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Surprising Health Benefits of a Fiber-Rich Diet

Surprising Health Benefits of a Fiber-Rich Diet


Since March is Colorectal Cancer Awareness Month and National Nutrition Month, it seems the ideal time to review some basic information about fiber and highlight some of the profound – and surprising – health benefits you’ll get by incorporating more fiber into your diet.

Facts on Fiber: Fiber is a natural (and healthy) carbohydrate. When you look at nutrition labels, you may see fiber labeled as soluble or insoluble. Soluble fiber (found in oat bran, barley, nuts, seeds, peas and some fruits and vegetables) absorbs water, which transforms it into a gel-like substance that slows digestion. In contrast, insoluble fiber speeds digestion by adding bulk to the stool; it is found in whole grains, wheat bran and some types of vegetables. Most plants (which is where fiber comes from) have both types, but usually more of one than the other.

Both types of fiber are healthy. A fiber-rich diet makes you feel full faster, so it helps you maintain a healthy weight. It has also been linked with easier weight loss and lower risk of diabetes. Note: If you don’t already eat a lot of fiber, add it to your diet gradually. Too much fiber too fast can cause a range of unpleasant digestive symptoms, including bloating, gas and cramps.

The Institute of Medicine recommends a minimum of 25 grams of daily fiber for women and 38 grams for men. The average adult only eats 15 grams of fiber per day. For reference, here are some foods and the fiber content:


  • 1 cup of chickpeas = 16 grams of fiber
  • 1 avocado = 6.75 grams of fiber
  • ½ cup of peanuts = 6.2 grams of fiber
  • 1 apple = 4.4 grams of fiber
  • 1 slice whole wheat bread = 1.9 grams of fiber


Surprising Health Benefits of a High-Fiber Diet

Fiber helps reduce your risk of colorectal cancer. People who eat a lot of fiber had a 35% lower risk of colorectal cancer, according to the four-year U.S. Polyp Prevention Trial. Researchers believe that the reduced cancer risk is because fiber moves food more quickly through the digestive system, minimizing cellular exposure to potential carcinogens as it removes waste more efficiently.

Another cancer-fighting benefit linked to fiber consumption is production of a substance called butyrate, created when bacteria in the lower intestine break down fiber. Butyrate protects against growth of tumors of the colon and rectum and also helps tamp down inflammation in the gut, which is associated with a 500 times greater risk of developing colorectal cancer.

Fiber lowers breast cancer risk – particularly when young women eat a fiber-rich diet.  Scientists have long been aware that eating plenty of fiber helps lower a woman’s risk of developing breast cancer, in part by binding to estrogen, which is associated with breast cancer developments. Now a new study from Harvard reports that for every additional 10g of dietary fiber eaten daily by women in adolescence and young adulthood, breast cancer risk is lowered 13%.

Fiber helps you breathe more easily – and it also helps lower your risk of developing lung cancer. Fiber promotes lung health in several important ways, including reduction of inflammation and the promotion of healthy levels of gut bacteria. It improves lung health overall and also promotes , respiratory function and reduces COPD risk as well.

Eating plenty of fiber during pregnancy helps protect your child from asthma. Inflammation and healthy gut bacteria help during pregnancy, too: A new study found lower rates of asthma (and respiratory illnesses in general) in the first years of life in the offspring of women who ate healthy amounts of dietary fiber. (Plus, many pregnant women complain about constipation and fiber helps with that, too!)

Fiber promotes heart health – and lowers the risk of a second cardiac event in patients who’ve already had one heart attack. The anti-inflammatory benefits of eating fiber are good for the heart too, both in keeping a strong heart healthy and in improving health after heart attack. A recent study found that eating fiber from cereal reduced risk of death in the nine years following a heart attack by 25%, with higher survival linked to higher rates of dietary fiber from cereal.

Fiber helps you sleep more deeply too! Though this is far from a complete list of the health benefits of eating fiber, we thought this might be a good one to end with – given that new research reports that 30% of Americans are sleep-deprived. A study just published in the Journal of Clinical Sleep Medicine compared the effects of different foods on slow-wave sleep (also called deep sleep). They found that when study participants ate the recommended diet, which included high-fiber foods low in saturated fat and sugar, they fell asleep faster and had longer periods of deeply restful sleep.