There are eight water-soluble B vitamins (collectively referred to as the B-complex vitamins) and vitamin C. This family of nutrients is called water-soluble because they dissolve in water (not in fat, like the fat-soluble vitamins).
Digestion and Absorption
Your body generally digests and absorbs all water-soluble vitamins in similar ways. They are absorbed mostly in the smaller intestine and to a lesser degree in the stomach. They are then routed to the liver via the blood. Most water-soluble vitamins are bound to proteins that enzymes must remove before they can be absorbed. It is from this reason that many of the B vitamins are found in animal proteins.
Absorption of these vitamins can be affected in many ways. For instance, if digestion is not working properly, enzymes may not be able to remove the vitamin from the protein. Certain medications and other nutrients and substances in food can also block absorption.
The body does not store these vitamins, so they generally do not have toxic effects when taken in large amounts. However, this is not recommended. Like many other nutrients, synergy is also important for the water-soluble family, so vitamin C and the B vitamins are best when taken in their natural forms.
Is this why B vitamins are best taken as a "complex"? Read on to the next section to find out!