There is a new article published about marmite that said to help your brain and reduce anxiety due to high levels of vitamin B12. https://www.yahoo.com/beauty/marmite-may-brain-food-study-says-041654428.html
I take B12 and I think it helps a little to prevent headaches. Never noticed its effect on anxiety. I was surprised that another supplement helped me to stay calm. It called glycine. Glycine is an amino acid and it sold as a food supplement. It is harmless.