The Nutritional Institute

If you feel constipated all the time or you’re not as regular as you’d like to be, you might be lacking in dietary fibre. Being irregular could also be due to the stress of modern-day life and low physical activity levels, but increasing your dietary fibre intake should give you some relief.

Dietary fibre refers to a group of carbohydrates that we cannot digest because we don’t have enzymes to break them down. Fibre is also often categorised according to its ability to dissolve in water: soluble fibre mixes with water in the gut to produce a gel-like substance, feeding the healthy bacteria in our gut, while insoluble fibre doesn’t mix with water and acts mostly as a bulking agent for our stools. However, both types are needed for a healthy bowel movement because insoluble fibre increases the size of our stools, while soluble fibres make them softer, allowing for smooth passage through our bowels.

Most foods contain a mixture of soluble and insoluble fibres, but are normally predominant in one type. In general, foods that are rich in insoluble fibres include: wheat or oat bran, whole grains, some nuts/seeds, most fruit (e.g. apples, raspberries, figs, kiwis, mangos, bananas, pears and strawberries) and vegetables with skin (e.g. spinach, sweet potato, zucchini, squash, cabbage, beetroot and parsnips). Foods rich in soluble fibre include: beans, lentils, peas, oats, barley, some nuts/seeds, and other types of fruit (blackberries, oranges, apricots, prunes and grapefruit) and vegetables (artichokes, Brussel sprouts, asparagus, broccoli, onions and carrots). Dark chocolate with a high cocoa content (>70%) is also a great source of soluble fibre alongside its high levels of polyphenols, which have been shown to improve insulin sensitivity and cardiovascular health – a double bonus indeed, but dark chocolate should still be consumed in moderation because it still contains sugar.

Dietary fibre doesn’t just keep you regular though. Dietary fibre may also prevent weight gain, reduce the risk of inflammatory disease and digestive tract disorders, and promote a healthy immune system. Mostly soluble fibre is known to feed your healthy bacteria, encouraging their growth. Obviously, the more healthy bacteria you have, the healthier you are. What these tiny organisms do is to produce some important nutrients by fermenting the fibre you ingest. These nutrients are known as short-chain fatty acids (SCFAs) and act as a source of energy for the cells lining our colon. SCFAs have also been reported to provide an array of health benefits, such as improvements in blood lipid profiles, blood sugar control, and reduced body weight and colon cancer risk. Soluble fibre is also thought to help regulate blood sugar levels, especially in type II diabetics, as it slows down the digestion and absorption of carbohydrates. This buffers the rise in blood glucose that normally follows a meal, and consequently the insulin response.

Current recommendations are for men to eat 38 grams of fibre per day and for women to eat 25 grams per day. Most people eating a typical Western diet fall short of their recommended dietary fibre intake, with the majority eating less than half the recommended amount. I actually think most of us could eat a bit more than the recommended amounts. But this is a fine balancing act because it is possible to overdo dietary fibre intake, especially if you increase your fibre intake too quickly over a short period of time. This can cause bloating, flatulence, abdominal pain, loose stools or, in some cases, even constipation. I know how contradictory that may sound but too much fibre, especially with a lack of water intake, can actually lead to hard bulky stools.

If you feel constipated and want to increase your fibre intake to give you some relief, start introducing a greater variety of foods, while making sure you drink enough water and also get some light exercise – going for a brisk walk will generally suffice. Perhaps also think about swapping some of your animal-based protein sources for plant-based protein ones because this will automatically raise your dietary fibre intake. Please don’t rely on fibre-fortified processed foods like cereal bars because these simply don’t have the same effects as the fibre present naturally in whole foods. In fact, whole foods offer additional nutrients on top of their fibre content, such as vitamins, minerals, antioxidants and phytochemicals. There is also no need to obsess about the number of grams you’re getting in… as long as you’re eating plenty of whole plant foods, then your dietary fibre intake should be more than sufficient to ensure a happy gut.