According to the almost-certainly-not-a-vested-interest-website wagyushop.com:
Wagyu beef is extremely rich in monounsaturated fatty acids and contains all of the essential amino acids, including omega-3 and omega-6 fatty acids. Essential fatty acids such as these are believed to lower risk of cardiovascular disease, cancer, Alzheimer’s and other conditions. The richly marbled beef also contains more conjugated linoleic acid (CLA), which is believed to have health benefits such as lowered risk of disease and diabetes.
Sounds like a miracle food!