In the natural health world, there exists a certain celebrity doctor whose opinion is actually worth its weight in gold. Dr. Oz is the go to health and wellness resource for millions of people. So when he gives his stamp of approval on a new miracle cure, there is an immediate and dramatic shift in the marketplace. And the market is still feeling the effect of his glowing endorsement of raspberry ketones for weight loss, which aired back in the spring of 2012. Raspberry ketones have skyrocketed from relatively unknown to a health staple in just a few short months. Right now, hundreds of thousands of people are shelling out millions of dollars–but does the product stand up to the hype?
“Raspberry Ketones: fat burner in a bottle!”[/quote]
Take a pill and shed fatty tissue from all over the body? No exercise or dietary changes needed? Sign me up! But, we all know about things that seem too good to be true….
Traditional Medical Use of Raspberries
Raspberry (Rubus idaeus) has been used safely in botanical medicine for centuries, namely as an aide to pregnancy and labor. Raspberry leaves contain tannins, which is thought to be the medicinally active constituent. Tannins are astringent, meaning they ‘knit’ proteins together, which is the purported mechanism of action. Traditional botanical medicine believed that raspberry leaf teas strengthen the tone of the uterus, and there is some evidence to support this use (here), but there is a general consensus that more studies are needed to evaluate its efficacy (here). Other traditional uses, mitigated through its astringing action, include healing/stopping diarrhea, mouth sores, conjunctivitis, and vaginal discharge.
Theoretical Weight Loss Mechanism of Raspberry Ketones
Raspberries were never traditionally used to for weight loss. Raspberry ketone is a phenolic compound, and are found in a variety of berries including raspberries, blackberries, and cranberries. In theory, they increase fat breakdown (lipolysis), by modulating the excitatory hormone norepinephrine. They are also thought to increase secretion of adiponectin, a hormone that is naturally expressed in higher amounts in slender people. Adiponection increases breakdown of fat (here), and may even work synergistically with leptin in the brain to help provide the ‘full’ sensation after eating (here).
Raspberry Ketones for Weight Loss – According to the Evidence
There may be something to raspberry ketones if they are truly capable of increasing fat metabolism and adiponectin hormone levels in humans. But Dr. Oz plays a trick on us that has become all too common in natural health. He uses words like “research” and “science” to validate his endorsements, which confuses people in to believing there is already real evidence that raspberry ketones are proven to provoke weight loss in humans:
Unfortunately, the research being eluded to comes from two small scale studies in rats. And while rat studies certainly trump having no studies at all, proclaiming something a miracle cure to the global obesity epidemic without a single human trial seems a wee bit premature. The first study found that raspberry ketones increased fat breakdown in rats fed a high fat diet (here). The second study showed that lipid metabolism was increased with raspberry ketones through an increased secretion of adiponectin (here). If we make the highly improbably assumption that the results are factual and reproducible, they may seem promising, but in reality they are not. We use animal studies to determine whether there is enough evidence to attempt human trials, but studies repeatedly show that findings from animal trials are very poor predictors in humans (here). So, even if raspberry ketones do invoke weight loss in rodents, it is unlikely the findings will directly translate to humans.
Raspberry Ketone Safety
Since there are no human studies on raspberry ketones, the safety of ingesting high doses of them is not known. If the proposed mechanism of action turns out to be true, and it does increase norepinephrine, they may not be safe for people with high blood pressure, heart disease, anxiety, and diabetes–in order words, they may not be safe for many of the overweight people being targeted for use.
Are Raspberry Ketones a Weight Loss Solution?
Until human studies exist, it is impossible to tell whether raspberry ketones have a real weight loss benefit, however it is highly unlikely that they do. When was the last time an over-hyped product had any real substance to it? Until we drop all the nonsense about simple, uninvolved, solutions to weight loss, we will not be addressing the core issue. Yes, it is true that some people have a predisposition to weight gain–but even those people worked hard over many years to gain their weight. Any solution that does not involve a long and difficult process of strict dietary and behavioral changes is, and will always be, ineffective. Weight loss does not happen over night, and shame on Dr. Oz for misleading the public in to believing it is possible.
In summary, all raspberry ketones will likely do is drain your wallet, not your waistline.