How Fiber Can Reduce Your Risk for Colorectal Cancer


Fiber is an important ingredient in any healthy diet. And it’s especially important for lowering your risk for colorectal cancer.

Colorectal cancer fast facts

Colorectal cancer is the 4th leading cause of death among women in the United States.

American Cancer Society estimates for 2024:

New colon cancer cases in women = 52,380

New rectal cancer cases in women = 18,890

What is fiber?

Fiber (aka roughage) = parts of food that your body doesn’t digest or absorb.

When it passes through your body, it helps lower cholesterol, helps control sugar levels and makes bowel movements regular.

There are 2 types of dietary fiber:

  • Soluble fiber
    • Dissolves in water
    • Helps lower cholesterol and blood sugar
    • Found in oats, peas, beans, carrots, apples and citrus fruits
  • Insoluble fiber
    • Helps keep your digestive system moving and reduces constipation
    • Found in whole wheat flour, nuts, beans and vegetables

How does fiber reduce colon cancer risk?

  • Improves bowel and colon health
  • Helps food move through the digestive system
  • Supports gut health and can reduce harmful inflammation
  • Helps move harmful chemicals out of your body sooner
  • Combines with gut bacteria to maintain bowel cell health

How much fiber do women need?

The USDA Dietary Guidelines for Americans suggest a daily intake of:

28 grams for women 19–30

25 grams for women 31–50

21 grams for women 51+

High-fiber foods

Fruits

  • Avocados
  • Berries
  • Pears
  • Apples
  • Bananas

Vegetables and Legumes

  • Lentils/beans
  • Peas
  • Broccoli
  • Brussels sprouts
  • Sweet potatoes

Nuts and Grains

  • Almonds
  • Quinoa
  • Barley
  • Brown rice
  • Whole-grain bread

A few ways you can get your recommended fiber

Get fiber into your breakfast

1 cup of instant oatmeal = 4 grams

1 cup of raspberries = 8 grams

1 ounce of chia seeds = 10 grams

1 banana = 3 grams

Use whole grains as a base for your lunch

1 cup of brown rice = 3.5 grams

1 cup of black beans = 15 grams

1 cup of sweet corn = 4 grams

2 medium carrots = 3 grams

Add legumes and non-starchy vegetables to dinner

1 cup of lentils = 15.5 grams

1 cup of green peas = 9 grams

1 cup of cauliflower = 2 grams

Choose high-fiber snacks

1/2 cup of sunflower seeds = 6 grams

1 pear = 5.5 grams

1 medium apple = 4.5 grams

3 cups of popcorn = 3.5 grams

1 ounce of almonds = 3.5 grams

1 ounce of pistachios = 3 grams

This educational resource was created with support from Merck.

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