The link between dietary fiber and cancer prevention is among the few well-documented and established correlatives today. Fiber is crucial to human health and provides many health benefits – but most Americans aren’t eating nearly enough.

What Is Fiber?

There are two kinds of dietary fiber, both sourced from plants. Different plants have higher or lower levels of each, which means eating a variety of vegetables and fruits provides both types of fiber.

  • Soluble fiber – Can be partially digested and lowers cholesterol by absorbing it, moving it through the digestive tract more quickly. The most common sources of soluble fiber include grains, oats, and most vegetables.
  • Insoluble fiber – Cannot be digested and adds bulk to stool. Insoluble fiber is found in fruits, beans, and nuts.

How Dietary Fiber Lowers Cancer Risk

Getting the recommended amounts of fiber improves overall metabolic health in several ways. These health benefits are linked primarily to cancer risk factors; there’s little direct evidence that fiber intake directly impacts tumor development.

  • Blood sugar – Dietary fiber helps lower blood pressure and maintain a healthy weight, two health conditions linked to cancer.
  • Improving gut health – Fiber helps feed “good” gut bacteria, benefiting digestive health and lowering cancer risk.
  • Reduce constipation – Eating enough fiber is an excellent way to stay regular.

Related: Ultraprocessed Food Linked to Excess Deaths

How Much Fiber Do I Need?

Experts recommend taking 25 – 30 grams of fiber daily from natural foods. Most Americans average roughly 15 grams or half of the healthy amount. This may play a role in the rise of colon cancer and other lower digestive tract cancers in the past two decades. Since 1995, colorectal cancer rates among people under 50 have nearly doubled from 11% to 20% in 2019.

Choosing a High-Fiber Diet

Ready to eat more fiber? It’s one of the most effective ways to substantially change your overall health, including lowering body weight and regulating blood sugar levels. These have a tremendous impact on your daily energy levels, mood, and even depression.

Increase Your Diet Intake in 4 Steps

Start slowly! Doubling your fiber intake overnight can cause cramps, bloating, and gas. Make small increases; aim to add a few grams every day over the course of a week or more.

Hydration is key. Fiber increases your need for adequate hydration. Be sure to get at least 8 cups of water per day and drink more if you’re active.

Choose raw fruits and vegetables. These have ample fiber and always eat the skins; that’s where the fiber is!

Opt for brown rice and whole-grain pasta instead of white rice or pasta made from white flour.

Should I Use Fiber Supplements?

The best source of dietary fiber or any nutrient is real food. If you’re struggling to mix adequate amounts of fiber into your diet, talk with your healthcare provider about safe and effective supplementation.

Stay Healthy, Active, and Informed with Less Cancer

Less Cancer is a nationally recognized non-profit prioritizing cancer prevention in the US. Our mission is to drive change through education and advocacy, representing families on environmental causes of cancer, food, and healthcare access. Learn more about Less Cancer U and how we do our work.