What is the use of vitamins in active form and minerals with high biological availability? What is meant by high biological availability?

Biological availability, or bioavailability in short, refers to the extent to which a specific ingredient becomes available at the target site in the body. The higher the bioavailability, the higher the absorption of this ingredient and the higher the quantity present in the body.
Bariatric surgery changes the body's needs. It is of crucial importance to select ingredients that are well absorbed by the body.

• Vitamins in active form no longer need to be transformed by the body and can immediately be absorbed by the body. 
• Minerals such as iron, magnesium, zinc, calcium, etc. in readily absorbable form (such as bisglycinate, fumarate and citrate) have a high bioavailability and are recommended to replenish deficiencies quickly. E.g. calcium citrate instead of calcium carbonate. Calcium citrate is 25% better absorbable than calcium carbonate and does not require an acidic environment for absorption (because the acidity of the stomach decreases after bariatric surgery). 

The right form of ingredients is not only important for high absorption by the body (high bioavailability), but also to reduce the occurrence of possible discomforts such as diarrhoea (zinc bisglycinate versus zinc gluconate).