But just because you have a gym membership that you actually use doesnât mean you canât also have a few things at home for doing other types of workouts that you donât have time for at the gym, or for those days that you just canât make it out the front door.
The inside wall of the small intestine needs to be thin, with a really big surface area. This allows absorption to happen quickly and efficiently. If the small intestine had a thick wall and a small surface area, a lot of digested food might pass out of the body before it had a chance to be absorbed.
Absorption of most of the B vitamins happens further down in the small intestine, in the ileum. The other type of vitamin, the fat-soluble ones such as A, D, E and K, need to dissolve in fat before they can make it into the body.