In recognition of March as National Nutrition Month, we will take this opportunity, in this space, to take a closer look at the macronutrient Protein.
It is almost a cliche that protein is a building block of tissues such as muscle, organs and bodily systems. But it is also an energy source. What many people do not realize is that, when taken in excess, protein is broken down (catabolized) to glycogen or fatty acids, which means if it is not “burned” as energy, it will be converted to fat.
Protein is made up of amino acids, which are similar to sugars in that they are constructed with a “carbon backbone”, made unique by the presence of an “amine group” containing Nitrogen. Amino acids can be broken down to molecules which enter metabolic pathways to produce energy which is either used or stored. Nitrogen, if not used to build protein structures, is excreted as Urea.
The bottom line is this: The human body requires 50-100 grams of protein per day to maintain muscle and organ systems. Since the body can only metabolize about 30 grams of protein at a time (per meal), protein intake should be evenly distributed throughout the day. The main source of proteins are meats and dairy products, but ALL foods (including vegetables and fruits) contain some protein. Older people who are experiencing loss of lean muscle mass over time, do require more protein to maintain their muscle mass. But, excess protein, over and above the body’s requirement to build tissue, will either be use as energy or stored as fat, like all excess calories.
The most important nutritional principle to keep in mind is that BALANCE of all he macronutrient food groups is the healthiest approach. We welcome your questions, comments and requests for assistance!
Dr. John Monaco