The war on rickets is an interesting example. Before the Industrial Revolution, rickets were not a real big issue- humans got plenty of sunlight and reasonably healthy diets. When people started to spend most of their days indoors, and pollutants blocked more and more of the UV hitting the ground, we started to see severe problems with vitamin D shortages in people, especially the young. Combine this with increasing problems getting calcium-rich foods for a variety of reasons and rickets became a real issue.
More recently, there are problems with people who cover themselves extensively for cultural purposes or to avoid sunlight to minimize the risk of skin cancer- but the very tools to prevent cancer also block the UVB needed to prevent rickets and other calcium issues. Rickets still occurs in places where people have a hard time getting enough calcium in their food- even if there is plenty of sunlight available- most often due to poverty.
Although we CAN get vitamin D through diet, not many foods have enough to really help, and those that do are not widely eaten. We need about 600Iu a day. That works out to about 20oz of tuna, eel, mackerel, or salmon; 30 eggs; almost 9lbs of beef liver; 1/2 tablespoon cod liver oil; about 4.5oz of UV-exposed mushrooms, or about 9lb or unexposed mushrooms; or 4.8 8oz glasses of vitamin D fortified milk a day. (Many cereals, etc. are also fortified- but usually to fairly low levels.)
Vitamin D supplements help as well, liquid more so than dry, but many experts are unsure if they are used by the body in the same way, and even more wonder if tortoises benefit much from them.
By the way- the bit you see in old Bugs Bunny cartoons about kids taking big spoonfuls of 'nasty' cod liver oil? That is based on a common preventative treatment for rickets!
By the way #2- many nutrition experts would tell you that you (and your kids) are probably a bit low in vitamin D right now. Most people in the Northern Hemisphere seem to be, and even Australia is struggling with this.
More recently, there are problems with people who cover themselves extensively for cultural purposes or to avoid sunlight to minimize the risk of skin cancer- but the very tools to prevent cancer also block the UVB needed to prevent rickets and other calcium issues. Rickets still occurs in places where people have a hard time getting enough calcium in their food- even if there is plenty of sunlight available- most often due to poverty.
Although we CAN get vitamin D through diet, not many foods have enough to really help, and those that do are not widely eaten. We need about 600Iu a day. That works out to about 20oz of tuna, eel, mackerel, or salmon; 30 eggs; almost 9lbs of beef liver; 1/2 tablespoon cod liver oil; about 4.5oz of UV-exposed mushrooms, or about 9lb or unexposed mushrooms; or 4.8 8oz glasses of vitamin D fortified milk a day. (Many cereals, etc. are also fortified- but usually to fairly low levels.)
Vitamin D supplements help as well, liquid more so than dry, but many experts are unsure if they are used by the body in the same way, and even more wonder if tortoises benefit much from them.
By the way- the bit you see in old Bugs Bunny cartoons about kids taking big spoonfuls of 'nasty' cod liver oil? That is based on a common preventative treatment for rickets!
By the way #2- many nutrition experts would tell you that you (and your kids) are probably a bit low in vitamin D right now. Most people in the Northern Hemisphere seem to be, and even Australia is struggling with this.
