Additionally, tofu is an excellent source of calcium, especially when it is made with calcium chloride or calcium sulfate. Sardinesalpaksoy / Getty Images351 milligrams per one can (3.75 ounces)Sardines are an excellent source of calcium. It is an excellent source of calcium and phosphorus, both vital for maintaining strong bones. They are rich in calcium, fiber, and protein, and provide essential nutrients such as iron, zinc, potassium, magnesium, and antioxidants. Fortified Foods and DrinksArx0nt / Getty ImagesMany foods and beverages are fortified with calcium, making it easier to meet your recommended daily intake.