What are substances not absorbed into the bloodstream from digestive system?

The substances that are not absorbed into the bloodstream from the digestive system are dietary fiber, certain plant compounds, some minerals, and some types of carbohydrates.

Dietary fiber: Dietary fiber is a type of complex carbohydrate that the human body cannot digest. It is found in plant foods such as fruits, vegetables, whole grains, and legumes. Dietary fiber helps to promote regularity and can help to lower cholesterol levels.

Certain plant compounds: Certain plant compounds, such as tannins and polyphenols, are not absorbed into the bloodstream. These compounds can help to protect the body from damage caused by free radicals.

Some minerals: Some minerals, such as iron and calcium, are not absorbed into the bloodstream very well. The absorption of these minerals can be improved by consuming them with foods that are rich in vitamin C.

Some types of carbohydrates: Some types of carbohydrates, such as resistant starch and oligosaccharides, are not absorbed into the bloodstream. These carbohydrates can help to promote the growth of beneficial bacteria in the gut.