Beta-glucans, lignin, inulin, pectin, hemicellulose, resistant starch: what is the similarity of all these nutrients or substances? These are actually some examples of dietary fibre that you can find in your foods. So, what is dietary fibre and why is it important in a healthy diet?
What is dietary fibre?
Dietary fibre, also called roughage, can be defined as the structural portion of a plant, and thus can be found in fruits, vegetables, legumes, beans, nuts, seeds and whole grains. A significant characteristic is that it cannot be completely broken down by our digestive enzymes, yet it plays an important role in digestive health.
There are a variety of dietary fibres with different solubility, viscosity and fermentability. Generally, dietary fibres are grouped into soluble and insoluble fibre, both of which contribute to our digestive health in different ways. Most diets consist of a combination of soluble and insoluble fibre (up to 75% from insoluble fibre and 25% from soluble fibre). Let’s learn more about these two groups of fibre:
- Soluble fibre dissolves in water. When it comes in contact with liquid, it will thicken and swell up, thus helping to make you feel full. It also helps in slowing down the absorption of sugar into blood and may be beneficial for weight loss. Some soluble fibres, such as inulin, also function as prebiotics that encourage the growth of good bacteria (probiotics) in the digestive tract. Examples of soluble fibres are pectin, inulin, alginates and raffinose, which can be found in oats, legumes, apples, bananas, oranges, carrots, potatoes, barley and beans.
- Insoluble fibre doesn’t dissolve in water. Instead, this type of fibre absorbs water in the lower gut tract, making the fibre more bulky. It helps to speed up the passage of waste through the colon, facilitating regular bowel movement. Insoluble fibre can also help to alleviate constipation. Examples of insoluble fibre include beta-glucans, lignin, xanthan gum, resistant starch and cellulose, which can be found in whole grains, cereals, rolled oats, brown rice and most vegetables.
Why is dietary fibre important?
Many studies have shown that sufficient dietary fibre intake is essential and beneficial for our overall health, and particularly for our digestive health. Consumption of dietary fibre increases the volume of food without increasing the calorie content to the same degree as digestible carbohydrates. This helps to promote satiety, reduce appetite, control food intake and manage weight.
Dietary fibre is also known to promote digestive health. Some dietary fibres serve as prebiotics that can promote the growth of good bacteria in the gut and help to maintain the balance of gut microbiota. Dietary fibres also promote regular bowel movement and prevent gastrointestinal symptoms such as constipation and diarrhoea.
Consumption of fibre has also been found to help in reducing sugar and cholesterol level in blood, among the risk factors of non-communicable diseases (NCDs). Consequently, this reduces the risk of NCDs such as heart disease, type 2 diabetes, stroke, hypertension and colorectal cancer, leading to a decrease in cardiovascular-related mortality and a better quality of life.
Dietary fibre intake in Malaysia
The National Health & Morbidity Survey (NHMS) 2019 found that 95% of Malaysian adults do not consume sufficient vegetables and fruits based on the recommended 5 servings a day. This is an increase from 92.5% in 2011 and 94% in 2015. Since vegetables and fruits are the main source of dietary fibre, this also indicates that our dietary fibre intake has been lacking.
The Recommended Nutrient Intakes for Malaysians recommends 20 to 30 g daily consumption of dietary fibre. This is accompanied with the recommendation of the Malaysian Healthy Plate by filling the first quarter of your plate with whole grains and the other half of your plate with vegetables and fruits. Have you managed to achieve this recommendation in your daily meals?
How to increase dietary fibre intake in diet?
Now that you’ve realised that your dietary fibre intake is lacking, what can you do to increase it? Here are some tips:
- Don’t worry about choosing a specific type of dietary fibre or fibre-rich food. All dietary fibres are good for you! Most foods actually contain both soluble and insoluble fibres, and you can get your dietary fibre from a variety of food sources.
- Start first by aiming to have at least 2 servings of fruits and 3 servings of vegetables every day. An easy way to accomplish this is by having a serving of veggies during your main meals (breakfast, lunch, dinner) and a serving of fruits as your snack (morning, afternoon).
- Next, choose whole grains (e.g., brown rice, millet, buckwheat, oats, barley, quinoa) over refined grains (e.g., white bread, white rice) as the former have higher dietary fibre compared with latter. Instead of white bread, white rice or plain pasta, pick wholegrain bread, brown rice and wholegrain pasta. Look for products with the claim of ‘high in fibre’ on the nutrition label. You can also begin by mixing white rice and brown rice for dinner or by having oatmeal for breakfast.
- Another option is to have more legumes, beans, nuts and seeds in your diet. Apart from increasing dietary fibre intake, these foods can also be an alternative source of proteins. Add your favourite beans or nuts to soups, stews, chilli or salads to boost nutrition, texture and flavour. They’re good as snacks too when eaten plain.
- Ideally the best way to get fibre is through natural sources, such as fruits, vegetables and whole grains, because they also provide important vitamins, minerals, and phytonutrients needed by your body for optimal health. However, if for some reasons, you have trouble meeting your dietary fibre intake, taking fibre supplements is an option to ensure this important nutrient remain part of your daily intake. It’s good to consult a nutritionist/dietitian on your daily nutritional needs, such as fibre intake.
People often talk about how carbohydrates, proteins, fats, vitamins and minerals are important nutrients for our health, but dietary fibre is sometimes left out from the conversation. Dietary fibre is not just important for digestive health, but also contributes to our overall health and well-being. Start including more dietary fibre as part of your healthy and balanced diet today