0:00 There's a vitamin on your kitchen counter and the nerves in your feet are the first place you'd notice it missing. Tomorrow morning 20 7, you'll stand at that counter with the kettle going and take it the way you have for years. Same tablet, same glass of water, the good brand, the one that costs more, and your toes have been numb since last November. All four of them, and the pab behind them worst at night. You told the doctor. She ran the blood test. Every line came back with a tick beside it. And that was the end of it. So, let me take that off you now. The food was never your problem. The brand was never your problem. Nobody has ever measured what's been draining the tank you were filling. Three things stand between the vitamin on that counter and the nerves in your feet. Three. All three invisible
0:47 on the panel your doctor ordered. Why your toes and not your liver? And what is the one thing that gives them back? You've probably guessed the vitamin's name already, and you're probably right. But the name is the easy half, and the name on its own is exactly what has failed you. It arrives in the last few minutes, along with the one number that decides how much of your feet can still come back. Before I say another word about nerves, I want to take you into a hospital ward in Boston in 1926. Because what happened there is the reason I'm not going to be alarmist with you. The disease was called pernicious anemia, and the name was honest. Pernicious meant deadly. The blood count fell. People went gray and breathless. And on the way down, something happened to their nerves that nobody could explain. Numb hands, feet that couldn't feel the
1:33 floor, a walk that turned into a stagger. The diagnosis gave you a few years, and there was nothing to do but watch. Two Boston physicians, George Minute and William Murphy, had heard about an odd finding from a researcher in Rochester named George Whipple. Whipple had been bleeding dogs, then feeding them different foods to see what brought their blood back. Liver did something the others didn't. Minet and Murphy decided to try it on people who were dying. On the 4th of May 1926 in Boston at a meeting of the Association of American Physicians, they stood up and described 45 patients. 45 followed for between 6 weeks and 2 years on a diet built around liver, between 120 and 240 gram of it a day, plus 120 g of
2:21 muscle meat. And it worked. Within 4 to 10 days, the young red cells in their blood went from about 1% to 8%. The yellow left their skin. 45 people who had been handed a death sentence were improved quickly and by the numbers. Here's the part that matters to your numb toes. Those patients did not fail because they had done something wrong. They were eating. They were trying. They had a deficit they could not have known about and could not have fixed by trying harder. And the moment somebody finally put back the right thing, the damage began to reverse. Nobody in that room knew what was in the liver doing the work. They wouldn't know for another 22 years, and the discovery nearly didn't happen at all. Whipple's dogs had been fed cooked liver, and cooked liver did
3:06 nothing. It was a laboratory technician who didn't follow the protocol properly that week and fed them raw liver instead. One careless man in one laboratory, and a decade of medicine turned on it. So, take this from the ward in 1926. What you're carrying is not decay, it's deprivation. There's a difference, and the difference is everything. The first of the three things standing between the vitamin and your nerves is not on your plate. It's in your prescriptions, and it's open right now. Here they are in the order I'll open them. One, the tap that's already open. Two, the test that measures the wrong thing. Three, the clock inside the nerve itself. Before that, I want two numbers out of you, and neither requires you to get up. Number
3:52 one, think about yesterday and name out loud every separate serving of animal food you ate. Meat, fish, eggs, dairy, anything that came from an animal. Count them, not what you generally eat yesterday. And notice where they came from. This vitamin is in animal food and almost nowhere else. Beef liver, 85 g. A piece the size of a deck of carbs, 70 micrograms. Clams same weight 17. Salmon two and a half. A cup of milk 1.3. One egg half a microgram. Two eggs in a cup of milk gets you to about 2 1/2 micrograms. And the daily requirement is 2.4. That is the requirement for a young man with a working stomach. Not for you.
4:39 Number two, count the prescription bottles in your house that have been on repeat for more than 2 years. Just count them. Now the bands because a number with nothing to compare it to means nothing. Below 65 about 1 in 25 adults has a genuinely low level on the standard cutoff. 65 and over about 1 in 20 into your 80s or into care and it's better than one in seven. I'll tell you which band surprised me. Not the old one. The 65 plus band sitting almost level with everybody else. 3.7% against 3.6 across all adults. That flatness isn't reassurance. It's a confession about the ruler. Move the line up by 150 picoggrams and those same people with the same blood go from 4% to
5:24 12. The number isn't measuring your body. It's measuring where somebody decided to draw. So the open tap, there are two prescriptions that are extremely common in exactly this age group. Both given for good reasons, both working as designed and both quietly drawing this vitamin down. The first is metformin. If you're carrying a diagnosis of type 2 diabetes or even pre-diabetes, there's a good chance you've been on it for years, and it's a good drug. I'm not here to talk you off it, but it interferes with the way the vitamin is taken up. In the diabetes prevention program run at 27 centers across the United States, more than a,000 people were assigned metformin, 850 milligrams twice a day, against a thousand on placebo. At five
6:10 years, 19% of the metformin group had a low or borderline low level against 9 and a half% of the others. And the risk rose with every year of use. That's why the American Diabetes Association's own standards of care tell clinicians to measure this periodically in people on long-term metformin, particularly if there's anemia or any hint of nerve trouble in the feet. It's in the guidelines, and I'd bet good money nobody has ever run that test on you. The second is the acid blocker, Omerazole, esoprazole, lancoprail. The little capsule a great many people over 55 have taken every morning for a decade because they took it for 8 weeks and never stopped. And here's what nobody explains at the pharmacy counter. The vitamin in your food isn't loose. It's
6:56 locked inside protein and acid is the key that releases it. Take away the acid and the vitamin stays locked in the meat while the meat goes past. In 2013, a case control study published in the Journal of the American Medical Association from a community setting in the United States found that two or more years of continuous acid suppression was associated with a substantially higher rate of this deficiency and that the rate fell again in people who stopped. Put those two together with me. One pill slows the way the vitamin comes out of your food. The other removes the acid you need to release it at all. You can do everything right at the table. the beef, the salmon, the eggs, the good brand. While the two things you take on your doctor's instruction, empty the tank from underneath. Picture a bath.
7:42 The tap is running properly. You have spent years making sure that tap is on, buying the right tap, reading about taps, and nobody has glanced down to see that the plug is out, the water level tells you nothing about the tap. It tells you the difference between what's coming in and what's leaving. And let me be exact because this is where health content goes crooked. Most people most of the time have enough slack in the system. What the trials show is a shift in the odds concentrated in people who've been on the drug for years and concentrated hardest in those who were already borderline. That's why the same pill that does nothing to your neighbor can matter to you. The measure everyone uses is a level in the blood. The vitamin's own level probably on your panel for 20 years. It's a genuinely
8:27 useful test. What it is not is a measurement of what your nerves have. Think about a warehouse. Your blood is the loading yard where the delivery sits before it goes anywhere. The nerve is the shop floor 200 m in where the work happens. A blood level tells you how much product is parked in the yard. It cannot tell you whether the shelves inside are bare. You can have a yard stacked to the roof and an empty shop floor. And every morning the truck rolls in and adds to the pile and the yard number looks magnificent. When the vitamin isn't reaching the cells, it's because the transport system that carries it into tissue is saturated or the tissue can't take it up. So the level sits there comfortable and reassuring while the cells downstream starve. This is the most common way this deficiency is missed. Not in an exotic
9:14 way, the ordinary way. So the level has a gray zone and you need the numbers under 200 pog per milliliter is plainly low. 200 to 300 is gray and official guidance in the United States says that if your level lands anywhere between 100 and 50 and 399, you should not be sent home on that number because a substantial share of the people in that range are functionally deficient and the level alone cannot tell you which. The way you find out is to measure what the vitamin does, not how much of it is floating about. It runs two enzymes and when it's missing, the raw material for those two enzymes backs up in the blood like a queue behind a closed till. One of those backed up chemicals is methylalonic acid. When the vitamin is short, it
9:59 climbs. Above 0.271 microles per liter, that counts as suggestive. The other is homocyine and above 15 micro moles per liter it points the same way. Remember three letters because this is the difference between a normal result and an answer. MMA methile melonic acid. In the hospitals that deal with the nerve damage from this MMA is the preferred marker because it's more specific than homoyine and less fussy about how the sample is handled. Now let me undercut my own case because you deserve the honest version. You have heard from people in my line of work that up to 40% of older adults are deficient. That number is inflated. It comes from studies that move the cutoff to 350, a line most laboratories don't use. On the
10:46 ordinary cutoff in American adults over 60, the honest figure is close to 4%. What is true is that the rate is far higher in the specific groups we've been talking about. The long-term metformin people, the long-term acid blocker people, the people with a thin stomach lining. 4% of everybody is not the same as 20% of you. But keep the warehouse in mind. 4% is also the number of people who are low by the yard's own measure. The people losing product inside the building never show up in it at all. A man in his 60s on metformin for his sugar and omrazole for his reflux, eating sensibly, feeling fine with a normal blood test on file. He isn't being careless. He's doing everything asked of him. And every year the amount inside his nerves drifts a little lower.
11:33 And every year the test he's given measures the yard instead of the shelves. Here's what that looks like when nobody watches it for a decade. It starts as a sensation you would never mention to another human being. Your feet not quite reporting the floor. A sock line still dented into your ankle at 9 at night. Shoes that fit beautifully at 8 in the morning. And by 4 in the afternoon, you're loosening the laces. Then the toe you can't feel testing the bath water. So you use your hand now and you never notice starting to. Then the third fall, the one that isn't on ice, isn't on a step, isn't on anything you can explain. Just an ankle folding in a hallway you have walked down for 30 years. And the one I'd bet most of you have felt and never once connected to a vitamin. Standing up in
12:19 the dark in a room you know perfectly well and the floor feeling further away than it looks. You put a hand out. You blame the lighting. There's a reason it happens at night. Your feet are giving your brain less information than they used to. None of that is dramatic. That's the problem. There's no moment to point at. There's only a slow narrowing of where you feel safe walking. Everything so far sounds like a supply problem. As if the answer is to eat more of something. It isn't. This is not a supply problem. It's a drain. And a drain doesn't care what you put in. That contradiction changes everything I've told you so far. Two men, both 55. One eats two eggs and a cup of milk at breakfast every day of his life, and never touches a supplement. The other lives on toast and tea and takes
13:05 nothing. Identical tables. What separates them isn't the breakfast. What separates them is whether anything has quietly been drawing the level down for the last 8 years. The body holds a reserve of this vitamin. 1 to 5 mg, enough to run for years on nothing. So the man living on his reserve can look perfectly, unremarkably normal for a very long time and then the reserve is gone and the whole bill arrives at once. Now look at where the bill arrives first. Not the heart, not the liver, the longest wires in your body in order of length. The toes, then the feet, then the ankle, then the hands. It's a distance problem. The nerve supplying your big toe runs over a meter. one meter with no junctions from the base of your spine to the end of your foot. Feed
13:51 a meter of nerve from a single cell body and the farthest end is the end that suffers first. That's why the tingling starts in the toes and not the thigh. And why a man can stub a toe he can't feel and find the bruise days later. And it goes further than the nerves. When the vitamin runs out in the long tracts inside the spinal cord, you get a specific injury with a specific name. Subacute combined degeneration of the spinal cord. Two columns of the cord are affected. The ones carrying vibration and position and the ones keeping your legs from collapsing. People with it can have feet that don't feel the floor and legs that seem to be working both at once. It is the version of this that ends in a wheelchair. And it is still in the countries with the best medicine on earth routinely missed on the first
14:36 visit. Which brings me to the thing that worries me most. The vitamin has a weak spot and there's a common gas that hits it directly. Nitrous oxide. Laughing gas. The stuff the dentist offers for a filling. The stuff in the drip for a colonoscopy. Some of the first reports of this nerve damage came from 14 dental practitioners breathing it in their own surgeries. And the mechanism turned out to be brutally simple. Nitrous oxide oxidizes the cobalt atom at the center of the vitamin and switches it off. Rust on the pin that holds a lock together. The vitamin is still there. It just doesn't turn. And here is the arithmetic that should make you pick up the phone. In a person with an ample reserve, a single afternoon of that gas does nothing. In a person already running low, the metformin person, the omerazole
15:24 person, the person whose level sits at 280 with a tick beside it, one exposure can trigger symptoms 2 to 6 weeks later. Numbness, unsteadiness, a walk that has become a stagger. One hit is enough once the tank is empty. So, I'll ask the question, the first half didn't raise. If one afternoon of gas can tip a nerve over the edge, how much of the damage does a nerve take back once it's finally given what it needs? And how long does it wait before it stops waiting? That answer is in the last few minutes. The number that should decide what you do this week before it. The third thing and the one objection I know you're holding. First, think back to the two numbers you counted at the start, the servings of animal food and the bottles on repeat, and do it again. Now, most of you will
16:10 find the same two numbers you found before, which is the point. Nothing in the last 12 minutes changed your diet. If your serving count was low, then it's low now. The third thing standing between the vitamin and your nerves is the clock inside the nerve. To explain it, I'm going to leave the body and go into cable engineering. Every nerve in your body is a wire. The signal travels down the inside of it, the axon, a thread about a hundth of a millimeter across the live metal. Wrapped around that thread, layer upon layer, is a fatty coating called the myelin sheath. Myelin is insulation. It does two jobs. It stops the signal leaking sideways into the tissue, and it makes the signal travel in leaps instead of trickles, jumping from gap to gap. Strip the insulation off a cable, and you don't
16:57 lose the current. You lose speed and accuracy, and you pick up noise from everything nearby. The vitamin is one of the raw materials for that insulation. And when it's missing, the body doesn't stop building myelin. That's the cruel part. It builds it out of the wrong fat. A chemical cube backs up. The raw material gets rerouted. And what gets laid down is a sheath that's brittle, chemically wrong, and slower at passing the signal. The wire is still intact. The insulation is counterfeit. Now, the good news, and the reason I started a 100 years ago in that Boston ward, counterfeit insulation can be replaced. The body will strip a bad sheath and rebuild it. But rebuilding a meter of insulation on one axon is not a repair you can rush. It happens over weeks and months, not days. And it only happens if
17:45 the raw material is there. Which brings us to the clock. And here I have to be honest in a way most videos on this subject will not be. If the injury is confined to the insulation, it comes back. Most people treated early recover most or all of what they lost and the cases are unambiguous on this. But if the deficiency runs long enough, the damage stops being a coding problem and becomes a wire problem. The axon itself begins to die. And there is no repair crew for a dead axon. Not at 65, not at any age. Once that has happened, the best on offer is to stop the progression and keep the rest. Two men then, same numb toes, same age. One asks for the test in the spring. One decides it's just age and asks two years later. They
18:31 are not the same patient and they will not have the same life and the only thing separating them is a date. The window is real. It isn't infinite and it doesn't announce when it closes. Now the objection. I know a lot of you are sitting there with it. My level came back normal. I've been tested. If the number is fine, why am I listening to 20 minutes of this? Fair. And for a great many people, that result is the correct result and there is nothing further to do. But a normal level rules out exactly one thing, too little cargo in the loading yard. It does not rule out cargo failing to leave the yard. That's why the test that matters in the gray zone is the other one, the three letters. And one more honest caveat, MMA climbs for other reasons, too. It runs higher in
19:17 people with reduced kidney function, and it drifts up with age on its own. So, the answer is never one number on one page. It's a conversation and you now have the vocabulary to start it. One practical caution for that conversation. If you take a B complex and if you've been worried about your nerves, you may well have been sold. One, turn the label round and find vitamin B6 pyodoxine. Many of these products carry 50 to 100 milligs. Your daily requirement is about 1 and a2 mg 30 to 60 times and B6 at those doses month after month is itself a documented cause of numbness and tingling in exactly the same feet. Regulators in Australia reviewed the cases and found reports at less than 50 mg a day. So the pill bought to protect
20:04 your nerves may contain something that mimics the problem and the two sensations are almost impossible to tell apart. If your feet are already numb, that label is worth 30 seconds. So, the tap, the yard, and the clock, all three now open. The answer's name arrives now, and I'm going to say it in one sentence because it was never meant to be a secret. The vitamin is B12. Vitamin B12 cobalamin. There's a reason it hides, and the reason is almost funny. It's the only one of the vitamins your body stockpiles. It holds 1 to 5 milligrams a thousand times a day's requirement and it will run for years on that reserve which means it fails silently. Nothing like any deficiency you have heard about. No dramatic collapse, numb toes,
20:51 an unsteady hallway, and a doctor looking at a tick on a page. It also hides because the market buried it. Walk into any pharmacy and you'll find it sold as a pickme up, the energy vitamin on a shelf next to the jins singh at doses that wouldn't move a marker in a mouse. And I'll give you the honest limit of that story right here. Giving B12 to somebody who already has enough does nothing at all for energy or endurance. That claim is marketing. Being low for 8 years is a completely different thing. And that's the case nobody screens for. And it hides behind the advice you'd get if you asked. Eat more meat. Sensible on the face of it, and it addresses a problem most people with this don't have. Remember the tap. If the plug is out, the 12th stake is
21:36 the same as the first. Here is the most specific instruction you will hear from me. Repeat it across a room. 1,000 micrograms a day. 1,000, a full milligram, 400 times the daily requirement, which sounds absurd until you know how little arrives. Swallow a tablet that size and roughly one and a half% gets in. About 15 micrograms, six times the requirement, delivered by a root that doesn't need your stomach acid and doesn't need the transport protein at all. It crosses the gut wall on its own. That is why the acid blocker story and the tablet story don't cancel each other out and why a big enough swallowed dose works in people whose stomachs no longer cooperate. Which form? Whatever is cheapest and available. The plain form cyanocobalamin is what the trials
22:24 used and the body converts it. Sublingual drops, sprays. There is no good evidence that any of it beats a tablet you swallow. There's no upper limit for B12. Nobody has managed to poison themselves with it. A few dollars a month and the only real risk is that you buy it and don't take it. And now the honest limit because I promised you one. Highdose swallowing has been compared head-to-head with injections in people with this deficiency. And in the trials that exist, it performed about as well. But those trials were small. 153 people in total across three studies and the reviewers who assessed them in a 2018 Cochran review graded the evidence low quality. It's what we have. It's consistent and I would still want to be inside a doctor's care if my feet were
23:10 numb rather than managing it alone. One last thing that is not the answer. Folic acid will fix the blood count and leave the nerves exactly where they are. If somebody is chasing an abnormal panel on your behalf, that's the trap to know about. So, four things in order. One, tonight, look at your prescriptions and find out which have been on repeat more than 2 years. Specifically, metformin and specifically any acid blocker. Write the names down. Don't stop anything yourself. A heartburn drug can be hiding a problem that needs treating. Just have the names. two. At your next appointment, ask for two numbers, not one. Your level and your methylalonic acid. Say the second one out loud, methylalonic acid, because the first is
23:55 already on the standard panel and the second is the one that gets left off. Three, if your level comes back anywhere between 150 and 400, don't accept a tick as an answer. That is the gray zone, and that is where the second number earns its place. Four, if it turns out you are low, ask about a thousand micrograms a day of the plain tablet and ask what to expect over the next three months because the marker moves in weeks and the feeling in your feet moves in months. Then have it rechecked. And a fifth thing, and it isn't for you. Somebody you know had a colonoscopy last year or a crown or a hip. If they are carrying either of those two prescriptions, that afternoon of gas is worth a mention. two minutes of your time. So, tomorrow morning 20 7, the
24:43 kettle going, the bottle on the counter with a vitamin in it that has been sitting there patient the whole time. Take it, but take the bottle to the appointment as well. Put it on the desk and ask the question out loud. Three things were standing between that tablet and the nerves in your feet. Two of them were in your house the whole time. Neither of them was the tablet. Your nervous system doesn't need more faith. It needs one blood test and one number with three letters in it. If you want to help me with something, leave me. Three things below. Your age, your country, and your two counts from the beginning. The animal foods from yesterday, and the bottles on repeat. I read those and they tell me more about this than any study I could site.
