7-Dehydrocholesterol has significant absorption of UV light at the lowest wavelengths of light found in sunlight (290-310 nm). Hence the need for full-spectrum lamps to emit UV-B radiation (UV-B light is defined here to be light between 290-315 NM).
In rare cases some vegans might not get enough fat or calories to produce adequate amounts of steroid hormones (which are produced from cholesterol). Two studies have shown vegans to have sex hormones on par with meat-eaters (1, 2), but one report showed vegan women to have lower levels of estrogen (3).
To get the full benefit of a vegan diet, vegans should do one of the following: 1  Eat fortified foods two or three times a day to get at least three micrograms (mcg or Âµg) of B12 a day or. 2  Take one B12 supplement daily providing at least 10 micrograms or. 3  Take a weekly B12 supplement providing at least 2000 micrograms.