Fibre and Gut Health

Written by: Nazish Taban Yazin

Why is Fibre Crucial for the Gut?

Growing up, we’ve all been told how important eating vegetables and fruits is for us. Interestingly, the current health market is now flooded with a wide variety of fibre supplements claiming to offer numerous health benefits as well. But ever wondered what fibre really does for us? Let’s delve into the world of fibre to find out why fibre is a crucial component of our diet that often doesn’t get the recognition it deserves.

What is Fibre?

Fibre, also known as roughage or bulk, is a type of carbohydrate found in plant-based foods like fruits, vegetables, whole grains, nuts, and seeds that our bodies cannot digest.

Though most carbohydrates are broken down into sugar molecules called glucose, as fibre cannot be broken down into sugar molecules, it helps to regulate the body’s use of sugars to keep hunger and blood sugar in check [1].

Types of Fibre

There are two main types of fibre: soluble fibre and insoluble fibre.

a) Soluble fibre:

  • Soluble fibre dissolves in water and forms a gel-like substance in the digestive tract. It can help lower cholesterol levels and regulate blood sugar levels.
  • It absorbs water in your gut so that the bulk passes through the gut more easily.
  • It also slows down the rate of digestion to reduce the sugar absorption rate and help you feel full longer.
  • Good sources of soluble fibre include oats, beans, apples, and citrus fruits.

b) Insoluble fibre:

  • Insoluble fibre doesn’t absorb water but adds bulk to feces and promotes regular bowel movements.
  • Foods with insoluble fibres include whole wheat products (especially wheat bran), quinoa, brown rice, legumes, leafy greens like kale, almonds, walnuts, seeds, and fruits with edible skins like pears and apples.

c) There is another fibre called Resistant Starch. It escapes digestion in the stomach and passes through the guts to become fuel for the bacteria in the large intestine. The bacteria ferment the resistant starch to produce SCFA (short-chain fatty acids), which enhance gut barrier integrity, immunity, and mineral absorption such as calcium, magnesium, and iron.

Health Benefits of Fibre

Constipation

Constipation is generally defined as having three or fewer bowel movements a week, difficulty or pain passing bowel movements, or small hard “pebbly” stool. Occasional bouts of constipation are common, but chronic constipation that does not resolve can lower quality of life and lead to symptoms of bloating, cramping, and even nausea. Chronic constipation increases the risk of diverticular disease and hemorrhoids [1].

One of the primary functions of fibre is to promote healthy digestion. Fibre acts as a natural laxative, helping to regulate bowel movements and prevent digestive issues. By adding bulk to the stool, fibre aids in the smooth passage of waste through the digestive tract, promoting regularity and overall gut health.

Fibre also plays a crucial role in supporting a healthy gut microbiome. The beneficial bacteria in our gut feed on fibre, producing short-chain fatty acids that help nourish the cells lining the colon and support immune function. A balanced gut microbiome is essential for proper digestion and overall health.

It is important to remember that drinking more fluids while eating more fibre can also help lessen these side effects [1].

Heart Disease

In addition to its digestive benefits, fibre has a positive impact on heart health.

Soluble fibre helps to lower blood cholesterol by interfering with bile acid production. Cholesterol is used to make bile acids in the liver. Soluble fibre binds to bile acids in the gut and excretes them from the body. Because of this reduced amount of available bile acids, the liver will pull cholesterol from the blood to make new bile acids, thereby lowering blood cholesterol [1]. By reducing cholesterol levels, fibre can lower the risk of heart disease and stroke.

Type 2 Diabetes

High-fibre foods tend to have a lower glycemic index (glycemic index rates carbohydrates according to how quickly they raise the blood glucose level) than refined carbohydrate sources, which have been stripped of most of their fibre [2].

Because the body is unable to absorb and break down fibre, it doesn’t cause a spike in blood sugar the way other carbohydrates can [3]. This helps to regulate blood sugar levels by slowing down the absorption of sugar into the bloodstream.

Weight Management

Furthermore, fibre can aid in weight management by promoting feelings of fullness and satiety. High-fibre foods take longer to digest, keeping you satisfied for longer periods and reducing the likelihood of overeating. By including a variety of fibre-rich foods in your diet, you can support healthy weight maintenance and overall well-being.

How Much Fibre Do We Need?

Many adults do not consume enough fibre – on average, most Australians consume 20–25g of fibre daily [4].

The Recommended daily fibre intake is:

  • Men = 30g of fibre each day
  • Women = 25g of fibre each day.

So, how do I add more fibre to my diet without eating too much? Here’s some tips!

  • Eat breakfast cereals that contain barley, wheat, or oats. Choose cereals that have whole grain as their first ingredient. Another tip is to look at the Nutrition Facts label and choose cereals with 20% or higher of the Daily Value (DV) for fibre [1].
  • Switch to wholemeal or multigrain bread and brown rice. If you are not a fan of the nutty taste of brown rice with your meals, you can explore other types of rice like wild rice, and red or black rice which also consist of more fibre than white rice.
  • Add an extra non-starchy vegetable to every evening meal. Start dinners with a salad. Or, add spinach, broccoli, or a bag of frozen mixed vegetables to your meals for a fibre boost.
  • Snack on crunchy raw vegetables or a handful of almonds instead of chips and crackers. Choose fruits and vegetables such as apples, pears, bananas, or baby carrots to snack on.

Not convinced yet? Let’s compare!

Higher fibre food choices Fibre (g) (approx.) Lower-fibre food choices Fibre (g) (approx.)
2 wholewheat cereal biscuits (e.g., Weetbix or Vita Brits) 3.2 1 cup puffed rice cereal 0.4
4 slices wholegrain bread 5.7 4 slices white bread 3.0
2 pieces of fruit (such as an apple and pear) 4.9 1 piece of fruit (apple) 1.4
1/2 cup canned fruit, undrained 1.7 1 cup frozen mixed vegetables 8.6
1 small, boiled potato (with skin on) 2.8 1 cup of mashed potato 1.7
1 cup brown rice 2.7 1 cup white cooked short-grain rice 1.0
2 wholemeal dry biscuits 1.5 2 plain dry biscuits 0.4
25 almonds 3.0 1 slice plain cake 0.6
Total 32.4 14.5

This shows that high-fibre alternative foods are not only abundant in fibre compared to refined foods but also almost similar or even lower in calories.

The Bottom Line

Fibre is a powerhouse nutrient with a wide range of health benefits. From promoting healthy digestion and supporting a balanced gut microbiome to improving heart health, regulating blood sugar levels, and aiding in weight management, it plays a crucial role in maintaining overall health and well-being. To reap the benefits of fibre, aim to include a variety of fibre-rich foods in your diet, such as fruits, vegetables, whole grains, nuts, and seeds. Remember to stay hydrated and gradually increase your fibre intake to prevent any digestive discomfort. Here’s to a healthier you, fueled by the power of fibre!

If you have any specific dietary concerns or questions about incorporating more fibre into your diet, don’t hesitate to book a consult with our dietitians for personalized guidance.

References:

  1. Harvard T.H. Chan School of Public Health – Fibre
  2. Healthline – Why is Fibre Good for You
  3. CDC – The Role of Fibre in Diabetes
  4. Better Health Victoria – Fibre in Food
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