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Q: Which amino acids cannot be synthesized by the human body?

A: The nine amino acids that cannot be synthesized by the human body are histidine, isoleucine, leucine, methionine, phenylalanine, tryptophan, threonine, and valine. However, some health experts believe that the body may not make enough of the other eleven nonessential amino acids for optimal health and growth.

The body burns more than 250 grams of protein every single day. This protein needs to be replaced, and amino acids are the building blocks used to build protein in the human body. Furthermore, the body also uses protein to build DNA and RNA , carry oxygen throughout the body, and supply some of the energy needed for daily activities. Protein also plays an active role in keeping you healthy by keeping cells healthy and helping your immune system fight off infections. Protein also plays an important role in mental health and well-being. Your body uses neurotransmitters, which are made from amino acids, to send messages to and from cells. Neurotransmitters control not only vital functions, such as heart rate, but also moods, by transmitting “feel-good” hormones such as serotonin (which is predominately made in the gut) and dopamine (which is produced in certain areas of the brain) to the parts of the brain that need them in order to work properly. If you don’t get enough protein in your diet, your brain will be unable to function optimally, and that can lead to problems such as depression and/or overt aggressiveness.

Chapter 1: Getting to Know Proteins and Protein-Rich Foods

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