The body needs vitamins and minerals to function properly, and the way these nutrients are absorbed can have a major impact on overall health. Fat-soluble vitamins A, D, E and K are absorbed in the intestinal lumen using the same mechanisms used for other lipids. Water-soluble vitamins C and B are absorbed directly into the blood during digestion, but they are also easily eliminated in the form of urine. This means that these vitamins must be replenished regularly for the body to have enough.
The small intestine is where vitamin absorption occurs, along with most other types of absorption. Water-soluble vitamins, such as vitamin C, have active means of transport for their absorption: molecules that collect them in the small intestine, in a section called the jejunum, which is approximately halfway through. These transports transport vitamin molecules through the cell walls of the intestine and deposit them in the body, where they can enter the bloodstream. Drinking plenty of fluids can improve the body's ability to absorb and transport these nutrients through diffusion.
For every vitamin or mineral deficiency, your body can begin to experience unique, serious, and rapid dysfunctional effects. Too much stomach acid can destroy some supplements before they can be absorbed, but an insufficient amount of acid will not allow certain vitamins, such as vitamin B12, to be well absorbed. Multivitamins or traditional vitamins are meant to save time to make sure you're getting all the vitamins you need. Eating a variety of fruits and vegetables of all colors is also recommended to ensure you're getting all the vitamins and minerals you need.
In addition, both water-soluble vitamins and minerals require specialized “transporters” found in the lining of intestinal cells to cross cell membranes and reach the blood. Fat-soluble vitamins and supplements, such as vitamin D and curcumin, should be combined with a fat source for more efficient absorption. This inhibition was not generalized to all members of the B vitamin family, since the absorption of riboflavin, folate and biotin was not affected (R). It is now well established that the intestinal absorption of water-soluble vitamins ascorbate, biotin, folate, niacin, pantothenic acid, pyridoxine, riboflavin and thiamine is carried out through specific processes mediated by transporters. In HSVCT1—YFP, the protein has been shown to be expressed exclusively in the apical membrane domain of these cells (see Figure 1 for a schematic representation of the membrane domains in which well-characterized vitamin transporters, including those of ascorbate, are expressed in intestinal epithelial cells).
Deficiency of this vitamin leads to a variety of clinical abnormalities including scurvy, poor wound healing, vasomotor instability, and connective tissue disorders. There are many factors that influence how vitamins and supplements are absorbed by the body. To maximize nutrient absorption it is important to consider two key points: drinking plenty of fluids to improve diffusion; and combining fat-soluble vitamins with a fat source for more efficient absorption.