But is green coffee bean extract really so miraculous?
Having been less than impressed with Oz’s assessment of raspberry ketones, African mango and the aforementioned Satiereal, we decided to look very closely at the data for green coffee bean extract and report the results here. Stick with us; this review is a bit long, but there’s a lot here to discuss!
Let’s start with the basics; what is green coffee bean?
Essentially, this is the raw coffee bean before it has been roasted and processed to make coffee. Green coffee bean is a rich source of something called chlorogenic acid, the compound to which the weight loss effects of this supplement are attributed.
If you watched this segment of the Dr. Oz show, you’ll have seen Oz ask his expert, naturopathic doctor and certified nutritionist Lindsey Duncan, why people couldn’t just drink coffee. Duncan patiently explains that roasting the coffee beans at 475 degrees “removes” the chlorogenic acid.
“Coffee is the most consumed food product in the world. In the last few years, a series of epidemiological studies have associated coffee consumption with health benefits, such as reduction of the relative risk of diabetes type 2 and Parkinson and Alzheimer diseases (1–3). In vitro and in vivo studies have attributed these beneficial properties of coffee mainly to the antioxidant capacity of the chlorogenic acids (CGA)4 (4–6), which are usually responsible for 2–5 g/100 g of roasted coffee composition (7,8). ”
Elissa then went on to say that…
“It is probably fair to say that roasting changes the relative amounts and nature of the chlorogenic acids in coffee; and green coffee beans may well be a superior source, but it is incorrect to imply that they’re missing from roasted, brewed coffee altogether. See also this: http://www.ncbi.nlm.nih.gov/pubmed/22432728 and this: http://www.ncbi.nlm.nih.gov/pubmed/22490054 – they do decline with roasting, but brewed coffee can still make a significant contribution.”
You might ask why this point is relevant to this discussion.
The reason why is simple; it goes to credibility. If you are wrong about the simple stuff, it is hard to attribute a ton of credence to the other things you say. For instance, I was less than impressed with Duncan when I read this statement on his blog on the Oz web site…
“The most recent study on green coffee bean published in the Diabetes, Metabolic Syndrome and Obesity journal followed a group of 16 adults who supplemented with green coffee bean for only 12 weeks.”
While this is not technically incorrect, Duncan seems to be the only one not reporting the true length of the study–which is 22 weeks. The PubMed study abstract clearly states 22 weeks, as does the recent write up in Science Daily.
Here is how the study worked; participants took a combination of a high dose green coffee extract, a low dose green coffee extract and a placebo – each for a period of 6 weeks, with a 2 week washout period between sessions (the exact sequence varied according to the group; there was a high-dose/low-dose/placebo sequence, a low-dose/placebo/high-dose sequence, and a placebo/high-dose/low-dose sequence).
So while Duncan is not incorrect—since the actual period of supplementation with the extract was only 12 weeks—and since he does not actually say the study was only 12 weeks long, that is certainly what one could imply from reading the statement above.
The only reason I can think of is that losing 17 pounds in 12 weeks (1.41 lbs per week) sounds a lot more miraculous than losing 17 pounds in 22 weeks (in reality, there is nothing particularly miraculous about either result, I am afraid).
Then Duncan goes on to say that study participants did not exercise, did not change their diet, and they lost weight regardless.
At this point he said something else. I had to stop and rewind the video segment several times to make sure I heard him correctly; Duncan reports that participants consumed 2400 calories and states “they burned only 400 calories, now that’s weight gain, not weight loss.”
Is Duncan seriously suggesting that an average 170-180 lbs individual only needs 400 calories per day to survive? A simple test with a BMR (basal metabolic rate) calculator will show you that the amount of calories required is actually closer to 4 times that number!
Second, while the number of calories consumed by participants (2400) is presented with some incredulity, it is well in line with what a maintenance diet should be for individuals in the weight range utilized in the study (approx 170 pounds). No, it’s not restrictive, but it certainly does not constitute a gross over consumption of calories implied by Duncan.
When trying to confirm the particulars of the study, things got a little odd and vague. If you read the study, you will find this statement…
“All subjects were counseled for diet and exercise compliance at every visit, with the initial interview to establish diet details at the start of the study done by the site nutritionist. Data gathered included daily calorie intake, nutrient composition, micronutrient intake, and incidence of binge eating.”
What’s odd about this is that the study abstract doesn’t reveal what “exercise and diet compliance” actually entails.
The implication of this statement is that participants were on some sort of standardized diet, and were expected to perform some sort of regular exercise. As Elissa noted…
“These folks may not have been on a ‘diet,’ in terms of significant food restriction, but there’s plenty of ‘soft’ evidence that suggests they were given a template of sorts, and encouraged to stick to it. For instance, look at the protein consumption numbers from the study here. It defies logic to believe that 16 people could eat a daily average of exactly 15.62 + 6.29 percent calories as protein throughout all three treatment arms, if they were just ‘winging it.’”
“Compliance”, after all, means “adherence to a recommended regimen.” If you’re not expected to exercise or change your diet, there’s nothing to be compliant with, is there?
Couple this inference with this Science Daily quote from one of the study’s lead authors, Joe Vinson…
“Based on our results, taking multiple capsules of green coffee extract a day—while eating a low-fat, healthful diet and exercising regularly—appears to be a safe, effective, inexpensive way to lose weight”.
… and the impression I get is that participants did exercise.
And, as we previously touched on, it does appear as if participants were dieting too. As Elissa puts it…
“… the diet stats are evidence of some instruction. They approximate 2400 cals, 60% carb, 25% fat, 15% protein for each “arm” of the study, with very little change over time. This is a pretty good match for your classic, dietician-supervised, “recommended” diet. Nonetheless, it’s strange that the authors don’t come right out and say what instructions or guidelines (if any) the subjects were given. Most other papers put this information front and center. It doesn’t matter if the subjects are on a controlled diet or simply told to not change anything – either way, they include this vital information.”
Other potential issues?
- This study is very small; only 16 participants. The smaller the study, the more possible it is that some anomaly—either positive or negative—can skew the results one way or another.
- Despite the fact that the study is over a year old, it is only published in a relatively new journal with no reported impact factor.
- The vagueness when it comes to discussing diet and exercise compliance is worrisome, since a regimented program would diminish the role of green coffee bean’s role in the weight loss.
- Dr Oz.’s “expert”, Lindsey Duncan, has a financial conflict of interest; he’s the CEO and lead formulator of Genesis Today, a supplement company that—get this—sells a green coffee extract product (it’s not the one we recommend, and we’ll tell you why in a moment).
So Does Green Coffee Extract (Chlorogenic Acid) Really Work?
So at the end of the day, where does that leave chlorogenic acid and green coffee bean when it comes to weight loss?
Well, one other in-house human study confirms green coffee’s effect on weight loss, as do a couple of animal based studies. So it’s not hard to believe it has some effect on weight loss. Additionally, studies show it may be useful to combat mild hypertension, as well to lower blood sugar levels.
So all in all, green coffee bean extract probably will provide some benefit to dieters.
However, there is nothing in any of the existing clinical data that supports this statement from Lindsey Duncan…
“What has me and the scientific community so excited about green coffee bean extract is that people don’t have to do anything different when taking this food supplement. They don’t need to exercise, and they don’t need to diet; they just appear to lose pounds fast.”
In my opinion, losing 1.4 pounds per week isn’t exactly fast, no matter how the diet was conducted or how generously you interpret the results. And, as we’ve discussed, while all the evidence suggests that study participants were on a standardized diet and exercise program of some sort, there is no way to know for sure.
And if we don’t know, then Dr Lindsey doesn’t know.
As such, it’s irresponsible to make such a statement.
In truth, the only people that are “buzzing” about green coffee extract are the folks on the Dr. Oz show and the folks selling the stuff; medical doctors and weight loss professionals see chlorogenic acid for what it really is; a mildly useful supplement that may help somewhat, if you’ve got your diet under control.
If you want to experiment with it, be my guest, but do so with realistic expectations; this is not a miracle pill!
If you want to experiment with green coffee extract, we recommend the Source Naturals brand product from iHerb, and not Dr. Lindsey’s own formulation. Why? Source Naturals contains the precise, proprietary extract used in the study (GCA®), contains a larger dose per pill (500mg vs. 400mg) and is cheaper (when purchased at iHerb).
SPECIAL NOTE: Apparently, the folks over at Genesis Today were not too happy with this review. Click here to read the email we received, and our response to it!