Vitamin D
Most people in Slovenia — vegan or not — need a supplement from autumn to spring.
- Supplement: everyone
Vitamin D isn’t really a vegan problem — it’s a “living far from the equator” problem. But vegans start with less of it, so it’s worth getting right.
Why you need it
Vitamin D helps your body control calcium and phosphate, which keep your bones, teeth and muscles healthy. Without enough, adults can develop bone pain (osteomalacia) and children rickets. It also supports the normal working of your immune system, though it can’t prevent or treat an infection on its own.
Why it matters for vegans
Your skin makes vitamin D from sunlight, and food usually adds only a little. The foods that contain it naturally are mostly animal ones — oily fish, eggs — so vegans get even less from food. In a large UK study, vegans had the lowest intake and the lowest blood levels of any group.
The sun, in Slovenia
From autumn to spring the sun is too weak at our latitude for your skin to make enough. Slovenia’s National Institute of Public Health (NIJZ) says the same, and a Slovenian study found that during the long winter (November to April) about 8 in 10 adults had too little vitamin D in their blood — among the highest rates in Europe.
In summer, short daily periods in the sun help — without letting your skin burn.
Where to get it
- Fortified foods: some plant drinks, spreads and breakfast cereals have vitamin D added — check the label.
- UV-exposed mushrooms: some mushrooms are grown under UV light and contain more vitamin D2.
Food alone won’t cover your needs, though. That is what a supplement is for.
Should you supplement?
Yes, at least from October to March — and all year if you are rarely outdoors, usually cover most of your skin, have dark skin, or are over 65.
- How much: the NHS advises 10 µg (400 IU) a day for everyone in autumn and winter. The European Food Safety Authority (EFSA) sets an adequate intake of 15 µg a day for adults; NIJZ uses 20 µg a day for people who make no vitamin D themselves.
- Which kind: vitamin D2 is always vegan. Vitamin D3 is vegan only when it comes from lichen — many D3 supplements are made from lanolin, from sheep’s wool. Check the label.
- Take it with food that contains some fat; vitamin D is fat-soluble.
Don’t take more than 100 µg (4,000 IU) a day unless a doctor tells you to. Too much over a long time can raise calcium in your blood and damage your bones, kidneys and heart. Check other supplements (such as multivitamins) so you don’t double up. You can’t overdose from sunlight.
If you take medicines for your heart, kidneys, liver, epilepsy or cancer, or steroids, ask your doctor or pharmacist before taking vitamin D.
How to check your levels
The usual test measures 25-hydroxy vitamin D in your blood. Testing everyone isn’t recommended, but it’s worth asking if you’re in a higher-risk group, or before taking higher doses. NIJZ considers levels above 50 nmol/L good and below 30 nmol/L insufficient.
Sources
- Vitamin D — NHS
- Vitamin D — The Vegan Society
- Dietary reference values for vitamin D (2016) — European Food Safety Authority (EFSA)
- Scientific opinion on the tolerable upper intake level for vitamin D (2023) — European Food Safety Authority (EFSA)
- Plasma concentrations of 25-hydroxyvitamin D in meat eaters, fish eaters, vegetarians and vegans: results from the EPIC-Oxford study (2011) — Public Health Nutrition (Crowe et al.)
- Nutrihealth Study: Seasonal Variation in Vitamin D Status Among the Slovenian Adult and Elderly Population (2020) — Nutrients (Hribar et al.)
- Vitamin D (2021) — Nacionalni inštitut za javno zdravje (NIJZ)
- 25-hydroxy vitamin D test — MedlinePlus (U.S. National Library of Medicine)
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