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).
The average number of years of vegan diet was 4.2 with a range of 1â25 y. Most of the vegans had followed a vegetarian diet before becoming vegans. The average number of years of following vegetarian dietary practices was 12.1 y with a range of 1â37 y. Of the 20 nonvegetarians, 7 regularly used multivitamin-mineral supplements, compared with 4 of 25 in the vegan group.