Calcium is found mainly in dairy products and vegetables. However, since it has the highest proportion of all minerals in the body and its recommended daily intake is 1000 mg, it can be difficult for some groups of people to take enough calcium. That's why vegans, athletes or the elderly often reach for nutritional supplements. It is also very beneficial for elderly for its ability to reduce the risk of osteoporosis. Calcium should be taken with vitamin D, which increases its absorption and maintains normal levels of calcium in the blood.