Amino acids…how can diet affect mental health?

We all know we need food to survive. However, the type of food we eat enhances our survival. When we eat protein-containing foods, they are broken down into amino acids which are the building blocks for neurotransmitters.For example, tryptophan is a precursor to serotonin, and tyrosine is a precursor to the neurotransmitters dopamine, epinephrine, and norepinephrine.1 It is important to understand the role neurotransmitter precursors play, because neurotransmitters are critical for proper mental health. Imbalances in neurotransmitters can result in low mood, anxiousness, and compulsive behavior.2, 3, 4

Amino AcidsAmino acids are made when protein is broken down in the small intestines and within cells.3 There are two groups of amino acids (Table 1). Nonessential amino acids can be made by the body from protein or other amino acids. Essential amino acids can only be obtained through the diet. Low protein diets mean fewer amino acids are available for making neurotransmitters. In addition, it is important to eat adequate amounts of amino acids, because they must compete with other dietary proteins for intestinal absorption and transport across cell membranes and the blood-brain barrier (BBB).5, 6

Figure 1. The blood-brain barrier acts as a wall to protect the brain and keep harmful substances out.

Figure 1. The blood-brain barrier acts as a wall to protect the brain and keep harmful substances out.

The BBB (Figure 1) consists of the endothelial cells lining the blood vessels in the brain. These cells serve as a fortress that guards and protects the brain from foreign substances.7 The tight junctions of the BBB make it difficult for foreign materials in the blood to enter the brain.8 Because of this obstacle, amino acids are assigned to specific carriers or transporters that allow them to get through the BBB.8, 9

Optimal health is built on a solid foundation and amino acids are its primary building blocks. In turn, an optimal nervous system is built on a foundation of healthy neurotransmitter levels, which requires a steady supply of amino acids in the diet. These kinds of strong foundations are critical for good mental health.

Guest author: Rachel Rixmann is a manager of the Clinical Support & Education Department at NeuroScience, Inc. and the resident expert in gastroenterology and nutrition.

References
1. Savelieva KV, Zhao S, Pogorelov VM et al. (2008). Genetic disruption of both tryptophan hydroxylase genes dramatically reduces serotonin and affects behavior in models sensitive to antidepressants. PloS ONE 3 (10): e3301.
 2. Delgado, P L, & Moreno, F A. (2000). Role of norepinephrine in depression. The Journal of clinical psychiatry, 61(1): 5−12.
 3. Nikolaus, S, Antke, C, Beu, M, et al. (2010). Cortical gaba, striatal dopamine and midbrain serotonin as the key players in compulsive and anxiety disorders−−results from in vivo imaging studies. Reviews in the neurosciences, 21(2): 119−139.
 4. Moeller SJ, Tomasi D, Honorio J, Volkow ND, Goldstein RZ. (2012). Dopaminergic involvement during mental fatigue in health and cocaine addiction. Transl Psychiatry, Published online Oct. 23.
 5. Berg, J., et al. (2002). Biochemistry. 632-633.
 6. http://faculty.washington.edu/chudler/bbb.html
 7. Matthews, D.M., Leonard, L. (1965). Absorption of protein digestion products: A review. Gut.
 8. Pietz, J., et al. (1999). Large neutral amino acids block phenylalanine transport into brain tissue in patients with phenylketonuria. J Clin Invest, 103(8): 1169-1178.
 9. Feurté, S., Gerozissis, K., Regnault, A., Paul, F.M. (2001). Plasma Trp/LNAA ratio increases during chronic ingestion of an alpha-lactalbumin diet in rats. Nutr Neurosci, 4(5):413-8.
 10. Oldendorf,W.H., Szabo,J. (1976). Amino acid assignment to one of three blood-brain barrier amino acid carriers. Am.J.Physiol, 230:94-98.
 11. http://www.sdmags.net/2012/01/breaching-the-blood-brain-barrier/
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4 Responses to Amino acids…how can diet affect mental health?

  1. Varaneka says:

    I’m very grateful for your food allergy and metal tests.

  2. Pingback: Nutrition Therapy | Mental-Health

  3. cis says:

    I was hoping for a bit more detail on this. The info here is quite generic and was already known to me.

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