Some research suggests that dietary fiber may protect against colorectal cancer. However, more research is needed to better understand the relationship between fiber intake and colorectal cancer.
Colorectal cancer refers to cancer that occurs in the colon or rectum. While the exact causes of colorectal cancer are unknown, some studies suggest that dietary habits may play a role. In particular, it’s
However, research on the relationship between fiber and colorectal cancer doesn’t yet offer a clear conclusion.
This article reviews the role that fiber may play in protecting against colorectal cancer, offers ways to get enough fiber, and discusses other tips for cancer prevention.
You’ll notice that the language used to share stats and other data points is pretty binary, fluctuating between the use of “male” and “female” or “men” and “women.”
Although we typically avoid language like this, specificity is key when reporting on research participants and clinical findings.
Unfortunately, the studies and surveys referenced in this article didn’t report data on, or include, participants who were transgender, nonbinary, gender nonconforming, genderqueer, agender, or genderless.
Over the past few decades, several studies have analyzed the relationship between fiber intake and colorectal cancer risk. Most of these older studies, including studies from 1997 and 1998, found that those with higher intakes of dietary fiber had a lower risk of getting colorectal cancer than those who didn’t eat as much fiber.
How dietary fiber protects against colorectal cancer isn’t fully understood, but a few mechanisms have been proposed. It’s believed that since fiber increases stool bulk and decreases transit time, it helps
Research continues to assess whether or not fiber has a protective effect against colorectal cancer, with varying results.
A 2018 review of 11 prospective cohort studiesconcluded that the risk of colon cancer was 14% to 21% lower in the group with the highest dietary fiber intake compared with the group with the lowest intake. Another review of studiesthat examined nine studies performed in eastern Asian countries found that six studies indicated that dietary fiber has a preventive effect on colon cancer, while three studies didn’t have this conclusion. A review of studies from 2019concluded that dietary fiber had a significant protective effect against the development of colorectal cancer in Asian adults.
It’s unclear how the type — soluble or insoluble — or source of dietary fiber contributes to the possible anticancer effects. For example, studies offer
Research has often been limited to certain populations or locations. There’s a need for more studies that include participants from more racial and ethnic backgrounds, age groups, and geographic locations. Additional research on how fiber affects colon cancer risk in males versus females is also needed.
Keep in mind, also, that studies that show a link between colorectal cancer and dietary fiber intake have primarily been observational. It’s not possible to identify if low fiber intake is actually a cause of this cancer or if it’s just associated with a greater risk.
What qualifies as a “high” fiber intake differs across research, but
The American Institute for Cancer Research (AICR) recommends a daily fiber intake of 30 grams per day to reduce cancer risk and suggests that each 10-gram serving of fiber per day decreases colorectal cancer risk by 7%.
This is in line with the
In addition to the possible protective effects against cancer,
Meeting fiber needs can be challenging. The
The best sources of dietary fiber include:
- whole grains
The two main types of fiber in foods are soluble and insoluble. Some foods are particularly high in one of these types, but most fiber-rich foods offer a mix of the two.
To help you meet the goal of approximately 30 grams of dietary fiber per day, here are some foods to incorporate into your meals:
- High fiber fruits: raspberries, pears, bananas, apples, avocado, dried fruits (unsweetened)
- High fiber vegetables: Brussels sprouts, artichokes, broccoli, green peas, celery, acorn squash
- Whole grains: oats, popcorn, barley, quinoa, bulgur, brown rice
- Legumes: lentils, chickpeas, black beans, split peas, white beans
- Nuts and seeds: chia seeds, milled flax seeds, almonds, pistachios, sesame seeds
To increase your fiber intake, try adding these foods to your meals throughout the day. For example, you can have oatmeal with raspberries at breakfast, broccoli with hummus (made with chickpeas) with lunch, and lentil soup for dinner.
If you don’t usually eat a high fiber diet, try to increase intake of fiber-rich foods gradually to prevent side effects like gas and bloating. It’s also helpful to drink a lot of water when you increase fiber intake to help it move through your system.
Finally, you may be wondering if taking fiber supplements is a beneficial way to increase fiber intake. Most experts, including the
In addition to getting enough fiber from foods, other diet and lifestyle habits may help protect against colorectal cancer.
Lack of physical activity, obesity, and an unbalanced diet, including high salt and red meat intake, have been
Here are the
- Maintain a moderate weight.
- Engage in 150 to 300 minutes of moderate intensity exercise or 75 to 100 minutes of vigorous intensity exercise per week.
- Limit sedentary behaviors like sitting and watching TV.
- Eat foods that are nutrient-dense, including fruits, vegetables, legumes and other plant proteins, whole grains, nuts, and seeds.
- Cut back on or avoid sugar-sweetened beverages, red and processed meats, and highly processed foods like packaged snacks and desserts.
- Limit alcohol use to no more than one drink per day for people assigned female at birth and no more than two drinks per day for people assigned male at birth, or avoid it completely.
It’s also very important for adults to get
The U.S. Preventive Services Task Force and the Centers for Disease Control and Prevention (CDC)
Some research suggests that dietary fiber may protect against colorectal cancer. However, more research is needed to better understand the extent of the protection that fiber provides and how much and what type of fiber is best.
Still, getting enough fiber — about 22 to 34 grams per day depending on age and sex — as part of a balanced diet is good for overall health and may help prevent colorectal and other cancers. In addition, regular colorectal cancer screening for adults ages 45 to 75 is very important for prevention and detection.
To meet fiber needs, try to incorporate more fruits, vegetables, legumes, nuts, seeds, and whole grains into your diet using some of the tips in this article.