Vitamin D is the one almost everyone runs low on in winter, vegan or not. The plant-friendly fix is D2 or lichen D3, plus fortified foods and sensible sun.
Vegan Brief·Evidence last reviewed July 6, 2026
This is a summary of the cited evidence, not medical advice.
RDA (most adults)600 IU (15 mcg)/day
Vegan formsD2, lichen D3
Also low inOmnivores in winter
01
The short version
Vitamin D is the nutrient where the vegan question and the everyone question are almost the same question. Sunlight makes it in your skin, few foods carry much of it, and a large share of people run low in winter regardless of diet. The US government fact sheet is direct about who is most at risk.
Primary source 01 / 03
Vitamin D deficiency is more common among people who are lactose intolerant, have a milk allergy, or follow an ovo-vegetarian or vegan diet.
So the honest framing is not that veganism causes a deficiency the rest of the world avoids. It is that a vegan diet removes the fortified dairy many people lean on, so the plant-based eater has to get it another way on purpose.
02
D2, D3, and the lichen option
There are two forms, and the difference matters for vegans because the common D3 supplement is animal-derived, from sheep's wool. The fact sheet describes the two forms.
Primary source 02 / 03
In foods and dietary supplements, vitamin D has two main forms, D2 (ergocalciferol) and D3 (cholecalciferol), that differ chemically only in their side-chain structures.
D2 is always plant-based. Vegan D3 exists too, made from lichen rather than wool. Either raises blood levels; fortified plant milks, some cereals, and UV-exposed mushrooms add more. What vitamin D reliably does is protect bone.
Primary source 03 / 03
Vitamin D sufficiency prevents rickets in children and osteomalacia in adults.
Omega-3s on a vegan dietFlax and walnuts give you the parent omega-3. Turning it into the ones your brain and heart use is inefficient, which is where algae oil comes in.
Calcium and bone health on a vegan dietThis is the page where being on veganism's side means telling you the uncomfortable finding: vegans break more bones in the data, and calcium is the lever that moves it.
Plant-based diets, bone health and fracture riskPublishing the unflattering finding is the point: in the best cohort, vegans broke more bones. The risk is real, it mostly tracks calcium, protein and body weight, and it is fixable.
Vitamin A on a vegan dietVegans get vitamin A the long way round: plants supply beta-carotene, and the body turns it into the active vitamin. The conversion is real but not identical in everyone, which is why the orange and dark-green vegetables earn their place.
Vitamin K and K2 on a vegan dietVitamin K1 is one of the easiest nutrients to get on a plant diet: it is what makes leafy greens green. K2 is the one people worry about, and the honest answer involves natto, gut bacteria, and your own biology.
Is Vitamin D3 (cholecalciferol) vegan?Is it vegan? · Vitamin D3 is usually made from lanolin in sheep's wool, but a lichen-derived vegan D3 exists, and D2 is plant-based. Check the label or ask.
Frequently asked
Is D2 or D3 better for vegans?
Both raise blood vitamin D. D2 is always plant-based; vegan D3 from lichen is also available. Either works as a reliable source.
Do vegans get enough vitamin D from the sun?
Skin makes vitamin D from sunlight, but in winter and at higher latitudes many people, vegan or not, fall short. A supplement or fortified foods covers the gap.
The primary sources
The documents this page quotes. Read them yourself.
