The Importance of Protein

Sure, we know protein is good for our muscles, but did you ever think about it being important for your brain?

Protein is one of 3 macronutrients vital to sustaining our bodies. Protein is composed up of amino acids chained together by peptide bonds. Protein, while important for the overall body, is particularly important for brain health.

Protein is important for creation of receptor sites, neurotransmitters and molecule transporter proteins.

A diet that is low in protein has been associated with symptoms of depression and anxiety. This may be in part due to a shortage of the amino acids, L-tryptophan and L-tryosine. These amino acids are the precursors to vital neurotransmitters such as serotonin, dopamine, and norepinephrine and more. Serotonin is important for regulating appetite, sleep, alertness, cognition, maintaining mood and feelings of well-being. Dopamine is responsible for motor control, arousal, motivation, pleasure and reward. Without a sufficient supply, the body may struggle to make enough of these neurotransmitters, leaving you deficient and feeling less then optimal.

Most vegan sources of protein contain little or no tryptophan and tyrosine, so unfortunately for those on a plant-based diet, these amino acids can be hard to come by. Tryptophan is the rarest essential amino acid in food. Tryptophan and tyrosine are most commonly in animal protein sources such as dairy and meat. A complete protein is a protein source that contains all 9 essential amino-acids. Most complete proteins come from animal products, but there are plant-sourced complete proteins available in some foods such as quinoa, soy, and hemp.

Eating a carbohydrate rich food with a protein source of tryptophan helps increase the absorption of tryptophan, converting it to serotonin. This occurs because of the insulin-mediated decrease in plasma levels of other large neutral amino-acids that may be competing with tryptophan for absorption. Have some rice with that chicken!

Things like stress, sleep deprivation, and use of caffeine, alcohol or drugs can disrupt and imbalance neurotransmitter levels in the brain. Studies show that tryptophan mediates stress response and recovery and is very important for maintaining mental wellness and cognitive performance during stress. Eating a protein rich meal after overexerting yourself is always a good idea.

Protein is also important because it builds transporting molecules that are essential to delivering chemical signals such as neurotransmitters. It also contributes to the construction of specific proteins such as BDNF that act as growth factors, and stimulate repair and regeneration of new brain cells. BDNF (Brain derived neurotrophic factor) has been shown to be extremely important for maintaining brain cells and creating neuroplasticity. BDNF is essential to learning and creating memories. It also has an involvement in helping overcome things like depression, anxiety, PTSD, and addiction.

Studies also show that protein in the diet activates areas of the brain responsible for regulating eating behavior and energy levels, due to a stronger signaling of the entire body’s energy resources.

Here are some foods with rich supply of tryptophan and tyrosine:

  • Animal Meat
  • Dairy products
  • Eggs
  • Soy
  • Spirulina
  • SeaWeed
  • Spinach
  • Fish/Seafood
  • Pumpkin, sunflower seeds, and almonds
  • Bananas
  • Dates
  • Legumes

 

Harris R. Lieberman. Amino Acid and Protein Requirements: Cognitive Performance, Stress, and Brain Function. Protein and Amino Acids, 1999. Pp. 289-307. Washington, D.C. National Academy Press.
http://www.nap.edu/openbook.php?record_id=9620&page=290

 

Marion Journel, Catherine Chaumontet, Nicolas Darcel, Gilles Fromentin, and Daniel Tomé. Brain Responses to High-Protein Diets. Adv Nutr May 2012 Adv Nutr vol. 3: 322-329, 2012

http://advances.nutrition.org/content/3/3/322.full

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