Brain fog suggestions by people who have mast cell illnesses. In approximate order of importance.
Going gluten-free. See low-allergen diet.
Getting better sleep. See sleep hygiene.
Drinking plenty of water.
Aerobic exercise.
Supplements, especially omega 3, vitamin B12 (cobalamin), vitamin D (calciferol), magnesium supplements, chlorella.
Fresh air.
Mind-body practices, especially meditation, mindfulness, deep breathing, somatic experiencing.
Phosphatidylcholine.
Cromlyn sodium in an over-the-counter nasal spray.
ADHD medications, such as Strattera.
Stopping my food triggers.
Mitochondrial cocktail.