High Blood pressure is sometimes treated with calcium supplements. Why? Well when you have a calcium deficiency you body releases calcitriol (a vitamin D metabolite made by the kidney), which constricts blood vessels (as well as promoting calcium absorption from the intestine and leaching calcium from your bones to restore low blood calcium levels). Constricted blood vessels = higher blood pressure.
Scientists have been discovering that people on this calcium treatment are also losing weight. It turns out that calcitrol also acts as a metabolic switch in fat cells, signaling them to hold on to fat. Getting plenty of calcium means that calcitrol production is supressed and that "hold on to fat" switch stays off.
The effect is more pronounced when you take in extra calcium via low fat dairy products (Leucine and other peptides found in whey can enhance the weight loss effect.)
Its a bit of a fad these days to avoid dairy, but it is a great source of calcium. One low fat fresh and fruity yogurt has 40% of your RDI for calcium and only 72 calories. You body can only absorb small amounts of calcium at a time so a few small servings spread through out the day (and not taken with coffee!) will give maximum effect.
Article in psychology today