Studies show that fiber is good for gut health. It helps prevent gastrointestinal problems, including diarrhea and constipation. It also reduces the risk of colon cancer, obesity, and diabetes. A diet high in fiber is essential for optimal gut health. You can find fiber in whole foods, such as fruits, vegetables, and beans. You can also get it from dietary supplements, such as inulin and arabinoxylan.
A high-fiber diet can be particularly beneficial for people with digestive issues
What is fiber?
Fiber is a carbohydrate that the body can't break down or absorb. It's found in whole grains, beans, and vegetables. It helps lower cholesterol, control blood sugar levels, and prevent constipation. Fiber is also known to help maintain healthy digestive function.
A high-fiber diet can be particularly beneficial for people with digestive issues like diverticulitis, hemorrhoids, and constipation. The cellulose in fruits, vegetables, and grains can help reduce these conditions by encouraging regularity and reducing the formation of hard stools.
Foods with both soluble and insoluble fiber are essential for a balanced diet. The best sources of fiber include whole grains, nuts and seeds, beans, and some fruits and vegetables. Try to make these foods a staple of your diet. You can also find some of these foods in smoothies or over-the-counter supplements formulated to help improve digestion and promote regularity.
Types of fiber soluble and insoluble
Fiber is made of complex carbohydrates that your body can't fully digest, giving it many health benefits. There are two main types: soluble and insoluble fiber, and each plays a different role in the digestive tract.
Soluble fiber dissolves in water to create a gel-like substance that slows digestion and helps lower blood cholesterol and glucose levels. You can find soluble fiber in foods such as oat bran, beans, apples, berries, and peas.
Insoluble fiber adds bulk to stool and speeds up transit time through the digestive tract, which wards off constipation and prevents an unhealthy buildup of waste in the colon. It also prevents uncomfortably hard or watery stools for people with digestive conditions like IBS and Chron's disease.
Most plant-based foods contain soluble and insoluble fiber, so try to get your daily recommended amount of each type of fiber through real food. Start your day with a bowl of oatmeal or whole grain toast, and stock up on vegetables and fruits.
Dietary sources of fiber
The best sources of dietary fiber are whole foods like beans (three-bean salad, chili, soup), brown rice and oats, fruit with the skin on, and vegetables (tomatoes, peppers, zucchini, greens). Many fruits and vegetables are high in soluble and insoluble fiber, but the highest sources include berries, prunes, figs, peaches, apricots, tomatoes, kale, collard greens, and carrots.
Aim for more whole foods than processed ones. For instance, drink whole fruits instead of juices. The process of juicing removes the fiber from the fruit. Avoid fiber supplements, as they don't provide the variety of nutrients in whole foods. A registered dietitian can help you determine your individual needs for dietary fiber.
Recommended daily intake of fiber
In the United States, most people need more fiber. Fiber is essential for digestive health, and the official dietary guidelines recommend that women eat 25 grams daily and men should consume 38 grams.
Benefits of Fiber for Gut Health
Prevents diverticular disease
Diverticulitis occurs when small, sac-like pouches (diverticula) form in the colon's lining. It can be painful, and doctors treat it with antibiotics, over-the-counter medicine, or surgically removing them. A diet low in fiber is linked to the development of diverticula. It is also tied to constipation, obesity, a lack of physical activity, and age. Researchers have found that eating more fiber helps prevent the condition by making stools softer and easier to pass, relieving pressure on the walls of the colon.
In addition, soluble fibers add bulk and weight to the stool to make it more easily passed. They also slow digestion and help the gut absorb nutrients from food. They may also help reduce inflammation and produce short-chain fatty acids that promote healthy bacteria. They come from various foods, including oats, barley, beans, and whole grains. Insoluble fiber comes from the skins, rinds, and seeds of fruits and vegetables, and nuts.
Studies have found that people who eat more fiber have lower rates of diverticulitis, hemorrhoids, and irritable bowel syndrome (IBS). Increasing fiber can help keep bowel movements regular, but it is vital to do so gradually to avoid bloating, gas, and diarrhea. Aim for a minimum of 30 grams of fiber per day from whole grains, vegetables, and fruit, and drink lots of water when adding more plant-based fiber to the diet.
Reduces the risk of colorectal cancer
A healthy gut depends on fiber to normalize bowel movements, lower cholesterol, control blood sugar and maintain a balance of bacteria that can help prevent chronic diseases like colorectal cancer. Researchers analyzed the diets of more than 4,600 people. They found that people who consumed higher amounts of both soluble and insoluble fiber had a reduced risk of incident distal colon adenoma. They also had a lower risk of recurrent adenoma and were less likely to die.
As the bacteria in your gut nosh on fiber, they produce byproducts called short-chain fatty acids that have been linked to positive health outcomes like lower inflammation and healthier digestive function. This may be one reason why a 2-week increase in fiber intake significantly alters the gut microbiome.
Soluble fiber creates stool bulk and helps "get things moving," which can help reduce constipation and symptoms like bloating and gas. According to registered dietitian Jess Cording, insoluble fiber helps speed up the transit time through your digestive system.
Alleviates symptoms of irritable bowel syndrome I
Many digestive conditions can be alleviated by increasing your dietary fiber intake, including IBS. A study published in 2017 found that a high-fiber diet improves gut health by regulating digestion and lowering the symptoms of IBS. It also reduces the risk of colorectal cancer, diverticular disease, and type 2 diabetes.
The good bacteria in your large intestine, the gut microbiome, thrive on fiber. They create short-chain fatty acids like butyrate, which help keep your colon healthy and protect against the proliferation of harmful bacteria.
In addition to feeding the gut microbiome, dietary fiber promotes gut movement by adding bulk to your stool. This increases your bowel movements, helps you expel waste more easily, and decreases the likelihood of constipation. In addition, fiber irritates the gut lining, releasing water and mucus. This adds bulk to your stool and speeds up its transit through the gastrointestinal tract.
Helps manage weight and prevent obesity
The body doesn't digest fiber and passes relatively intact through your stomach, small intestine, and colon. This means it doesn't raise blood sugar like carbohydrates, which helps control your weight and lower your risk of type 2 diabetes. The fiber also stimulates the growth of healthy bacteria in your digestive tract, known as your gut microbiome.
The types of food you eat determine the composition of your gut microbiome, and it's essential to have diversity in this community of bacteria. Research has shown that diets low in fiber and high in processed foods lead to less diverse gut bacteria, which may increase your risk of obesity and chronic diseases like gastrointestinal disorders, colorectal cancer, and metabolic syndrome.
Both soluble and insoluble fiber are essential for gut health. Soluble fiber absorbs water to create stool "bulk" and nourishes the good bacteria in your large intestine, called the gut microbiome. These bacteria produce short-chain fatty acids, including butyrate, that benefit your gut and overall health.
In addition, dietary fiber can help you feel full longer because it slows the absorption of fat and sugar from your meal. This enables you to control your appetite and eat less. However, if you decide to increase your fiber intake, it's best to do so slowly to avoid uncomfortable digestive issues such as gas, bloating, and cramps.
Lowers the risk of developing hemorrhoids
Getting enough fiber can help prevent hemorrhoids or piles. These are inflamed and swollen veins around the anus or in the lower rectum, where stool collects before it passes out of the body. The risk of developing hemorrhoids increases with age and during pregnancy as the tissues that support these areas become stretched or weaker. Eating a diet rich in fiber from whole foods can help reduce the risk of piles by providing plenty of food for the healthy bacteria that live in the large intestine.
Hemorrhoids often are caused or aggravated by constipation, which slows the passage of food and waste through the digestive tract. Getting enough fiber from various foods helps prevent constipation by bulking the stool and promoting regular bowel movements.
In addition to improving blood glucose levels, lowering cholesterol, and managing body weight, adding more fiber to the diet can help control inflammation. According to a 2021 study published in the journal "Nutrients," specific gut microbes use the complex carbohydrates in dietary fiber as fuel for fermentation reactions and produce postbiotic compounds called short-chain fatty acids (SCFAs). These SCFAs have been shown to reduce intestinal inflammation, promote healthy colon cells and reduce the intestinal permeability that can lead to chronic diseases like obesity and diabetes.
Additional Benefits of Fiber
Reduces cholesterol levels
While the CDC says that only 10% of Americans eat enough fiber, this is especially important for those with heart disease. Research shows that a diet high in soluble fiber can significantly reduce total and LDL or "bad" cholesterol, attenuating atherosclerosis and decreasing the risk of heart disease. Fiber-rich foods include vegetables, fruits, whole grains, nuts, and seeds. When choosing cereals, look for those that list a whole grain as the first ingredient and choose those with at least 20 percent of the recommended daily value of fiber.
Promotes satiety and aids in weight management
Several studies have shown that fiber may help lose weight by reducing appetite and energy intake. These effects are due to the delayed digestion of dietary fats and proteins and the addition of water, which promotes satiety. In epidemiologic studies, a high-fiber diet is associated with lower body weight. However, the precise mechanisms by which fiber impacts satiety and food intake remain unclear.
Controls blood sugar levels
Fiber, a non-digestible carbohydrate in plant foods like whole grains, fruits, vegetables, and nuts, helps keep your digestive tract regular. It's also crucial for your heart as it reduces blood sugar levels and triglycerides. Its other health benefits include promoting a healthy weight, improving colon cancer risk, controlling cholesterol, and enhancing immunity.
The Bottom Line
Whether you're an expert dieter or simply a shopper at your local grocery store, you've likely been admonished by doctors and seen plenty of products in the cereal aisle with fiber emblazoned across the label. But while it's certainly an essential nutrient, experts agree you should always try to get the bulk of your fiber from whole foods like fruits, vegetables, beans, and whole grains before reaching for a supplement.
The American Dietetic Association recommends women get 21 to 25 grams of dietary fiber daily and men up to 38 grams. While there are many benefits to a high-fiber diet, some of the most significant include a reduced risk for constipation and an overall lower risk of disease, including heart disease, diabetes, and cancer.
There are two types of dietary fiber: soluble and insoluble. Soluble fiber combines with water to create bulk and helps the body absorb nutrients. Insoluble fiber promotes regularity by moving food through the digestive tract and colon.
Foods with soluble and insoluble fiber are a great way to help ensure you're getting enough of this nutrient. Some good options include berries, whole grains, nuts and seeds, avocados, beans, and legumes. A diet high in fiber also supports healthy weight loss and maintenance, reduced risk of heart disease and diabetes, and an improved mood.
If you need help to hit your daily fiber goal, there are a few easy ways to increase your eating amount. Swapping out processed foods for those made with whole-grain ingredients is a simple first step. Other examples include starting the day with a bowl of steel-cut oatmeal, whole grain toast, or a bowl of yogurt with fruit on top; and adding chia seeds (which have 10 grams per serving) to smoothies and drinks for an extra boost.
You can also eat more fiber-rich foods by replacing fruit juices with whole fruit; and making a salad starter of non-starchy greens, such as kale, spinach, or mixed baby greens, and by adding vegetables like diced peppers, spinach, or cauliflower to casseroles, stir-fry dishes, and soups. Remember to keep a bag of almonds, flaxseeds, or chia seeds handy for a snack and to bulk up baked goods. You can also use whole wheat flour, crushed bran, or uncooked oats to add fiber to your recipes. And add legumes, such as kidney, lima, navy beans, garbanzo beans, or lentils, to your meals for an extra fiber punch.
