How food is digested part 2


So following on from last week’s blog, we are moving with our food through the body into the next stage of the digestive tract which is the small intestine. The small intestine is the longest part of the digestive tract, and is between 6-7 metres long made up of one, very bent and twirly muscular tube which ensures that food is broken down enough and has the right chemicals added for the body to absorb it easily.

The first part of the small intestine is the duodenum which receives the food released from the stomach and is where all the chemicals such as enzymes are mixed in. The duodenum is the shortest part of the small intestine, but is responsible for absorbing nutrients such as calcium, iron, different B vitamins, fat soluble vitamins such as A, D, E, and K, magnesium, and phosphorus to name a few! Food is then pushed along through muscular contractions to the jejunum, where more nutrients are absorbed through little finger like projections called villi. There are millions of villi in your digestive tract, and this ensures that as many nutrients as possible can be absorbed. Nutrients such as folate, vitamin B6, vitamin C, thiamine, riboflavin, niacin, and a variety of those that are absorbed in the duodenum get another chance to be absorbed in the large intestine. Some fats, carbohydrates, and proteins in their smallest forms are absorbed in the jejunum at both the start and end points.

Food then passes on to the ileum which is the final part of the small intestine where more absorption occurs (this is why it is so long! To give all the nutrients as chances to be absorbed in the best amount possible). The ileum is the longest section of the small intestine, and it is where products such as bile salts and acids are absorbed to be reused by the body again, and where nutrients such as vitamin C, vitamin B12, folate, vitamin D and K are absorbed to name a few.  The food has begun looking very different by this stage of the digestive process.

From there the food passes through into the large intestine, otherwise known as the colon (and goes past the appendix), where it takes a journey up, across, and down to reach the end point of the rectum where stool is held under it is released. In the large intestine, water, sodium, chloride, potassium, vitamin K, and biotin are absorbed as the mass of food (which no longer looks like food) passes through. The muscles in the large intestine are circular, and push the mass through by contracting and moving like a Mexican wave! (just for a visual). Food is then excreted when the bowels tell them brain to release, or when new food makes its way into the small intestine and needs to remove the product at the end of make way for new food to be digested.

The end point of food matter being passed from the body probably doesn’t need a description. But know the wonderful process of how food passes through the body and how nutrients are absorbed has been laid out in a simple way for all to see.

If you do have any questions, please consult one of our Accredited Practising Dietitians.