Sorry guys, we're not talking about getting laid. We're talking about vitamin D. That essential nutrient with an identity complex? Is it a vitamin? Is it a hormone? Does it really matter? ¯\_(ツ)_/¯
All you need to know is how you get enough of it this winter.
(Neither Aubergines nor Emojis are a good source of Vitamin D - Photo Credit)
So, what's the scoop?
Earlier this year the Scientific Advisory Committee on Nutrition published a review of pretty much ALL THE SCIENCE - give or take - on vitamin D. I read the report so you don't have to. Basically SACN decided we need to up our game - doubling the recommended daily intake from 5 to 10 µg/day. This is a big deal because we all basically already have a D-ficiency - yeah I went there. Ok, so, an average adult in the UK has an intake equivalent to 2.8 µg per day - that's super low and not even enough to meet the old recs, nevermind the new ones.
If this were a test we'd all get a D. Ok I'll stop now.
Cool, so just tell me where to get it and we'll be done here.
Hold up, not so fast. Vitamin D isn't like a regular nutrient that you just get from food. That would be too easy. Vitamin D is kinda freaky - but in a good way. It's one of the few nutrients that your bod can actually make by itself - pretty badass.
Annoyingly for such a cool nutrient, some asshole decided to give it the twee as hell name, the 'Sunshine vitamin' because people think it's made by the sun in your skin. That's only half the story - basically the action of sunlight on our skin converts cholesterol in our skin cells into an intermediate compound. This intermediate circulates to the liver where it gets converted again. Then, finally in the kidneys it gets converted to the D. Cool story brah. The point is, we need sunlight to help us make the vitamin D - but let's give the liver and kidneys some credit too.
TL;DR: No sunshine - No D.
Here's the problem - The UK is way the hell up north, and as I'm sure you're acutely aware of, we're not exposed to the sun between October and April. In other words we're not getting any D action in the Autumn/Winter months.
Even in the summer - pollution, darker skin pigmentation, and how much we cover up can all affect how much D we get.
Skin synthesis is the main source of vitamin D for most people, but we can get some from our diet.
There aren't that many great sources of vitamin D though; SACN point out that egg yolks are a pretty good source containing 12.6 µg/100g - but it's not a great idea to chug 100g of egg yolk erryday. To translate this into something a bit more meaningful - 1 large egg (~60g) (i.e. yolk + white) only has 1 µg. Around 1/10th of the recommended amount you need for the day. Pretty sucky.
Oily fish is another rich source - a 100g portion of salmon has around 13 µg of vitamin D (D2+D3). BUT again, no one is smashing 100g of salmon everyday (and if you are then you better check yourself - the NHS recommends no more than 4 portions of oily fish/week because pollutants).
Animal products like meat, fat, liver and kidney (so much eww in this sentence) also contain vitamin D (0.1-1.5 μg/100 g) but maybe don't eat a kilo of meat per day?
Most margarine in the UK is fortified with vitamin D - again though, you shouldn't be eating a shit load of marg, but you probably already knew that.
Wild mushrooms are a pretty good source of vitamin D, but not the ones you buy in the shops - those guys are grown in the dark and like people, plants need UVB to make the D. UVB exposed 'shrooms might go a little way towards your daily rec, but the type of vitamin D they make (D2) isn't as biologically active as the stuff you make yourself or get from animal foods (which is D3).
So, dietary sources can be pretty inconsistent and unreliable ways to get the D and SACN concedes that it's difficult to get enough D in your diet alone. So, what should we do?
In part 2 of my blog - I'll tell you how to GUARENTEE you get the D, I'll talk about safe ways to get the D, and all the benefits of getting it on the regular - make sure you sign up to my newsletter here to get it delivered to your inbox. And while you're there, have a listen to my latest podcast episode where I discuss supplementation, the microbiome plus Chrononutrition.