Could Short, Dark Days Be Harming your Health? Discover Why, and How to Fix It!
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With the clocks going back last weekend, there’s been a stark difference in daylight hours. I don’t know about you, but it’s around about this time of year when all I want to do is cosy up and hibernate (if this sounds like you, you’ll love this article, by the way!).
The winter blues aren’t just about missing the feel of sunshine, or being fed up of the cold and the rain, though. There are very real physiological changes that happen - or can happen - in our bodies, if we don’t ensure we’re taking the right steps to look after them.
From your immune system to your mental health, there’s one key ingredient that goes missing on cold, dark days: ‘the sunshine vitamin’…AKA Vitamin D.
If you want to boost your immune system, mood, AND keep your bones healthy - amongst other benefits - vitamin D is essential year-round.
In this article, you’re going to learn exactly why we need vitamin D, whether to supplement with it (download our FREE QUIZ to find out!) and exactly HOW to supplement if you want to avoid throwing your money down the drain…
Ready? Let’s dive in!
What is Vitamin D?
Vitamin D - referred to as ‘the sunshine vitamin’, is a fat-soluble vitamin essential for maintaining the health of our bones, teeth, and plays an important role in our immune systems . It's unique because our bodies can produce it when our skin is exposed to sunlight, which is why it’s often called "the sunshine vitamin."
Vitamin D has several crucial roles in the body - meaning a vitamin D deficiency can lead to the following:
Poor Bone Health: Vitamin D helps the body absorb calcium and phosphorus, minerals that are essential for strong bones and teeth. Without enough Vitamin D, bones can become thin, brittle, or misshapen.
Weak Immune System: Vitamin D helps modulate the immune response, which is important for protecting against infections and diseases. Without enough, you may be more susceptible to illness.
Lower Mood: Some research links adequate Vitamin D levels with mood regulation, possibly showing a link between vitamin D deficiency and depression.
From this, you can see that it’s a pretty important vitamin… right? And yet as we enter the darker months, it becomes harder and harder to get an adequate amount of vitamin D - so where do we get it from?
Sources of Vitamin D
Vitamin D can be obtained from three main sources: sunlight, diet, and supplements.
Sunlight is a primary source of vitamin D; when skin is exposed to UVB rays, the body produces Vitamin D naturally. This amount synthesised will vary based on factors like geographic location, skin pigmentation, time of day and season. It is recommended that you get anywhere between 5-30 minutes of sunlight exposure daily, particularly between the hours of 10am and 4pm, prioritising exposure to the face, arms and legs (without sunscreen). It should also be noted that UBV - the rays responsible for vitamin D synthesis - cannot penetrate through glass so sitting in the sunshine by the window, reading a book, will unfortunately, not help you produce vitamin D but it might help lift your mood.
But what about when you live somewhere where, for around 6 months of the year, sunlight is minimal, and when it is sunny you’re usually wrapped up warm and getting very little sun exposure on your skin? Or if you spend very little time outside regardless of the time of year?
This is where diet comes in. Certain foods that are high in vitamin D include:
fatty fish (like salmon, mackerel, and sardines)
liver
egg yolks
some milk, orange juice, and cereal products are fortified with added vitamin D to help combat deficiencies
‘So if I eat these foods regularly, I’ll be fine, right?’
Not necessarily.
Obtaining the recommended daily intake of vitamin D from diet alone is generally considered difficult, and will be made even more challenging if you have any dietary restrictions, because vitamin D actually comes in two main forms. Without boring you with the biochemistry of that (I’ll make it brief, I promise):
Vitamin D2 (Ergocalciferol) is primarily found in plant-based sources like mushrooms (yum!) and fortified foods
Vitamin D3 (Cholecalciferol) is the form of the vitamin produced by our skin in response to sunlight and found in animal-based sources such as fatty fish (eg. salmon), liver, and egg yolks
The latter - from sunlight and animal sources - is more potent and effective at raising blood levels of Vitamin D in the body, meaning that if you follow a plant-based diet, you’re more susceptible to deficiencies.
So, if sunlight and diet aren’t enough, that leaves us with supplementation. In this next section, we’ll cover exactly how much vitamin D you need, and whether you should consider a vitamin D supplement - don’t miss our handy FREE quiz to help you out!
How Much Vitamin D Do I Need?
The recommended daily amount is 10 micrograms - also written as mcg or μg. Vitamin D dose is also often expressed as ‘International Units’ or ‘IU’. 1 microgram = 40IU, so the recommended daily amount in IU is 400 IU.
Download our FREE QUIZ to determine if you’re at risk of vitamin D deficiency.
In the UK, the NHS recommend all adults take a daily 10μg or 400IU vitamin D supplement throughout the autumn and winter months, and for adults with other risk factors for deficiency to consider taking a supplement throughout the entire year, too.
Some groups of people with a higher risk of vitamin D deficiency include:
Older adults
People with dark skin
People with limited fat absorption
People with obesity
Those who have undergone gastric bypass surgery
+ MORE - take our FREE quiz to check for your risk factors!
Common questions around vitamin D supplements…
“Is there anyone who shouldn’t follow these recommendations?”
Yes. If you fall into the following categories:
You’re already taking a vitamin D supplement or medication that contains vitamin D
You’re under 18
If you’re under the care of a renal, endocrinology, or cancer specialist, you should always check before taking any supplements
If you have certain medical conditions, such as kidney stones (past or present), hyperparathyroidism, cancer, severe kidney disease, sarcoidosis or high vitamin D levels.
We always recommend checking with your doctor if you’re unsure, especially if you have any medical conditions or are taking other medications or supplements.
"Can I get too much Vitamin D from my diet or supplements?"
Yes. Yes you can. Excess amounts of vitamin D are toxic. In extreme cases, vitamin D toxicity will result in kidney failure, calcification of soft tissues throughout the body (including in coronary vessels and heart valves), cardiac arrhythmias (a heart beat that doesn’t fit the standard rhythm), and even death. This might sound scary, but the recommended dose of 10μg or 400IU is just 10% of the 100μg or 4000IU that’s generally considered safe. Basically, don’t take 10 times the recommended dose, and you’ll be fine.
“Can I get too much vitamin D from sunlight?”
You cannot. At least not from natural sunlight. The processes that your body performs to produce vitamin D will often produce various non-vitamin D forms and as such limit the amount of vitamin D you can synthesise from the sun. That said, if you needed any more reasons to avoid using a tanning bed (UV exposure is the most preventable cause of skin cancer, and tanning beds drastically increase your risk!), using one can also elevate serum (blood) vitamin D levels to above normal, which we don’t want!
“Aren’t supplements bad for me?”
Supplements from reputable brands, taken for the right purposes and in the right doses are considered safe. Generally, the dangers associated with supplements include
taking a supplement that isn’t appropriate for you, such as if you have certain health conditions, or are taking certain medications
taking supplements not as recommended - e.g. in excessive quantities
using supplements as an alternative for a healthy diet, not in conjunction with
contamination with other substances, which is particularly important if you’re an athlete subject to anti-doping measures (drugs testing).
If you’re unsure about taking supplements, we always recommend checking with your doctor that they’re safe for you. We would never recommend supplements as an alternative to a healthy diet - they are simply an addition.
If you’re concerned about contamination, or if you’re an athlete, opt for a supplement that’s batch tested and has the Informed Sport logo. You can find up-to-date information about which supplements are Informed Sport certified, as well as more about the program, here.
Ready to combat the dark days?
If you’re struggling with the darker nights and colder weather - even with healthy vitamin D levels - why not check out our recent article, beating the winter blues? It contains some great tips about how to tackle your winter months, including establishing a routine that gets you out in what limited sun we do have, as well as keeping up healthy nutrition habits (cozy meal prep, anyone?)
Remember: Vitamin D isn't just another nutrient; it’s a cornerstone for our bone strength, immune defences, and mental health. And while the gloomy months may make it harder to soak up those vital sun rays, a thoughtful approach—whether through dietary adjustments, safe sun exposure, or a well-chosen supplement—can keep your Vitamin D levels right where they need to be.
Questions? Get in touch HERE and I’ll get back to you ASAP!
P.S. If you’re interested in vitamin D, you might also like our recent article all about creatine supplements! It covers everything you need to know about the most researched workout supplement out there - including common myths to look out for! We’d love to hear what you think!
Oh, and don’t forget to check out our FREE guides here and workout programmes here
