A Firefighters Guide to Understanding Fiber.
Summarized and Written by Rhonda Cohen MFF, EMT, RDN, LDN, CSN
I find it interesting that the sound of a sneeze elicits the words “Bless You”, however, the sound of a fart elicits laughter, and can cause people to leave a room. Both are natural body functions, yet they bring about vastly different responses. Farting can tell you a lot about your digestive health. It is a sign that you are getting adequate fiber in your diet, or perhaps need to include additional sources of fiber.
Dietary fiber, also known as roughage and bulk, is one of the most important nutrients, however, only an estimated 5% of Americans meet the recommended minimum daily intake. Fiber is a complex carbohydrate found in plant cell walls. All plants contain varying types of fiber which accounts for the wide variety of fiber found in food. While fiber is considered a fundamental part of a healthy diet, not all fiber is created equal. Some types are highly beneficial, while others can cause digestive problems for some people. Humans cannot digest fiber as we lack the enzyme needed to break it down. Therefore, fiber passes through the digestive system relatively unchanged.
The current recommendations for fiber intake are 25 grams per day for women 19-50 years of age, 21 grams per day for women 50+ years of age; 38 grams per day for men 19-50 years of age, and 30 grams for men 50+ years of age.
Fiber is defined as dietary, functional, and total. Dietary fiber consists of non-digestible carbohydrates and lignin which are naturally found in all plants. While it cannot be digested or absorbed by humans, dietary fiber keeps the gut healthy, and reduces the risk of chronic health conditions. Functional fiber is removed and isolated from whole foods, then added to supplements, processed and fortified foods. Manufacturers use this process to increase the fiber content in food products. Total fiber is the sum of dietary and functional fiber.
There are two types of dietary fiber which are classified based on their solubility in water, soluble and insoluble. Soluble fiber dissolves in water forming a gel-like substance in the gut. Soluble fiber controls hunger by slowing digestion and the absorption of nutrients, increasing satiety (feeling of fullness). Foods containing soluble fiber tend to have a low caloric content, reducing the risk of metabolic syndrome by supporting a healthy weight.
Additionally, soluble fiber helps maintain healthy cholesterol levels, reduces the risk of heart disease, regulates blood sugar levels to reduce the risk of insulin resistance or diabetes, reduces your risk of cancers such as colorectal and breast, supports bowel function and regularity, reduces the development of hemorrhoids, increases immunity, improves brain function, binds to toxins such as lead and mercury so they can be eliminated from the body, assists in balancing hormone levels by removing excess estrogen, and bolsters gut health by increasing the number and balance of healthy gut bacteria, creating a healthy microbiome. When soluble fiber is lacking, waste products can reabsorb in the intestines, undermining the body’s attempts at detoxifying itself. Foods containing soluble fiber include oats, barley, nuts, chia seeds, flaxseed, kidney beans, black beans, lima beans, garbanzo beans, peas, turnips, Brussels sprouts, broccoli, sweet potatoes, apples, carrots, avocados, pears, apricots, and citrus fruits.
Insoluble fiber does not dissolve in water. It remains relatively intact during digestion and therefore is not a source of calories or carbohydrates. Instead, it absorbs fluid and adds bulk to stool, assisting the passage of food and waste products through the digestive system, and reducing constipation by improving bowel regularity and transit time. Insoluble fiber is found in whole grains, wheat bran, high-fiber breakfast cereals, high-fiber bread, whole wheat pasta, barley, nuts, seeds, beans, green beans, carrots, celery, cauliflower, zucchini, corn, dark green leafy vegetables such as kale and spinach, kiwi fruit, grapes, raspberries, blackberries, raisins, and prunes.
Another way of classifying fiber is by its viscosity. Soluble fiber is either viscous or non-viscous describing the thickness of the gel formed when mixed with water. When a thick gel forms, it is viscous. Viscous fibers promote satiety by slowing the digestion and absorption of nutrients, improving glycemic control, and reducing blood cholesterol concentration. In addition, they are resistant to fermentation which promotes optimal bowel function by allowing for the softening of hard stool, as well as firming loose/liquid stool. There are four main viscous fibers. Pectins are extracted from pears, apples, oranges, grapefruits, and lemons. Beta-glucans are sugars found in bacteria, fungi, yeasts, algae and plants including oats, barley, wheat, rye, sorghum, rice, mushrooms, and seaweed. Guar gum from the Indian cluster/guar bean is found in beans, gravies, sauces, soups, ice cream, yogurt, breakfast cereals, marinades, and almond/soy/coconut milk. Psyllium is isolated from psyllium seed husks and added to bread, cereal bars, cereal, and rice cakes.
Non-viscous soluble fibers are fully fermented. Fermentability refers to the rate and extent fiber is able to be digested by the gut bacteria in the large intestine. Fermentable fiber, including oats, barley, fruits, vegetables, pectins, inulin, oligofructose, and beta-glucans serve as food for the beneficial “good” bacteria in your gut, influencing the composition of the gut microbiota.
Fermentation releases gasses and short-chain fatty acids such as butyrate that help reduce your risk of cancer, Crohn’s Disease, Ulcerative Colitis, and Irritable Bowel Syndrome (IBS). Fermentable fiber has the potential to induce significant amounts of flatulence and stomach cramps, especially if people are not used to eating a high-fiber diet. Fibers that are not broken down by bacteria are non-fermentable, remaining completely intact during digestion (ex: wheat bran). They promote bowel regularity by adding bulk and weight to stool, making it easier to pass.
Fiber promotes prebiotic growth. Prebiotics are fibers that get fermented in the gut and serve as food for probiotics to improve the gut microbiome, creating a healthier digestive system, improving overall health. Probiotics are foods or supplements that contain live microorganisms that maintain or improve the “good bacteria, normal microflora” in the body which provide many health benefits. Food sources with prebiotic properties include oats, leeks, garlic, onions, asparagus, soybeans, artichokes, and bananas.
As fiber passes through the large intestine, it encounters normal bacteria that aid in digestion. As bacterial metabolism occurs, gas is produced as a byproduct. If too much fiber is consumed it can cause bloating, cramping, and flatulence causing discomfort to first responders during calls, training exercises, workouts, and while performing work-shift responsibilities. In addition, undigested fiber increases stool mass and volume, as well as pulling water into the large intestine. The feeling of heaviness, and possible complications with diarrhea or constipation result in discomfort, decreasing optimal work performance. Foods high in fiber are good for your health, however adding too much fiber too quickly can promote intestinal gas, bloating, and cramping. Fiber should be increased slowly over a few weeks. This allows the natural bacteria in your digestive system to adjust to the change. It is important to drink plenty of water as fluid is necessary to assist in pushing fiber through the digestive tract.
Suggestions on how to increase fiber in your diet:
- Include a high-fiber cereal (5 or more grams per serving) for breakfast. Add nuts and berries to further increase the fiber content. Choose cereal with “whole grain” as the first ingredient, and 20% or higher of the Daily Value (DV) for fiber.
- Consume at least half of your grains as whole grains (oatmeal, brown or wild rice, bulgur, quinoa, barley, buckwheat, corn, millet).
- Choose whole grain bread or tortillas with at least 3 grams of fiber per serving.
- Snack on fresh fruit (including edible skins), raw vegetables, popcorn, nuts, whole grain crackers, and dried fruits. Monitor your portion size when choosing nuts and dried fruits as they are high in calories.
- Add fiber to baked goods (berries, nuts/seeds, dried fruit, whole grain/wheat flour, oats, oat bran, or wheat bran).
- Add leafy greens and the edible skin on fruit when making smoothies.
- Add beans, legumes, and vegetables to salads, soups, stir-fries, chili, and stews.
- Sprinkle ground flaxseed on cereals, salads, grains, and vegetable dishes.
- Add fruit and nuts to cereal, salad, yogurt, or cottage cheese.
Use the % Daily Value (DV) to identify a high or low-fiber food. 20% DV or more dietary fiber per serving is considered high. 5% DV or less dietary fiber per serving is considered low.
Due to the fact that the amount of fiber varies in different plant foods, it is important to eat a wide variety of high-fiber foods to maximize the health benefits. If you are concerned that your diet does not contain adequate fiber, there are fiber supplements available to help you meet your needs. However, it is encouraged to obtain fiber from natural food sources first as foods also contain vitamins, minerals, and other healthy compounds that supplements do not have.
When choosing a supplement, it is important to determine the type of fiber and ingredients that make up the supplement to ensure the effectiveness of the results you are wanting to achieve (improving cholesterol, treating constipation, lowering blood glucose, etc.). It is important to note that the supplement industry is not well regulated by the Food and Drug Administration (FDA). Third-party testing on fiber supplements does not appear to be customary. Therefore, it is important to choose a supplement manufactured by reputable companies in facilities that adhere to current quality manufacturing practices. Before taking any supplement it is important to consult with your Health Care Provider to avoid a potentially harmful drug-nutrient interaction. Fiber supplements may reduce or delay the absorption of certain medications, and produce adverse side effects. It is important to drink at least 8 ounces of liquids with your supplement to avoid constipation.
There are many types of dietary fibers that come from a range of plant foods. Eating a wide variety of plant foods provides many physical and mental health benefits while improving your overall wellness. Do your best to include fiber with every snack and meal.
FRF Fiber Snacks
Try these energy bites for a high-fiber snack on the go, to make you go.
2 cups rolled oats
½ cup unsweetened coconut
¼ cup ground flaxseed
¾ cup peanut butter
½ cup honey or maple syrup
½ cup mini chocolate chips
Hand mix all ingredients in a bowl. Scoop out one tablespoon of the ingredients and roll into approximately a one-inch ball. Continue until all ingredients are used. Store bites in a sealed container and refrigerate until ready to eat. If too sticky, add more rolled oats.
Nutrition facts per serving (one-inch rolled bite):
Calories: 150 -- Fat: 7 grams -- Saturated Fat: 2 grams -- Fiber: 5 grams -- Sugar: 9 grams -- Protein: 3 grams
Rhonda Cohen has served 30 plus years as a Firefighter and EMT with the Wheaton Volunteer Rescue Squad in Montgomery County, MD. She encourages and inspires First Responders to perform optimally by providing individualized nutrition, fitness, and wellness education and training. She is a graduate of the University of Maryland, where she earned a BS in Nutrition and Dietetics. She went on to become a Registered Dietitian, Licensed Dietitian Nutritionist, and Certified Sports Nutritionist.
We are excited to have Rhonda join the FRF Nation. You can reach out to her with any questions (Click here).