Are Mushrooms High in Vitamin D? UV Mushrooms, Sun, Cooking

Ordinary mushrooms grown in the dark are not high in vitamin D: UK food tables put raw white mushrooms at 0.0 µg per 100 g. Mushrooms exposed to ultraviolet light make vitamin D2 the way skin makes D3, and a 2018 review found them likely to hold more than 10 µg per 100 g up to their best-before date, "higher than the level in most vitamin D-containing foods".^{1, 2} Sliced button mushrooms in strong midday summer sun reached 17.6 µg per 100 g in 15 minutes,³ cooking keeps 62 to 88% of it,⁴ and in trials mushroom D2 raised blood vitamin D as much as a supplement where people started low, and little where they started high.^{5, 6, 7} Part of the vitamin D guide and the vitamins and minerals guide.

Do mushrooms contain vitamin D?

Only after light. Mushrooms are rich in ergosterol, and ultraviolet light "such as sunlight or a UV lamp" converts it: "The most common form of vitamin D in mushrooms is D2, with lesser amounts of vitamins D3 and D4".² Without it there is little to measure: a German trial recorded under 1 µg per 100 g in button mushrooms before irradiation, and the UK tables list raw white mushrooms at 0.0 µg and dried at 0.0.^{1, 5} UV-treated packs say so; an unlabelled pack will be near the food-table figure.

How much vitamin D is in UV-exposed mushrooms, per 100 g and per portion?

The 80 g column is arithmetic from the per-100 g figure, raw.

The fish and the rest are on which foods are highest in vitamin D.

Which mushroom has the most vitamin D?

The one that saw the most UV light. A Thai survey of twelve species found lung oyster mushrooms at 15.88 µg per 100 g raw and wild termite mushrooms at 7.15 µg, the rest "negligible amounts (0.06 to 2.31 µg per 100 g)".⁸ The plain button mushroom, once exposed, matched or passed them: 17.6 µg per 100 g after 15 minutes of sun, 491 µg after a laboratory UV-B dose of 1.5 J/cm².^{3, 5} Chestnut and portobello are the same species as white button, so none starts ahead. UV-exposed mushrooms also carry "lesser amounts" of D3 and D4; what D4 does in people is untested, so it is not counted.²

Can you put shop-bought mushrooms in the sun?

Yes: in summer, outdoors, sliced. The Danish-German study laid sliced button mushrooms in Central European midday sun. Vitamin D2 rose steadily through the first hour, from 0.1 to 3.9 µg per gram dry weight, then plateaued, and "Two hours of additional exposure triggered a significant decline".³ Fifteen minutes gave the 17.6 µg per 100 g figure, "comparable to levels found in fatty fish like the Atlantic salmon".

Two limits. Mushrooms need the UV-B that skin needs, and the NHS states that "between October and early March we do not make enough vitamin D from sunlight", so a January tray will not reproduce a July result.⁹ And the study worked in open air; window glass filters out most UV-B, so a sill behind a closed window is not the test it ran. Open the window or use the garden.

Does cooking remove the vitamin D?

Some, not most. A Danish study boiled, steamed, microwaved, pan-fried and oven-baked button mushrooms and found 62 to 88% of the vitamin D2 retained, a real loss, while vitamin D3 in rainbow trout stayed at 85 to 114%.⁴ In Thailand, boiling, stir-frying and grilling kept 64.0%, 58.8% and 64.7%, not significantly different.⁸ Rehydrated dried UV-treated mushrooms kept 95% or more through cooking, frying and baking significantly more than boiling.¹⁰ Storage is the other loss: dried UV-treated mushrooms, vacuum-sealed in the dark, kept 100%, 93% and 58% at three, six and twelve months.¹¹ Fresh UV mushrooms stay "above 10 µg/100 g" to the best-before date: cook within it, and fry or bake rather than boil.²

Do mushrooms raise your vitamin D level?

In trials, yes where people started low. In a five-week German winter trial, 26 young adults at or below 50 nmol/L had 700 µg of vitamin D2 a week as soup from UV-B-treated button mushrooms, as a D2 supplement, or placebo; 25-hydroxyvitamin D rose 3.9 nmol/L a week on the soup and 4.7 on the supplement, "not different".⁵ That is a research dose, equal to the NHS 100 µg a day ceiling. In Finland, 27 volunteers below 60 nmol/L had 14 µg a day of D2 from freeze-dried wild mushrooms, a 14 µg supplement, or nothing for three weeks; both raised the marker and did not differ from each other (P = 0.317).⁶

Where people started high, the total did not move. In California, 38 adults averaging 83 nmol/L ate UV mushrooms supplying 8.8 or 17.1 µg a day for six weeks: the D2 marker rose, the D3 marker fell, and the vitamin D2 "did not affect vitamin D status, because 25(OH)D3 decreased proportionally".¹² Pooling six trials: no significant rise overall (P = 0.12); 15.2 nmol/L in the three European trials with a mean baseline of 38.6 nmol/L; no significant effect (P = 0.83) in the three US trials at 81.5 nmol/L.⁷ A 2024 meta-analysis of fortified foods found UV mushrooms the one vehicle short of significance (P = 0.06).¹³ A test that "barely made any change" usually means that pattern: cooking losses, a starting level that was not low, or both.

Then D2 against D3. The UK's Scientific Advisory Committee on Nutrition concluded in 2024: "Both vitamin D2 and vitamin D3 increase blood 25(OH)D concentrations, and both forms prevent and treat vitamin D deficiency." In daily-dose trials of 5 to 25 µg it found "an advantage of vitamin D3 over D2 in raising blood 25(OH)D concentration of about 8nmol per litre", adding that "the difference in estimated effect between the 2 forms may not be reliable".¹⁴ The NHS: "All types of vitamin D work in this way."¹⁵ The head-to-head trials, with their dosing pattern: a 2012 meta-analysis found D3 raised the marker more overall (P = 0.001), significant with a single large (bolus) dose and "lost with daily supplementation";¹⁶ a 2017 UK winter trial of 335 women on 15 µg a day found both forms rose against placebo, D3 by about 16 nmol/L more;¹⁷ a 2024 review of 12 daily-dose comparisons put D2 10.39 nmol/L lower, a gap that lost significance above a BMI of 25 (first author at a mushroom producer, declared).¹⁸ What vitamin D2 (ergocalciferol) is has every trial.

How many mushrooms a day for vitamin D?

An 80 g portion of retail UV-exposed mushrooms holds about 8 µg raw, close to the NHS 10 µg a day, and at 62 to 88% retention leaves roughly 5 to 7 µg on the plate.^{2, 4, 9} The NHS still advises that, because "it's difficult for people to get enough vitamin D from food alone", everyone "should consider taking a daily supplement containing 10 micrograms of vitamin D during the autumn and winter"; vitamin D contributes to the maintenance of normal bones, teeth and muscle function and to the normal function of the immune system, whatever supplies it. The ceiling is for supplements: "Do not take more than 100 micrograms (4,000 IU) of vitamin D a day as it could be harmful."⁹ To eat mushrooms for vitamin D: buy UV-treated packs or sun your own in summer, fry or bake, eat before the date. How to check your vitamin D levels covers the NHS route.

Frequently asked questions

What is a vitamin D mushroom?

A mushroom exposed to UV light after harvest so that its ergosterol converts to vitamin D2, and labelled so. Before its best-before date it is likely to hold more than 10 µg per 100 g, against 0.0 µg dark-grown.^{1, 2}

Does the body use vitamin D from mushrooms?

Yes. Across the pooled trials the D2 marker rose 20.6 nmol/L and the D3 marker fell 13.3, so the total rose where people started low.⁷ SACN's conclusion covers mushroom D2: both forms prevent and treat vitamin D deficiency.¹⁴

Can vegans rely on mushrooms for vitamin D?

UV mushrooms are the one unfortified plant food with a substantial amount per serving.² The NHS autumn and winter advice applies to everyone; which vitamin D is best for vegans sets out D2 and lichen D3 by their evidence.

Are mushrooms good for anything else?

That is the mushrooms cluster's question: see the Wellgard mushrooms guide, what lion's mane mushroom is good for and what mushroom powder is used for.

Sources

1. Composition of Foods Integrated Dataset (CoFID) 2021. gov.uk.
2. Cardwell G, et al. Mushrooms as a source of dietary vitamin D. Nutrients, 2018. PubMed 30322118.
3. Urbain P, Jakobsen J. Sunlight dose-response in button mushrooms. J Agric Food Chem, 2015. PubMed 26314311.
4. Ložnjak P, Jakobsen J. Vitamin D stability after household cooking. Food Chem, 2018. PubMed 29548435.
5. Urbain P, et al. UV-B mushroom vitamin D2 bioavailability trial. Eur J Clin Nutr, 2011. PubMed 21540874.
6. Outila TA, et al. Vitamin D from wild mushrooms. Am J Clin Nutr, 1999. PubMed 9925129.
7. Cashman KD, et al. UV mushrooms and vitamin D status. J Nutr, 2016. PubMed 26865648.
8. Sridonpai P, et al. Vitamin D in Thai mushrooms. Foods, 2023. PubMed 37297386.
9. NHS. Vitamin D. Reviewed 3 August 2020. nhs.uk.
10. Cardwell G, et al. Cooking retention in UV-irradiated dried mushrooms. Food Chem, 2023. PubMed 37224637.
11. Cardwell G, et al. Storage retention in UV-irradiated dried mushrooms. Foods, 2023. PubMed 37048250.
12. Stephensen CB, et al. Mushroom ergocalciferol and 25(OH)D. J Nutr, 2012. PubMed 22623385.
13. Cashman KD, O'Neill CM. Food vehicles for vitamin D fortification. J Steroid Biochem Mol Biol, 2024. PubMed 38141736.
14. SACN. Fortifying foods and drinks with vitamin D: summary, 23 May 2024. gov.uk.
15. NHS. Common questions about colecalciferol. Reviewed 10 January 2023. nhs.uk.
16. Tripkovic L, et al. Vitamin D2 versus D3 meta-analysis. Am J Clin Nutr, 2012. PubMed 22552031.
17. Tripkovic L, et al. Daily 15 μg D2 versus D3 in winter, 335 women. Am J Clin Nutr, 2017. PubMed 28679555.
18. van den Heuvel EG, et al. Daily D2 versus D3 meta-analysis. Adv Nutr, 2024. PubMed 37865222.

General information, not medical advice; your GP can arrange a blood test and advise on dose.