This is complete nonsense. Beefheart is a perfect good food for discus. It's simply very lean protein. Some beefheart products come with additives, such as shrimp, fish, spinach, vitamins, etc, although there is absolutely no evidence that these do anything. Beefheart is not lacking in any of the nutrients contained in these ingredients. I know an old time breeder in Ohio that raised 5 generations of discus solely on beefheart.
Having said that, there is no magic food. I've seen very nice adult discus raised solely on flake food. Another local hobbyists raised beautiful discus solely on VibraBites. Changing large quantities of water frequently will do much more to get you quality discus than any specific food.