Calcium and Vitamin D. Calcium and vitamin D are two of the most important nutrients for bone and muscle health. Calcium can be found in dairy products, leafy green vegetables, almonds and calcium-fortified foods and juices.Vitamin D helps the body absorb calcium, so many fortified products with calcium also have added vitamin D. This vitamin also boosts muscle strength and helps prevent muscle weakness.alcium can be found in dairy products, leafy green vegetables, almonds and calcium-fortified foods and juices. Vitamin D helps the body absorb calcium, so many fortified products with calcium also have added vitamin D. This vitamin also boosts muscle strength and helps prevent muscle weakness.