We’ve all heard of vitamin D – it’s one of the most well-known nutrients and most common supplements available. However, what you might not know is that vitamin D is that it’s not technically a vitamin. You can top up some of your vitamin D levels through diet (we tend to get about 10 per cent of our intake through food), but it’s mainly manufactured by the body in response to sun exposure, which actually makes it a type of hormone.
The next thing to say is, if you live in the UK, you’re probably not getting enough sunlight (especially during the winter months) to produce enough vitamin D to stay healthy, and will likely need to supplement your intake.
Vitamin D is essential because it helps the body regulate calcium and phosphate levels and keeps bones, teeth and muscles healthy. It’s found in foods like oily fish, red meat, egg yolks and some fortified foods. However, you won’t be able to get the levels you need from diet alone.
The NHS advises that “a lack of vitamin D can lead to bone deformities such as rickets in children, and bone pain caused by a condition called osteomalacia in adults. Government advice is that everyone should consider taking a daily vitamin D supplement during the autumn and winter.”
Low levels of vitamin D have also been linked to mood disorders such as anxiety and depression and a lack of this essential hormone can contribute to the symptoms of seasonal affective disorder (SAD) which, according to the Royal College of Psychiatrists, affects 3 per cent of the population.
We asked experts to weigh in and explain what causes vitamin D deficiency, the important signs to look out for, and the dangers involved with not getting enough. Read on for the facts and the best ways to top up your levels to stay healthy and happy this winter.
What causes vitamin D deficiency?
As sunlight is our main natural source of vitamin D, short winter days and cloud cover can have an impact when it comes to getting enough vitamin D. Maz Packham, nutritionist at Nourishful Nutrition, explains that “we synthesise vitamin D in the skin in response to UV light – more specifically to UVB – so, it’s not surprising many of us in the UK are deficient or have insufficient levels due to seasonal factors.”
Nutritional therapist Eve Kalinik agrees, adding that even those living in “sunnier climes might be deficient, if using SPF and not exposing skin at all. But, of course, there has to be a balance here,” it’s still important to protect your skin from sun damage and the associated health risks that come with that.
While it is possible to source some vitamin D through diet, it will be a small amount. Hannah Alderson, registered BANT nutritionist and hormone specialist advises that “we can get a little from food – such as mushrooms, oily fish, dairy, and eggs – but that’s not really going to cut it.”
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There are a few further things to consider when looking at the causes of vitamin D deficiency. According to Kalinik: “Some people suffer from a lack of absorption as a result of poor gut health and/or conditions such as Crohn’s and coeliac disease.” She adds that “Some groups are just [more] vulnerable to vitamin D deficiency, like those of a certain age, or those with darker skin.”
According to the National Institutes of Health, individuals with darker skin are more likely to have lower vitamin D levels than those with lighter skin. This is all to do with the level of melanin in the skin. Individuals with lighter skin tones have less melanin and this allows them to absorb UVB radiation more efficiently and produce vitamin D more effectively than those with more melanin.
What are the signs of vitamin D deficiency?
Deficiency can show up in many ways. Kalinik says, first and foremost, an unexplained “susceptibility to infections and viruses” might be a sign, given that vitamin D is a crucial component of robust immune function. Signs of deficiency may also present as “bone pain or muscle weakness (since vitamin D helps with the balance of calcium in the body) or even low mood and fatigue, which can often be associated with SAD.”
Alderson says there’s a hormonal element to consider, too. “Vitamin D plays a role in reproduction and glucose balance, and therefore PCOS (polycystic ovary syndrome), with the prevalence of vitamin D deficiency in women with PCOS being around 67-85 per cent.” So, it’s worth paying attention to possible hormonal imbalances and all their attendant symptoms, too.
What should I do if I’m vitamin D deficient?
The first thing you could do is try an at-home blood test – they’re readily available and give a good indication of your current status. A blood test can also let you know exactly how deficient you are. Some vitamin D supplements are stronger than others, so if your levels are only slightly below the recommended level, you might only need a low dose of vitamin D. For other people, a much higher dose might be needed.
Taking the wrong dose can have adverse effects because it is possible to take too much vitamin D – ever heard the phrase “you can have too much of a good thing?” If in doubt regarding your dosage, check in with your doctor to arrange a test or ask them to explain the results of your at-home test to you.
Packham adds that you can try to increase your levels of vitamin D by upping your exposure to direct sunlight. “Aim for 25 to 30 minutes in the midday sun, as levels are more abundant when the sun is highest in the sky, making the vitamin D synthesising process more efficient.”
The experts all advise making sure oily fish and egg yolks are a part of your diet. However, all experts concede that even if you took all of the steps above, supplementing is in all likelihood going to be the way to go, especially during the winter months in the UK.
We’ve put together a handy guide to the best vitamin D supplements, with picks tailored to your lifestyle from approved brands. Choose from easy-to-swallow softgels to sprays, affordable subscriptions and supplements with added nutrients to keep you healthy through the winter and beyond.
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