Vitamin D is only present in small amounts in our food. Most of the body's required vitamin D is formed after the sun hits the skin (and the more skin exposed the higher the dose). The amount of vitamin D in food versus the amount produced from the sun are as follows:-
- cod liver oil (1 tbsp):1360 International Units (IU)
- cooked tuna, sardines, mackerel or salmon: (100g): 200-360 IU
- shiitake mushrooms (fresh 100g): 100 IU (dried 100g): 1600 IU
- egg yolk: 20 IU
- fortified dairy products, orange juice or cereals (one serving): 60-100 IU
- full-body exposure to UVB (15-20minutes in summer): 10,000 IU
The recommended daily oral dose of vitamin D is at least 1000 IU per day (in food
or a pill). The recommended (Cancer Society of NZ) dose of sunlight to maintain
vitamin D levels is half the time it takes to burn, a day. You cannot overdose on
vitamin D from the sun as the body stops making it if the levels in the blood become
(Information disseminated by Glenne Findon - gonatural communications.)
Source: Scientific American, November 2007. (See the NIWA view and also some relevant UK authorities' links.)
In Dressed To Kill: The Link Between Breast Cancer and Bras, by Sydney Ross Singer and Soma Grismaijer, Avery , the husband-and-wife researchers/authors, say the way a woman's brassiere hampers the normal circulation of lymph causes cellular wastes and toxins to pool in the breasts. Years of such exposure make cancer more likely.
They surveyed more than 4700 women, questioning their attitudes to their breasts and wearing bras. They included approximately equal numbers who had had and had not had breast cancer.
They found that going bra-less is associated with a 21-fold reduction in the incidence of breast cancer compared with the general standard population, that wearing a bra for less than twelve hours a day is associated with a 10% greater incidence; and that wearing a bra all the time is associated with a 125-fold greater incidence than in those who never do.
Their conclusion: women who want to avoid breast cancer should wear a bra for the shortest period of time possible - certainly for less than twelve hours daily. This is no surprise, given the world statistics on breast cancer... Where there are no bras, there is little cancer.
The authors further postulate that the risk to health from an impeded lymphatic system may extend to the whole body and all restrictive clothing. They say that this handicap to our immune system should be termed Chronic Clothing Constriction to characterise the long-term effect that tight clothing has on tissues by inhibiting lymphatic drainage.