Fiber or dietary fiber is a plant component characterized by β-type chemical bonds and is NOT digestible for humans; however, although not considered a real nutrient, fiber is certainly a very important food component for the correct functioning of the body, in particular the intestine.
Soluble and insoluble fiber
Fiber is divided into soluble and insoluble , and performs numerous functions; between these:
- It gives a sense of satiety
- It regulates intestinal peristalsis and promotes the systematic evacuation of feces
- Removes waste from the intestines
- Modulates/slows down the absorption of fats and sugars
- Limits the absorption of cholesterol
- Reduces glycemic and insulin surges
- Partially feeds the intestinal bacterial flora
What is that
A diet low in fiber decreases fecal volume and hinders the physiological (nervous) process of triggering peristaltic segmentation and advancement contractions.
On the other hand, although the collective tendency is to eat LITTLE fiber compared to the recommendations (which suggest around 30g/day), in certain “pathological” cases it is necessary to drastically limit it to reduce unwanted disorders or symptoms ; This diet is called a low-fiber diet or low-residue diet .
Who is it suitable for?
The function of the low fiber or low residue diet is to reduce the laxative effect on the digestive tract ; the cases in which it may be necessary to apply it are mainly:
- Irritable bowel syndrome
- Colitis (inflammatory, infectious, chemical, etc.)
- Intolerances and allergies
- Pharmacological therapies
- Radioactive therapy
- Intestinal resection (for tumor, Crohn’s disease , or ulcerative colitis )
- Preparations for endoscopic diagnostic investigations of the intestinal tract (e.g. colonoscopy )
Logically, when normal physical conditions are restored (if possible), the low residue diet should be interrupted by replenishing the recommended amount of dietary fibre.
In practical terms, the low fiber or low residue diet is a nutritional scheme poor in fruit , vegetables , cereals and legumes which, if present, MUST be processed/refined in order to eliminate at least the typical external covering (peel, pericarp or other fibrous integuments, etc.) notoriously rich in this element (essentially, whole grains should be avoided ).
Although not correlated with the intake of dietary fibre, milk and dairy products (or foods containing them) can also be limited/interrupted in the administration of the low residue diet; this choice is not random and is based on the concept that, in most intestinal suffering, the lactase enzymes present on the mucosa are drastically reduced, causing bacterial fermentation of lactose and the consequent associated symptoms (see food intolerance to lactose ). To correctly manage the low residue diet it is advisable:
- Scrutinize food labels carefully
- Make sure each food serving provides no more than 1g of total fiber .
See an Example of a Low Residue Diet »
Cooking methods for the low-fiber or low-residue diet are moderate and nonviolent; they should never excessively trigger the Maillard reaction and/or the production of molecules that are toxic/irritating to the intestinal mucosa ( acrylamide , acrolein , polycyclic aromatic hydrocarbons , etc.). The following are recommended: boiling, steaming , microwave cooking and pressure cooking ; in case, even slow stewing . Grilling , frying , toasting and baking at very high temperatures without a lid are NOT RECOMMENDED . Another useful tip is to avoid or not use too much spices , such as pepper , chilli , curry , coriander , cumin , etc.
- In the event that the low residue diet causes an excessively “stringent” effect on the stool, it is advisable first of all to increase the water intake (compromised by the elimination of fruit and vegetables ) and, only at a later time, to reintroduce the fiber little by little.
- The low fiber or low residue diet determines a secondary reduction of a good portion of mineral salts ( magnesium , potassium , etc.), vitamin C , B-carotene and vitamin K ; It is therefore advisable to evaluate together with your doctor the possibility of using a good food supplement to maintain sufficient nutritional intake of these nutrients .