Irrespective of their debated health benefits, there are also conflicting opinions as to the effect adding milk to tea has on the antioxidants contained therein. Studies have indicated that the casein proteins in milk can bind to the polyphenols in black tea and form complexes. Whilst some research has suggested that this could impact on the amounts of antioxidants gained by drinking tea, others have suggested that this does not actually affect the concentration of antioxidants in the blood after ingestion, as the protein-polyphenol complexes can be broken down during digestion.