BDNF and irritable bowel syndrome: As shown in Figure 7E (IBS gut/degenerative brain axis), BDNF level was significantly increased by VitD3 NS 100 nM (p < 0.05) compared to LPS 100 ng/mL + H2O2 200 μM (51%, p < 0.05) and the other VitD3 forms (28% vs. VitD3 Physical Mix 100 nM and 24% vs. VitD3 Sigma 100 nM, p < 0.05).