Are You Getting Enough Fiber?

The latest science suggests our fiber-poor diets trigger inflammation and contribute to a range of related diseases.

An article in the Wall St Journal states protein may be hot, but it’s fiber that Americans need to eat a lot more of.  The latest science suggests fiber is more consequential to our health than previously understood. Found in fruits, vegetables, beans, whole grains and other plant foods, it fills us up and aids digestion. It lowers cholesterol and helps keep blood-sugar levels stable. People who eat high-fiber diets have lower risks of obesity, Type 2 diabetes, heart disease and several types of cancer, according to studies. 

More recently, researchers believe they’ve discovered how not getting enough fiber can lead to chronic disease. Fiber is critical for the healthy functioning of the gut microbiome, the collection of microbes that inhabit our digestive tract. A lack of fiber causes changes in the microbiome that can trigger immune dysfunction and chronic inflammation, which is implicated in a host of diseases. 

People with a 2,000 calorie-a-day diet should eat 2.5 cups of beans, peas and lentils a week, up from the currently recommended 1.5 cups, according to a December report from the committee.  The current federal dietary guidelines recommend 25 grams of fiber a day for women ages 31 to 50, 21 grams a day for women over 50, and 3o grams for men over 50.  If you’re a male under 50 it is 38 grams a day. But more than 90% of women and 97% of men don’t meet the recommendations. On an average day, they consume about 15 grams and 18 grams respectively, according to federal data.  

Starving your gut’s bacteria

Fiber is a part of plants our bodies largely can’t digest. But when it gets to our large intestine, it acts as food for our microbiome. When our gut bacteria consume, or ferment, fiber, they create substances called short-chain fatty acids, says Justin Sonnenburg, a professor of microbiology and immunology at Stanford University. 

“These magic molecules play a really important role in regulating our metabolism and immune function,” he says. “If you’re not consuming fiber, your immune system may be more inflammatory,” he says. 

When you don’t get enough fiber, the problem isn’t just that you don’t make enough of the good short-chain fatty acids. Starved of the fiber they like to eat, your bacteria start to devour your own gut lining, says Abigail Johnson, associate director of the Nutrition Coordinating Center at the University of Minnesota School of Public Health.  Specifically, bacteria can erode the mucus layer that lines your gut and is supposed to keep bacteria from entering your bloodstream. The resulting “leakiness” can drive inflammation throughout the body, she says.   

How to get more fiber

The best way is to eat a variety of fruits, vegetables, whole grains, beans, nuts and seeds, Johnson says. That way you’ll get a range of soluble and insoluble fibers.

Breakfast is an easy place to add fiber, notes the University of Rhode Island’s Vadiveloo. She recommends oatmeal or a whole grain cereal with fruit and nuts. And make a rule that when you’re hungry, first reach for a piece of fruit or a vegetable like baby carrots or cucumber slices. Make popcorn (but go easy on the salt) for a snack.  

Add fiber slowly and drink more water as you do, advises Beth Czerwony, a registered dietitian at the Cleveland Clinic Center for Human Nutrition. Some people can feel pressure or bloating when adding fiber too quickly, she says. 

What about fiber-enriched products and supplements?

Fiber supplements and cereal, bars and drinks with added fiber are proliferating on store shelves. But individual types of fiber act differently on the microbiome, says Andrew Gewirtz, a professor at Georgia State University who has conducted several related studies. To get the full health benefits of fiber, it’s important to eat a variety of naturally fiber-rich foods and not rely on supplements, which usually contain only one or two types of fiber.

So change your diet and for breakfast include oatmeal with fruit.  I love apple slices, blueberries, granola and nuts on my oatmeal.  For lunch and dinner include vegetables and beans along with your chicken, fish or occasional red meat. 

Constipation and Cholesterol

Other advantages of fiber is constipation.  Dietary fiber increases the weight and size of stool and softens it, making it easier to pass.  A high-fiber diet may lower the risk of swollen veins in the anus and lower rectum called hemorrhoids. Eating plenty of fiber also may help lower the risk of a condition called diverticulitis that involves small, inflamed pouches in the colon wall. A high-fiber diet is linked with a lower risk of colorectal cancer as well. Some fiber also serves as food for "good" bacteria in the gut. It's known as fermented fiber. It may play a role in lowering the risk of diseases of the colon.

Soluble fiber found in beans, oats, flaxseed and oat bran may keep the body from absorbing some of the cholesterol in other foods. As a result, that may lower low-density lipoprotein, also called "bad," cholesterol levels in the blood. High-fiber foods may have other effects on heart health, such as lowering blood pressure and lessening swelling in the body called inflammation.

Diabetes

In people with diabetes, fiber may slow the absorption of sugar and help improve blood sugar levels. That's especially true of soluble fiber. A healthy diet that includes both soluble and insoluble fiber also may lower the risk of type 2 diabetes.

Weight Management

High-fiber foods tend to be more filling than low-fiber foods. So you're likely to eat less and stay satisfied longer. High-fiber foods also tend to take longer to eat and to be less energy dense than low-fiber foods. That means they have fewer calories for the same volume of food.

Getting more fiber is linked with a lower risk of dying of any health condition, including heart disease.  So make sure you’re getting enough fiber.