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).
: If one is not getting enough calories from a vegan diet, there are a few ways to remedy that. For example, one can snacks that are between 100 to 200 calories. How Do Vegans Get Protein? : But where do you get your protein? but wheat, oatmeal, or potatoes, we would easily take in more than enough protein.