Wheat bran and whole grains, as well as the skins of many fruits and vegetables, and seeds, are rich sources of insoluble fibre. The outer fibre layer is often removed in food processing by milling, peeling, boiling or extracting and so people are often not eating enough insoluble fibre.
Insoluble fibre makes stools heavier and speeds their passage through the gut. Like a sponge, it absorbs many times its weight in water, swelling up and helping to eliminate feces and relieve constipation.
Soluble Fibre
Soluble fibre is found in oats, legumes (peas, kidney beans, lentils), some seeds, brown rice, barley, oats, fruits (such as apples), some green vegetables (such as broccoli) and potatoes.
Soluble fibre breaks down as it passes though the digestive tract, resulting in a gel that traps some substances related to high cholesterol. Evidence exists that soluble fibre may reduce heart disease risks by reducing the absorption of cholesterol into the bloodstream.
Recent studies have found that people consuming high-fibre diets have lower total cholesterol levels and may be less likely to form harmful blood clots than those who consume less soluble fibre. A recent USA report found that, in sufficient amounts, fibre apparently reduced heart disease risks among men who ate more than 25 grams per day, compared to those consuming less than 15 grams daily.
Why we need dietary fibre
Let’s take a good look at how fibre can help us:
Insoluble fibre:
- Delays gastric emptying time and the absorption of nutrients from the small intestine;
- Sweeps debris out of the gut, thereby improving nutrient absorption;
- Bulks stools;
- Accelerates colonic transit time;
- Regulates bowels better than other laxatives;
- Promotes colon health;
- Supports weight loss;
Soluble fibre has the following benefits in addition to the benefits above!
- Escorts cholesterol and triglycerides out of the body and inhibits their production in the liver;
- Assists with the elimination of toxins, and heavy metals in the body;
- Stimulates pancreatic enzyme release and activity;
- Stabilizes blood glucose by slowing down glucose absorption;
- Aids in weight loss by providing a feeling of fullness and reducing calorie absorption;
- Improves bowel regularity by absorbing water;
- Speeds the passage/elimination of waste from your system, by significantly increasing colonic transit time;
- Eases irritable bowel syndrome (IBS) in some cases;
- Soothes our intestines;
- Helps to stabalise blood sugar levels: We have all experienced blood sugar fluctuations, which cause us, for example, to be fine one minute and exhausted the next. Soluble fibre from legumes, barley and oats can help to regulate blood sugar swings by delaying the intestinal absorption of sugar and so helps to maintain energy balance in the body;
- Protects against heart disease: Several large studies in America, Finland and Norway have found that people who eat relatively large amounts of wholegrain cereals have significantly lower rates of heart disease and stroke. It’s thought that a particular type of fibre called soluble fibre may be partly responsible as it helps to lower blood cholesterol levels;
- Reduces excess blood fats;
- Combats constipation;
- In the bowel, bacteria convert fibre into short chain fatty acids, which provide energy for the body and may help protect against cancer;
- Mucilage sooths irritated intestinal linings;
- Feeds friendly bowel bacteria;
- Escorts bile acids, toxins and cholesterol out of the body;
- Lowers the GI of carbohydrates by stabalising insulin function.
On the reverse side, not having enough fibre in the diet is at least partly responsible for a number of problems, including:
- Elevated cholesterol;
- Low and high blood sugar levels;
- Bowel stagnation;
- Colon cancer and other cancers;
- Diabetes;
- High blood pressure;
- Certain types of heart disease.
The Department of Health recommends that you consume a minimum of 18 grams of dietary fibre per day, from a variety of foods whose constituents contain fibre. Although it does not differentiate between types of fibre.
Research suggests that 35-50 grams (1-2 ounces) per day brings optimum bowel health for adults, but the average person only gets about 12 grams per day.
Where do I get fibre? What are high fibre foods?
Foods from plant sources are the only ones that supply us with enough fibre necessary for health. Animal products lack fibre. High fibre foods include:
- Unprocessed seeds like flax, psyllium, sesame, sunflower and chia, and nuts (but not the oils from them);
- Wheat, oat, barley, and rice bran and other whole grains such as brown rice (but not the white rice or white flour made from them);
- Certain vegetables such as beets, asparagus, broccoli, artichokes, carrots, brussels sprouts, parsnips, spinach, and yams (excluding one-celled greens);
- Mucilaginous herbs like slippery elm;
- Several kinds of seaweed such as kelp or dulse;
- Legumes such as kidney, lima, pinto, navy and soy beans, chickpeas, lentils, and peas;
- Pectin of some fruits such as apples, pears, prunes and raspberries;
- Supplements of concentrated fiber.
Diets deprived of fibre can be corrected by incorporating more of the fiber-rich foods (such as the ones listed above) into your diet, or by adding fibre supplements to fiber-poor foods.
Can fibre help with weight loss?
Fibre can be a useful ally on a weight loss plan:
- Most dietary fibre does not contain any calories, which means that fibre rich foods are often lower in calories than foods containing no/small amount of fibre.
- Fibre also takes longer to chew, which automatically slows down your eating speed. By doing this it gives your brain longer to register feelings of fullness, so you are less likely to overeat.
- Fibre rich foods also act like a sponge and absorb and hold onto water as it is chewed in the mouth and passes to the stomach. Fibre rich foods will swell up in the stomach and help you feel full.
- Fibre stays in the stomach longer, keeping you full and less likely to want to snack between meals.
