Vitamin D is an essential fat-soluble vitamin needed for healthy bones, muscles, and a strong immune system. Low vitamin D levels are linked to a range of conditions like osteoporosis, heart disease, diabetes, cancer, and depression. If you lack vitamin D, it’s essential to know what could be causing this and how to increase your levels.
The main cause of vitamin D deficiency is a lack of exposure to sunlight.
Your body can make all the vitamin D you need. But this can only happen when your skin is exposed to sunlight. So during autumn and winter, when sunlight exposure is at an all-time low, it’s really common for your vitamin D levels to drop — putting you at risk of developing a deficiency, which is linked to depression.
You can check your vitamin D levels as part of a vitamins blood test. And you can prevent or treat a deficiency with our premium vitamin D supplements.
You can also get vitamin D from food, but most people don't get enough this way. Good dietary sources of vitamin D include:
Apart from lack of sunshine, there are other causes of low vitamin D. You might also be at an increased risk of developing vitamin D deficiency if you:
In the UK, 40% of people aged 19-64 years old are estimated to be vitamin D deficient during the winter months.
Find out about the link between vitamin D and COVID-19.
Most people with vitamin D deficiency don’t show any symptoms. When symptoms do occur, they can be vague and might include:
You can treat a deficiency with our vegan vitamin D supplements.
You can measure your levels at home with a vitamins blood test.
This test will measure your levels of 25-hydroxy vitamin D, and the reference ranges are:
Certain inflammatory diseases might make it challenging to interpret your vitamin D levels. These include:
In these cases, it's best to work with your doctor and get specialist input.
Find out about the link between vitamin D and muscle recovery.
During spring and summer, extra sun exposure can help to boost your vitamin D levels. If you're out for long periods in the sun, it's essential to cover up or wear sun protection to protect yourself from sun damage and skin cancer.
During autumn and winter, Public Health England advises that everyone should consider taking a 10 mcg (400 IU) daily vitamin D supplement from October to March to prevent low vitamin D levels. And if you’re more at risk of having low levels, they recommend taking them year-round.
The recommended doses include:
If your levels are already low, taking up to 25 mcg (1,000 IU) a day is suitable for all adults.
Remember that some medical conditions mean that you should take lower doses. It’s best to follow the advice of your GP in these cases.
Craig, W. J. (2009). Health effects of vegan diets. The American journal of clinical nutrition, 89(5), 1627S-1633S.
National Health Services (2017). Health: A-Z: Vitamins and minerals: Vitamin D. Retrieved 4 November 2021 from https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/.
National Institute of Health (2018). Office of dietary supplements. Vitamin D: Fact sheet for health professionals. Retrieved 4 November 2021 from https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
Public Health England (2020). Statement from PHE and NICE on vitamin D supplementation during winter. Accessed 4 November 2021 from https://www.gov.uk/government/publications/
Royal Osteoporosis Society (2019). Vitamin D and bone health: a practical clinical guideline for patient management. Accessed 4 November 2021 from theros.org.uk/clinical-publications-and-resources
Dawson-Hughes, B. Vitamin D deficiency in adults: Definition, clinical manifestations, and treatment. In Mulder, JE (Ed.), UpToDate. Accessed 4 November 2021 from https://www.uptodate.com/contents/vitamin-d-deficiency-in-adults-definition-clinical-manifestations-and-treatment