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Does Irvingia Really Deliver Rapid Weight Loss? Part 2

Posted Nov 29 2008 10:02am

I found a study on  irvingia  -  The effect of Irvingia gabonensis seeds on body weight and blood lipids of obese subjects in Cameroon  - published in 2005.  You can read it yourself here. I’ve  excerpted  parts below - if you are really interested, go read the source, as my interpretation could be off. 

Here’s the gist of their study:

A total of 40 obese subjects aged between 19 and 55 years were selected from a group responding to a radio advertisement. After physical examination and laboratory screening tests, diabetics, pregnant and lactating women were excluded. None of these subjects took any weight reducing medication and none was following any specific diet.

Subjects were given two different types of capsules containing 350 mg of  Irvingia   gabonensis seed extract (active formulation)… Three capsules were taken three times daily, one-half hour before meals (a total daily amount of 3.15 g of  Irvingia   gabonensis  seed extract) with a glass of warm water… The subjects were also interviewed about their physical activity and food intake during the trial, and were instructed to eat a low fat diet (1800  Kcal ) as well as keep a record for seven consecutive days (using household measurements).

OK - these folks were taking way more  irvingia  than Life Extension recommends -  Life Extension recommends 150 mg twice per day, while the people in this study were taking 3 grams of the stuff - more than 10 times the amount.

So what Life Extension is reporting is somewhat ‘apples-to-oranges’ as this study and it’s results can’t really be compared when the dose is so different. These people were also  counseled  to adhere to a low fat diet, which helps to obscure the actual change from  irvingia  alone as it introduces a second variable - does any measured change have to do with the  irvingia, the low-fat diet, or a combo of both?

This question can’t be answered from this study, in my estimation. 

Let’s continue. Here’s what it says about  irvingia’s  impact on body composition:

Irvingia  gabonensis induced a decrease in weight of 2.91 ± 1.48% (p < 0.0001) after two weeks and 5.6 ± 2.7% (p < 0,0001) after one month. Although the percentage of body fat was not significantly reduced with both placebo and  IG, the waist circumference (5.07 ± 3.18%; p < 0.0001) and hip circumference (3.42 ± 2.12%; p < 0,0001) were significantly reduced by  IG. A reduction of 1.32 ± 0.41% (p < 0.02) and 2.23 ± 1.05% (p < 0.05) was observed with the placebo after two and four weeks respectively of treatment.

What I translate this to mean:

  • Someone weighing 200 lbs. could expect to lose 10 lbs. in a month
  • As body fat isn’t  significantly  different in the control group and the  irvingia  group, the weight loss must come from water, muscle, or the study didn’t control this variable properly.
  • If you started out with a 40 inch waist, you were a 38 inch waist after a month.

OK - that’s not bad - but as this study only lasted a month, we can’t see the acceleration of weight loss  betwen  month 1 and month 2 described in the  Life Extension article.

Some impressive results were seen in blood pressure and serum cholesterol:

Effect of  Irvingia   gabonensis  on systolic ( SBP ) and diastolic ( DBP ) blood pressure

 Treatment period (weeks)
SBP  ( mmHg )Active136.41 ± 19.57132.66 ± 18.48*132.83 ± 17.97*
 Placebo134 ± 5.05121.5 ± 5.89123.83 ± 2.92
DBP  ( mmHg )Active98.5 ± 19.5297.5 ± 22.8094.08 ± 11.07
 placebo93.50 ± 10.3193.83 ± 7.4191.5 ± 6.53

These reductions aren’t bad, but  bringing  down each number by 5 doesn’t seem to be all that amazing - and again - might it have had something to do with the low fat diet? Who knows? And what’s with the seemingly large margins of error here? And why would they vary so much between the active and placebo group?

For example: the margin of error for the first reading of the folks taking  irvingia  has a margin of error of +/- 19.57. For the placebo group, it’s +/- 5.05. 

Why would this differ by almost a factor of 4?

Next up is the reported effect on blood total cholesterol (TC), triglyceride ( TRI ), high density  lipoprotein cholesterol ( HDL -c), low density  lipoprotein  cholesterol ( LDL -c) and glucose.

  T-cholesterolTRIHDL-cLDL -cLDL / HDLT- cho / HDLGLUCOSE
ActiveInitial215 ± 55.12162 ± 33.1561.23 ± 20.36121.37 ± 36.31.98 ± 1.783.51 ± 2.703.8 ± 1.92
 Final130.68 ± 39.589.22 ± 55.6389.9 ± 28.4466.08 ± 34.270.735 ± 1.201.45 ± 1.382.57 ± 1.03
PlaceboInitial163.70 ± 25.32130.65 ± 37.8231.38 ± 25.21105.06 ± 11.865.05 ± 3.946.44 ± 3.373.6 ± 0.41
 Final158.36 ± 30.46100.52 ± 32.5541.20 ± 19.5398.55 ± 27.993.19 ± 1.854.51 ± 2.073.9 ± 0.74

Again, looking at the reductions, it seems impressive, but do you notice that the active group starts out with total cholesterol at 215 and the placebo group at 163? The active group is defined as having high cholesterol by that number, and the control group has cholesterol that would be characterized by some as dangerously low.

I’m just a dope, but shouldn’t the control group be more or less the same as the active group in a well-designed study?

And where do you find 20 obese people with an average total cholesterol of 163? Not around here.

Also - the reported margin of error again still seems high.

Now - I have no right interpreting these results - I’m no researcher. If any one of the really smart people that read this  blog  see a mistake in my understanding, please post. 

But what I’m seeing is what I would say is an interesting study that leads one to believe  something is going on here, but it is too poorly designed to tell us what.

Our researchers do have some speculation on what’s happening here. This is where research is replaced by guesswork. That’s not necessarily bad - an educated guess is better than saying: I dunno, but it is what it is - a guess:

The soluble fibre of the seed of  Irvingia   gabonensis  like other forms of water-soluble dietary fibres, are “bulk-forming” laxatives.  Irvingia   gabonensis  seeds delay stomach emptying, leading to a more gradual absorption of dietary sugar. This effect can reduce the elevation of blood sugar levels that is typical after a meal.

Controlled studies have found that after-meal blood sugar levels are lower in people with diabetes and overall diabetic control is improved with soluble fibre-enriched diets according to preliminary and controlled trials. 

Like other soluble fibers,  Irvingia   gabonensis  seed fibre can bind to bile acids in the gut and carry them out of the body in the  faeces, which requires the body to convert more cholesterol into bile acids. This can result in the lowering of blood cholesterol as well as other blood lipids. Studies have shown that supplementation with several grams per day of soluble fibre significantly reduced total blood cholesterol,  LDL  cholesterol, and triglycerides and in some cases raised  HDL  cholesterol, these being comparable with effects noticed with  Irvingiagabonensis.

I’ve edited this somewhat for clarity, though I don’t think I’ve altered their point:  irvingia  is a bulk-forming laxative (like  psyllium  - Metamucil) and this type of fiber is already known to improve cholesterol numbers.

As they don’t mention weight loss at all, I imagine that they have no clue as to why anyone lost weight, but were too embarrassed to admit it.

The only conclusion that I come to after reading this is that any fiber therapy, like Metamucil, can help reduce blood lipids, and Metamucil is way cheaper than  irvingia.

I’m still considering it - one poorly designed study (in my estimation) does not prove nor disprove anything.

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