Intro to Vitamin D
Vitamin D is not your standard vitamin. Sneakily enough, it is actually a hormone that functions throughout your whole body performing a variety of important tasks that are essential for optimal health.
It is also a fat-soluble vitamin which means that it dissolves (and is often found) in various fats and oils.
There are two main forms that are found in our bodies:
Vitamin D3 – also known as Cholecalciferol
Vitamin D2 – also known as Ergocalciferol
There are studies that suggest that Vitamin D3 is almost twice as effective at raising blood levels of Vitamin D as the D2 variety. D3 is also the natural type of Vitamin D that the body produces when it is exposed to sunlight – by far the best way of obtaining your daily dosage of Vitamin D. So this type is what I will be referring to here on out.
Why I’m deficient and you might be too
By the far the most efficient and potent method of getting your necessary daily Vitamin D amounts is through sunlight exposure. Your skin is covered in receptors waiting for the necessary sunlight in order to start producing the vital vitamin. The ultraviolet B (UVB) rays from the sun provide the energy needed for the reaction to occur. The NHS states that you are at a greater risk of deficiency if you:
- aren’t often outdoors – for example, if you’re frail, housebound, or just don’t like going outside
- are in an institution like a care home
- usually wear clothes that cover up most of your skin when outdoors
Also, people with dark skin from African, African-Caribbean and South Asian backgrounds may also not get enough vitamin D from sunlight.
If you live in a place that is generally sunny all year round and live fairly close to the equator, the likelihood is that you are not deficient in Vitamin D. Not only am I jealous of your geographical position, but this post is probably irrelevant to you. Unless of course, you are educating yourself to look after your frozen friends in the north.
If you are like me, one of the frozen friends in the north, or you match one of the other criteria on the list, then you may be experiencing some degree of Vitamin D deficiency. Not only is winter characterised by grey clouds and not a lot of sunlight, but even the sunlight that we do receive tends to be too weak to make any meaningful amounts of Vitamin D in the body. The essential UVB rays simply don’t have the energy to make the desired reaction occur.
Also, whether it is winter or summer, if you try to be sneaky and open your curtains and bask in the glorious sunlight from behind the glass, I hate to burst your Vitamin D-boosting bubble. For the very same reason that you can’t get a suntan from behind glass, you also can’t get any Vitamin D from the sun this way. The ultraviolet rays can’t penetrate glass, so you are going to need to step outside or stick your head out of the window to get the actual benefits.
Symptoms and long-term effects of deficiency
All joking aside, there are quite a few symptoms of Vitamin D deficiency and some of them can be quite serious.
The problem is that the symptoms can often be subtle and aren’t usually recognised as being as a result of Vitamin D deficiency.
Healthline outlines 8 possible symptoms and has many studies to back all of the claims up. If you aren’t that interested in the science or explanations, then simply skim read the bold points to get all you need to know.
Here is a brief summary of the main 5:
- Getting sick or infected often – Vitamin D helps in keeping your immune system strong to fight off illness. Winter time is known as flu season but not many people know that this is largely down to our bodies being Vitamin D deficient due to a lack of significant sun exposure. Research has clearly shown that vitamin D deficiency is part of the seasonal nature of cold and flu outbreaks – less sunlight means less vitamin D, which leads to lower immunity and more illness.
- Fatigue and tiredness – An observational study in female nurses found a strong connection between low vitamin D levels and self-reported fatigue. What’s more, the researchers found that 89% of the nurses were deficient in the vitamin.
- Bone and back pain – Vitamin D plays a vital role in the body’s process of absorbing calcium. In particular the absorption of calcium into the bones. Without Vitamin D, bones and joints are left weakened and severe deficiency causes the disease called rickets.
- Depression – Depression is associated with low vitamin D levels and some studies have found that supplementing improves mood. Some controlled studies have shown that giving vitamin D to people who are deficient helps improve depression, including seasonal depression that occurs during the colder months. This is also something that relates to something that I briefly touched upon in a previous blog post about better sleep. In particular, the science behind the ‘winter blues’ and how Vitamin D can possibly help to combat that.
- Muscle pain – There have been links made between muscle pain and Vitamin D deficiency. This is because the vitamin D receptor is present in nerve cells called nociceptors, which sense pain and one study in rats showed that a deficiency led to pain and sensitivity due to stimulation of nociceptors in muscles. Furthermore, in another study, 71% of people with chronic pain were found to be deficient. This doesn’t necessarily suggest cause and effect, but it is still very suggestive nonetheless.
With regard to the longer term effects of chronically low levels of Vitamin D, one study indicates that people with low vitamin D levels have a much greater risk of heart disease, diabetes (both type 1 and type 2), cancer, dementia and autoimmune diseases like multiple sclerosis, to name just a few. Vitamin D deficiency has also been linked with osteoporosis, reduced mineral density and increased risk of falls and fractures in the elderly.
Natural Food Sources with Vitamin D
I hope that the previous section didn’t scare you too much, but it is important to know these things in order to keep your human machine well-oiled and functioning at its best, especially during the winter where Vitamin D is hard to come by.
There are a number of foods that contain good levels of Vitamin D, but you would need to eat them every day in order to reach the desired daily dose of Vitamin D (which we will cover in the next section). Even still, they are certainly worth trying to incorporate into your diet over the reduced-sunshine months. They include fatty fish such as salmon, mackerel, trout, tuna and swordfish. Fortified dairy products also tend to contain good levels of Vitamin D and so does egg yolk. If you can stomach it, liver is probably your best source of Vitamin D from foods and that includes Cod Liver Oil.
Dosages and recommendations
I am not a doctor so before prescribing yourself with Vitamin D supplementation, I highly encourage you to do some research on any areas of concern for yourself and speak to a medical professional if necessary.
For adults and children over 5 years old, the NHS says this:
During the autumn and winter, you need to get vitamin D from your diet because the sun isn’t strong enough for the body to make vitamin D.
But since it’s difficult for people to get enough vitamin D from food alone, everyone (including pregnant and breastfeeding women) should consider taking a daily supplement containing 10mcg of vitamin D during the autumn and winter.
Between late March/early April to the end of September, most people can get all the vitamin D they need through sunlight on their skin and from a balanced diet. You may choose not to take a vitamin D supplement during these months.
If you choose to take vitamin D supplements, 10mcg a day will be enough for most people.
Don’t take more than 100mcg of vitamin D a day as it could be harmful. This applies to adults, including pregnant and breastfeeding women and the elderly, and children aged 11-17 years.
Children aged 1-10 years shouldn’t have more than 50mcg a day. Infants under 12 months shouldn’t have more than 25mcg a day.
So the general range for adults is 10mcg to an absolute max of 100mcg a day. But as the NHS also points out: some people have medical conditions that mean they may not be able to safely take as much. Again, if in doubt, you should consult your doctor.
It is also worth remembering that Vitamin D is a fat-soluble vitamin so is only able to do its job when digested or dissolved with fats. Therefore if you do choose to supplement it, make sure you have it with a meal or it can also go down nicely with a cup of butter coffee!
Sitting here nodding, Daniel. 🙂
I take a supplement (spasmodically, I must admit) throughout the year in the cooler months; and have, at least, 2 or 3 fish meals per week (generally salmon and sardines). During our summer in Australia (now) I like to take, at least, 10 to 15 mins of sunshine most days. Our glorious summers make this a pleasure!
That’s great to hear, Carolyn!
I must admit I do love some smoked salmon and tuna every now and then. Unfortunately, in the UK the weather is very rarely optimal for getting good levels of Vitamin D, even in our ‘summer’ as you might know! So I am certainly contemplating supplementing this for most of the year.
I would love to experience a hot Australian summer one day!