Vitamin D for Vegans
A well-planned vegan diet covers most nutrients — but vitamin D is a genuine gap. Almost all natural D3 (cholecalciferol) sources are animal, and D2 (ergocalciferol) from fungi is less potent per IU. Vegans need to be deliberate.
Sources compared
| Source | Form | Typical dose |
|---|---|---|
| Lichen-derived D3 | Cholecalciferol | 1,000–5,000 IU |
| Ergocalciferol (D2) | Ergocalciferol | 1,000–5,000 IU |
| UV-exposed mushrooms | D2 | 200–500 IU per serving |
| Fortified soy/oat/almond milk | Usually D2, sometimes D3 | 80–120 IU per cup |
| Fortified orange juice | D3 or D2 | 100 IU per cup |
| Fortified breakfast cereals | Usually D3 | 40–100 IU per serving |
Should vegans take D2 or lichen D3?
Lichen D3 if you can afford it — it raises serum 25(OH)D more effectively per IU and produces steadier levels. D2 works, but you need a higher dose (~1.5–2× the equivalent D3 dose) and it clears faster, so trough levels dip lower between doses. Costs of lichen D3 have fallen; a year's supply is now $20–40 in the US and UK.
Sun exposure
Cutaneous synthesis works the same regardless of diet. Sensible sun exposure remains the most bioavailable vitamin D source for anyone during the UVB season. Vegans at high latitudes still hit the vitamin D winter (~November through February) and need supplementation during those months.
Testing considerations
Standard 25(OH)D lab assays measure total 25(OH)D2 + 25(OH)D3. If you supplement with D2, some older assays may underestimate your total status — modern LC-MS/MS methods measure both forms accurately. If you're on D2 and your result is unexpectedly low, ask your lab about the assay used.
Recommended vegan protocol
- Daily lichen-derived vitamin D3 1,000–2,000 IU with a fat-containing meal.
- Include UV-exposed mushrooms or fortified plant milks as regular dietary sources.
- Test serum 25(OH)D at end of winter (February–March) — vegans have higher deficiency rates in cohort studies.
- During UVB season, sensible sun exposure (10–30 minutes midday, 2–3× weekly).