Flank steak used in this carne asada recipe is a very lean cut of beef with a high amount of protein, amino acids, iron, and zinc.  Here are some health benefits of steak:   Protein:  Steak is a powerful source of protein to fuel your body. It is excellent for helping to build muscle and for maintaining muscle mass.  Even fit individuals can suffer muscle atrophy if they do not consume enough protein which contains amino acids (the building blocks of protein).  Protein can also help repair muscles from wear and tear and to relieve muscle aches. Amino acids:  Steak also contains the dietary amino acid called beta-alanine, which helps form a dipeptide called carnosine, which is crucial to support physical activity.  Healthy levels of carnosine reduce fatigue and improves muscle performance, endurance and precision during physical activity. Iron:  Steak contains high levels of iron which is absorbed more quickly than iron found in supplements and even some vegetables.  Iron is needed to carry oxygen tofrom the lungs to all parts of the body.  Your body also needs iron to make some hormones and keep your hair, skin and nails healthy.  If you do not have enough iron, you won’t have healthy oxygen circulation, which will cause fatigue and grogginess. Zinc:  A (3.5-ounce) serving of beef contains 4.8 mg of zinc, which is 44% of the Daily Value.  Zinc is vital for a healthy immune system, correctly synthesizing DNA, and healing wounds.