- Fiber has many benefits, especially for digestive health, and may even reduce the risk of colon cancer.
- The FDA recommends women consume between 21 and 25 grams of fiber per day, whereas men should eat between 30 and 38 grams daily.
- Fiber is easy to incorporate into your diet, as it's found in many foods, like whole grain breads, berries, and nuts.
Fiber is more important to your diet than you might think, and chances are you're not getting enough of it.
Most Americans only consume about half of the recommended amount of fiber they need, says Nate Favini, MD, an internist and Medical Lead at preventative care practice Forward. That's because the average American diet is high in processed foods, which are often devoid of fiber.
Over the past 10 years, researchers have found fiber can improve your life expectancy and decrease your risk for certain health conditions. Meanwhile, not getting enough fiber can have an adverse impact on your health.
1. Fiber is important for gut health
The trillions of naturally occuring bacteria in your gut feed on fiber as it's digested. In fact, complex carbohydrates like the ones found in whole grains, beans, and legumes are some of your gut bacteria's favorite things to feast on.
Gut bacteria, which collectively make up the "gut microbiome," are important because they extract vitamins and minerals your stomach acid leaves behind. Your colon then absorbs nutritional building blocks such as Vitamin K, B12, thiamin, and folate and puts them to work in your bloodstream.
Researchers are just beginning to understand all that these hungry bacteria do. But a 2011 paper published in Surgical Clinics of North America found the gut microbiome supports metabolism, contributes to your immune system, regulates energy levels, and much more.
Prebiotic foods are especially beneficial for gut health. These foods, like onions and garlic, contain "fermented fiber." As the bacteria in your colon break down fermented fiber, gases are produced.
These gases can cause discomfort in the lower tract of your digestive system as they inflate your colon, and lead to bloating. To get the full benefits of fiber without the discomfort, add fiber to your diet slowly, increasing the amount you consume slightly over the course of weeks or months.
2. Fiber may help you lose weight
Both insoluble and soluble fiber slow your digestion, which can signal to your body that it's not in a huge hurry to eat again. This helps you feel fuller for longer, and therefore may reduce your caloric intake.
A 2017 study published in Food and Nutrition Research of 40 college-aged women found that inulin fiber — a naturally occurring soluble fiber found in foods like bananas, garlic, and onions — significantly reduced appetite.
During the study, participants were given either a placebo or water mixed with 16 grams of inulin fiber and told to drink it first thing in the morning. After drinking the mixture for seven days, researchers assessed participants' appetite. The inulin fiber group reported feeling less hunger and consumed an average of 21% fewer calories at lunch than the placebo group.
3. Fiber can regulate blood sugar spikes
Many foods rich in fiber can help regulate blood sugar levels thanks to their lower glycemic index. The glycemic index ranks different foods based on their blood sugar level impact. It's important to stabilize your blood sugar levels, as too many spikes over long periods of time can contribute to weight gain and type 2 diabetes.
"Eating more fiber can help with stabilizing blood sugar, because fiber slows the absorption of sugar in your intestines," says Favini. While adding fiber to your diet can help stabilize blood sugar levels, it's also important to decrease sugar consumption. A high sugar diet creates an environment where harmful bacteria thrive.
Results from a 2016 study published in Experimental and Therapeutic Medicine with 117 study participants found that fiber effectively regulated blood sugar levels. Participants were given 0, 10, or 20 grams of supplemental soluble fiber each day for a month. After a month, fasting blood glucose and triglyceride levels significantly improved in the groups who were given fiber.
4. Fiber may reduce constipation
For some people, consuming fiber can relieve constipation. That's because fiber adds bulk to your stool, helping it to clear out.
A 2016 medical review published in Alimentary Pharmacology and Therapeutics synthesized the results of seven different randomized controlled trials. They found that 77% of adult participants successfully treated some chronic constipation symptoms by consuming more dietary fiber. However, researchers found that flatulence also increased with a higher fiber intake, which could lead to abdominal discomfort.
If you're trying to treat constipation, both soluble and insoluble fiber will help. However, be aware fiber can sometimes make constipation worse, especially if you are dehydrated. Make sure that you are drinking plenty of water as you slowly increase your fiber intake.
5. Fiber improves heart health
Fiber also plays a role in cholesterol management by limiting the amount of cholesterol released into the bloodstream. According to the Mayo Clinic, eating five to 10 additional grams of soluble fiber per day can reduce low-density lipoprotein (LDL) cholesterol, otherwise known as "bad" cholesterol.
High cholesterol levels are closely linked to heart disease. This could explain why individuals who eat a high-fiber diet have a significantly lower risk of developing heart conditions such as hypertension, stroke, and heart disease.
6. Fiber may reduce your risk of some cancers
Not only does eating fiber promote overall gut health, but it may also reduce your risk of developing colon and other digestive related cancers.
A 2015 study published in the American Journal of Clinical Nutrition with 33,971 participants found that people who consume high amounts of fiber from cereals and fruits were at a lower risk of developing colon cancer.
The link between fiber and other types of cancer is still unclear. However, a 2009 study published in The American Journal of Clinical Nutrition with 185,000 post-menopausal women found that those who consumed more dietary fiber were at a lower risk of breast cancer.