The absorption of most nutrients occurs in the small intestine, while water absorption occurs mainly in the large intestine, which is the final part of the intestinal tract.
However, before being absorbed, foods need to be broken into smaller pieces, process that starts from chewing. Then the stomach acid helps digest the proteins and as the food goes through the intestine, it is being digested and absorbed.
Absorption of nutrients in the small intestine
The small intestine is where most of the digestion and absorption of nutrients takes place. It is 3 to 4 meters long and is divided into 3 parts: duodenum, jejunum and ileum, which absorb the following nutrients:
- Fats;
- Cholesterol;
- Carbohydrates;
- Proteins;
- Water;
- Vitamins: A, C, E, D, K, complex B;
- Minerals: iron, calcium, magnesium, zinc, chlorine.
The food ingested takes about 3 to 10 hours to run through the small intestine.
In addition, it is important to remember that the stomach participates in the process of alcohol absorption and is responsible for the production of the intrinsic factor, substance necessary for the absorption of vitamin B12 and prevention of anemias.
Absorption of nutrients in the large intestine
The large intestine is responsible for the formation of feces and is where the intestinal flora bacteria, which help in the production of vitamins K, B12, thiamine and riboflavin.
The nutrients absorbed in this part are mainly water, biotin, sodium and fats made with short chain fatty acids.
The fibers present in the diet are important for the formation of feces and help the passage of the fecal cake through the intestine, being also the source of food for the intestinal flora.
What can impair the absorption of nutrients
You should be aware of diseases that may impair the absorption of nutrients, as it may be necessary to use dietary supplements recommended by your doctor or nutritionist. Among these diseases are:
- Short bowel syndrome;
- Ulcers in the stomach;
- Cirrhosis;
- Pancreatitis;
- Cancer;
- Cystic fibrosis;
- Hipo or Hyperthyroidism;
- Diabetes;
- Celiac disease;
- Crohn's disease;
- AIDS;
- Giardiasis.
In addition, people who undergo surgery to remove part of the intestine, liver or pancreas, or who use colostomy may also have problems in absorbing nutrients, and should follow the doctor's or nutritionist's recommendations to improve nutrition. See the symptoms of cancer in the gut.
