Wellness Wednesday – Protein Absorption & Utilization

By: Ed Lippie

For decades, nutritional science has taught us that protein absorption is limited to an ambiguous range of 20ish-50ish grams per serving based on the body weight of the individual consuming it. Conventional wisdom indicates that any amount of protein over the weight-dependent dose of 1.2-1.6 gms/kg would be oxidized as energy while putting undue strain on your kidneys. However, a recently published study in Cell Reports Medicine suggests that the upper absorption limit may be considerably higher than previously thought. In fact, there may be no upper limit in volume or duration. 

This means that more significant amounts of protein (50-100gms) consumed in a single meal may be fully utilized by the body as part of muscle protein synthesis (MPS) over an extended period, much longer than previously believed. Meanwhile, other research has revealed that a minimum dose of leucine-rich protein is required to trigger MPS. Leucine is an essential amino acid and is critical in initializing MPS, I’ve listed Leucine rich foods below for your convenience. This emerging body of work in the study of protein absorption is essentially raising the floor for adequate protein intake while simultaneously raising the ceiling for what can be used by the human body.

Leucine Rich Foods:

1. Chicken & Turkey
2. Beef
3. Salmon
4. Soy Beans
5. Legumes 
6. Tuna

Continuing to divide .8-1.0 grams of protein per pound of body weight across three meals per day still seems to be the best strategy to maximize MPS and optimize health, especially during the second half of life when anabolic processes are challenged to a greater degree. The latest peer-reviewed research I’ve referenced establishes a wider margin for error on the high side, allowing more protein to be eaten and utilized from high-protein meals.