The health benefits of fibres

by Carmen Miletta Cossa

The word fibre comes from the Latin word fibra, meaning thread, string, filament, entrails. Dietary fiber refers to nutrients in the diet that are not digested by gastrointestinal enzymes.

Dietary fibre is a type of carbohydrate, however you will not find dietary fibres listed in food labels as digestible carbohydrate. Fibre is only found in foods that come from plants. Foods such as meat, fish and dairy products don't contain any fibre.

Dietary Fibre is commonly classified as soluble or insoluble.

Soluble fibre is found in oats, peas, beans, apples, citrus fruits, carrots, barley.

The dietary fibre in some foods can be broken down by the bacteria in the lower intestine relatively quickly. This type of fibre has been called soluble or rapidly fermentable fibre and it is digested in the upper part of the large intestine.

In-Soluble fibre is found in Whole-wheat flour, wheat bran, nuts, beans and vegetables, such as cauliflower, green beans and potatoes.

Fibres known as insoluble or poorly fermentable are very difficult to break down. This means that they travel much further down the large intestine before bacteria can act on them.

Many foods contain both soluble and insoluble fibre. In general, the more natural and unprocessed the food is, the higher it is in fibre. Refined or “white” foods, such as white bread, white rice, and pastries, had all or most of their fibre removed.

Recommended daily intake of fibres

Current recommendations from the United States National Academy of Sciences, Institute of Medicine, suggest that adults should consume 20–35 grams of dietary fibre per day. The same daily recommendation comes from the World Health Organization (WHO). However the average American daily intake of dietary fibre is only 12–18 grams. 

Health benefits:

Fibres help weight control

Prospective studies[1] report that people who consume higher amounts of fibre weigh less than people who consume less. Another study[2] reported that in a 20-months period, every 1 gr. increase in total fibre consumed per day, decreased body weight by 0.25 kg.

Dietary fibre’s ability to decrease body weight or attenuate weight gain could be due to at least two factors:

  1. Soluble fibre, when fermented in the large intestine, produces glucagon-like peptide (GLP-1) and peptide YY (PYY) .These two gut hormones play a role inducing satiety.
  2. High-fibre foods tend to take longer to eat and to be less "energy dense". This means they have fewer calories for the same volume of food.

Fibres normalize bowel movements

Dietary fibre increases the weight and size of your stool and softens it. A bulky stool is easier to process, decreasing chances of constipation. If you have loose, watery stools, fibres may help to solidify the stool because they absorb water and add bulk. A high-fibre diet may lower your risk of developing haemorrhoids and small pouches in your colon.

Fibres prevent type II diabetes

Diets high in fibre help control blood sugar levels and can decrease the risk of developing type 2 diabetes.

A research[3] followed 75,000 people for 14 years. People who ate more than 15 g of fibre per day had significantly lower diabetes risk. People who ate high amounts of insoluble fibre (more than 17 g/day) or cereal fibre (more than 8 g/day) had less type II diabetes risk than people who had lower intakes while soluble fibre intake was not associated with diabetes risk.

Fibres prevent breast cancer

A 2016 study[4] led by researchers at Harvard T.H. Chan School of Public Health showed findings that higher fibre intake reduces breast cancer risk, suggesting that fibre intake during adolescence and early adulthood may be particularly important.

Women who eat more high-fibre foods during adolescence and young adulthood, including vegetables and fruit, may have significantly lower breast cancer risk than those who eat less dietary fibre when young.

Fibres cause a lower risk of heart disease

Fibre, particularly soluble fibre, is an important element of any heart-healthy diet. Eating a diet high in fibre can improve cholesterol levels by lowering LDL (bad) cholesterol.

A high fibre intake can also reduce risk for metabolic syndrome, coronary heart disease, diabetes, and stroke. Another Harvard study found that a high total dietary fibre intake was linked to a 40 percent lower risk of coronary heart disease[5]

How can I get more fibres in my diet?

  • Eat more fruits and vegetables: 5 portions per day. Eat fruits with the skin when possible. Skin has more fibres!
  • Choose wholegrain and multi-seeds bread, brown pasta and rise instead of white option
  • Add pulses like beans, lentils or chickpeas to stews, curries and salads.
  • For snacks, try fresh fruit, vegetable sticks, rye crackers, oatcakes and unsalted nuts or seeds.

Click here to know the amount of fibres in different food.

[1] Slavin, J.L. Position of the American Dietetic Association: Health implications of dietary fiber. J. Am. Diet. Assoc2008
[2] Tucker, L.A.; Thomas, K.S. Increasing total fiber intake reduces risk of weight and fat gains in women. J. Nutr. 2009
[3] Hopping, B.N.; Erber, E.; Grandinetti, A.; Park, S.Y.; Kolonel, L.N.; Maskarinec, G. Dietary fiber, magnesium, and glycemic load alter risk of type 2 diabetes in a multiethnic cohort in Hawaii. J. Nutr. 2010
[4] arvid MS, Eliassen AH, Cho E, Liao X, Chen WY, Willett WC. Dietary fiber intake in young adults and breast cancer risk. Pediatrics 2016
[5] Rimm EB, Ascherio A, Giovannucci E, Spiegelman D, Stampfer MJ, Willett WC. Vegetable, fruit, and cereal fiber intake and risk of coronary heart disease among men. JAMA. 1996