An absorption factor is the measurement of a specific substance's ability to absorb radiant energy.
It is called intrinsic factor, which enables the absorption of B12. Intrinsic factor is found in the parietal cells (mucosa cells) of the stomach lining.
If you want just one factor, body weight could be it. Heart rate can also affect absorption rates. Muscle to fat ration can affect absorption. Whether you have recently eaten or drank water can be a factor. Alcohol can also affect absorption rates. Pick one I guess.
b12
The MFP factor is a special factor found in meat, fish, and poultry that enhances iron absorption.
"Intrisic factor" is necessary for B12 absorption
Intrinsic factor
An essential factor is the absorption of carbon dioxide from the atmosphere; also the acid rains.
Kitchen paper is designed to have a high absorption factor.
B12 is the vitamin that requires intrinsic factor for absorption. B12 is also known as cobalamin.
One factor that affects the rate of absorption is the molecule size. Particle size, lipid water solubility, and the degree of ionization are also three other factors that affect the rate of absorption.
Intrinsic factor, which is made in the stomach.
Intrinsic factor is secreted by the parietal cells and is critical for absorption of B12. When the body attacks the parietal cells b12 deficiency results which is called "pernicious anemia."