Jun 25 , 2021
Written by Alexandra Spring
Why We Need Fibre
Fibre, that almost-nutrient we often associate with bland bran cereals, does more for us than prevent constipation. Not only are there many different ways to get enough fibre, but it can also benefit our cardiovascular health, prevent digestive system inflammation, and even prevent some cancers.
What Is Fibre, And Where Do We Find It?
Fibre is made up of indigestible carbohydrates, and can be either insoluble or soluble. Insoluble fibre and its benefits are more widely known, as it is the type responsible for preventing constipation. It doesn’t dissolve in water, instead it draws water into the colon and increases the size of bowel movements so we can remove toxins more readily. Soluble fibre dissolves into a gel that helps to feed beneficial gut bacteria. Potatoes, fruit peel, green vegetables, nuts and seeds are some sources of insoluble fibre. Sources of soluble fibre include oats, beans, legumes and some vegetables.
Some of the best sources of fibre include:
- Avocadoes, with 10 grams of fibre per cup (150 grams) on average.
- Artichokes, containing around 10 grams of fibre per 120-gram vegetable.
- Black beans, with 15 grams of fibre per 172-gram cup.
- Coconut, with 7.2 grams per 80-gram cup
- Flaxseeds, with 2.8 grams of fibre per tablespoon (10 grams).
- Lentils, containing almost 16 grams per 200-gram cup.
- Split peas, containing around 16.3 grams per cup (almost 200 grams).
Fibre And Gut Health
The most well-known benefit of fibre is its ability to relieve constipation, but how effective is it? Some studies don’t find any improvement in constipation, especially with isolated fibre supplements. Research comparing wheat bran with psyllium, however, found that psyllium is 3.4 times more effective in increasing bowel movement volume and water content. This effect leads to reduced constipation and straining. On the other hand, wheat bran can make bowel movements harder and more difficult to pass, and draws in water by an irritating effect. Psyllium is more soothing; you can sprinkle it onto cereal or add it to homemade pancakes.
Optimal fibre intake could also reduce the risk of inflammatory bowel disease (IBD), which includes both ulcerative colitis and Crohn’s disease. While ulcerative colitis only affects superficial layers of the large intestine, Crohn’s disease can involve the entire digestive system and penetrate the deep layers. Compared to the lowest category, people in the highest category of fibre intake had a 20% lower risk of ulcerative colitis, and a 56% reduced risk of Crohn’s disease.
Some of fibre’s anti-inflammatory properties come from one of its fermentation products, butyrate. Butyrate can protect the integrity of your intestinal lining, which prevents more inflammation as a result of tissue damage and bacteria moving into the bloodstream.
Fibre And Cardiovascular Health
Cardiovascular disease is the top cause of death globally, but improving your diet and lifestyle has profound protective effects. A combination of high cholesterol, inflammation and high blood pressure is the typical origin of cardiovascular disease.
We know that fibre can help to lower inflammation, and it may reduce cholesterol too. A study comparing oat porridge to wheat noodles found that the fibre in oats can significantly cut cholesterol levels. Replacing the noodles with 100 grams of oat porridge led to a drop in total cholesterol from 6.26 to 5.85mmol/L, and in the “bad” LDL cholesterol from 4.3 to 3.91mmol/L. The reason why it worked was that the soluble fibre in oats, known as beta-glucans, is able to increase bile acid secretion and change its metabolism. Bile acids are made from cholesterol, and if they are reabsorbed they may be changed back.
Fibre May Reduce Your Risk of Cancer
As roughly 40% of people are statistically expected to develop cancer in their lifetime, we need prevention. Fortunately, increasing our fibre intake may be one simple method of protection.
Breast cancer is one of the most common types of cancer in the world. However, a research review demonstrates a 12% reduction in breast cancer risk between the highest and lowest fibre intakes, with a 4% drop in the disease from every 10-gram increase in consumption. Fibre is thought to protect against cancer by binding to toxins, both metabolic waste products and environmental pollutants. These include old oestrogens, that may be reabsorbed and stimulate breast tissue growth without fibre.
Another common type of cancer is colon cancer, which has polyps as a transition stage between normal tissue and dangerous tumours. Research on a high-fibre, low-fat diet rich in fruit and vegetables found that people who followed their dietary advice had a 35% lower risk of polyps returning. As the above study on breast cancer also discussed, fibre is used as a food source for anti-inflammatory, tissue-protecting species of bacteria, and is fermented into short-chain fatty acids, which may also have a protective effect against inflammation and cancer.
Fibre does much more for us than relieve constipation. It can help reduce digestive inflammation, prevent cardiovascular disease and even lower our risk of certain cancers. However, the type of fibre matters. Supplements and wheat bran are often irritating, ineffective and boring, while oats, psyllium and a wide range of fruit and vegetables can fit into many recipes and are more helpful.