The key to proper function of the brain comes down to the integrity of the blood–brain barrier (BBB), as well as the integrity of axons, neurons, and mitochondrial membranes. The blood–brain barrier has the important function of letting nutrients and certain small molecules into the brain tissue while allowing waste to be eliminated. In addition, the composition of the cerebral spinal fluid (CSF) is important to consider along with its relationship with the glymphatic circulatory system (GCS) function of bathing the brain tissue with CSF four times daily. The glymphatic circulatory system has been more recently understood as separate from the body’s lymphatic system. If damage to the membranes of these neurons occurs to any extent, the entire cell will be absolutely compromised in its ability to complete its purpose in electrical signaling. The vagus nerve is the largest nerve network in the body impacting multiple systems including immune, gastrointestinal function, and others. Increased permeability of the BBB is synergistically worsened by increased small intestinal permeability for a number of reasons. Excessive permeability in the small intestine can be a sign of leakage of bacterial endotoxin, as well as food allergens, into the brain, leading to more damage to brain tissue. The brain is 60% fat, so it makes sense that consuming adequate fat intake in the diet helps nourish the cells of the brain. It is also important to restore the BBB in order to prevent brain autoimmunity, brain damage from free radicals, neuro-inflammatory molecules, neurotoxins, and electromagnetic fields. Nutritional support for the BBB includes optimizing fatty acids and phospholipid dietary and supplemental intake, increasing lipid protectors like fat soluble vitamins and CoQ10, and increasing polyphenols found in blueberries, especially wild blueberries, in order to decrease oxidative damage. Sulforaphane can activate the brain’s own anti-inflammatory and antioxidant systems. Sulforaphane supplements may not be very effective. Glucoraphanin is the stored form of sulforaphane in cruciferous vegetables. In order to yield usable sulforaphane, glucoraphanin requires the enzyme myrosinase for it to be converted into sulforaphane. Cooking cruciferous vegetables destroys the myrosinase enzyme, thus very little sulforaphane can be obtained from steamed or fried cruciferous vegetables. It is important when eating raw cruciferous vegetables to have a healthy gut microbiome in order to enable some myrosinase activity. The best sources of glucoraphanin include broccoli sprouts and raw broccoli. When considering maintenance or improvement in neuroplasticity, one must consider increasing the levels of various trophic factors, such as nerve growth factor, neurotrophin, and brain-derived neurotrophic factor (BDNF). Increasing levels of BDNF may lead to axonal and dendritic sprouting, nerve stem cell differentiation, and may enhance synaptogenesis. Aerobic exercise done in the training heart rate zone (220-age) 70–80% for 30–45 minutes can increase BDNF as well as prevent loss of genetic telomere length. Aerobic exercise can also activate NRF2 gene responses. These gene responses can decrease brain inflammation and oxidative stress, which can improve neuronal and mitochondrial membranes. EGCG green tea extract is also beneficial, either by drinking green tea or by taking 200–400 mg/day. Taurine is an amino acid that can improve brain structure through a number of mechanisms. It can protect the brain against osmotic changes, has a neurotrophic effect, can activate nerve stem cells, and can enhance neurite (axon or dendrite) growth.
