Have You Heard About The Vitamin D Winter? - Why It Matters to You - Dr Gill

Hello and welcome back to the channel. My name is Dr James Gill and you've joined me for another clinical skills adjacent video. You see, a lot of the time we'll hear people talking about vitamin D and I'm frequently asked to check vitamin D levels at work but I thought it might be worthwhile to do a bit of a supplementation video about vitamin D. You see, vitamin D is not actually a vitamin. Some slash most slash a lot of the time. Let me explain. How can a chemical change whether it is or isn't something? You see, the definition of a vitamin is an organic compound that is required for an organism to live but crucially cannot be synthesized by that organism. To that end, you'd imagine the very first vitamin would be vitamin A but actually that wasn't the case. Vitamin B1 was discovered in 1926 although the concept of a vital amine was identified or at least coined in 1912. Vitamin D3 or cholecalciferol, the sunshine vitamin as a lot of people will describe it, is made in the skin. We know that so surely that means it's not a vitamin by that very definition unless that is you live in part of the world where at certain times of the year the sunlight is not strong enough to enable vitamin D production in which case the body can't produce the cholecalciferol and you're required to consume it through your diet i.e. it's a vitamin. So where in the world would you have to be that cholecalciferol becomes a vitamin? Surely it's got to be something like the arctic or something like that? Well actually it's a little bit more complex than just whereabouts you live as your skin type will also affect the vitamin D generation. I mean nobody's going to be surprised to find that people of Scandinavian origin and other origins around that latitude have the ability to produce higher amounts of vitamin D for a set unit of sun exposure than other skin types but putting the complicating factor of skin color aside the UK's national institute for clinical excellence states latitudes above 37 degrees sunlight containing UVB radiation is limited i.e. over the winter your vitamin D level in production in the skin is going to be negligible. Now despite having been a scout in my younger days I was a little surprised to find that 37 degrees north is actually kind of level with the Mediterranean Sea. I'd naively thought it was going to be somewhere like Scotland or above. Basically between October and March above 37 degrees north but certainly for the entirety of the UK the sun doesn't rise high enough in the sky for us to produce enough vitamin D from those UV rays. Now why does it matter as I said the sun doesn't rise high enough in the sky? Thank you for watching this far in the vitamin D video. I'd like to give you something and I do mean that literally. I've been trying to think about ways that I could potentially monetize the channel and honestly most of them I don't like. So what I've decided to do rather than charge students for things which I'm just going to give it away free. So the script that I've written for the this vitamin D video because it does help me to write out what I'm going to say sometimes before I do so you can have it and I'm going to do that with all future sort of long form videos like this. I'm going to have the script and I'm going to let you guys download it and to try and help myself with that I've actually partnered up with a company called New PDF and they're going to help me to take the scripts that I have for you and convert them into PDFs that you can keep, annotate, write on or whatever and I think that's a way that works for me to give to you guys and at same time be able to monetize the channel. In terms of using New PDF I would say download it. There's a link in the description where you can download it and have it as a way of storing the PDFs that I'm going to give you and you can annotate, write notes across those documents and use them hopefully as revision tools and crucially from my perspective although I'm confident in the things that I've written I always think it's worthwhile to double check things there is the option to use the AI part of the software to actually check have I made any glaring errors this I need to myself review from you know alternative sources my textbooks and things before I send those out to you so please have a look at New PDF you can see the link in the description and also please click on the link to download the vitamin D script hopefully it'll be useful for yourself and if so please put any comments and things about how you found the script and extra things that you'd like us to build into them over time so this is the first one that I've done so basically it's straightforward here's my cognitive vitamin D vomit if you will however depending on what those feedback comments are we might add more you know references potentially put in questions and things like that and answers as well and we'll hopefully build more interactive PDFs using the New PDF system as well so back to the regular video but please have a look at these now why does it matter as I said the sun doesn't rise high enough in the sky see over winter when the sun stays low near the horizon pulling that more GCSE geography we're actually that sunlight is passing through an awful lot of ozone and general atmosphere i.e we get a lot of that vitamin D absorbed by that interfacing therefore the sunlight that actually hits our skin is insufficient to generate that vitamin D also the fact that we're only exposing our face and hands means that almost nothing is going to be produced at that time so we kind of have a vitamin D winter as such the current recommendations are that everybody in UK should take approximately 400 international units of vitamin D daily unless there are reasons for extra caution e.g patients with hypercalcemia that being raised levels of calcium chronic kidney disease renal stones or potentially certain medications like digoxin they should avoid supplementary vitamin D unless told explicitly to by their doctor the point about hypercalcemia raised calcium is particularly important as vitamin D will increase the absorption of calcium from the intestine making an already raised calcium level even higher then when run into medical risks of hypercalcemia which at medical school were taught the eight memoir of stones bones moans and psychic groans these highlight that hypercalcemia can cause renal stones bone pain as calcium is often being pulled from the bones abdominal groans because of constipation and abdominal pain potentially nausea and vomiting and also pancreatitis and finally there's psychic groans because we can get depression memory loss fatigue and impaired concentration all can happen with raised levels of calcium giving us those psychic groans in the eight memoir it's also worthwhile highlighting we can also get an irregular heartbeat but for some reason that doesn't fit into their eight memoir now we suggest that people should perhaps have no more than 400 international units 400 iu that might seem a little bit low but there is a reason vitamin d can also be toxic so it's why we say most people can take safely 400 international units and certainly nobody should be taking more than 4 000 international units daily unless they've been advised to by their doctor because of toxic levels of vitamin d so why might we suggest that somebody does take more than 500 international units of vitamin d firstly if they test efficient but we'll come to that later you see end stage renal disease might need vitamin d supplementation as the kidneys produce the one two five dihydroxy vitamin d if you've got renal disease then you're not producing that precursor that the sun is going to be able to convert to the vitamin d3 in the skin liver disease can also impair vitamin d production and low-fat diets can reduce vitamin d intake certain medications those that reduce fat absorption like allostat or cholestyramine can reduce your vitamin d absorption because vitamin d is one of the dake d a k e vitamins that are all fat soluble steroids laxatives can also reduce vitamin d absorption and some anticonvulsants can actually increase vitamin d breakdown so going to push lower we mentioned the possibility of being found to have low vitamin d levels but even at that point there is a debate about the levels of deficiency versus insufficiency firstly when you're dealing with things like that you need to make sure that your vitamin d levels that you're reading are the same so often it's discussed in nanomoles per liter and nanograms per milliliter and actually those two values can look quite similar at a simple glance in the uk we use nanomoles per liter but even so there's going to be a debate as to where our actual thresholds are one source will say 25 nanomoles per liter is deficient conversely you'll find another one that says that 30 to 70 nanomoles per liter is insufficient whereas a third one is going to tell you that 15 nanomoles per liter is the threshold for deficiency what possible reason for this perhaps is that not all vitamin d tests are created equal there can be up to a 40 percent variability in the outcome of some tests so when we're doing testing medically we need to make sure we're using the gold standard that being a liquid chromatograph test ie if you're buying your test in the shops i would put some considerable question mark on the data that's providing it so so given there are confounding variables as well as looking at the tests you're using you need to look at your source material the royal society for osteoporosis in 2018 stated that the 15 nanomoles per liter is sufficient for most people as ever there is a raft of conflicting data here there some studies will say that 75 to 125 nanomoles per liter range is sufficient and in fact might be protected for certain types of cancer conversely the food nutrition board in america will say that between 70 and 120 nanomoles per liter of vitamin d has been associated with an increase in all causes of mortality so you're really changing from one hand to the other so i go back to that comment from the royal osteoporosis society that sufficiency should be about 50 nanomoles per liter in most people in reality what we can probably infer is that 50 to 75 nanomoles is probably the sweet spot and the greater levels particularly when we're getting the 200 nanomole per liter level are going to be considered to be toxic now that does bring me back to the idea of taking 400 international units daily over winter now given that we should ideally be using sunscreen to protect our skin from sun damage throughout the rest of the year there is guidance from the nhs on taking 400 international units of vitamin d daily across the year as would be appropriate for those who are using sunscreen in sunny weather the issue with thresholds is they feed into problematic research on vitamin d there are studies looking at vitamin d with regard to mood modulation but as you'll see although we do know that vitamin d has a relationship with producing serotonin it's far from clear-cut in terms of what does what when you look at the data a measure analysis of randomized controlled trials which for clarification is probably the silver medal when it comes to the best form of research that suggested that when patients were supplemented with vitamin d there was seen to be a moderate improvement in depression however when we looked at non-patients there was no change in mood or depression type features but not symptoms in non-patients when they had vitamin d supplementation conversely other studies have found no benefit in depression supplementation in patients so we've got conflicts there it's probable that there is a benefit from vitamin d and food even possibly sleep however people will often joke there's a big difference between shop-bought serotonin and natural sources we may see a similar thing with vitamin d taking a small 400 international unit of vitamin d supplement over the winter period is likely to keep our levels within healthy ranges which might be associated with positive health benefits but come summer being out in the natural sunshine the warmth the positivity of seeing the light coming through the trees or bouncing off the windows at you all of those are going to be associated with positive health benefits and positive mental health changes so it's going to be very difficult to separate those changes being as a result of being out in the sun and the positivity that causes us versus the increase in vitamin d that we will see from that being out in the sun as for me under the gray skies of the uk i'm going to be keeping taking my vitamin d supplement but i'm also going to head outside as soon as i can when the weather finally starts to shed the gloomy gray of winter so i hope that's been a useful overview for you on how vitamin d levels are tested and the cautions about shop-bought vitamin d testing versus those that your doctor is going to be able to do and understanding whether or not it might be worthwhile speaking to your doctor about supplementation or testing if you are concerned that you might have an issue there with that in mind take care and i'll see you in the next one cheerio