Thursdays with Dr. Tadashi

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FIBER!

Let’s get personal. How was your last bowel movement? Was it firm or loose? Did you have to exert pressure or was it a “smooth landing” into the toilet bowl? Were you able to read a whole chapter of a novel while on the “can” or were you in and out of the bathroom quickly?

As many of you many know, fiber contributes a great deal to the quality (and quantity) of your bowel movements. Fiber is a type of carbohydrate that is, for the most part, indigestible. Other carbohydrates get broken down into simple sugars (glucose, fructose, and galactose) within our body after interacting with digestive enzymes and fluids, but fiber will stay intact. There are many ways to classify the different varieties of fiber, but the most common is to categorize them is by their solubility:

As fiber travels through the stomach and small intestines, they stay intact, but once they reach the large intestine/colon, the fibers interact with our diverse colonies of innate bacterial flora and go through a fermentation process. This fermentation process produces three main by-products (>95%) in the forms of short chain fatty acids:

As a whole, fiber increases the bulk to help move food through our digestive system, increasing regularity and helping prevent constipation, while feeding our diverse gut flora that produce very important by-products to keep our body functioning well.

Unfortunately, our modern American diet does not provide us with ample amounts of dietary fiber. Different sources state that Americans eat less than 20%-50% of the recommended amounts of dietary fiber [3]. The National Academy of Sciences (NAS) and the Institute of Medicine has recommendations based on age and sex. In general, for men and women between 19-50 years old, they recommend 38 grams and 25 grams of fiber per day, respectively. One of the many reasons for our low fiber intake is eating too many animal products, which contain ZERO fiber, and not eating enough fruits, vegetables, legumes, and whole grains.

The lack of fiber within our diet may be one of the many causes of cardiovascular diseases, obesity, diabetes, hyperlipidemia (high cholesterol levels), inflammatory bowel disease, hemorrhoids, diverticulosis (out pouching of the large intestines), diverticulitis (infections of the diverticulosis), and many more [4]. Many research papers have proven time and time again the importance of fiber in our diet to prevent chronic diseases, like:

  • Hyperlipidemia (high cholesterol): the viscous, gel-like consistency of soluble fiber within our gastrointestinal tract traps LDL (the ‘bad’ cholesterol), preventing them from being absorbed in our body; rather it is excreted within our bowel movements.
  • Cardiovascular Disease: researchers have found that a high total dietary fiber intake was linked to a 40% lower risk of coronary heart disease [5].
  • Type 2 Diabetes: without fiber, sugars get absorbed within our body at a startling rate, causing sugar spikes, which, when continued for a long time, leads to insulin resistant type-2 diabetes. Increased fiber intake decreased the risk of getting type 2 diabetes by half [6]! A diet high in fiber also increases the level of a hormone called glucagon-like peptide-1 (GLP-1), which acts to decrease blood sugar levels [7].

As you can see, fiber intake has great benefits to our body! Here are some of my recommendations to increase your intake on a regular basis to make yourself….well, more regular:

  • If you love your breakfast smoothies, add a tablespoon of psyllium husk into it. It’ll give your smoothie a thicker consistency and it’s tasteless!
  • Eat raw vegetables (like celery, broccoli, and carrots) for snacks, instead of chips or processed foods. For you over achievers, make yourself some simple homemade hummus for even more fiber (click here for a simple recipe!)
  • Rather than drinking fruit juices, eat whole fruits, especially raspberries, mangos, apples, and pears.
  • Substitute beans or legumes (highest in fiber per serving size) for meat (which has no fiber).
  • Replace white rice/bread/pasta with brown rice and whole grain products.
  • If you’re a soup lover, like I am, ditch the boring chicken noodle soups and make yourself a red lentil soup filled with veggies (like this one!).

References:

Wong JM1, de Souza R, Kendall CW, Emam A, Jenkins DJ. Colonic health: fermentation and short chain fatty acids. J Clin Gastroenterol. 2006 Mar; 40(3):235-43.
Hugenholtz F, Mullaney JA, Kleerebezem M, et al. Modulation of the microbial fermentation in the gut by fermentable carbohydrates. Bioactive Carbohydrates and Dietary Fiber 01/2013; 2(2):133—142.
Clemens R, Kranz S, Mobley A, Nicklas T, Raimondi P, et al. Filing America’s fiber intake gap: summary of a roundtable to probe realistic solutions with a focus on grain-based foods. J Nutr 2012; 1390s-1401s.
Eswaran S, Muir J, Chey WD. Fiber and functional gastrointestinal disorders. Am J Gastroenterol 2013;108:718-27.
Rimm EB, Ascherio A, Giovannucci E, Spiegelman D, Stampfer MJ, Willett WC. Vegetable, fruit, and cereal fiber intake and risk of coronary heart disease among men. JAMA. 1996;275:447-51.
Schulze MB, Liu S, Rimm EB, Manson JE, Willett WC, Hu FB. Glycemic index, glycemic load, and dietary fiber intake and incidence of type 2 diabetes in younger and middle-aged men. Am J Clin Nutr. 2004;80:348-56.
Fukii H, Iwase M, Ohkuma T, et al. Impact of dietary fiber intake on glycemic control, cardiovascular risk factors and chronic kidney disease in Japanese patients with type 2 diabetes mellitus: the Fukuoka Diabetes Registry. Nutr J. 2013; 12: 159. Published online 2013 December 11. doi: 10.1186/1475-2891-12-159.