T Nation

Can Fiber Affect Absorption?

Hey…I remember reading somewhere a while back that fiber can affect protein and other nutrient’s absorption into the body. I’m just curious how much it affects it, if there is any truth to this in the first place.

I’ve been taking Metamucil twice a day (long story – let’s just say I have to) and also eating salad and fruits/vegetables as well. Now there’s now way I can stop taking in this fiber, but I can add more protein if need be.


Consuming a lot of some types of fiber can interfere with mineral absorption by binding to minerals in the intestines, but the degree to which that occurs is minimal. So, if you are consuming adequate minerals, there is no need to worry.

As for fiber interfering with protein absorption …I’ve never read nor heard anything about that. It may interfere with protein and other macronutrients if you consume so much that it displaces energy- and nutrient-dense foods. Otherwise, eating protein and fiber together is nothing to be concerned about.

I think the worries about protein absorption are related to how fast stuff moves through the GI - basically, if you’re taking in so much fiber that it gives you explosive shits all the time, protein isn’t absorbing correctly. Unless you’re painting your siding a lovely shade of brown, though, I wouldn’t be concerned (as Angelbutt said).


Fiber doesn’t give you explosive shits unless you are adversely reacting to the food that contained the fiber. The right amount of fiber will keep digestion functioning at a pace that facilitates adequate absorption. It keeps things regular, so to speak…not too fast and not too slow.

Plus, the more fiber you eat does not perfectly coincide with faster digestion; too much fiber can actually block the intestines.

Bottom line: Eat fiber, but don’t overdo it.

Ooh, I made a mistake in my last post.

Too much fiber CAN give you diarrhea. What happens is that, although fiber absorbs water to make stool bulkier, too much fiber at once absorbs water faster than it can handle, causing diarrhea.

Okay, I feel better now :slight_smile:

My apologies.