Beef liver is known for containing a high concentration of vitamin A -- each slice provides over 400 percent of the recommended daily allowance of vitamin A for an adult -- but it is also a rich source of a variety of essential minerals, including copper, phosphorus, selenium, zinc and iron.opper aids in collagen and red blood cell synthesis and promotes the function of the immune and nervous systems. Eating copper-rich foods may lessen your risk of osteoporosis and osteoarthritis, though be aware that regularly consuming more than 10,000 micrograms of copper a day may result in kidney or liver damage.