What is Dietary Fiber?
Dietary fiber, often referred to as roughage or bulk, includes the parts of plant foods that your body can't digest or absorb. Unlike other food components, such as fats, proteins, or carbohydrates, which your body breaks down and absorbs, fiber isn't digested by your body. Instead, it passes relatively intact through your stomach, small intestine, and colon and out of your body.
Types of Dietary Fiber
Fiber is commonly classified into two categories: soluble and insoluble.
Soluble fiber dissolves in water to form a gel-like substance. It can help lower blood cholesterol and glucose levels. Soluble fiber is found in oats, peas, beans, apples, citrus fruits, carrots, barley, and psyllium.
Insoluble fiber promotes the movement of material through your digestive system and increases stool bulk, so it can be beneficial for those who struggle with constipation or irregular stools. Whole-wheat flour, wheat bran, nuts, beans, and vegetables, such as cauliflower, green beans, and potatoes, are good sources of insoluble fiber.
How Does Dietary Fiber Affect Cancer Risk?
Numerous studies have suggested that a diet high in fiber is associated with a reduced
risk of certain types of cancer, particularly
colorectal cancer. Fiber may help protect against cancer by improving bowel function, which can help to remove potential carcinogens from the body more quickly. Fiber also promotes the growth of beneficial bacteria in the colon, which produce substances that help to protect colon cells from becoming cancerous.
Mechanisms of Action
There are several mechanisms through which dietary fiber may reduce cancer risk: Binding Carcinogens: Fiber can bind to potential carcinogens and remove them from the body.
Short-chain Fatty Acids: Fermentation of fiber in the colon produces short-chain fatty acids that may inhibit the growth of cancer cells.
Weight Control: High-fiber foods are more filling, which can help control weight. Obesity is a risk factor for several types of cancer.
Recommended Intake of Dietary Fiber
The
American Institute for Cancer Research recommends aiming for at least 30 grams of dietary fiber per day from food sources. It's important to consume a variety of fiber-rich foods to benefit from the different types of fiber.
Dietary Sources of Fiber
Good sources of dietary fiber include: Fruits such as berries, apples, and pears
Vegetables including broccoli, carrots, and leafy greens
Legumes like beans, lentils, and chickpeas
Whole grains such as oats, barley, and quinoa
Nuts and seeds
Potential Risks and Considerations
While dietary fiber is generally beneficial, it's important to increase fiber intake gradually to avoid gastrointestinal discomfort such as bloating and gas. Additionally, in rare cases, very high fiber intake could interfere with the absorption of certain minerals. It's always a good idea to consult with a healthcare provider or a dietitian when making significant changes to your diet.Conclusion
Incorporating a variety of high-fiber foods into your diet may not only help to reduce the risk of some cancers but also provide numerous other health benefits. Always aim for a balanced diet rich in fruits, vegetables, whole grains, and legumes to achieve optimal health.
