Fiber: A Friend to the Gut and Beyond
You have likely heard the word “fiber” in association with food and health. While it is a common term, many are confused about the role fiber plays in the body, where to find it in food, and how to try to increase our intake of fiber day to day.
Definition and Types of Fiber
Fiber is a type of carbohydrate that the body cannot digest or break down. Though most carbohydrates are broken down into sugar molecules called glucose, fiber cannot be broken down into sugar molecules, and instead passes through the body undigested.
There are two types of fiber: insoluble and soluble. Insoluble fiber does not dissolve in liquids, but rather passes through the intestines intact, absorbing water and trapping waste which is essential for healthy bowel movements and digestive function. Soluble fiber combines with water in the digestive tract to form a gel-like substance which is fermented by microbes living in the colon (the final section of the intestines).
Finding Fiber in Food
Fiber is only found naturally in plants - specifically whole, unrefined plant foods. Lucky for us, this is a broad and diverse category of food. In addition to fruits and vegetables, plant foods include beans and legumes, mushrooms, whole grains, nuts, and seeds, which also often contain protein, fat, micronutrients, vitamins, and minerals. It is not necessary to know which type of fiber is found in which foods. By eating a variety of plant foods throughout the day or week, we will naturally consume a balance of both soluble and insoluble fibers.
Eating a fiber-rich diet is one of the most impactful ways to support digestive/gut health and minimize inflammation, which leads to better metabolic and mental health, which are highly interconnected. The vast majority of Americans don’t get the recommended amounts of fiber day to day. Children and adults need at least 25 to 35 grams of fiber per day for good health, but most Americans get only about 15 grams a day.
From a culinary standpoint, fiber-rich foods offer a diversity of flavors, textures, characteristics, and qualities. This diversity means endless possibilities for interesting, delicious, and affordable dishes that also happen to be highly nourishing.
For some simple steps to adding in more fiber-rich foods into your diet, consider some of these ideas:
Add vegetables
Add vegetables, especially greens, wherever you can! A handful (or more) of chopped deep green leafy vegetables to a soup or stew, scrambled with eggs, or simple sauteed greens increases fiber, texture, and flavor. Use flavorful herbs, spices, aromatics (onions, garlic, ginger) to make it delicious. Frozen greens like spinach are affordable and convenient to keep on hand. Try this sauteed greens recipe.
Whole Grains
Whole Grains like rolled or steel-cut oats, brown rice, quinoa, millet, wild rice, amaranth, farro, kernza, teff, etc. are highest in fiber when eaten in their whole, intact form. Additionally, whole grains provide B-vitamins and a bit of healthy fat and protein.
Nuts and seeds
These are all stars when it comes to fiber, as well as healthy fats, important minerals, and vitamins. Make raw or dry-roasted nuts and seeds part of your oatmeal/porridge, on a salad, or as a topping for a bowl or curry dish. The “butter” form of nuts and seeds is also a wonderful source of fiber, and can be used in sauces and even in baking. Make sure to look at the ingredients and avoid nut/seed butters with added (usually ‘hydrogenated) oils or sugars.
Incorporate aromatics
Sautee some mushrooms with a bit of onion and/or garlic to add to greens, salads, or topping for a protein or bowl.
If you have not been eating much fiber on a regular basis, it’s important to start slowly and gradually increase your fiber intake. Starting with oats, cooked vegetables (roasted/sauteed rather than raw), fruits, and lentils are some easier-digested fiber rich foods to begin increasing your daily fiber intake.
Fiber’s Functions
This fermentation process produces Short Chain Fatty Acids (SCFAs) which stimulate the intestines to release important metabolic hormones such as Peptide YY and Glucagon-like Peptide 1 (GLP1). The natural release of these hormones helps to regulate appetite and insulin/glucose metabolism. SCFAs also have important roles in reducing inflammation in the gut and the rest of the body, and communication between the gut and brain. Both types of fiber help regulate how the body digests and absorbs dietary sugars by slowing down the absorption of sugar in the blood. This leads to a feeling of satiety (satisfaction).
Fiber and Blood Sugar
An example of how a food’s fiber content affects the blood sugar levels is in this simple contrast: drinking a glass of apple juice compared to eating an apple with its skin. The apple juice does not need to be chewed, and leads to a rapid rise in blood sugar since there is nothing to slow down its absorption into the bloodstream. In contrast, chewing the fibers of an apple’s skin and inner fruit allows for those sugars to be absorbed slowly and gradually. The presence of fiber also helps slow down the pace of eating (because we need to chew fiber-rich foods), regulates our digestive system, and keeps our hunger more balanced and our energy steady.
Regardless of your fiber consumption, adequate water intake (best consumed between meals, rather than just before or during meals) is also an important partner to our friend, fiber.