蘑菇的细胞膜里有一种叫麦角固醇的成分，晒到紫外线会变成维生素 D2，所以晒过太阳或经过紫外线处理的蘑菇，是少数不来自动物的维生素 D 来源；讲紫外线照出维生素 D 的一章细说这一步。野生蘑菇要当心：认不准的野生蘑菇不要采来吃；吃过野生蘑菇后出现呕吐、腹泻等不适，哪怕后来看着好转了，也要立刻去急诊，并把剩下的蘑菇带上。
U.S. Department of Agriculture, Agricultural Research Service. (2019). FoodData Central: Mushrooms, white / crimini / portabella, raw, cooked, and UV-exposed. Very low calorie; riboflavin, niacin, pantothenic acid, selenium, copper; UV-treated mushrooms supply vitamin D2. fdc.nal.usda.gov
Keegan, R. J. H., Lu, Z., Bogusz, J. M., Williams, J. E., & Holick, M. F. (2013). Photobiology of vitamin D in mushrooms and its bioavailability in humans. Dermato-Endocrinology, 5(1), 165-176. UV exposure converts mushroom ergosterol to vitamin D2, which raises human 25(OH)D. 10.4161/derm.23321
Cardwell, G., Bornman, J. F., James, A. P., & Black, L. J. (2018). A review of mushrooms as a potential source of dietary vitamin D. Nutrients, 10(10), 1498. UV-treated mushrooms can reach substantial vitamin D2 levels; dark-grown mushrooms are very low. 10.3390/nu10101498
National Institutes of Health, Office of Dietary Supplements. (2024). Vitamin D — Fact Sheet for Health Professionals. Fact sheet (updated June 27, 2025; Wayback snapshot 20 September 2026): 25(OH)D below 30 nmol/L (12 ng/mL) is associated with deficiency, 30 to below 50 nmol/L is generally considered inadequate, 50 nmol/L (20 ng/mL) or more is sufficient for most people, and above 125 nmol/L (50 ng/mL) can be associated with adverse effects; RDA 600 IU (15 mcg) to age 70 and 800 IU (20 mcg) above 70; adult UL 4,000 IU (100 mcg); older people and people with darker skin (more melanin) make less vitamin D from sunlight (fact sheet). ods.od.nih.gov/factsheets/VitaminD-HealthProfessional
National Institutes of Health, Office of Dietary Supplements. (2021). Selenium — Fact Sheet for Health Professionals. Table 2: Brazil nuts, 1 ounce (6-8 nuts), 544 mcg selenium (989% DV); the text says Brazil nuts contain 68-91 mcg per nut and could cause selenium toxicity if consumed regularly, and that values from other analyses vary widely. The version read carries 'Updated: April 15, 2024' (Wayback Machine snapshot of 31 December 2024), newer than the 2021 date above (fact sheet, read 2026-09-24). The September 4, 2025 update (Wayback snapshot 19 September 2026) adds: the body absorbs up to about 90% of selenium from selenomethionine, selenium-enriched yeast, selenite and selenate; selenium-only supplements typically contain 100 to 400 mcg; Keshan disease, an endemic cardiomyopathy first identified in 1935 in low-selenium parts of China, fell dramatically after selenium intervention trials in the 1970s-1990s; in 2017 the American Thyroid Association issued a weak recommendation against selenium supplements for TPOAb-positive pregnant women (fact sheet). ods.od.nih.gov/factsheets/Selenium-HealthProfessional