Citrus associated with a 10% reduction in odds of developing breast cancer. Oranges were historically used for their high content of vitamin C, which prevents scurvy. Scurvy is caused by vitamin C deficiency, and can be prevented by having 10 milligrams of vitamin C a day. An early sign of scurvy is fatigue. If ignored, later symptoms are bleeding and bruising easily. British sailors were given a ration of citrus fruits on long voyages to prevent the onset of scurvy, hence the British nickname of Limey. Pectin is a structural heteropolysaccharide contained in the primary cell walls of plants. Limes and
Vitamin D deficiency deficiency has been associated with urbanisation in terms of both air pollution, which blocks UV light, and an increase in the number of people working indoors. The elderly are generally exposed to less UV light due to hospitalisation, immobility, institutionalisation, and being housebound, leading to decreased levels of vitamin D. The reduced pigmentation of light-skinned individuals may result in higher vitamin D levels and that, because melanin acts like a sun-block, dark-skinned individuals, in particular, may require extra vitamin D to avoid deficiency at higher latitudes. The natural selection hypothesis suggests that lighter skin color evolved to optimise vitamin D