While it's best to try to feed your body the nutrition it needs with a balanced diet, vitamins and supplements can be used to fill in the gaps you may be missing. Some people have food allergies or aversions to foods that offer the nutrients required by our bodies and simply can't get these nutrients via food sources. Pills, powders, and liquids will never replace the plethora of benefits your body gets from fresh fruits and vegetables, eggs, dairy products, fish, whole grains, and high-quality fats. However, if you're lactose intolerant, a calcium supplement would be to your benefit.