Digestion uses more energy than any other system in the body. After all, it takes a lot of energy to concentrate hydrochloric acid in your stomach (inside of a body that is NOT acidic). It also takes a lot of energy to then produce the enzymes that finish the job by breaking down the fats and proteins. Carbohydrates are also broken down by enzymes, but that process actually starts in the mouth.
All of us could benefit by taking digestive enzymes to aid in this process. But those who are blood type A need even more support. If you are not producing enough enzymes, then you will not be able to get all of the goodness from your foods and supplements.