Addressing the Optics on Fiber: It’s More Than Just a Gut Feeling
What is fiber good for?
Alright, let’s talk about fiber, because who doesn’t love a nutrient sidekick that quietly does all the dirty work while you are off pretending that green juice is the real hero. Fiber is classified as a non-digestible carbohydrate, which means it does not give us energy nor does it contain calories. National daily fiber recommendations can range from as low as 18-20 gm/day in Japan to as high as 45 gm/day in some European countries. It doesn’t matter, because whichever way you slice it, worldwide fiber intake is inadequately low.
It is widely understood that fiber helps with the passing of stool during a bowel movement, but research has shown that it plays a much larger role in our longevity as a whole. Gut health is a trendy topic that comes up when people want to learn about quick and easy weight loss, brain fog, energy, and bloating from social media; but it all still depends on dietary fiber. The point of this article will be to refocus the topic of gut health while moving away from trendy green powders that do not work and center it back to good ol’ reliable fiber. When we talk about gut health from a nutrition standpoint, we are analyzing the gut microbiota also known as the gut microbiome. These are the colonies of bacteria that make up the living environment lining the walls of our digestive tract. When these bacteria are happy and well-fed our food can be digested properly and we lower the risk of developing chronic diseases induced by chronic inflammation. The depletion of certain bacterial species of the gut increases inflammation causing diseases such as inflammatory bowel disease, colon cancer, autoimmune disease, and obesity. All in all, fiber plays a part in the prevention of such conditions. Eating a low-fiber diet disrupts your ecosystem and puts you at a larger risk of developing inflammatory diseases of the gut, cardiovascular diseases, certain cancers, and high blood sugar.
The Brain-Gut Axis
The brain-gut axis is a network of nerves that connects the brain and the gut; it acts as a pathway for biochemical signaling between the two organ systems. When this connection is properly regulated our mood, focus, digestion, and energy levels remain properly regulated. Fiber acts as a prebiotic, feeding beneficial bacteria in the gut which then produce metabolites like short-chain fatty acids that can directly influence brain function and neurotransmitter production. Studies suggest a link between higher fiber intake and improved cognitive function, including memory and mood regulation, potentially due to the gut-brain axis. No, fiber is not going to cure depression or suddenly give you photographic-memory, but the link between poor cognitive function and an unhealthy gut is heavily researched and a very intriguing topic that deserves more of a spotlight.
The Gut, Heart health, and Blood Sugar
As prebiotics (fiber) enter the large intestine they are fermented by the probiotics (good bacteria) living inside of our intestine. This fermentation helps the growth of our microbiome bacteria population which helps aid the process of digestion and pass our stool more easily. There are two types of fiber, insoluble and soluble. Insoluble fiber does not dissolve in water and adds bulk to our stool. This bulking process helps food move more quickly through the large intestine and out through the anus. When dealing with constipation it may mean you are not getting enough insoluble fiber in the diet. Soluble fiber is water soluble and forms a gel substance when it comes into contact with moisture. It slows down the digestive process and it’s the most interesting form of fiber. What it does is act as a filter for our nutrients. It slows down the absorption of simple carbs (sugar) and LDL cholesterol (bad cholesterol). More specifically, it may delay and prevent some fat from being absorbed entirely; therefore slightly reducing overall fat intake from a high-fat meal that contains soluble fiber. Through this process, the incorporation of soluble fiber in the diet will lower your LDL cholesterol and blood sugar over time and keep those levels stable. Before or during eating a high-fat or high-carbohydrate meal, such as a burger and fries, having a side salad or eating a whole wheat bun will be beneficial for maintaining healthy blood sugar and cholesterol levels.
Cancers
Colon cancer and rectal cancer are the leading cancers affecting people under the age of 50 right now. The Western diet is typically very low in fiber and high in refined carbs and high saturated fats creating a larger risk for developing such cancers. Maintaining proper gut health through the incorporation of fiber is more than just a trendy lifestyle full of green powder and debloating gummies, it’s a necessary way of life that should be the bare minimum of protecting the body from disease.
Food Sources of Fiber
The American recommendation for daily fiber intake for 25 gm/day for women and 38 gm/day for men ages 50 and younger. The recommendation for adults 50 and older is 21 gm/day for women and 30 gm/day for men. Good sources of fiber in food include whole grains. Whole grains include whole wheat pasta, whole wheat bread, oats, barley, and brown rice. One cup of whole wheat spaghetti has about 6 gm of fiber. Cereals are an honorable mention as well they are made from grains so try to find cereals made from whole grains and low in added sugar. Beans and lentils are an obvious one; pinto beans, black beans, green peas, chickpeas, black-eyed peas. One cup of cooked pinto beans contains 15 gm of fiber. High-fiber fruits include raspberries, avocados, apples, strawberries, blackberries, blueberries, pears, and bananas. One cup of berries has about 3 gm of fiber, while an avocado packs a whopping 14 gm of fiber in one medium whole avocado! (That is almost half the daily requirement). High-fiber vegetables include broccoli, brussels sprouts, sweet potatoes, and artichokes. One cup of cooked brussels sprouts delivers about 6 gm of fiber straight to the gut. Nuts and seeds are an excellent source of dietary fiber; almonds, pistachios, pecans, chia seeds, flax seeds, and pumpkin seeds. Chia seeds contain about 10 gm of fiber in just 2.5 tablespoons! One oz of almonds contain 3.1 gm of fiber. Sources of soluble fiber include oats, bananas, apples, peas, beans, and chia seeds. Sources of insoluble fibers include vegetables, whole grains, and nuts.
Fiber beverages and supplements
Fiber is now more easily obtainable through products that are focused on maintaining health for those who do not typically put nutrition at the forefront when eating. There are fiber supplements like psyllium husk capsules. There are soda brands that contain fiber because of ingredients like chicory root inulin and cassava root fiber. Blending up smoothies is going to be far better than juicing. Juicing strips fruits of their pulp which holds all the fiber and delivers sugar straight to the gut. Blending fruit in a smoothie maintains the fiber content in the pulp of the fruit/vegetables delivering all the nutrients. The fiber content of a smoothie will allow your body to slowly absorb the natural sugars from the plant, avoiding blood sugar spikes, just as nature intended.
Sources:
Makki K, Deehan EC, Walter J, Bäckhed F. The Impact of Dietary Fiber on Gut Microbiota in Host Health and Disease. Cell Host & Microbe. 2018;23(6):705-715. doi:https://doi.org/10.1016/j.chom.2018.05.012
Kaur N, Gupta AK. Applications of inulin and oligofructose in health and nutrition. Journal of Biosciences. 2002;27(7):703-714. doi:https://doi.org/10.1007/bf02708379
Kumar K. Which Foods Are High in Insoluble Fiber? MedicineNet. Published September 9, 2021. https://www.medicinenet.com/which_foods_are_high_in_insoluble_fiber/article.htm
Berding K, Carbia C, Cryan JF. Going with the grain: Fiber, cognition, and the microbiota-gut-brain-axis. Experimental Biology and Medicine. 2021;246(7):796-811. doi:https://doi.org/10.1177/1535370221995785
