Re: Which takes longer to digest, soluble fibre or protein?

Hello. Fiber can interfere with the absorption of minerals. As a matter of fact, I've just answered that question, ( Does fiber interfere with the absorption of calcium). Don't worry though, as Oscar Wilde wrote, "I may have said the same thing before...but my explanation, I am sure, will always be different."

It is insoluble fiber that is a concern regarding the binding of minerals, but only when eaten in excess. However, keep in mind that foods usually contain both soluble and insoluble fiber. For example, 1 cup of cooked oatmeal has about 2 grams of soluble fiber and 1.8 grams of the insoluble type. All-Bran consists mostly of insoluble fiber, but may contain up to 25% soluble fiber, while carrots contain almost equal amounts of both.

Various types of soluble fiber bind with bile acids, resulting in a decrease in blood cholesterol. The effects of a high-fiber diet regarding the binding of minerals is insignificant, with benefits far outweighing any inherent risks. The binding of minerals is not due to the indigestibility of fiber, but rather to natural chemicals found in them, such as, phytic acid and oxalic acid.

There is no biological reason why you need to separate foods into a certain order. The body is more than adept at handling food in any sequence it goes in. Besides, most food comes packaged in various nutritive components anyway, such as; carbohydrates, protein, fat, vitamins, minerals, water and hundreds of other chemicals.

The digestive system starts breaking down such components in the mouth, then mashes it up in the stomach, and breaks it down further in the small intestine, where nutrients get absorbed into the bloodstream. This is the point where we say that nutrients are digested. The remaining undigested material is called fiber, which travels down the colon into the rectum, where it exits. Obviously, fiber's trip takes much longer than does protein. Protein takes about 2 to 3 hours to digest, whereas it can take 14 to 30 hours before undigested material passes through. (For more on this see my answer on: " How long does the entire digestive process take?").

We humans are an omnivorous species, so consequently our digestive system was designed to handle just about any food in any sequence one could think of. The main problem regarding food in today's society in affluent nations, such as the United States, is not the combination of foods, but rather its overconsumption.

Hope that helps,

Peter Bosani.

References:  Food and Nutrtion - Life Science Library
             Data from Plant Fiber in Foods - James W. Anderson