Nutrients that Reduce BBB permeability (blood-brain permeability)
Alpha Lipoic Acid – The alpha R form is the one most easily utilized by the body. Supplementation with alpha lipoic acid inhibits progress of tau protein toward fibrils of plaque, reduces cognitive decline, lipid peroxidation, inflammation, and tau-induced iron overload.  The R form of ALA is better absorbed.
Baicelein – appears to be able to cross the blood-brain barrier (BBB), and may play a role in healing the BBB by reducing permeability.  Good food sources include Arnucca apples. wine, tea, citrus fruits, dark chocolate, and herbs.
Curcumin – in animal studies may help restore blood-brain barrier permeability. 
Glucocorticosteroid (GC) treatment. Glucocorticoids are powerful medicines that fight inflammation and work with your immune system to treat wide range of health problems. GCs were shown to restore BBB integrity in patients with MS. 
Resveratrol given to Alzheimer’s patients, appears to restore the integrity of the blood-brain barrier, reducing the ability of harmful immune molecules secreted by immune cells to infiltrate from the body into brain tissues. 
 Chen M, Lai L, Li X, Zhang X, He X, et al. (2016). Baicalein attenuates neurological deficits and preserves blood-brain barrier integrity in a rat model of intracerebral hemorrhage. Neurochem Res. 41:3095-3102.
 Wang CX, Xie GB, Zhou CH, Zhang XS, Li T, et al. (2015). Baicalein alleviates early brain injury after experimental subarachnoid hemorrhage in rats: Possible involvement of TLR4/NF-κB-mediated inflammatory pathway. Brain Res. 1594:245-
 J Surg Res 2017 Jan;207:85-91. doi: 10.1016/j.jss.2016.08.090. Epub 2016 Sep 3.
 Miller DH, Thompson AJ, Morrissey SP, MacManus DG, Moore SG, et al. (1992). High dose steroids in acute relapses of multi-ple sclerosis: MRI evidence for a possible mechanism of therapeutic effect. J Neurol Neurosurg Psychiatry. Jun; 55(6):450-3.