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Not getting much sun? You could be low on vitamin D. The symptoms of vitamin D deficiency can sneak up on you – this nutrient does more for your body than you might think
Summary
1Causes of vitamin D deficiency
Did you know that around 90% of the vitamin D you need comes from time spent in the sun?
2Who’s more at risk?
If you’re mostly indoors, covered up or living somewhere with little sun, you could be missing out…
3Vitamin D and diet
Some foods naturally contain vitamin D, with oily fish like salmon, mackerel and sardines…
You’ve probably heard vitamin D called the "sunshine vitamin" – and for good reason. Our bodies make most of it when our skin is exposed to sunlight.1 But with busy indoor lifestyles, cloudy climates and layers of SPF (which we still love for skin protection), getting enough isn't always as easy as stepping outside.
So we’re diving into why vitamin D matters, what can cause a deficiency, the telltale signs to look out for, who’s more likely to be running low and how you can give your levels a little support.
What are the causes of vitamin D deficiency?
Did you know that around 90% of the vitamin D you need comes from time spent in the sun?2
But here’s the catch… Despite its sunny nickname, a surprising number of people in the UK are falling short. Around one in six adults and nearly one in five children aren’t getting enough vitamin D.3 And certain groups are more at risk – older adults, anyone who spends a lot of time indoors and people with darker skin tones, particularly from Black and South Asian backgrounds, may find it harder to produce enough.4,5
So keeping an eye on your vitamin D levels is quite important, especially if you fall into one of those higher-risk groups.
Who’s more at risk of vitamin D deficiency?
If you’re following a plant-based diet
If you’re vegan or plant-based, you might be at a higher risk of vitamin D deficiency as most natural sources like oily fish, egg yolks, red meat, liver and dairy are off the table.6 Since vitamin D is key for bone health, immunity and more, it’s important to get enough from other sources.7
So load up on fortified foods like plant milks, cereals and orange juice, and consider taking a high-quality vitamin D supplement, especially if you don’t get much sun.
In fact, the NHS recommends that 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 10 micrograms of vitamin D during the autumn and winter.1
Those not exposed to sunlight
If you’re mostly indoors, covered up or living somewhere with little sun, you could be missing out on this vital vit. Without enough vitamin D, your bones, immune system and potentially even your mood can take a hit.7
A little safe sun exposure can go a long way, but if sunlight’s in short supply, make sure to get your vitamin D from dietary sources or a good supplement.
People with darker skin
Melanin is the natural pigment that gives our skin its colour, and it acts like a built-in sunscreen by soaking up harmful UV rays to protect our skin (though, SPF is still needed of course).8,9
But there’s a trade-off, because melanin blocks some of that sunlight, it also makes it harder for the body to produce vit D. This means that people with darker skin need to spend more time in the sun to make the same amount as someone with lighter skin.10
The elderly
As we get older, it becomes harder for our bodies to make and use vitamin D the way they used to. That’s partly because we tend to spend less time in the sun but also because our skin gets less efficient at producing it as we age.11
Here are some reasons why elderly people might not get enough vitamin D from sunlight:1
- If they're frail or housebound
- If they live in a care home
- If they usually wear clothing that covers most of their skin outdoors
Lack of vitamin D symptoms
Low vitamin D symptoms vary from person to person. In fact most people are asymptomatic (which means they don’t show or produce any symptoms). And when symptoms do show up, they’re usually pretty vague, like feeling tired all the time or having general aches and pains.12
Because these signs are so subtle, vitamin D deficiency can easily fly under the radar. It's usually easier to spot when the deficiency is more severe, especially if classic symptoms or bone-related issues start to appear.12
But, if you think you’re at risk, look out for these symptoms that may appear in those with moderate to severe prolonged vitamin D deficiency:
Did you know that low vitamin D levels are associated with weakened muscle strength as you age?13
Vitamin D plays a big role in keeping your muscles strong and working the way they should.
And here’s something even more important: getting enough vitamin D can also reduce your risk of falls that come from muscle weakness and balance issues in the elderly. So it’s not just about strength – it’s about staying steady and confident on your feet, too.14,15,16
Severely low vitamin D levels can do more than just leave you feeling a bit off – they can actually lead to more serious health issues. In kids, a lack of vitamin D can cause a condition called rickets. It’s pretty rare these days, but when it does happen, it can make bones soft and bendy as they grow. Some children (especially African American infants and children) may be more at risk.17,18
For adults, the grown-up version of rickets is called osteomalacia. It might sound like a mouthful, but it basically means your bones aren't as strong as they should be. This can lead to bone pain, muscle weakness and an overall feeling of being achy and worn down.17,18
If you’re constantly feeling low on energy, especially as you get older, vitamin D probably isn’t the first thing you’d think to check. But it turns out that low levels of this vitamin could be part of the problem.
Low levels of certain vitamins and minerals can leave you feeling more tired than usual. And while vitamin D isn’t a direct cause of fatigue, being deficient may still play a role – so it’s worth keeping your levels in check as part of your overall wellbeing.
When your body doesn’t get enough vitamin D, your bones can start to feel the impact. You might notice a dull, achy sensation. That’s because vitamin D plays a vital role in keeping bones strong and healthy.19
Without enough of it, bones can become softer and more prone to damage, increasing the risk of fractures even from minor bumps or falls. Over time, a deficiency can quietly weaken your bone structure, making injuries more likely and recovery slower.20
Think of your immune system as your body’s personal defence squad, always on standby to fight off bugs and viruses. Vitamin D plays a behind-the-scenes but crucial role, helping to keep those immune cells sharp, balanced and ready for action when it counts.21-23
Making sure you’re getting enough vitamin D is a simple step that can go a long way in helping to keep your immune system strong.
What to do if you think you have low vitamin D
If you’re wondering whether you might be low in vitamin D, it’s always a good idea to have a chat with your GP or a healthcare professional. They can help you figure out if testing is needed and guide you on the best way to increase your levels safely – especially if you're thinking about taking supplements.
Everyone’s needs are a little different, so getting expert advice can really make a difference.
How to increase vitamin D in your diet
Some foods naturally contain vitamin D, with oily fish like salmon, mackerel and sardines topping the list. They're not only rich in this vital nutrient but also great for your heart and brain. Egg yolks and red meat also provide small amounts and mushrooms exposed to sunlight can offer a plant-based option too.1,24,25
On top of natural sources, many everyday foods are now fortified with vitamin D to help fill the gap. Think breakfast cereals, plant-based milk alternatives like soy or oat milk and even some brands of orange juice and yogurt. These can be especially helpful during the darker winter months or if you're not getting enough sunlight. Adding a few of these to your regular diet can be a simple yet delicious way to support your vitamin D levels without much effort.1,24,25
The final say
Vitamin D plays a big role in how we feel every day, from supporting our bones and immune system to helping with energy. The good news? With a few simple tweaks like getting a bit more sun (safely), adding the right foods to your plate and speaking with a healthcare professional when needed, you can keep your levels right where they should be.
So, whether you're soaking up the sun or stocking your kitchen with vitamin D-rich options, your body will thank you.
This article provides informational advice and is not a substitute for medical care. Curated by experts for accuracy, we take great care to ensure the information is up-to-date and relevant. However, you should always consult your GP or healthcare professional before using supplements or alternative products, particularly if you have medical conditions or are under supervision.
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2. Holick MF. Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease. The American Journal of Clinical Nutrition. 2004 Dec 1;80(6):1678S1688S
3. Department of Health and Social Care. New review launched into vitamin D intake to help tackle health disparities [Internet]. GOV.UK. 2022. Available from: https://www.gov.uk/government/news/new-review-launched-into-vitamin-d-intake-to-help-tackle-health-disparities
4. Department of Health and Social Care. New review launched into vitamin D intake to help tackle health disparities [Internet]. GOV.UK. 2022. Available from: https://www.gov.uk/government/news/new-review-launched-into-vitamin-d-intake-to-help-tackle-health-disparities
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7. National Institutes of Health. Vitamin D [Internet]. National Institutes of Health. 2022. Available from: https://ods.od.nih.gov/factsheets/VitaminD-Consumer/
8. Schlessinger DI, Schlessinger J, Anoruo M. Biochemistry, Melanin [Internet]. Nih.gov. StatPearls Publishing; 2023. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459156/
9. Brenner M, Hearing VJ. The protective role of melanin against UV damage in human skin. Photochemistry and Photobiology [Internet]. 2007 Nov 16;84(3):539–49. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2671032/
10. Webb A, Kazantzidis A, Kift R, Farrar M, Wilkinson J, Rhodes L. Colour Counts: Sunlight and Skin Type as Drivers of Vitamin D Deficiency at UK Latitudes. Nutrients. 2018 Apr 7;10(4):457.
11. Giustina A, Bouillon R, Dawson-Hughes B, Ebeling PR, Lazaretti-Castro M, Lips P, et al. Vitamin D in the older population: a consensus statement. Endocrine. 2022 Oct 26;79(1).
12. Dr Mary Harding. Vitamin D Deficiency [Internet]. Patient.info. 2017. Available from: https://patient.info/bones-joints-muscles/osteoporosis-leaflet/vitamin-d-deficiency
13. Aspell N, Laird E, Healy M, Lawlor B, O’Sullivan M. Vitamin D Deficiency Is Associated With Impaired Muscle Strength And Physical Performance In Community-Dwelling Older Adults: Findings From The English Longitudinal Study Of Ageing. Clinical Interventions in Aging. 2019 Oct;Volume 14:1751–61.
14. Ceglia L. Vitamin D and its role in skeletal muscle. Current Opinion in Clinical Nutrition and Metabolic Care. 2009 Nov;12(6):628–33.
15. Vitamin D and risk of falling [Internet]. European Food Safety Authority. 2011 [cited 2025 May 28]. Available from: https://www.efsa.europa.eu/en/efsajournal/pub/2382
16. Wei FL, Li T, Gao QY, Huang Y, Zhou CP, Wang W, et al. Association Between Vitamin D Supplementation and Fall Prevention. Frontiers in Endocrinology. 2022 Aug 10;13.
17. MedlinePlus. Vitamin D Deficiency [Internet]. Medlineplus.gov. National Library of Medicine; 2019. Available from: https://medlineplus.gov/vitaminddeficiency.html
18. NHS . Overview - Rickets and osteomalacia [Internet]. NHS. 2018. Available from: https://www.nhs.uk/conditions/rickets-and-osteomalacia/
19. Vitamin D in Orthopaedics What is Vitamin D and how does it work? [Internet]. Available from: https://www.esht.nhs.uk/wp-content/uploads/2021/06/0926.pdf
20. Patient Information Sheet: Vitamin D Summary Why do we need Vitamin D? Where do we get Vitamin D from? Sunlight [Internet]. Available from: https://swlimo.southwestlondon.icb.nhs.uk/wp-content/uploads/SWL-Vitamin-D-PIL-Accessible-V1.1.pdf
21. Aranow C. Vitamin D and the Immune System. Journal of investigative medicine : the official publication of the American Federation for Clinical Research [Internet]. 2011 Aug;59(6):881. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3166406/
22. Amirhossein Ghaseminejad-Raeini, Ghaderi A, Sharafi A, Behrad Nematollahi-Sani, Moossavi M, Afshin Derakhshani, et al. Immunomodulatory actions of vitamin D in various immune-related disorders: a comprehensive review. Frontiers in Immunology [Internet]. 2023 Jul 14;14. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10379649/
23. Gholamreza Daryabor, Nasser Gholijani, Fatemeh Rezaei Kahmini. A review of the critical role of vitamin D axis on the immune system. Experimental and Molecular Pathology. 2023 Aug 1;132-133:104866–6.
24. British Heart Foundation. Foods high in vitamin D [Internet]. Bhf.org.uk. British Heart Foundation; 2022. Available from: https://www.bhf.org.uk/informationsupport/heart-matters-magazine/nutrition/ask-the-expert/foods-high-in-vitamin-d
25. National Institutes of Health. Vitamin D [Internet]. National Institutes of Health. 2024. Available from: https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
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