Tobacco is an excellent laxative.

Simplest and best "cure" for dandruff is to wash your hair less often. Shampoo removes all the oil from your scalp, respect your body it doesn't produce oil by mistake.

It's because of the intensity of the light. Conditions of both unusual brightness or darkness increase the body's use of vitamin A. Polar bears store so much vitamin A in their livers that it's dangerously poisonous to eat. I dont remember the toxic levels but they're well above general requirements, because A's fat soluble the liver can store quite large amounts so for a normal life style I reckon a pound of pig's liver a month is plenty. It's a long time ago that I looked into these things so you might want to check if you're planning more than half a pound a day.

You should be able to buy it at a local health food shop. In order for your body to absorb it you need to take them with some kind of fat/oil, a bacon sandwich should do the trick. Spending a lot of time on the computer also increases the need for vitamin A.

Dandelion leaves are a good source (also extremely high vitamin C content) but you should eat them untreated in a salad, they have a diuretic effect but the body quickly acclimatises. I hate watching my mother poisoning dandelions, one of the great wasted resources in the UK.

I think an increase in vitamin A intake might help dandruff, liver is the best source.