Confused about dietary protein?   What’s better food or supplements?

Proteins are an essential nutrient for optimal growth, repairing or replacing tissue, immune functions and fluid regulation.  Once consumed in the diet proteins are broken down into the building blocks of life, amino acids.  There are 20 amino acids, 9 of which are considered essential (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine): this means that we must consume through dietary sources.  Consumption of proteins also helps with feeling full.  Here is what you need to know about protein.

Protein Absorption

Once we consume a dietary protein source, through digestion the body will extract the essential amino acids.  This process works best with the consumption of dietary sources such as beef, chicken, poultry, fish and plants.  Consumption of individual amino acids does not help optimize absorption and can create imbalances.  For example, lysine (essential amino acid) and arginine (non-essential amino acid) are absorbed by the same transported, so an excess of lysine can impair absorption of arginine.  The following amino acids are most likely to cause toxicity when consumed in large quantities:  histidine, methionine and cysteine (non-essential).   Choose whole food sources to meet your protein needs.

High Quality vs Lower Quality proteins

Can also be referred to as complete or incomplete proteins.  This is not a reference to one kind being worse.  It is simply referencing whether a dietary source contains all 9 essential amino acids.  If the dietary source contains all 9 essential amino acids in enough amounts, then it is a high quality or complete protein.  Animal sources are high quality.  Plant sources except for soy bean and quinoa seed are considered lower quality or incomplete proteins.   This means that they don’t contain enough amounts of all 9 essential amino acids.  So, for example grains, nuts and seeds lack lysine.  Vegetable and legumes lack methionine.  We can combine the sources, referred to as complementary proteins, and create a high-quality protein source by providing all 9 essential amino acids.   Consuming black beans and rice would create a high-quality protein source.   In the past it was thought that the beans and rice needed to be consumed in the same meal to be effective, however this is no longer the case.  They just need to be consumed within a reasonable period, 24-48 hours.  Why you ask?  Through the digestive process both high- and low-quality proteins are broken down to the individual amino acids, absorbed through the small intestine, stored in the liver and reassembled as needed by the body.  So ultimately, we just need to make sure there are enough essential amino acids in the amino acid pool.

Protein needs

Most individuals consume more than enough protein.  The general recommendation is between 0.8-1.0 gram per kilogram of body weight per day (0.8-1.0 g/kg/d).  Example a 100 kg (220 pounds) person would need 80-100 grams of protein per day.   If you are highly active, training hard, or recovering from a traumatic injury the need could be 1.4-2.0 g/kg/d.

For most protein consumption comes in the form of fast or convenience foods such as hamburgers, tacos, chicken tenders and nuggets.   These sources are also paired up with saturated fats, highly process breads or breading, fried foods and sodas.   These extra calories combined with low nutrient value contributes to an expanding waist line and poor health.  Ideally you would like to consume dietary protein through a combination of whole some sources such as lean cuts of meat, chicken, fish and by consuming a variety of plant sources.   The benefit of adding plant sources of proteins is that you add a high nutrient item with low calories.

It is important to note that excess consumption of protein can place a strain on the kidneys.  In addition, once the amino acid pool is full the body cannot store additional amino acids.  The amino acids the body cannot use will ultimately be stored as fat. Any excess consumption of proteins, carbohydrates and fats will be stored as fat.