Time to rethink salt | Jens Titze | TEDxNashvilleSalon

things at very unconventional places and it's a story about how their work is challenging some basic assumptions we have made for a very long time about salt in our body we all know it if you eat a lot of salt for a day or two you will drink a lot of water why is that because that salt somehow traps water into biological systems so if we store sodium in our body we store water that's the knowledge simple but is it good enough is it enough to study a human being for a day or two and draw a conclusion with the same thing happen if we'd stood would study him for a week or a month for a year and what on earth does all that have to do with the trip to Mars well think about it how would you measure salt intake in a human being over a long period of time can you calculate how much salt was in a breakfast in the morning or will be on Christmas Eve no me neither what would we need to really control salt intake in a human being we would have to lock him in a box control all the food that goes inside the box and measure all the urine that comes outside and we would have to do that not for a day or two we would have to do that for weeks or months or perhaps a year and that would not be very kind but perhaps perhaps there are already some people who have been locked into a box with controlled food intake collecting all the urine and now you got it on a trip to Mars we should study salt metabolism on a trip to Mars now as you know there is no Mars mission underway so we had to turn to the best thing available on earth and that was in the northwest of Moscow at the Institute of biomedical problems of the Russian Academy of Sciences here you see 12 young man standing in front of the Mars 500 simulator in the Institute and now believe it or not these 12 men agreed to be locked into this box and simulate a flight to Mars and suddenly the impossible was possible these guys would know exactly what they had for breakfast what they had for lunch and what they would have for dinner and we would know how much salt they not for a day or two but for weeks and months well in a year why a year because of fly to Mars will take 520 days this was our one-in-a-million chance to find out whether common sense really made sense on the long term what would we want what did we find well when we studied them on a high salt diet for a day or two we found everything that I had learned in a textbook they accumulated salt and they accumulated water but when we then continued and measured their excretion for a week and four months something spooky happened these guys accumulated salt but we could not find any signs of water overload so somehow the salt had not trapped water talk about a shock this overturned everything that I had learned in school and of course nobody believed it but we believed in our data and that led us to all different kinds of questions I had always used a blood sample to measure sodium but you never this blood sample wouldn't tell me anything I would know a concentration but I could not see the salt in the body and the question was where were these salt stores hidden so we needed something to see the salt in the body and the blood sample of course would not help so we found an answer to this question through a method called magnetic resonance imaging MRI with these big machines you may have seen in a TV show or in a hospital you can measure some elements in the body and if you now change the mode of this machine into the sodium mode then you suddenly can detect the hidden sodium stores in the body look at the picture of this 85 year old man his tissue shine white his storing sodium today we know that we all store sodium we store it in our skin and in our muscle some of us store more sodium we all store it with age but those who store more of it have more likely adhere hypertension or diabetes or infections so sodium storage was the first mystery these Mars guys help us solve but in other words yet to come and that was about sold and thirst in the short-term world everything makes sense I got always thirsty when I had my grandmother's chicken noodle soup and the bartender of course knows the trick about the salted peanuts they will make him sell more drinks but again there's a problem of time granny and bartender only observed for one to two hours what happens but they of course do not know what happens for weeks or months so we thought that our Marcin oats perhaps could give us a question - that - and they delivered yet another spooky finding because when we had them on a high-salt diet not for a day or two but for weeks and months these guys drank less and it produced more urine so how on earth can that be how where did the water come from if they didn't drink it we looked into their kidneys and we found that when they were not ice all died there was more sodium in the urine at least one thing that was in line with the textbook but we also found that the water was somehow a little bit hesitant to follow the sodium and go down the tube so what was holding the water back there's something that was holding holding the water back was urea another substance so the so the urea was holding back the water in the kidney the salt was excreted and that meant that urea was used to conserve water when salt intake was high so salt intake is associated with water conservation not water excretion as we always thought but that now led to yet another question urea is produced by the liver so what's the kidney really left alone with these problems with high salt intake we could not answer these questions in our marzo notes because we could not study their liver in the box that's why we turn to mice and when we fed mice a high-salt diet indeed the liver started producing more urea to give it to the liver so that the word liver to give it to the kidney sorry so that the kidney can conserve water but net now led to the next question because the liver needs a lot of energy to produce the urea where did this energy come from now the answer to this question is simple right if you need more energy you you eat more when we had our minds on a high-salt diet they ate twenty to thirty percent more food so what do we learn from that and what does that mean for our daily lives well before the Mars 500 crew everything in my world was simple I only when I was talking about salt I was only thinking about how about sodium and how much water was excreted by the kidney and that was all that there was to know now we start to understand then on the long-term this is about energy metabolism because our body needs energy to produce the urea to hold back the water when the salt is excreted and that leads to something like we do not know how to call it yet because all that isn't new but this is something like like stress eating and this stress eating might be perhaps even more important than the well established connection between salt and blood pressure because it puts you on track to obesity diabetes metabolic syndrome so this new connection between salt and energy metabolism leads me to the last two questions of this forgive me what happens if you take away the extra calories and needless to say if we took away the extra calories when - when highs all died they lost weight because the calories didn't come in but they didn't take the calories from fat they stole the energy from muscle why was that because muscle protein not only is a great energy reservoir it also contains a lot of nitrogen and nitrogen is an essential component of the recipe that the liver uses to produce urea and help the kidney conserve water when the salt is excreted and now the last question about our margin notes this last mystery they gave us how is it possible that you drink less and make more urine when you're in a high salt diet well what they did is that they transferred fuel into energy urea and water and if you produce more water in your body you drink less simple so that's actually the story I wanted to tell you about the marzo notes but there's one thing I do not want you to take away from that if you are on a diet you please do not go home tonight and eat more salt and hope that you will lose more weight well first of all you will be powerfully hungry and view you perhaps will hate me for that second the hormonal changes that all these induces are really not not really healthy and third and that's perhaps the most important thing for you now you won't take the calories from the fat you will lose muscle mass and that's not the kind of weight loss you've been dreaming off so don't do it even if you are heading for Mars thank you [Applause]

Channel: TEDx Talks

Views: 15,721

Rating: 4.6170211 out of 5

Keywords: TEDxTalks, English, Health, Biology, Biomechanics, Body, Chemistry, Food, Heart health, Medicine, Public health, Science

Id: jQQPBmnIuCY

Length: 13min 33sec (813 seconds)

Published: Mon Sep 25 2017