04/12/2025
Sunlight and vitamin D generated in mushrooms!
Humans have preserved mushrooms through sun-drying for thousands of years, without appreciating that the process made the mushroom a significant source of vitamin D. The abundant ergosterol present in mushrooms is converted to vitamin D2 through exposure to any source of UV light, such as the sun, as demonstrated in studies.
In one particular study, on a cloudless, mid-summer day, with just 15 minutes of sun exposure the vitamin D content of mushrooms rose from close to zero to about 18 mcg/100g fresh weight, which exceeds the daily requirements of vitamin D.
After one hour in the sun the level had risen to a maximum of 32 mcg/100g mushrooms, which wasn't bettered even after six hours of sun exposure.
This study suggests that placing mushrooms in only 10-15 minutes of summer sun will give you your daily D needs in a single serve (100g or 3 button mushrooms).