Wednesday, May 27, 2009
I recently came across the website for LepToThin, a weight loss supplement which targets the hormone leptin. Although leptin induces satiety (in addition to many other functions), most obese individuals develop leptin resistance. Individuals who are resistant to leptin require more food before they feel full, making weight loss or even weight maintenance increasingly difficult.
Every so often someone comes out with a treatment that "cures" leptin resistance. This is somewhat of a holy grail for obesity treatments - if obese individuals were more sensitive to leptin, weight loss and weight maintenance would both more manageable. LepToThin claims to do just that - reducing leptin resistance, thereby reducing food intake, increasing metabolism, and reducing body weight. However, as usual with this type of product, the evidence to support that claim is exceedingly thin.
The active ingredient in LepToThin is called berberine, a plant extract from China which has been touted as a natural cure for diabetes. To be fair, there is some evidence to suggest that berberine has positive effects on glucose metabolism. For example, in a paper in the journal Diabetes, Lee and colleagues report that giving obese rats 380mg of berberine for each kilogram of body weight for two weeks resulted in significant weight loss and improved glucose metabolism. That sounds pretty impressive. However, for a person my size, it would take over 26,600mg of berberine to match the dose that was given to the obese rats in the study by Lee et al. How much berberine is in a daily dose of LepToThin? Less than 1,200mg. That means that if I were to take the recommended dose of LepToThin, I would receive less than 5% of the dose which resulted in weight loss in obese rats in the study by Lee et al. Perhaps more importantly, I could not find a single study reporting that berberine is associated with weight loss of any magnitude in humans.
A website associated with of LepToThin claims that it is "nature's most powerful and studied weight loss agent that works directly on the brain". That seems odd given that the above-mentioned study by Lee and colleagues is the only study that I have been able to find showing any relationship between berberine and weight loss. To find out where all these studies were hiding, I emailed the people who run LeptinResearch.org, an "educational" website with strong links to LepToThin, to ask if they knew of any clinical trials showing that berberine or LepToThin are associated with weight loss in humans. Unfortunately the email address listed on their website is not a real email address. That is not a good sign. And the more time you spend on the LepToThin website, the more it starts to look like many of the other weight loss gimmicks we've profiled in the past.
First, there are grandiose claims, with absolutely no science to back them up. For example, the LepToThin website claims that it is the "First Product To Effectively Control Leptin Resistance", but provide no links to research backing up that statement, and my searches of PubMed and Google Scholar suggest that there are none. Ron Spallone, a naturopathic doctor affiliated with LepToThin, says that "It's not a stretch to say that this could be one of the most researched and promising weight loss supplements to come out in the last 20 years." Seeing as there is not a single paper evaluating their product on PubMed or Google Scholar, nor any evidence to suggest that the active ingredient can reduce body weight in humans, that statement is far more than a stretch.
As with many weight loss products, the real gems are found in the Frequently Asked Questions section of the website. For example:
Question: How easy is the program to use?
Answer: Very easy....
Question: Are Core Innovations™ [the makers of LepToThin] products safe to use?
Question: As a vegetarian, can I use this program?
Answer: Yes you can! It was designed for everyone.
And my personal favourite:
Question: Will I see a flatter stomach?
Answer: ...LepToThin targets the breakdown of visceral fat or WAT (White Adipose Tissue). This is the unhealthy type of fat that's a proven contributor to disease and premature death. It can actually strangle your organs. Studies show there is a correlation between visceral fat and heart disease.
First of all, visceral fat does not strangle your organs! I cannot stress that enough. Visceral fat is a bad thing, but it doesn't strangle your organs, either literally or figuratively. Further, the terms visceral fat and white adipose tissue are not interchangeable. White adipose tissue is found throughout the body, not just within the visceral cavity. It is never a good sign when the makers of a "scientific" product, clearly do not understand basic physiology.
It should also be noted that contrary to the answer provided to that final question, there is no evidence suggesting that berberine (the active ingredient in LepToThin) targets visceral fat. None. In fact, the above-mentioned study by Lee et al., says that "both visceral and subcutaneous fat depots were similarly reduced by berberine". It would be difficult to come up with a worse answer to such a simple question.
So, what is the final verdict? I will admit that in writing this post, I came across some interesting studies on berberine, and I would be very interested to see more research into the subject. However, given that absolutely no research suggests that LepToThin's active ingredient is associated with weight loss in humans, and that the makers of LepToThin clearly have a poor understanding of basic physiology, this product doesn't seem like a likely cure for obesity. For more on LepToThin, please visit their website by clicking here.
To receive information on other weight loss
1. Human Chorionic Gonadotropin
2. Acai Berry Scam Exposed: We Called It!
3. Slender Shaper: Another Fat Loss Gimmick?
Lee, Y. (2006). Berberine, a Natural Plant Product, Activates AMP-Activated Protein Kinase With Beneficial Metabolic Effects in Diabetic and Insulin-Resistant States Diabetes, 55 (8), 2256-2264 DOI: 10.2337/db06-0006
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