Fast Facts: Dietary Fiber

Also spelled dietary fibre – gotta love English!

Dietary fibers encompass a vast array of digestion-resistant components found in plant-based foods. They fall into two basic categories: Soluble fiber and insoluble fiber, which have different benefits for the digestive tract. Soluble fibers are found predominantly in fruits, vegetables, legumes like beans and lentils, and plant extracts, and provide a food source for your beneficial gut bacteria. Insoluble fiber is found in whole grains, vegetables and woody plants, and provides meal bulk, satiety (feelings of fullness), and helps prevent constipation.

While dietary fiber is not absorbed by the body, it still plays an important role in digestive and overall health. Adequate fiber intakes can help with weight loss and weight management by increasing feeling of fullness, and as it is slow to be processed by the body, is an effective tool for hunger management. Fiber consumption has been linked in lower risks of several diseases, including multiple cancers of the digestive tract.

The recommended daily intake is approximately 25-30g of fiber. While many people routinely fall below this, you can boost your intake by choosing food including more beans and lentils, fruit and vegetables, whole grains, and other delicious whole food options. Choosing whole foods that are high in fiber will also provide a diet rich in a variety of other nutrients (vitamins and minerals) as well. No supplements needed!

Dietary Fibre is involved in:

• Decreasing risk of cardiovascular and metabolic disease by changing the rate and level of absorption and metabolism of some dietary fat and carbohydrate molecules, leading to lower cholesterol, lower triglycerides, and more steady levels of blood glucose (blood sugar) and insulin
• Decreasing risk of colon or bowel cancers by decreasing exposure of intestinal lining to potential cancer-causing molecules, both by increasing the volume of total food digested and decreasing the time food spends in the digestive tract
• Speeds the passage of food through the digestive system and adds bulk to stool, increasing regular bowel movements and alleviating and preventing constipation
• Weight loss, weight maintenance, and appetite control, through increased meal bulk with a relatively low number of calories, fats, and added sugars, as well as making you feel full faster
• May increase absorption of other nutrients, such as calcium and magnesium
• Appears to decrease systemic inflammation levels that are inherent to many disease states, including diabetes, cancers, Alzheimer’s disease, and others

Great Ideas for Increasing Fiber Intake

Low fiber intakes are often due to high intakes of processed foods, animal-based foods, and low intakes of plant-based foods. You can increase your fiber intake by including an extra salad, veggies, or fruit in with your daily meals. Some common high-fiber foods and their dietary fiber content are listed below.

• Romaine or Cos lettuce: 1 cup shredded = 1g
• Tomato: 1 small = 1.1g
• Cabbage: 1 cup shredded = 1.8g
• Quinoa: 1 cup = 5.8g
• Brown rice: 1 cup = 3.5 g
• Kidney beans:  1 cup = 11g
• Chickpeas: 1 cup = 12g
• Black beans (also called black turtle beans): 1 cup = 15g
• Celery: 1 large stalk = 1g
• Carrot: 1 medium = 1.4g
• Apple: 1 medium = 4.4g
• Banana: 1 small = 2.6g
• Kiwifruit: 1 medium = 2.1 g

Can I get too much fiber?

The National Academy of Sciences has not set a tolerable upper limit on dietary fiber intake. There are some health conditions that can call for a low fiber intake, so if you aren’t sure if you are in this category, talk to your doctor. In general, most health conditions will benefit from increased dietary fiber levels. Evidence also indicates that the higher your average intake, the more protective benefits you’ll enjoy.

What happens if I don’t get enough fiber?

Low intakes can lead to excessive weight gain and increased disease risks, however low fiber intakes alone do not seem to be solely responsible for any specific health condition. So while you may not be used to eating a high-fibre diet, you can easily increase your fibre intake by adding a piece of fruit or some veggie sticks. Any increased intake will provide benefits, even if you don’t hit the daily 25g mark!

 

Want to try out a quick and delicious high fiber lunch? Try this Chickpea and Feta Salad!

 

References

Dhingra D, Michael M, Rajput H, et al. (2012) Dietary fibre in foods: a review. J Food Sci Technol, 49(3), 255-66.

Kaczmarczyk, M. M., Miller, M. J., & Freund, G. G. (2012). The health benefits of dietary fiber: Beyond the usual suspects of type 2 diabetes mellitus, cardiovascular disease and colon cancer. Metabolism, 61(8), 1058-1066. doi:10.1016/j.metabol.2012.01.017

Marlett, J. A., McBurney, M. I., & Slavin, J. L. (2002). Position of the American Dietetic Association: Health Implications of Dietary Fiber. Journal of the American Dietetic Association, 102(7), 993-1000.