Fiber
Arguably not the most exciting topic but if feeling good, eating healthy and losing weight are on your list of priorities, then understanding fiber is key.
What is fiber?
‘Dietary fiber’ is the term we use to describe the part of plant foods that isn’t digested or absorbed in the small intestine. Rather, it is completely or partly fermented in the large intestine. Fibre is only naturally found in plant foods, but nowadays we’re finding other foods, such as dairy, with added fibre extracts.
Resistant starch
Resistant starch is a type of dietary fiber that is not digested but, rather, fermented by bacteria in the colon. Found in legumes, seeds, grains, green bananas and certain cooked and cooled starchy foods (such as potatoes and rice) the amount of resistant starch depends on how a food is prepared. Resistant starch is one of the favorite foods of our gut bacteria.
Soluble fiber
Soluble fiber mixes with water in the gut and forms a gel-like substance that slows down digestion. This helps us to feel fuller for longer, while giving our body time to absorb nutrients and delay the absorption of sugar into our blood stream. Psyllium husk, legumes, oats and ground flax seeds are all high in soluble fiber.
Insoluble fiber
Insoluble fiber doesn’t mix with water but acts as a bulking agent in our bowel.
Insoluble fibre draws water into the bowel, softening the stool and making it easier to pass. Therefore, insoluble fibre is often recommended to help prevent constipation and improve regularity. Examples of foods high in insoluble fibre are bran products, whole wheat, legumes and nuts.
Functional fiber
Functional fiber is dietary fiber taken from the food it’s naturally found in and added to food products or processed foods. It can also be produced synthetically. Examples include, Metamucil (psyllium), and Benefiber (wheat dextrin).
Chicory root extract, also known as inulin, is added to many products, such as snackbars, to increase fibre and sweetness. While functional fiber may be used to increase your fiber intake, having many whole food sources of fiber means you benefit not only from the fiber itself, but the other nutrients found in these valuable foods.
Why is fiber good for us?
The functions of fiber, mainly in our large intestine, are what make it so good for us. One thing fiber does is give bulk to the waste products that find their way down to our bowel. Our bowel is one long muscular tube and, like any muscle in our body, it needs exercise. The bulk from fibre gives our bowel muscles a good work out, helping to prevent conditions such as haemorrhoids and diverticular disease.
Fibre reduces the speed of digestion, giving our body time to harvest the nutrients we need to keep healthy. Slowing digestion also helps stabilise blood sugar levels and helps us feel fuller for longer.
Fiber is also a prebiotic (food for our gut bacteria) which helps us grow a healthier balance of flora. There’s lots of research linking gut bacteria to mental health, heart health, diabetes risk (types 1 and 2), inflammatory bowel disease and weight.
As dietary fiber is fermented by the bacteria living in our bowel, they produce short-chain fatty acids that can help reduce inflammation and the risk of certain types of cancer. Fibre can also increase the feeling of fullness and improve insulin sensitivity.
Certain types of fiber seem to help maintain the health of the cells that line our digestive system. They do this through protecting and maintaining the mucous layer, as well as ensuring a healthy balance of gut bacteria that protect our digestive tract lining.
How much fiber do we need?
The Ministry of Health’s suggested dietary targets are 28g daily for women and 38g daily for men, however the 2008 National Nutrition Survey indicated the average fiber intake for adults was only around 20g a day.
Furthermore, a recent analysis of research showed, for adults, 25g-29g of fiber daily is beneficial for our cardiac and metabolic health. The data also suggest that more is better, so 30g is the magic number to enhance both our short and long-term health. Other research has found having 30 or more different fiber sources every week is associated with greater microbial diversity in our gut.
How does fiber help me…
Lose weight
Diets high in fiber or whole grains can help people who are overweight to lose weight in several ways. First, there’s a link between inflammation, body weight and gut bacteria, and a diet high in fibre improves the gut bacteria profile, so it’s similar to that of someone who is a healthy weight. Studies have shown that (high-fiber) prebiotic foods can help with weight loss. Second, the time it takes to chew fiber foods, and their physical bulk, can help us feel full. Finally, that fullness lasts longer because a gel-like substance some fiber forms slows the release of sugar into the blood after eating. This means we’re likely to eat fewer unneeded kilojoules, helping us to shed any unwanted kilos.
Reduce risk of type 2 diabetes
A large European study of approximately 12,000 people found that fiber from vegetables and wholegrains can reduce the risk of developing type 2 diabetes. Higher fiber foods moderate the rise in blood sugar after eating, meaning the body doesn’t have to produce as much insulin. Gut bacteria also play a role in inflammation, a condition that may predispose people to type 2 diabetes and can play a part in weight regulation. Obesity is an important risk factor for the development of type 2 diabetes.
Protect your heart
A high-fiber diet may help protect your heart by reducing cholesterol levels in the blood, and improving blood sugar levels, blood pressure and weight which are all risk factors for heart disease. Fiber is thought to help protect your heart by increasing short-chain fatty acid production (which reduces inflammation and cholesterol production) and forming gel-like substances in the bowel may reduce sugar and cholesterol absorption.
Prevent cancer
Higher intakes of fiber are associated with lower rates of colon cancer. They are also thought to be associated with lower rates of oesophageal adenocarcinoma and pancreatic, gastric, endometrial, breast and renal cancers. Butyrate, which is one of the short-chain fatty acids produced by the fermentation of fiber in our bowel, is important in gene regulation which may reduce the risk of tumor growth.
Improve my gut health
As mentioned earlier, carbohydrates and dietary fiber are the favorite foods of our gut bacteria, and gut health is important in making sure the rest of our body is healthy. Gut bacteria ferment some types of dietary fiber to produce by-products that affect our health. Short-chain fatty acids are the main health improving by-products, influencing inflammation, cancer cell formation, transit time of matter through our digestive system and nutrient uptake. The type of fiber, as well as the amount we eat, changes the bacterial profile of our digestive system.
referenced from healthfood.com