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Medicine United States Science

US Gained a Decade of Flynn-Effect IQ Points After Adding Iodine To Salt 270

Posted by Soulskill
from the you're-saying-we-could-have-been-dumber? dept.
cold fjord writes "I wish it was always this easy. Business Insider reports, 'Iodized salt is so ubiquitous that we barely notice it. Few people know why it even exists. Iodine deficiency remains the world's leading cause of preventable mental retardation. According to a new study (abstract), its introduction in America in 1924 had an effect so profound that it raised the country's IQ. A new NBER working paper from James Feyrer, Dimitra Politi, and David N. Weil finds that the population in iodine-deficient areas saw IQs rise by a full standard deviation, which is 15 points, after iodized salt was introduced.... The mental impacts were unknown, the program was started to fight goiter, so these effects were an extremely fortunate, unintended side effect.'"
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US Gained a Decade of Flynn-Effect IQ Points After Adding Iodine To Salt

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  • by Megane (129182) on Tuesday July 23, 2013 @07:18PM (#44366439) Homepage
    What is the Flynn Effect? [wikipedia.org]
  • by Anonymous Coward on Tuesday July 23, 2013 @07:25PM (#44366477)

    And now we've got people in the US trying to avoid "iodized salt" because it's a "processed food" and they want "natural mineral salts". Of course they don't even know why salt is iodized -- they think it's a "preservative" (you know, cause salt goes bad) or somesuch -- and while they might be getting enough iodine elsewhere they certainly aren't regulating their intake to ensure as much. It's almost as bad as the folks who want "pectin-free" jam.

    • by ScottCooperDotNet (929575) on Tuesday July 23, 2013 @07:34PM (#44366529)

      I try to avoid salt when possible because so much food is overloaded with it, so I'm a little over the daily recommended value instead of double of it.

      Salt isn't just a preservative but a way to make lesser-quality food taste better, so the market gives a financial incentive to salt up everything.

    • . . . so don't use the salt, and just take iodine . . . straight up, or on the rocks . . .

    • by amiga3D (567632)

      I knew when I was a kid that the iodine was added for thyroid health. I remember asking my Dad about it after sitting at the table one day staring at the little girl in the raincoat on the Morton salt box. He grew up in the 30's so I guess they heard about it back then.

    • by iggymanz (596061)

      so they use sea salt instead, what's the problem?

    • by adolf (21054)

      I live in Ohio (right in the middle of the goiter belt) and I don't buy iodized salt. I just buy the bulk-packed sea salt that my local coffee house sells for cheap -- not because it doesn't have iodine added to it, but because it tastes better to me.

      But that doesn't even matter, because I only add salt to things where it is useful.

      I toss some in when cooking pasta, or cooking down onions or other vegetables, or making pickles, and that's really about it. There is no salt shaker on the dining room table.

      I

      • by TMB (70166)

        Salt is an ingredient whose apparent strength depends strongly on how acclimated you are to it. So if you don't use much salt, it doesn't take much for food to taste like nothing but salt, but if you use a fair bit then you need a fair bit or food tastes bland.

        • by adolf (21054)

          Salt is an ingredient whose apparent strength depends strongly on how acclimated you are to it. So if you don't use much salt, it doesn't take much for food to taste like nothing but salt, but if you use a fair bit then you need a fair bit or food tastes bland.

          I suppose that makes sense.

          Perhaps salt is like capsaicin or alcohol in this way: People around me cringe when I load up a baked potato with some sour cream, shredded cheese, and an entire finely-chopped fresh ghost pepper. To me, it's quite warm, b

    • by fermion (181285)
      And of course other try to over simplify the situation by claiming that processed food is required for us to be healthy.

      It is not. You know what food contains half the iodine you need in a day. A potato. Each one real baked potato a day, maybe a glass of milk if you so desire, include some sea salt, which does contain natural iodine along with other trace minerals. In fact mined salt also contains trace minerals, but they are removed, and then the iodine in added back in, albeit in higher quantities.

  • by Anonymous Coward on Tuesday July 23, 2013 @07:27PM (#44366495)

    Simply meeting the basic needs of the general public brings huge gains.

    There used to be a stereotype that all southerners were lazy and terrible workers. Turns out they were really just riddled with parasites (That train your energy and make you tired) Basic sanitation (Even things a simple as proper outhouses dug deep enough) solved that problem amazingly well. Many poor nations struggle with this problem today, however.

    The Army started school lunch programs because malnourished children were growing up stunted and short (among other health problems), and made for awful soldiers.

    • There used to be a stereotype that all southerners were lazy and terrible workers. Turns out they were really just riddled with parasites.

      What kind of parasites, and why did they have more of them than damnyankees? Serious question.

      • by Ken McE (599217)
        You get more insects and disease in general in places where it's warmer.
      • by ShanghaiBill (739463) on Tuesday July 23, 2013 @08:15PM (#44366781)

        What kind of parasites, and why did they have more of them than damnyankees? Serious question.

        A number of energy and grown sapping diseases, such as malaria and yellow fever, were common in the American South in the 19th century, but uncommon in the North. But the biggest culprit was probably hookworms [wikipedia.org], which cause "intellectual, cognitive and growth retardation". Average IQ in the South increased significantly as hookworms were eradicated in the early 20th century.

        We might get another gain if we eradicate toxoplasmosis [wikipedia.org], a parasite spread by cats. It is believed by some to depress intelligence and novelty seeking behavior in humans.

    • by Intropy (2009018) on Tuesday July 23, 2013 @07:51PM (#44366635)
      I believe you are referring to hookworms, which were found in an estimated 40%-70% of people living in the Southern US in the early 1900s in sufficient amounts to cause disease. They cause anemia and fatigue. They're expelled in feces, and can live in soil for a while. The problem was them digging out of outhouses through the soil and finding their way into people walking around barefoot. The solution was to dig deeper outhouses, so that the hookworm couldn't live in the soil long enough to reach the surface, and to wear shoes. On the flip side, there's serious current research into using small-scale hookworm infestation as a treatment for inflammatory diseases, including crohn's and multiple sclerosis.
      • The way I heard it was that it was the use of untreated fertilizer in the fields and gardens that was the primary cause of the infections.

        I suppose, sitting barefoot in an outhouse with no floor, that the hookworms working their way up from the pit could be a contributive factor.

        But, shoes, yes. One of the reasons for the tradition of wooden geta in Japan was the general use of untreated (human) fertilizer in the rice paddies. The tradition of taking the shoes off on entering the house was also in no small

    • Wow, parasites that can be trained? Maybe all they needed was better schooling - for the parasites.
  • by Okian Warrior (537106) on Tuesday July 23, 2013 @08:11PM (#44366751) Homepage Journal

    A lot of people in the US live in the so-called Goiter Belt [blogspot.com], which is a band of the northernmost state (or two) of the US. Roughly speaking, the other states were once a vast inland ocean swamp, so the soil become infused with Iodine form the ocean. This gets into the water supply, with the result that Northern residents have far less Iodine in their diet than southern states.

    Another source of Iodine used to be bread - Iodine was used as a dough conditioner in bread, so a little bit got into the food chain that way. Some of the effect we're seeing might also be due to the rise of manufactured bread in the US.

    More recently, however, bread makers have started using Bromine instead of Iodine. Bromine binds to Iodine receptors so not only are we no longer getting Iodine from bread, we're less able to process the Iodine we do get.

    There's also the question of how much Iodine we need to be healthy. There's good evidence for the minimum amount to prevent disease, but that may (and for those of you in the medical community, note that I'm saying "may") be lower than the optimum amount.

    Note that doctors will tell you that 150ug is the maximum Iodine you should ever take (more would be toxic!) and yet occasionally use Iodine to enhance contrast [wikipedia.org] in radiological studies, which puts as much as 20 mg in the blood stream. The RDA value is 100x less than used by doctors in some studies studies [drmyhill.co.uk] to treat disease.

    There's also disagreement [food.gov.uk] as to what the minimum daily intake should be.

    We really should be studying these things. Unfortunately, a supplement that anyone could buy which will clear a patient's symptoms is incompatible with an expensive FDA-tested drug that requires office visits to administer. The medical community won't make money on supplements, so they aren't studied very well. There's enormous economic pressure against research into health (as opposed to research into disease).

    • by cold fjord (826450) on Tuesday July 23, 2013 @08:55PM (#44366991)

      Did you see the goiter rate charts in the article? I found them astonishing.

      I was also surprised by the low rates in Oklahoma and New Mexico. I wonder if that is because they were getting their salt from Texas? Texas did have a very low rate.

    • by russotto (537200)

      Note that doctors will tell you that 150ug is the maximum Iodine you should ever take (more would be toxic!)

      No, the recommended dietary allowance (RDA) is not intended as a maximum dosage! The long-term upper intake level is 1.1mg. Note long-term.

      and yet occasionally use Iodine to enhance contrast in radiological studies, which puts as much as 20 mg in the blood stream.

      It's not used all that much, because many patients have a bad reaction to it.

    • by brycen (301938)
      And when it comes to how to supplement iodine in remote areas, it turns out to be pretty easy:

      A new approach to combatting iodine deficiency in developing countries: the controlled release of iodine in water by a silicone elastomer.
      A Fisch, E Pichard, T Prazuck, R Sebbag, G Torres, G Gernez, M Gentilini
      Am J Public Health. 1993 April; 83(4): 540–545. PMCID: PMC1694489 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1694489/

      As long as the local shamans don't
  • by fuzzyfuzzyfungus (1223518) on Tuesday July 23, 2013 @08:25PM (#44366825) Journal

    'Cretinism' [wikipedia.org], the sufficiently-severe-to-be-clinically-obvious manifestation of iodine deficiency has been known for a considerable length of time, in places without sufficient soil iodine. I would imagine that smaller gains would only be a surprise if you thought that everybody not obviously diseased was fully healthy, rather than frequently mildly subnormal.

  • I use a potassium / sodium / iodine blend, like Morton Lite Salt, in everything I cook or bake, and one of those sea salt grinders at the table. This keeps everyone at the table happy, and heathly.

  • by jtownatpunk.net (245670) on Tuesday July 23, 2013 @10:36PM (#44367407)

    Can anyone explain why my Morton's Popcorn Salt isn't iodized?

  • Technically lack of iodine cause mental retardation, or a lowering of IQ, so using iodized salt in a population wouldn't actually increase IQ the IQ of the population, it would simply protect against the degredation caused by iodine insufficiency.

  • I think it is interesting that the generation affected by the iodized salt brain boost would have just been coming of age when WW2 struck. The US would have entered the war with quite a few soldiers that would have been noticeably more intelligent than their fathers in WW1. I expect it must have helped given the increasing technical sophistication of warfare at the time. Smarter soldiers also tend to do better on the battlefield in general.

  • and we took the lead out, and yet it seems in the US, people on the whole are stupider then ever. There must be some sort of reverse Flynn effect compensating for all this. I'd like to blame reality TV, but that's likely just a system.
  • Did you see what they were wearing back then? I'm not surprised we're superior to those knuckle draggers, lol. Plus, they practically ate lead paint chips and drank water from lead pipes.

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