For an individual of any age, fibre is a significant factor to consider when planning which foods to eat. It can be broken up into two definitions. The first of which is called dietary fibre. Non-digestible carbohydrates (as well as lignin), that are intrinsic and intact in plants, fit into this category. The second definition is known as functional fibre, comprised of isolated, non-digestible carbohydrates, that are extracted or manufactured in order to provide benefits to humans. If determining the total amount of fibre consumed during a certain time period, one would identify the sum of their dietary and functional fibre intake.
Fibre can also be sorted into two different boxes. Labelled “soluble”, the first one would contain pectin, gums, and mucilages. Some foods that possess these compounds are fruits, legumes, oats, and particular vegetables. Deemed “insoluble”, cellulose, hemicellulose, and lignin would be found in the second box. Examples of foods that are sources of these items are cereals, grains, nuts, seeds, and corn bran, as well as specific fruits and vegetables. This type of fibre cannot be used by the health-promoting bacteria that reside in the colon (also called the large intestine), whereas soluble fibres can.
There are a number of effects on nutrient digestion and absorption that can be attributed to fibre. Firstly, it delays the emptying of the stomach while altering (speeding up) the transit time of foods in the small intestine. In addition, it lowers the function of digestive enzymes, the diffusion of nutrients, the glycemic response to food items, and lipid absorption. Lastly, fibre increases the release of bile acids and decreases cholesterolemia, in other words, the presence of cholesterol in the blood. An important note is that energy for the body cannot be obtained from cholesterol.
Mentioned previously, soluble fibres are fermented by the health-promoting bacteria that line the colon. Due to the fermentation of fibre, these bacteria can acquire energy and other substances, such as nitrogen, that support their growth. This process of fermentation produces short-chain fatty acids, which can be used by the body with beneficial results. It occurs primarily in the cecum (a pouch that is sometimes referred to as the beginning of the large intestine and joined to the appendix) as well as in the ascending portion of the colon (the first part of this organ).
Short-chain fatty acids are the cause of many outcomes within the digestive tract. They stimulate water and sodium absorption into the mucosal cells of the large intestine, plus support the differentiation of these same cells. Furthermore, they reduce the acidity levels in this organ, which lowers the dissolvability of bile and raises the extent of calcium binding to bile and fatty acids. It is maintained that this possibly exerts a protective effect against colon cancer. They also offer energy for colonic cells and inhibit hepatic (associated with the liver) cholesterol synthesis. Finally, short-chain fatty acids enhance both the blood flow in the large intestine and the immune function in this area, as well as prevent the growth of cells that might be harmful to the body.
In terms of insoluble fibres, the substances that are classified as such are either poorly utilized or non-fermentable. However, they play a crucial role in the improvement of colonic health through exerting a detoxifying effect.
Surrounding recommendations for fibre intake, Health Canada has put forth a daily reference value as of 2019. For a 2000 calorie diet, they suggest the consumption of 25 g of fibre. The World Health Organization offers a more general direction, also decided in 2019, of 25 to 40 g in regards to daily fibre. For adults who are 50 years of age or older, the above recommendations apply.
When considering how to meet one of the guidelines, this can be done by ingesting certain foods on a regular basis. These include whole-grain products, vegetables, fruits, and legumes. While the importance of obtaining a healthy amount of fibre from the diet is highlighted here, it is equally important to achieve and maintain variety (when it comes to energy intake) as much as possible. This can be applied to both fibre-rich foods along with other meals and snacks that provide different nutritional benefits.
According to Mayo Clinic, the following recipes (among a long list on the website) contain a high amount of fibre:
- Artichoke dip
- Chicken and zucchini quesadilla
- Crispy potato skins
- Grilled pineapple
- High-calorie, high-protein smoothie (lactose-free or otherwise)
- Strawberry shortcake
- Black bean wrap
- Grilled cod with crispy citrus salad
- Macaroni and cheese
- Pasta salad with mixed vegetables
- Quinoa stuffed peppers
- Shepard’s pie
- Vegetarian chili with tofu
- Veggie pizza
- Beet burgers
For information on further dishes and how to create the ones mentioned above, the page found at this link can be visited and explored: High-fiber recipes. The remainder of the material presented was retrieved from Dr. Rolando Ceddia