Last week I wrote about Konstantin Monastyrsky, author of the book “Fiber Menace” and the eponymous website, www.fibermenace.com. I said that my skeptical alarms were going off because Monastyrsky was crying out against mainstream science, accusing scientists of participating in a massive conspiracy to cover up the truth about the “fiber menace.” Mr. Monastyrsky himself left a couple of comments defending himself and looking forward to part II. I’m pretty sure you’re not going to like what I’m about to say, Konstantin.
To be blunt, Mr. Monastyrsky’s website is rife with half-truths, distortions, and deceptive (ab)use of sources, making his claims on the subject of fiber at the very least in the category of “not proved,” and at worst he is disseminating what could be some very poor medical advice. This is a long post, but it only covers some of the misinformation on Mr. Monastyrsky’s website.
A perfect example is the reference he left in our comments section, to an article from the Harvard School of Public Health that he seems to like quoting (http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fiber-full-story/index.html#3 ). Monastyrsky uses the following excerpt: “Fiber intake has also been linked with the metabolic syndrome, a constellation of factors that increases the chances of developing heart disease and diabetes.” Sounds pretty bad. But here’s the full quote:
Fiber intake has also been linked with the metabolic syndrome, a constellation of factors that increases the chances of developing heart disease and diabetes. These factors include high blood pressure, high insulin levels, excess weight (especially around the abdomen), high levels of triglycerides, the body’s main fat-carrying particle, and low levels of HDL (good) cholesterol. Several studies suggest that higher intake of cereal fiber and whole grains may somehow ward off this increasingly common syndrome (emphasis mine).
The Harvard paper references these studies: http://www.ncbi.nlm.nih.gov/pubmed/14747241?dopt=Citation and http://www.ncbi.nlm.nih.gov/pubmed/12145012?dopt=Citation.
In fact, if you really want to learn something about fiber, that Harvard article is an excellent place to start. On to the meat of the post – or shall we say the fiber?
The heart of fibermenace.com is the section called “Top 12 myths about Fiber.” A full discussion of all 12 points would take up a whole lot of space and time, but let’s take a look at my favorites, shall we?
Myth #1: For maximum health, obtain 30 to 40 g of fiber daily from fresh fruits and vegetables. The website shows a picture of 10 pieces of fruit and 10 tablespoons of sugar, enough to give any diabetic fits, both literally and figuratively. Luckily, the truth is not so dire. What happened to the vegetables? They have far less sugar than fruit. And what about whole grains? High in fiber, low in sugar – check, for examples, the nutrition tables provided by the American Dietetic Association at www.eatright.com. In any case, everything I’ve read about fruit and fiber says to be careful about having too much fruit, and that different fruit gets assimilated in different ways by the body – and fruit brings in other valuable nutrients as well.
Myth#2: Fiber reduces blood sugar levels and prevents diabetes, metabolic disorders, and weight gain. Here Monastyrsky claims that by slowing down the assimilation of sugars into the blood, the diabetic is “…fooling no one but a glucose meter.” The sugar we eat still gets assimilated into the bloodstream eventually. But for a diabetic, that’s exactly the point – to keep blood sugar from spiking too high. It’s the spike in blood sugar that is dangerous for the diabetic.
Let’s jump ahead to Myth#5: Insoluble fiber promotes a healthy digestive tract and reduces cancer risks. Now Monastyrsky abuses his sources. First, he cites this study (http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=pubmed&dopt=AbstractPlus&list_uids=10770979&query_hl=1). The study shows that a low fat, high fiber diet has no effect on the recurrence of colorectal adenomas. This recurrence is a precursor to most major bowel cancers. Fair enough, but this is a very narrow piece of the cancer puzzle. The study only looks at patients who have already had colorectal adenomas, and so are already at a high risk for bowel cancer. So the dietary change doesn’t help at that point. Monastyrsky then goes on to cite the article from the Harvard School of Public Health (http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fiber-full-story/index.html) again, which indeed expresses the idea that fiber does little to prevent colon cancer. Score one for Konstantin… temporarily. The rest of the article goes on to contradict just about everything on the Fiber Menace website! Here’s a pithy quote:
Long heralded as part of a healthy diet, fiber appears to reduce the risk of developing various conditions, including heart disease, diabetes, diverticular disease, and constipation. Despite what many people may think, however, fiber probably has little, if any effect on colon cancer risk.
The beat goes on with heart disease and diverticular disease. Monastyrsky quotes a paper written by Linda Van Den Horn, PhD RD, of the American Heart Association thusly:
The rate of CHD [nb: coronary heart disease] mortality was reported to be inversely associated with fiber intake across 20 industrialized nations, but adjustment for fat intake removed the association. Similarly, a 20-year cohort study of 1,001 middle-aged men in Ireland and Boston reported a significant inverse association between fiber intake and risk of CHD, but the association diminished when other risk factors were controlled.
Sounds like fiber doesn’t help, doesn’t it? Here is the concluding paragraph of Van Den Horn’s paper (http://circ.ahajournals.org/cgi/content/full/95/12/2701 ):
The greatest impact on lowering total and LDL cholesterol is derived from reduced intakes of saturated fat and cholesterol as well as weight reduction in obese persons. Diets high in complex carbohydrates and fiber are associated with reduced mortality rates from CHD and other chronic diseases. Fiber found in oats, barley, and pectin-rich fruits and vegetables provides adjunctive lipid-lowering benefits beyond those achieved by reductions in total and saturated fat alone. The AHA recommends a total dietary fiber intake of 25 to 30 g/d from foods, not supplements, to ensure nutrient adequacy and maximize the cholesterol-lowering impact of a fat-modified diet (emphasis mine again). Current dietary fiber intakes among adults in the United States average about 15 g, or half the recommended amount.
What does the Harvard article link to? This: (http://www.ncbi.nlm.nih.gov/pubmed/8627965?dopt=Citation )
Our results suggest an inverse association between fiber intake and MI (nb: myocardial infarction. You know, heart attack). These results support current national dietary guidelines to increase dietary fiber intake and suggest that fiber, independent of fat intake, is an important dietary component for the prevention of coronary disease.
On diverticular disease, Monastyrsky spends a lot of time ridiculing the notion that fiber helps, but a study linked to by that Harvard paper says the following ( http://www.ncbi.nlm.nih.gov/pubmed/9521633?dopt=Citation ):
Our findings provide evidence for the hypothesis that a diet high in dietary fiber decreases the risk of diverticular disease, and this result was not sensitive to the use of different analytic techniques to define dietary fiber. Our findings suggest that the insoluble component of fiber was significantly associated with a decreased risk of diverticular disease, and this inverse association was particularly strong for cellulose.
By the way, both the above studies, on MI and diverticular disease, show as much as a 40% reduction.
I think I may just stick with my doctor’s advice and eat a diet high in fiber, but low in non-fiber carbs. What do you think?