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).
A vegan diet is one that eliminates all animal products and focuses only on plant-based foods. That not only means no meat, but also means no dairy and no eggs. Most vegans also try to avoid processed animal products, like gelatin, that sometimes get added to foods that seem like they would otherwise be vegan. Because the diet is low in calories, cholesterol and saturated fat, going vegan tends to help with weight loss and helps normalize your cholesterol and blood pressure. While more and more restaurants are offering vegan options, it can be hard to find a place to eat out in some parts of the country.