Can we add whey protein supplementation in patients with Parkinson's disease without interfering with levodopa response?

Objective: The main endpoint of the study was to evaluate if a daily intake of whey protein-based dietary supplement causes a worse response to levodopa in people with Parkinson's Disease (PWPD).
Background: In PWPD, the competition between large neutral aminoacids and levodopa at intestinal absorption level may interfere with dopaminergic therapy's (DRT) effect; therefore, protein redistribution dietary regimen has been suggested. Many dietary supplementations are available to help people in balancing the protein intake and overcoming muscle mass loss. However, most of the products contain protein and could potentially affect levodopa action in PWPD.
Methods: We performed a randomised single blind monocentric study on PWPD admitted in the rehabilitative unit for a 4-week multidisciplined intensive aerobic rehabilitation treatment. All patients received a standard protein redistribution dietary regimen plus a whey protein-based oral formula ( N  = 26) or Magnesium ( N  = 25) twice daily for 28 days. Neurological assessment and physical evaluation were conducted before (T0) and after (T1) rehabilitative treatment; DRT was recorded T0 and T1 as well. The delta of changes within groups in neurological (UPDRS III) and physical (TUG, 6 MW) evaluation scales was compared between groups.
Results: Groups were comparable at baseline in clinical and demographic data; at T1, both groups showed a decrease in UPDRS III, TUG and 6 MWT and no differences between deltas were found. DRT remained stable in both groups.
Conclusions: Our results show that whey protein supplementation does not interfere with DRT's efficacy and can be used in PWPD who need a protein supplementation without restrictions in intake hours.