Dietary Fiber: Overlooked & Underappreciated

By Luis Olivares

The importance of healthy eating habits for maintaining or improving one's overall health and fitness level is well established. Anyone with even a cursory understanding of nutrition knows the value of a diet based on quality protein and carbohydrates and low in fat, with emphasis on unsaturated rather than saturated fats. It's even likely that the differences between simple and complex carbs, and the relative benefits and drawbacks of each, have nowadays become common knowledge. Consumers are more educated than ever before, which is encouraging given the rising incidence of obesity around the world and in the United States in particular. Yet there is one crucial element of a healthy diet that, despite its ready availability and myriad potential health benefits, is quite often overlooked by average folks and fitness veterans alike.

Americans are not eating enough fiber. The Food and Nutrition Board of the Institute of Medicine recommends an average daily intake of 38 grams of fiber for adult men and 25 grams for adult women (under the age of 50) 1, yet estimates place the average American adult's daily fiber intake at about half that range 2. What's more, it appears that the average person is likely unclear on or unaware of the difference between soluble and insoluble fiber and the respective roles they play in digestive health. Perhaps it's this confusion over what exactly fiber is and what it does that is partially to blame for its conspicuous absence from the American diet, which experts are beginning to suggest might be partially responsible for some of the country's most prevalent health concerns, such as obesity and cardiovascular disease 3. Therefore, a little background seems in order.

Dietary fiber is defined as the edible parts of plant foods that are resistant to digestion and absorption in the small intestine 4. Insoluble fiber absorbs water and aids in pushing digested matter through the intestinal tract, a crucial component of overall health. This is likely what most people think of when the word "roughage" comes to mind. Soluble fiber, on the other hand, is metabolized via fermentation in the large intestine, producing valuable short-chain fatty acids (SCFAs) and, unfortunately, gas. It is this fermentation and production of SCFAs that is so important and beneficial to both a person's digestive and overall health.

The fermentation process involves the soluble fiber being broken down by the bacteria living in the large intestine. This intestinal flora is crucial to digestive health. Equally crucial is the balance between these "good" bacteria and the unavoidable harmful bacteria with which they coexist. However, factors such as antibiotic treatments and poor eating habits can easily lead to bacterial imbalance. By including viable amounts of soluble fiber in their diet, a person can essentially "feed" these productive bacteria and cause the positive bacteria population to flourish. But this prebiotic benefit of soluble fiber is only the beginning.

Where soluble fiber really imparts its full benefits is the production of SCFAs. Short-chain fatty acids are known to provide a whole host of benefits to a person's health. Increased SCFA production is linked to an increase in mineral absorption due to nourishing effects on the intestinal lining, thereby strengthening bone health 5. Specific SCFAs, such as propionate, have demonstrated the ability to lower cholesterol levels 6, thereby offering a protective effect against cardiovascular disease. SCFAs support the immune system, and also aid in blood glucose regulation, which is of particular benefit to diabetics. And they offer protection against and mediation of a number of gastrointestinal disorders, including diverticulitis, colitis, irritable bowel syndrome, constipation, and polyposis 7,8,9. There has also been some suggestion that SCFAs may reduce the risk of colorectal cancer, though that link has yet to be particularly well-established 10.

Clearly, a diet high in fiber is remarkably good for one's overall health. Not only that, but it's a key component in any weight management program as well. Adequate fiber intake regulates blood sugar, maintains energy levels, and also has the effect of keeping a person feeling fuller, longer, allowing for greater control over calorie consumption. Increasing one's fiber intake can go a long way towards successfully shedding those last few pounds.

The benefits of this simple dietary addition are truly too good to ignore. That said, the question arises of where to find quality sources of dietary fiber. All plant foods contain some degree of both soluble and insoluble fiber. So a good place to start would be to simply eat more fruits and vegetables. Specifically, legumes such as beans, peas, and peanuts are some of the most fiber-rich foods available 11. Whole grains, oats, and flaxseed are also excellent fiber sources. And the grocery store cereal aisle is lined with all kinds of bran cereals that provide convenient low-calorie sources of dietary fiber. Fiber sources are everywhere, and offer a variety of flavors and textures. Maintaining a fiber-rich diet is probably a lot easier than most people realize - and it can also be quite delicious.

Also of note is the increasing popularity of fiber supplementation. No longer simply reserved for the elderly, powdered fiber supplements offer a quick and easy alternative to altering one's diet. The recently popularized açaí berry is one example. Açaí berries are unique among fruit in their enormously high fiber content, and as a result have become widely available in powdered form as a fiber and weight loss supplement. Also worth pointing out is BSN's own SYNTHA-6™, the ultra-premium sustained-release protein powder. Unique among protein supplements, it has long been enriched with a healthy amount of dietary fiber due to its beneficial effects on digestion, increased protein utilization and satiety. Turns out it may also help prevent cardiovascular and gastrointestinal disease as well.

The facts are quite clear: dietary fiber is a wonderful contributor to human health and well-being, and yet Americans are not consuming nearly enough of it. Factors such as diets far too centered on simple carbs and fat and a general lack of awareness are the likeliest culprits. But a fiber-rich diet is actually quite easily achieved, and can provide numerous rewards for minimal investment. Take SYNTHA-6™ for example; fiber doesn't have to be boring. With eight mouth-watering flavors, increasing fiber intake can actually be delicious! Additionally, you can simply eat an apple or flesh out that plate of chicken with some beans and rice. Spoon some peanut butter on some celery, and maybe even top it with raisins (that's a fiber trifecta). Increasing fiber intake can be simple and enjoyable, and the potential benefits cannot be overstated.

References

1. Linus Pauling Institute at Oregon State University, Micronutrient Information Center: Fiber. http://lpi.oregonstate.edu/infocenter/phytochemicals/fiber/
2. Harvard School of Public Health, The Nutrition Source: Fiber. http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fiber-full-story/index.html
3. USDA and Dept. of Health and Human Services Dietary Guidelines for Americans, 2005. http://www.health.gov/dietaryguidelines/dga2005/document/html/chapter2.htm
4. The Definition of Dietary Fiber." http://www.aaccnet.org/DietaryFiber/pdfs/dietfiber.pdf
5. The Journal of Nutrition. "Prebiotics, Probiotics, and Synbiotics Affect Mineral Absorption, Bone Mineral Content, and Bone Structure." http://jn.nutrition.org/cgi/content/full/137/3/838S
6. Journal of Clinical Gastroenterology. "Colonic Health: Fermentation and Short Chain Fatty Acids." http://www.jcge.com/pt/re/jclngastro/abstract.00004836-200603000-00015.htm
7. Linus Pauling Institute at Oregon State University, Ibid.
8. The Journal of Nutrition, Ibid.
9. About.com: Nutrition: Prebiotics and Probiotics. http://nutrition.about.com/od/therapeuticnutrition1/p/pro_prebiotics.htm
10. New England Journal of Medicine. "Dietary Fiber and the Risk of Colorectal Cancer and Adenoma in Women." http://content.nejm.org/cgi/content/abstract/340/3/169
11. USDA and Dept. of Health and Human Services Dietary Guidelines for Americans 2005: Appendix B. Food Sources of Selected Nutrients. http://www.health.gov/dietaryguidelines/dga2005/document/html/appendixB.htm

The information contained here is provided for informational purposes only and is not meant to substitute for the advice provided by your doctor or other health care professional. You should not use the information available on or through the Web Site (including, but not limited to, information that may be provided on the Web Site by healthcare or nutrition professionals employed by or contracting with BSN) for diagnosing or treating a health problem or disease, or prescribing any medication. Information and statements regarding dietary supplements have not been evaluated by the Food and Drug Administration and are not intended to diagnose, treat, cure, or prevent any disease. You should read carefully all product packaging prior to use.

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