What is dietary fibre?
Dietary fibre is a carbohydrate and the structural part of plant foods – such as vegetables, fruits and grains. Unlike other carb sources, dietary fibre is a non-glycemic carbohydrate. The human body is unable to digest or breakdown fibre, meaning that it cannot be broken down into digestible sugar molecules, thus is not a source of absorbable glucose. Despite this, ingested fibre can be fermented in the colon to produce short-chain fatty acids which can be used as a source of energy. There are two kinds of fibre: soluble and insoluble.
Soluble fibre dissolves in water to form a gel like substance, enabling digestion to be slowed. This not only helps to lower blood cholesterol levels, but slowing digestion also allows blood glucose levels to remain steady, avoiding blood glucose spikes.
Some sources of soluble fibre include: fruits (apples, bananas, citrus fruits, pears, figs, prunes, strawberries, avocados, and apricots), vegetables (carrots, broccoli, brussel sprouts, green cabbage, and cauliflower), legumes (lentils, black beans, kidney beans, garbanzo beans, lima beans, and green peas), chia seeds, flax seeds, psyllium, barley, oats, and oat bran.
In contrast, insoluble fibre does not dissolve in water and works to stimulate the movement of intestinal content through the digestive system, this adds bulk to one’s stool. Insoluble fibre is of large benefit to help normalize bowel movements – preventing constipation and irregular stools. Insoluble fibre is of particular importance for those with inflammatory bowl diseases (IBD) as it helps to optimize gut health.
Some insoluble, fibre rich food sources include: nuts (almonds & peanuts), whole grains, cereals, wheat bran, whole-wheat flour, brown rice and the skins of various fruits and vegetables – like kiwis! 🙂
Recommendations for individualized dietary fibre intake depend on a number of factors such as age, gender, and energy intake. As a general guideline, it is recommended that Canadian women consume ~25 grams of fibre per day and men consume ~38 grams of fibre per day. Meeting these recommendations daily poses numerous benefits to your health!
The physiological roles and benefits of adequate dietary fibre consumption:
Individuals who consume adequate amounts of dietary fibre are at significantly lower risk for developing hypertension (HTN), type 2 diabetes, coronary heart disease (CHD) obesity, stroke, and certain gastrointestinal (GI) diseases. Here’s why:
- Sufficient fibre intake helps to lower blood pressure and serum cholesterol levels – Bile is a greenish-brown alkaline substance that aids in digestion. The liver uses blood cholesterol to make bile. On a high fibre diet, bile binds to fibre and is excreted in the feces. Alternatively, on a low fibre diet, much of the cholesterol in bile is absorbed back into the bloodstream, elevating ones blood cholesterol levels. Given this, soluble fibre helps to lower cholesterol by binding to bile. Abiding by a high fibre diet works to decrease cholesterol, reducing your risk of acquiring various cardiovascular diseases.
- An ample intake of soluble fibre improves glycemia and insulin sensitivity (helps control blood sugar levels) in both non-diabetic and diabetic individuals – Persistent elevated blood sugar levels leads to chronic insulin circulation. Chronic insulin circulation induces insulin resistance and/or impaired glucose tolerance, often leading to the development of type 2 diabetes. Eating adequate amounts of fibre avoids this by slowing the rate of digestion. This helps to better regulate blood sugar levels as levels remain relatively consistent and are not spiked rapidly. Additionally, ingesting adequate amounts of fibre acts as a glycemic index reduction, this enables the body to release insulin at a slower rate, again, controlling blood glucose levels and avoiding glucose spikes. This reduces ones risk of acquiring type 2 diabetes.
- Adequate fibre intake normalizes bowel movements – Without going into too much gross detail, adequate fibre intake both softens and increases the bulk of your stool, making it easier to pass – this limits constipation. Additionally, ample fibre intake limits diarrhea and watery stools by allowing for the absorption of water – this adds bulk to the stool and helps it to solidify. Eating adequate amounts of fibre mitigates both constipation and diarrhea, helping to maintain optimal bowel health.
- Sufficient fibre intake helps with weight control and has potential to enhance weight loss – Adequate fibre intake results in increased satiety, leading you to feel satisfied after meals and full for longer. Foods rich in fibre are more filling in comparison to low-fibre foods. This prevents both over eating and hunger between meals, often leading to a decrease in energy intake and weight loss.
- High fibre intake benefits numerous gastrointestinal disorders that are often seen with IBD such as: Gastroesophageal Reflux Disease (GERD), hemorrhoids, diverticulitis, duodenal ulcer, and constipation – A high intake of dietary fibre in comparison to a low dietary intake has potential to alleviate negative GI discomfort, minimize symptoms, lessen gastric acid production, reduce reoccurring inflammation, and is likely to be a protective measure and prevent the reoccurrences of flare ups. For these reasons, a high fibre diet is often suggested for the management and prevention of various GI issues. It is important to keep in mind that individual nutritional needs vary. Specifically for those with GI complications, foods that cause GI discomfort vary based on the individual. For those with GI disorders consult a health professional prior to making drastic changes to your diet!
- Prebiotic fibres have potential to enhance immune function (& are GREAT for your gut health!!) – Non-digestible carbs (such as probiotics and fibres) can be fermented in the colon, promoting the stimulation of the growth of beneficial bacteria in the colon. This encourages the generation of short-chain fatty acids, in turn stimulating the immune system.
For these reasons, fibre is an important part of your diet!
If you intend to increase your fibre intake, add fibre to your diet slowly and increase the amount gradually. Increasing your fibre intake too quickly has potential to result in negative implications such as abdominal bloating, stomach cramping and constipation. Additionally, increasing your fibre intake gradually gives the bacteria naturally present in your GI tract a chance to adjust to the change.
Tips for increasing dietary fibre in your diet:
- Choose whole grain products more often – try sources such as barley, wild rice, brown rice, whole-wheat pasta, bulgur wheat, buckwheat, whole wheat couscous, quinoa, wheat germ, lentil pasta, and edamame pasta.
- Sneak fibre into your cooking and baking – some examples include: substituting whole-grain flour into baked goods, adding seeds (chia or hemp) to spaghetti sauces, adding beans and lentils into soups, or adding a few tablespoons of fibre rich food sources into snacks like yogurt bowls, smoothies, and cereals. This is an easy way to boost your fibre content and often you can’t even taste it!
- Consume more fruits and vegetables – not only are fruits and veg rich in fibre, but rich in various vitamins and minerals too!
- Incorporate more legumes into your diet – eating more plant based food sources will not only boost your fibre intake but will come with various other benefits to your health!
- Choose snack foods that are rich in fibre – choose snack foods such as granola bars, cereals, crackers, gorps, granolas, and even popcorn that are rich in fibre.
- Take time to read nutrition labels while grocery shopping – choose products that contain a high amount of fibre. Foods that contain at least four grams of fibre per serving are considered a rich source of fibre. Foods “very high” in fibre have at least six grams per serving.
- Consider a fibre supplement – Although meeting your daily fibre recommendations through whole foods in comparison to a fibre supplement is preferred, if you find yourself habitually failing to consume an adequate amount of fibre, a fibre supplement may be a good idea. Consult a health professional prior to taking fibre supplements as some have potential to result in negative health implications.
So….Why is fibre a staple in your diet?
Fibre is an important part of your diet for numerous reasons as it poses many benefits to your health. In addition to the discussed advantages of consuming an adequate amount, fibre is a great source of various vitamins, minerals and antioxidants. To reap the benefits of fibre, you need to drink adequate amounts of water – fibre depends on water! When abiding by a high fibre diet, drinking enough water is particularly important as this prevents constipation and promotes movement throughout the GI tract.
Fibre is an important staple in your diet for the many benefits it has to your health!
Enjoy your weekend, I hope it’s filled with fibre!
Anderson, J., Baird, P., Davis Jr, R., Ferreri, S., Knudtson, M., & Koraym, A. et al. (2009). Health benefits of dietary fiber. Nutrition Reviews, 67(4), 188-205. doi: 10.1111/j.1753-4887.2009.00189.x
Health Canada., (2019). Fibre – Canada.ca. Retrieved 23 March 2020, from https://www.canada.ca/en/health-canada/services/nutrients/fibre.html
High Fiber Diet: Types of Food & Health Benefits. (2019). Retrieved 25 March 2020, from https://my.clevelandclinic.org/health/articles/14400-improving-your-health-with-fiber