Avoiding Fiber: A Counterintuitive Solution to Constipation?

I’ve posted on this blog about fiber and colon cancer, noting a lack of evidence supporting a protection by fiber on this disease. But what about the effect of fiber on other maladies? What about the condition fiber is supposed to be most effective at treating? Yep, I’m talking about constipation. Here’s a study I came across recently:

Ho KS, Tan CY, Mohd Daud MA, Seow-Choen F. Stopping or reducing dietary fiber intake reduces constipation and its associated symptoms. World J Gastroenterol. 2012 Sep 7;18(33):4593-6.

In this trial, researcher recruited 63 people with constipation. All participants were asked to reduce their fiber intake as low as they could for 6 months. By 6 months 41 subjects were eating almost no fiber, 16 were eating a low fiber diet, and 6 were eating a comparatively high fiber diet. Thus, this was not technically a randomized trial, although the different groups were compared with each other in the style of a controlled trial.

The high fiber group saw no relief of symptoms at all, but they were small in numbers, older, and were clearly poor compliers. Let’s ignore them and look at the low versus almost no fiber groups.


Among those on the low fiber diet, there was a 20 to 30% reduction in the number of people with constipation, anal bleeding, bloating, and abdominal pain. Among the 41 people on the nearly no fiber diets, not a single person had any of these aforementioned symptoms. Everyone who followed this fiber free diet was free from constipation.

This type of study demands further investigation, since it is clearly weak on its own. Still, the results seem incredible. Hopefully future studies will help us determine how legitimate these results are by using a well randomized control group and, ideally, isolating fiber sources (e.g. Soluble and insoluble).


Magnesium, Heart Attacks, and Electrolytes

Magnesium appears to be an incredibly popular nutrient amongst many in the nutrition community. It’s nearly unfettered acclaim is almost odd, given that for nearly every food or nutrient there seems to be some group, however small, that disputes what the majority believes its health effects to be. Surely magnesium produces profound improvements to insulin sensitivity and, to some degree, brings about other health benefits. Magnesium is even one of the few supplements I take from time to time. However, is magnesium’s good reputation truly without reproach?

Today let’s look at a study from 1993:

Galløe AM, Rasmussen HS, Jørgensen LN, Aurup P, Balsløv S, Cintin C, Graudal N, McNair P. Influence of oral magnesium supplementation on cardiac events among survivors of an acute myocardial infarction. BMJ. 1993 Sep 4;307(6904):585-7.

This is one of the few long term studies on oral magnesium. 468 heart attack survivors were given either 360 mg of magnesium or a placebo for one year. Did this mineral help prevent future heart problems?

No. In fact, although not statistically significant, those taking the magnesium supplement had roughly 30-40% more heart attacks and about 40-50% more “cardiac events”.

The question is, why? Honestly, I don’t know. Personally, I think an imbalance of electrolytes (magnesium, sodium, calcium, potassium, etc.) can be problematic. I hope to explore this in the future.

Changing Up This Blog (Also Niacin, LDL, and Atherosclerosis)

This blog doesn’t get much activity these days, so I’ve decided to use it to post about studies I find interesting. These will be brief and not very in depth. First up, a clinical trial published in the NEJM in 2009:

Taylor AJ, Villines TC, Stanek EJ, Devine PJ, Griffen L, Miller M, Weissman NJ, Turco M. Extended-release niacin or ezetimibe and carotid intima-media thickness. N Engl J Med. 2009 Nov 26;361(22):2113-22.

This study looked at atherosclerosis progression in 200 people (mostly men) with low LDL (below 100; all were taking a statin) and low HDL (below 50-55). These subjects either had heart disease or were at a high risk of it. Subjects were given one of two drugs: niacin (technically vitamin B3 btw) or ezetimibe. The former is known to lower triglycerides, raise HDL, and slightly lower LDL while the latter is known only to lower LDL. Sure enough, this is pretty much what these compounds did:

Picture 8

So what was the effect on atherosclerosis?


Ezetimibe produced no significant effect on artery thickness (which could be good—for all we know without this drug atherosclerosis would worsened rather than stayed constant). Meanwhile, the niacin user saw a net regression, meaning they saw an apparent reversal of atherosclerosis. Cool stuff. If this study is to be believed it provides evidence that lowering LDL isn’t all their is to reversing plaque build up int he arteries. Lower triglycerides and higher HDL may be important as well.