These 7 Supplements Can Make MCAS WORSE For Some: 1. Methylated B Vitamins (esp. methylfolate + methyl B12): too stimulating for sensitive COMT MAO A 2. Fermented Probiotics: High in histamine producers, can trigger Mast cells are hypersensitive immune cells that release histamine and other inflammatory mediatorsoften in response to oxidative stress, environmental toxins, and immune imbalance. Many patients with MCAS have low levels of glutathione. Glutathione Benefits, Uses and Best Practices Olympia Pharmacy Glutathione: Master Antioxidant, Reducing Oxidative Stress, and Detoxification S Acetyl Glutathione Active Form of Glutathione for Immune Health