Some researchers argue that osteoporosis results from loss of the collagen bone matrix, which is more responsible for bone strength than its mineral filling. Although calcium's role in bone development gets the most attention, research into its effect on other parts of the body has been going on for years. Here's an update. The connection between calcium intake and atherosclerosis is unclear. Atherosclerosis, the most common arterial disease, is marked by cholesterol deposits in the artery walls.
Some research shows higher calcium intake protects against atherosclerosis in humans and in animals.
But not all calcium sources provide the same benefit. This may be because other components in milk increase body levels of atherosclerotic homocysteine, an amino acid implicated in heart disease. Other studies show calcium intake has no effect on heart disease, and some researchers have even suggested a connection between calcium deposition in arterial walls and calcium intake. 13-17 Research on calcium and high blood pressure has also yielded mixed results. The large-scale Iowa Women's Health Study of 34,702 women found that women with the highest intakes of calcium and vitamin D from foods cut their risk of rectal cancer by almost half.