Is fiber the secret to a healthier gut?


by Vani Paleti, MD

Mar 25, 2019

Thanks to the keto diet, Whole 30 and other “fad diets,” the majority of our nutrition-related conversations tend to revolve around macronutrients — carbohydrates, fats and proteins — as well as added sugar and highly-processed foods. (All good things to pay attention to.)

But what about dietary fiber? I’d venture to guess that you don’t put much thought into this particular area of your diet.

A quick education on fiber and colorectal cancer

Would you be surprised to learn that most Americans (95 percent of us, in fact) do not meet the daily standard requirement of dietary fiber, which is 30-40 grams? If you’re like most Americans, your daily intake is probably more in the range of 15 grams. In a nutshell, fiber is the indigestible part of plant foods. Fiber is mostly found in fruits, vegetables, legumes and whole grains, and is an important part of our diet for many reasons. There are two type of fiber: soluble and insoluble.

  • Soluble fiber (found in oatmeal, nuts, beans, lentils and some fruits) helps lower glucose levels and blood cholesterol.
  • Insoluble fiber (found in wheat, brown rice and green leafy vegetables) promotes digestive regularity and eliminates toxic waste from the colon.

Eating enough fiber is key to a healthy gut, and a healthy gut (meaning your small intestine and large intestine, or colon) is critical for preventing diseases like colon cancer, which is the third most commonly diagnosed cancer in the U.S. and the second-leading cause of cancer deaths. Colorectal cancer is strongly linked to lifestyle and dietary habits, meaning those small daily diet choices we make truly do matter.

The importance and future of high fiber, “plant slant” diets

When we look at the longstanding and time-tested DASH and Mediterranean diets, as well as the more recent Whole Food Plant-Based diet, there is a recurring theme: plants. Hence, we refer to these diets as “plant slant” diets.

Vegetables, fruits and whole grains make up 80-90 percent of these food pyramids, along with increased emphasis on physical activity and strong social support. All of these diets are rich in natural fibers, which help regulate blood sugar and lipid metabolism. This also helps regulate your bowels, decreasing what we call “transit time” and as a result, constipation.

Most Americans’ diets rely too heavily on fat and protein, and not enough on fiber. A recent study revealed that when fat (mostly saturated fat) constituted up to 40-45 percent of a person’s total calorie intake, he or she faced an increased risk of colorectal cancer. But when only 10-15 percent of the diet was made up of fat, the individual’s risk was significantly lower.

I’m passionate about educating people on how to lower their risk of colorectal cancer by focusing on gut health and nutrition. This isn’t just something I tell my patients. It’s a lifestyle I live myself — in case you’re curious, my family and I follow a whole food plant-based diet.

How to increase your fiber intake

Are you convinced yet that fiber is the key to a healthy gut? Here’s how to start integrating more high-fiber foods into your diet.

Eat more of this…

Foods that are high in fiber and low in fat seem to improve gut health and have a protective effect against colon cancer. These are some of your “gut healthy” foods:

  • Leafy green vegetables (spinach, collard greens)
  • Cruciferous vegetables (broccoli, cabbage and cauliflower)
  • Whole fruits (berries)
  • Whole grains (barley, quinoa, brown rice)
  • Legumes (beans, lentils)

Opt for foods that are rich in fiber, and include a mix of both prebiotics and probiotics in your diet. These foods help optimize your gut microbiome, keeping your gut happy and healthy. Prebiotics include leeks, onions, garlic and oats. Probiotics include yogurt with active cultures, kefir and certain minimally-fermented products such as sauerkraut, kimchi and kombucha.

And less of this…

On the contrary, foods that are high in fat and low in fiber are not considered “gut healthy.” In fact, quite the opposite. Red meat, smoked barbecue, highly-processed foods, foods high in sugar, alcohol — these items make up a large portion of the Standard American Diet ( SAD) and have been strongly linked to an increased risk for colorectal cancer, obesity, and several metabolic diseases including heart disease, stroke and diabetes, just to name a few.

For a gut healthy diet, enjoy these foods in moderation:

  • Beef
  • Lamb
  • Pork
  • Butter
  • Cheese
  • Deep-fried foods
  • Pastries, pies, cookies and other sweets

The average person can have a well-regulated gut by eating nutritionally-balanced foods without supplements or vitamins, but certain health conditions may require additional nutritional support. So, don’t forget to check with your primary care doctor before undertaking any major dietary changes.

There you have it — all the information you need to start building a healthy diet for a healthy gut. Just remember: fiber is the key. The other key to a healthy gut? Getting screened for colon cancer.

About the Author

Vani Paleti, MD, is a gastroenterologist on the medical staff at Baylor Scott & White Specialty Clinic – Killeen Hemingway. She is specialized in treating gastrointestinal and liver diseases, and is passionate about preventing and screening for colorectal cancer. She has special interest in the prevention and treatment of obesity. In treating patients, she places an emphasis on gut health and plant-based nutrition. Apart from being a physician, Dr. Paleti is a mother of two and in her free time loves to spend time with her family, run outdoors and listen to audiobooks. She is passionate about promoting a healthy lifestyle and enjoys trying out new, healthy and easy recipes. She and her family follow whole food plant-based nutrition.

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