16 Aug Protein 101
As a continuation from my Carbohydrate 101 article, I have broken down another well-known macronutrient called protein. In this post, I will take you through what proteins are, how they are created, and some common foods that contain them.
What are proteins?
Proteins are organic compounds made from smaller building blocks called amino acids (these can be thought of as tiny lego pieces). Proteins are critical for many functions and structures within the human body including antibodies, transporters, neurotransmitters, hormones, enzymes and structural components. To help illustrate the importance of proteins, approximately 50% of the dry weight (after the removal of water) from a single human cell is from protein.
What are amino acids?
As I referenced earlier, proteins are created through the accumulation of amino acids (tiny lego pieces ultimately creating a larger structure). There are approximately 140 amino acids that exist in nature; however, only 20 are required and coded by our DNA in order for humans to survive. Various combinations of these 20 amino acids make up all the proteins found within our body. Digging deeper into these amino acids, there are two distinct groups of amino acids essential and non-essential. Essential amino acids are amino acids that our body is unable to synthesize (create) either at all or in sufficient amounts to meet the demands of the growth and maintenance of the human body. Essential amino acids are ones that can be readily synthesized by our body and utilized for specific functions. Below I have provided a list of the 20 amino acids associated with the human body and further divided them into the essential and non-essential groups.
How are proteins made?
Protein formation follows a very specific developmental sequence after being coded from our DNA. This sequence can be simplified as phases of protein-folding, which starts with the specific sequence of amino acids in a polypeptide chain (Primary Structure). When amino acids are joined together by peptide bonds you create what is known as a peptide, the prefix “poly” implies there are many of these peptides joined together. When the hydrogen bonds in the primary structure start interacting with other molecular structures causing folding or coiling this is now know as a the Secondary Structure. At this point the protein is folded so much that it resembles a globular shape which is known as the Tertiary Structure. Many of the proteins in our body have many subunits to them or many Tertiary Structures. When multiple tertiary sub-units are incorporated into one function protein unit, we have a Quaternary Structure.
Histidine (infants only)
Where do I get protein?
Some common sources of protein include: Beef, Chicken breast, Chicken Thigh, Turkey, Salmon fillet, Egg, Cow’s Milk, Goat and Sheep milk, Mozzarella cheese, almonds and cottage cheese. Typically all sources of meat contain a significant amount of protein as well dairy products.
Recommended Daily Allowance (RDA):
As with many things in life, protein carries a “U” type relationship where too little protein can have significant negative repercussions as can too much protein. The general safe recommendation known as recommended daily allowance (RDA) for adults is 0.8 grams of protein per kilogram of body weight per day. The protein RDA for children is 0.85-1.52 g/kg/day. The RDA for women who are pregnant and lactating is 1.1g/kg/day to account for growth and development.