national origin or sociocultural groups. People may choose to report more than one race to indicate their racial mixture, such as 'American Indian' and 'White.' People who identify their origin as Hispanic, Latino, or Spanish may be of any race."
I was a recipient of the official American Community Survey from the Census just in the last week. I filled out the survey according to questions I was asked. For race, for all of my family members, I put in "other" as the race and filled in "human" for the response below that. (For the decennial census back in 2010, we filled out the form in the expected way by the federal definitions, holding our noses while we did that.) Both times, we filled in national ancestry according to the known countries of origin of ancestors, which is quite a diverse mixture for my children.
As Henry Harpending wrote back in 2006: "On the other hand, information about the race of patients will be useless as soon as we discover and can type cheaply the underlying genes that are responsible for the associations. Can races be enumerated in any unambiguous way? Of course not, and this is well known not only to scientists but also to anyone on the street." Chapter 16: Anthropological Genetics: Present and Future in Anthropological Genetics: Theory, Methods and Applications (2006), edited by Michael Crawford.
People with dark skin can experience vitamin D deficiency in northern climates. One of the many symptoms is hypertension.
Some estimates are that you need 10 times more sun exposure to produce the same amount of vitamin D as a person with pale skin.
Agree with the part of constant stress.[0][1] Some full moons ago I took pills that among other effects also had a side effect of increasing blood pressure. Which they absolutely did to me until one day I postponed them in the last minute only to feel the side effect the same way as usual a few minutes later when they should have reached the blood stream.
From that day that side effects disappeared. Our brains plays games with us. About 30%[1] of us seems more prone to this[2] than others.
[0]: context: JulianMorrisons post was downvoted when I commented. I read it as funny, not SJW, and I agree that constant stress seems to be a big issue.)
[1]: See vixen99s explanation for what seems like the dry facts about the link between skin color and hypertension
> The answer is that, despite the dietary claims that are made for all kinds of foods, actually substantiating how eating influences human health is notoriously difficult.
This. Have you noticed how recommendations change over years? Nutritionists don't have much of a clue, but press usually takes them by the face value and makes a new truth out of their words.
We actually know a lot about nutrition, but if something are good for A and bad for B and you only learn about this stuff through several intermediaries. Then it's going to come across in a very odd miss mash of conflicting reports.
Diabetes, heart disease, and Crohn's are just a few examples where diets can make a huge difference.
Don't beleve me? Feel free to avoid vitamin C. Wait, no that’s a bad idea.
PS: Now if you’re in the search for optimum heath then yea that's a huge unknown. But, if you ever talk to a nutritionist they can actually back up their advice.
I don't think Crohn's fits your pattern here. My expertise/bias is that I've had it for about 35 years.
The topic here is controlling body systems based on the chemistry of what's being consumed.
A Crohn's diet has two important factors, which don't really look at the chemicals introduced into the body very much at all. Most important is a purely mechanical component: because scar tissue and adhesions can cause strictures, areas of limited diameter and stretch in the intestines, it's necessary to avoid stuff that might get stuck, like popcorn and other seeds. A second issue, possibly more important but only very poorly understood, is the environment presented to intestinal flora. There's chemistry to that (like carb mix) but, not with respect to the parent organism.
Most people with Chron's disease should avoid spicy food due to chemical irritation and sure the mechanical issues are also important.
However, a nutritionist will suggest a heathy low fiber diet when dealing with a partial obstruction etc. Eggs vs red meat might seem like a simple change, but once a range of dietary restrictions show up a heathy diet becomes a lot more difficult.
Anyway my point was there is a lot of practical diet research out there.
PS: Chrones also frequently causes issues with nutrient absorption and a high protein diet is useful for healing. So, there are some classically nutrition based changes.
One of the major issues is that the way to collect info on dietary intake is really hard. It is typically a food diary or a food recall, both of which are flush with issues, all of which are well known to academic researchers, but are passed over by journalists.
Even if salt per se isn't bad for you, if you avoid sodium, that forces you to make healthier food choices. There is a correlation between "crap food" and "loaded with salt". Or, more generally, "loaded with sodium".
This is simply because the addition of sodium compounds to food is a processing step. Right off the bat, anything which contains lots of sodium is almost certainly a processed food.
Let's look at it another way: Q: what do a slice of fresh meat or fish, a carrot and an apple have in common? A: no added sodium! No salt, no baking powder, no monosodium glutamate, ...
Salt is also abused by senseless cooks who don't take pride in creating flavor. They just throw stuff together and douse it with salt. You can almost measure a restaurant by how salty are the offerings. Approximately, the saltier the cooking, the more they just care about money (and therefore use lower quality ingredients, which they mask with salt or salt-containing sauces, flavor enhancers like MSG, or excessive spicing).
From my own experience, I'd say that the right amount of salt is highly dependent on your diet. For example, when I restrict my carb intake I notice I need to add more salt to my food or I will get cramps and feel generally dehydrated. Drinking more water doesn't help, I just go to the bathroom more often. Adding more salt to my food works, however.
Unfortunately, I can find absolutely no scientific evidence to back this theory up. I just try to listen to the signals from my body, and it works for me.
One of the meds I'm on is a potassium-sparing diuretic (spironolactone), so I actually need more sodium than most people lest I mess up my electrolyte balance and get leg cramps.
I'm not sure what you mean by bleaching. Salt is a mineral (it's sodium chloride - NaCl). The only other mineral "added to it" is iodine in iodized salt. The iodine is added to prevent iodine deficiency.
Nothing to do with bleaching, but have you ever bothered to look up the actual ingredients of table salt? Morton's, for instance, is >99% NaCl, yet also contains dextrose and calcium silicate.
When I was younger I played competitive sports and used to suffer from cramping relatively often. I cured this condition by adding a pinch of celtic sea salt to a glass of water in the morning.
The only thing dangerous about salt is table salt that is bleached and has chemicals added. If you can get good salts like himalayan pink salt and celtic sea salt, you are in the money.
Salt is the most efficient nutrient for the body. Provides essential minerals as well as a sleuth of other positive health properties.
edit: Pink salt is not pink because more chemicals were added.
The more common "refined" table salts have been been stripped of their minerals during processing, which manufacturers then sell to supplement companies. It makes the unmistakable point that the producers of table salts are intentionally stripping what they know to be the most nutritious part of the salt, and actually increasing profits by malnourishing their own customers.
> The only thing dangerous about salt is table salt that is bleached and has chemicals added. If you can get good salts like himalayan pink salt and celtic sea salt, you are in the money.
You're mixing paranoias here. Pink/sea salt differ from table salt primarily in that they have more chemicals - that's what gives them more color/flavor. If you're concerned with the iodine supplementation, enjoy your goiter...
Fearmongering about bleach in salt is a little weird considering its chemical formula is NaClO and its primary component is used to make your tap water safe to drink. When used, it degrades to water and salt as the oxygen pops off to oxidize impurities.
>When used, it degrades to water and salt as the oxygen pops off to oxidize impurities.
Are you saying that the chlorine in drinking water turns to salt through oxidization? How is the Na added, specifically? I'm asking because when I moved to NYC from Denmark, I initially had a hard time even eating salad at restaurants because I could taste the chlorine from the tap water it was rinsed in. Is it just because there will always be pure chlorine remnants in the water?
> edit: Pink salt is not pink because more chemicals were added.
It is pink because there are more chemicals in it than just sodium chloride (pink salt gets it from iron oxide (rust), grey sea salt is usually from clay). Those chemicals occur naturally, but they're still chemicals. There are more chemicals in pink salt than table salt, regardless of their source.
> Check out this link
Completely lacks sources, and the site's a bunch of "mercury causes autism!" pseudoscience. That specific article makes false claims. For example, "Unadulterated sea salt usually contains more iodide than iodized table salt does."
> It is a myth (often also false advertising) that “natural” sea salt contains significant amounts of iodine. The iodide content of seawater is only 64 µg/kg or 2.1 mg I/kg NaCl. In evaporatively prepared salt, the iodide/chloride ratio is even lower because of iodine loss; crystallization processes leave iodide selectively in the mother liquor.
Nothing to do with the OP, but where did you come up with this? Table salt is NOT composed of exactly two elements. NaCl is. The two are not the same. Table salt often contains additional anti-caking agents (e.g. calcium silicate) and stabilizers such a dextrose. Iodized table salt doesn't contain elemental iodine, which is lethal at 30mg/kg, but some salt such as potassium iodide.
FWIW, most chefs recommend using coarse kosher salt and not iodized salt (which as pointed out, has iodine and additives). In Rhulman's "Twenty" he writes, "It's important to use the same brand of salt or your won't be able to teach yourself how to season consistently. Diamond Crystal is flakier than Morton's so that the same volume is saltier than Diamond Crystal; a tablespoon of Morton's weighs more." Morton's coarse kosher is 1 tbsp = 1/2 ounce = 15 grams.
People are downvoting you because they think that they know that salt is only NaCl.
They refuse to understand that nature does not provide NaCl. Chemistry made people think they could purify non-edible salt. They removed all trace elements and people got diseases caused by a lack of those elements. So companies readded iodine to cure the obvious problems.
I agree completely with you, I will only take proper natural salt, not bogus purified chemical salt.
Nothing wrong with enjoying your sea salt - you'll probably get plenty of iodine from water, flour, milk, eggs, seafood, etc. - but goiters and other mineral deficiency-related diseases happened long before we started making purified salt with chemistry.
> Chinese physicians of the Tang Dynasty (618–907) were the first to successfully treat patients with goitre by using the iodine-rich thyroid gland of animals such as sheep and pigs—in raw, pill, or powdered form.
> Goitre was previously common in many areas that were deficient in iodine in the soil. For example, in the English Midlands, the condition was known as Derbyshire Neck. In the United States, goitre was found in the Great Lakes, Midwest, and Intermountain regions. The condition now is practically absent in affluent nations, where table salt is supplemented with iodine. However, it is still prevalent in India, China Central Asia and Central Africa.
> Nothing wrong with enjoying your sea salt - you'll probably get plenty of iodine from water, flour, milk, eggs, seafood, etc.
Seaweed an even more potent source of iodine, and the Japanese eat a lot of it. The concentration of iodine in these marine plants ranges from 0.5-8.0 mg/g. Terrestrial plants, in contrast, contain only trace amounts of iodine, 0.001 mg/g.
In 1964, the Nutrition Section of Japan's Bureau of Public Health found that people in Japan consumed a daily average of 4.5 g of seaweed with measured iodine content of 3.1 mg/g, or 13.8 mg of iodine. Saltwater fish and shellfish contain iodine, but one would have to eat 15-25 pounds of fish to get 13 mg of iodine.
[Nutrition Section, Bureau of Public Health. Nutrition in Japan, 1964. Tokyo, Japan: Ministry of Health and Welfare; 1965. ]
At the end of the day it is utterly irrelevant ... the US has a major food issue, only seconded by the fat Mexicans - and salt is certainly not any major problem here. Most likely the findings simply imply that our body copes well with a bit "too much" or "too little" salt intake from nuitrition. I mean you still get plenty of "salt" from your water.
The problem is sugar, carbonhydrate-based food, red meat and fat, fat, fat - everytime I watch documentaries about the US (f.x. about the fucked up prison system) I wonder about how it is possible that almost every single police guy or warden is that fat - or the other extreme a bulk of muscles. I mean sorry - but salt - that's nothing the US has to worry about.
Go back or forward or sideways a few months and you'll find people authoritatively saying what you just said with all the nouns rearranged (turns out fat isn't so bad! etc). Modern nutrition seems like an endless merry-go-round mindfuck. (Not saying non-modern is any better of course)
Ehhhh sort of but not really. There's weird back-and-forth on fat as in "the food you eat contains fat" often in the context of fad diets and over-enthusiastic newspapers drawing unrealistic conclusions from medical journals. But I don't think there's any ambiguity that being fat is not healthy.
> Modern nutrition seems like an endless merry-go-round mindfuck. (Not saying non-modern is any better of course)
Agree. I can see two reasons for this. One is that all humans are biochemically unique. A diet that works well for one person won't necessarily work well for another.
The other reason is the food industry financing "research". For example, sugar companies financing studies that tell you that artificial sweeteners are unhealthy.
Actually, there seems to be one more reason. Cultural "taboos". For example, lots of people will tell you that eating too much sugar, fat, salt etc. are bad, BUT you never hear that eating too much protein is bad, even though there is research that shows this. Seems like there's some sort of taboo against saying anything bad about protein.
I just accidentally bought a Dr Pepper from a vending machine instead of a diet coke. It has 24g of sugar. Ludicrous. I had four mouthfuls before i started literally palpitating.
The diet coke is also associated with diet issues. Mainly that the pseudo sugars trick the brain into expecting a rise in bloodsugar level that never comes, leading to a crash.
So is a plate full of pasta or a few slices of bread or even worse juice.
Carbs from sugar and non-sugar are used exactly the same way in your body. Heck people say that soda has so much sugar you would vomit if it wasn't for some additives, but apple juice has more sugar per oz than soda and it doesn't have additives to make you not vomit. Just like life you have to have balance in your diet (I have to much sugar) but it doesn't really matter what sweet you drink or carb that you eat. They all turn into glucose. Now fruit and vegetables will have some other nutrients but in terms of too much sugar people over simplify.
The human body has numerous overlapping pathways for salt regulation. Salt (sodium chloride) plays a major role in the osmolality (electrolyte concentration) of blood. A drop in the sodium concentration results in the release of renin, which causes changes in vascular constriction, sympathetic activity, and sodium reabsorption itself.
This seems like a great research question for systems biology, although it would require some detailed modeling.