Protein is an essential nutrient for achieving health and fitness goals, but not all proteins are created equal. Different types of proteins have different digestion rates, and understanding how these rates vary can help you optimize your protein intake. A medium-digested protein is typically defined as one that is digested within 3 to 3 and a half hours, slower than whey protein, which is digested in an hour or two, but faster than casein, which takes more than 4 hours to digest. The maximum rate at which a fast-absorbing protein, such as whey, can be absorbed is about 8 to 10 grams per hour.
This means that it's important to space out your protein intake throughout the day, since you won't be able to eat and properly absorb your daily protein needs in a single session. Digesting proteins in the stomach takes longer than digesting carbohydrates, but less than digesting fat. Eating a protein-rich meal increases the amount of time needed to sufficiently break down the food in the stomach. Food stays in your stomach longer, making you feel full longer.
Proteins are not equally digestible; their proteolytic susceptibility varies depending on their source and processing method. Incomplete digestion increases the fermentation of microbial proteins in the colon (putrefaction), which produces toxic metabolites that can induce inflammation in vitro and have been associated with inflammation in vivo. To avoid putrefaction-induced intestinal inflammation, protein sources and processing methods must be adapted to the consumer's digestive capacity. Proteins that are easy to digest have shorter amino acid chains, while those that are more difficult to digest have longer chains.
Fast-digesting proteins tend to be lower in essential amino acids, while slow-digesting proteins tend to be higher. Unless you eat it raw, the first step in digesting an egg (or any other protein food) is to chew it. The teeth begin to mechanically break down large pieces of eggs into smaller pieces that can be swallowed. The salivary glands provide some saliva to facilitate swallowing and the passage of the partially crushed egg through the esophagus.
The crushed egg pieces enter the stomach through the esophageal sphincter. The stomach releases gastric juices that contain hydrochloric acid and the enzyme pepsin, which initiate the breakdown of protein. The acidity of the stomach facilitates the deployment of proteins, which still retain part of their three-dimensional structure after cooking, and helps to break down the protein aggregates that form during cooking. Pepsin, which is secreted by the cells that line the stomach, dismantles protein chains into ever smaller fragments.
Individual human beings differ in their digestive capacity for proteins according to phenotypes, in particular disease states. Beyond measurements of ial digestibility and protein digestibility, less invasive, rapid and economical techniques are needed to monitor the degree of digestion and fermentation of proteins in order to personalize protein nutrition. Biomarkers of the digestive capacity and efficiency of proteins can be identified with sets of tools such as peptidomics, metabolomics, microbial sequencing and multiplexed protein analysis of fecal and urine samples. By monitoring the digestive function of individual proteins, diets can be adapted by selecting the right protein source and processing it to suit individual needs in order to minimize colon decay and thus optimize gut health.
If you're looking for a convenient way to get all three types of proteins - whey, casein and egg - into your diet without artificial sweeteners or flavors, consider a high-quality protein powder blend like whey/casein/egg powder mix. More research is needed to fully understand the consequences of oxidation on protein digestibility. This means that any extra protein will go to other parts of your body or be excreted through your urine.
