January
2008
Fun With Fiber: The Real Scoop
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How is your colon doing? Cecum?
One of our most cherished pleasures in life happens to be challenging conventional wisdom (CW). You never would’ve guessed, right? After all the talk of meat and fat this week, we’ve been feeling, well, rather off. We figured it was the perfect time to take on everyone’s favorite gristly subject: fiber.
CW says Americans need serious fiber in their diets. And by “fiber” CW often means bran buds, whole wheat, psyllium husks - you know, sticks and twigs roughage. We’re talking that 1980’s Saturday Night Live bit about Super Colon Blow cereal. Let’s just say that the more sensitive among us, in particular, want to broach the question: “Is this really the best way?”
So, we thought we’d do some digging. Our ventures into the bowels of fiber research turned up some stimulating information. (O.K., we’ll stop.) First, let’s sit back and enjoy a brief gastronomical lesson. Anyone for some popcorn before we start? (Moving on!)
What is the point of fiber anyway? What does it do? Well, on one hand, soluble fiber (vegetables, fruit, oatmeal, and legumes that partially dissolve in water) enhances the thickness of the stomach’s contents. This slows stomach emptying. While this can give the body more time to absorb nutrients, it can also “trap” minerals like calcium or zinc, binding them up in such a way that they don’t have the opportunity to be absorbed. Insoluble fiber (like whole grains, seeds and fruit skins) increases the mass of the stool, which actually moves the stool more quickly through the intestines. Insoluble fibers pass through the digestive system relatively intact. Continuing on…
Let’s explore the reasons we’re supposed to incorporate fiber into our diets and what some sources have to say.
Fiber helps keep you regular
Some of us can reliably mark off our daily calendars, we’re so consistent. Others, well, not so much. For some of us, things come easily. Others, well, we won’t go there.
Whatever the issue, fiber can help, or so says CW. While our personal experiences don’t directly challenge that claim, our research showed a less than comforting picture of the long-term effects.
Some research shows that the very fiber we turn to with perfectly innocent intentions can become a serious monkey on our backs. It turns out, we may have to continually up the ante over time until we’re in over our heads - or behinds, so to speak.
The key to a healthy gastronomical tract is not roughage but bacteria. The large intestine’s natural bacteria, which help comprise stool bulk, maintain water content and soften the stool. (Sounds like those ads, huh?) Fiber, particularly excessive insoluble fiber, offering a quick jump start to things is not the natural catalyst for a healthy excretory system.
Finally, when it comes to long term “issues,” The American College of Gastroenterology Functional Gastrointestinal Disorders Task Force didn’t find fiber to be an effective treatment for chronic constipation.
Fiber lowers cholesterol
We’ve been talking about the cholesterol issue a lot this past week. As you’ve likely read, we believe cholesterol numbers aren’t the secret code to your health or longevity prospects.
Studies, some reliable and some not, have shown relatively minor changes in cholesterol as a result of higher fiber intake. These same changes have not carried over as predictors of heart disease. (I think I hear a broken record.) Furthermore, these “improvements” in cholesterol had a difficult price for some subjects in terms of gastrointestinal troubles.
Fiber lowers your risk of cancer
It’s usually colon cancer that people mean here, and the studies vary much more than you likely hear. The New England Journal of Medicine and The Lancet include studies that show high fiber diets do not lower the risk of cancer or incidence of polyps, a common precursor to cancer.
But maybe we’re onto something…. Some studies, including a study published in the International Journal of Cancer, break down the fiber sources of their subjects. And guess what? Researchers found that vegetable based fiber (as opposed to that from cereal and fruit) was the most cancer protective. The study focused on those with a risk of prostate cancer, but other researchers and physicians extend this claim to suggest a vegetable based high fiber diet in lieu of carbohydrate fiber sources.
Fiber helps prevent and/or treat diabetes
Here we find ourselves back to the question of what kind of fiber. The standard recommendation for diabetics is soluble fiber. A study in the Journal of Clinical Epidemiology found that high vegetable consumption (in this case, raw) was consistent with an 80% lower incidence of Type 2 diabetes. Studies using carbohydrate sources have not shown these kinds of results.
Soluble fiber slows stomach emptying, which prevents the body from being flooded with glucose at the same rate as it would be with a low fiber meal (assuming a high glycemic load in the meal). But therein lies the pertinent question: if you maintain a diet with low glycemic load, do you really need to slow the digestion process with fiber? Hmm. If that fiber were adding a plethora of nutrients, as found in vegetables, then the answer would be yes. But as for a fiber source without all those nutrients? Not so convincing.
We’ll let you take it from here. We hope we’ve given you something interesting to chew on. Send us your perspectives and suggestions on the fiber question.
Peter Guthrie Flickr Photo (CC)
Further Reading:
Jimmy Moore: Fiber Folly Finally Fizzled
That’s Fit: Coffee - A Good Source of… Fiber?
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Technorati Tags: fiber, digestion, constipation
One thing soluble fiber can be a huge help with is, as counterintuitive as this may sound, chronic diarrhea as seen with IBS. My understanding is that when soluble fiber dissolves, it creates a sort of gel, adding bulk, but in a smooth way, to what’s going through your intestines. (I’m trying to not gross people out here. Working?) Anyway, this is a case where slowing intestinal transit is *super* helpful. It also gives your intestines something to grip, so to speak, lessening the severity of the spasms that are often a part of IBS. Fun times! Taking a soluble fiber supplement (I’m talking 10, 12, even 16 grams daily) has made me a much happier, healthier person. Of course, not everyone has IBS. But in terms of what fiber can do for you, people think of it as a laxative, when, especially in terms of soluble fiber, it actually functions quite differently.
Mark, Gary Taubes agrees with you. Also, there are cultures such as the Inuit and Masai who traditionally ate no plant foods whatsoever. These people are very healthy as long as they stick to their traditional diets. Although I have heard reports of constipation among the Masai. Another thing to note is they both eat fermented foods. Maybe those contribute to intestinal health?
Because you mentioned it…
http://www.youtube.com/watch?v=d9wl3l5_LI0
Ah, I miss Phil Hartman.
I’m glad to see this post - I am a much happier person with less fiber in my diet.
My doctor in 2002, when I first went low carb: But you’ll be constipated!
Me: Doctor, I **** once a day. Isn’t that enough? Or did you want me to go back to my old 5 times a day habit.
Very good article!
While we should get healthy fiber from fruits and vegetables, we should avoid “bran” fiber like the plague. Bran fiber causes lots of issues related to the gut health which we have already shown is the real marker for health (and risks of cancer). The grain is not our friend…but just a cheap source of “fiber” that is marketed by any company selling processed foods…they are not selling health, just their product as “healthy”. Huge difference.
Sorry for the double comment…but just came across this also in relation to the Africans and low incidence of colon cancer research…and how the “Bran” industry jumped on that bandwagon.
“Commercial interests were quick to see the potential in the recommendation and jump on the bran wagon. Burkitt’s recommendation was based on vegetable fibre, but bran (cereal fibre) has a far higher fibre content and bran was a practically worthless by-product of the milling process that, until then, had been thrown away. Almost overnight, it became a highly priced profit maker. Although totally inedible, backed by Burkitt’s fibre hypothesis, bran could now be promoted as a valuable food. But Dr. Hugh Trowell, Burkitt’s partner and another strong advocate of dietary fibre, stated in 1974 that:”A serious confusion of thought is produced by referring to the dietary fibre hypothesis as the bran hypothesis, for many Africans do not consume cereal or bran”"
good read overall
http://easydiagnosis.com/articles/cholesterol3.html
…Mr..HNY..So do we presume you have read Good Cals Bad Cals.. and what sayeth yee about it pleasum ?
I love fiber in all its many forms. My problem is not getting enough of it but figuring out how much is too much before I overindulge. There’s nothing like congratulating oneself on eating plenty of fiber only to wake up the next morning with a gut full of pain and a pressing need to find the potty.
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