-16% Abdominal Fat on a Cornstarch Diet? No Problem If You Add 4 Teaspoons of Black Pepper to Your Meals!

Image 1: According to Wood et al. (1988) black pepper contains between 3-8% piperine. A teaspoon of black pepper would thus deliver have 60-160mg piperine, which would mean that you would have to swallow roughly 4 of those to get the fat loss effect (if it does translate to humans)

I don't know if you have realized it, but if you are taking any "high quality" dietary supplements, chances are that one of the minor ingredients on its label is "piperine", the alkaloid that is responsible for the pungent taste of black pepper. The reason, why manufacturers keep adding this spicy ingredient to their formulas is not its anti-oxidant potency, not its stimulating effect on the digestive enzymes of pancreas or even its ability to significantly reduce the gastrointestinal food transit time, no it is because piperine messes with the way your liver metabolizes drugs (piperine inhibits both the drug transporter P-glycoprotein and the major drug-metabolizing enzyme CYP3A4; Bardhwaj. 2002). Yet, while everybody seems to be freaking out about possible medical interactions of St. John's Wort, nobody appears to care about piperine... the credo seems to be "As long as it enhances the delivery of my curcumin it must be a good thing!" That it could as well enhance the bioavailability of a lot of other things, you'd rather have your liver clear from your system as fast as possible, is largely ignored, though.

Note: It always amazes me how scientists design their experimental diets. Usually we have those "high fat diets" that then turn out to be high fat + high carb (like 40% carb, 50% fat, 10% protein). So I was curious what a "high carbohydrate, high fat" diet (HCHF) would look like. Well, let me put it like that. I am not sure, whether the control diet that consisted of a meat-free rat and mouse feed (Specialty Feeds, Australia) that was mixed with cornstarch (yes, the devil! ;-) and water was so much "healthier" than the fattening HCHF diet where part of the cornstarch and the water was replaced with condensed milk, fructose and beef tallow... I mean, condensed milk and beef tallow do sound pretty good, and let's be honest even "normal" corn starch is probably not much better than pure fructose... what do you say? "Scientific Idiocy?" Well, I didn't say that ;-)

So far for the bad news. Now for the good one: A recent study from the University of Southern Queensland found that the addition of ~30mg piperine per kg body weight to the chow of 8-9 week old male Wistar rats, who were fed a high carbohydrate + high fat diet for 16 weeks (cf. red box above), ...

[...] reduced blood pressure, improved cardiac and liver structure and function, reduced oxidative stress, and attenuated inflammatory and metabolic changes induced by HCHF diet as compared to CS diet.

Moreover, the addition of 30mg/kg piperine (=4.86mg/kg for humans) kept the rats on the "typical Western diet" (high carbs + high fat) healthy, it also kept them reasonably lean and, more importantly, it also reduced the weight of the abdominal fat pads by -16% in the "control" (=high carb) group (cf. figure 1).

Figure 1: Changes in dietary intake and body composition of male Wistar rats receiving 30mg/kg piperine in their cornstarch (control) or high carbohydrate + high fat (HCHF); values relative to unsupplemented control (data calculated based on Diwan. 2011)

If you have a closer look at the dietary and body compositional data, I've compiled for you in figure 1, you will also realize that all that happened, although the rats who received the piperine in their chow consumed +7% (cornstarch) and +16% (HCHF) more calories than their peers. This is not only further evidence for the ludicrousness of the calories in vs. calories out hypothesis it also goes to show that the rats did not simply stop eating, because they felt that their chow was too spicy ;-)

Figure 2: Changes in inflammatory markers and anti-oxidant status of male Wistar rats receiving 30mg/kg piperine in their cornstarch (control) or high carbohydrate + high fat (HCHF); values relative to unsupplemented control (data calculated based on Diwan. 2011)

For those of you who are also interested in their health (for the general public, I often get the impression that looking good is more important for many than feeling good), it may also be worth to have a look at the changes in inflammatory markers and anti-oxidant status in figure 2. After all, the data indicates that the piperine supplemented animals exhibited statistically significant (* p<0.05) reductions in the high carb + high fat induced elevations in C-reactive protein (one of the few markers of which scientists still believe that it is a realiable predictor of heart disease), uric acid and reactive oxygen specimen. Moreover, the total antioxidant status of the HCHF + piperine fed rats improved and was not statistically different from the rats in the cornstarch group at the end of the 16 weeks treatment period.

A potential fat-burner with a bitter after taste

Although Kim et al. observed similar effects in another recent study on mice, who were fed the classic high-fat diet for 3 weeks (the study compared piperine to pipernonaline, and dehydropipernonaline, Kim. 2011), these positive results do yet still have a peppery, ahh... I mean bitter after-taste. Yes, piperine exerted beneficial effects on body composition in both groups and had ameliorated the negative effects of the high carbohydrate + high fat diet on inflammatory markers (most importantly C-reactive protein) and anti-oxidant status and thusly prevented fibrosis, inflammation, and the accumulation of mast cells in the heart and liver of the animal, BUT in view of the colorful poly-pharmacological OTC self-doctoring approaches of many of the self-proclaimed "health conscious" consumers, I am kind of worried that the addition of 400mg of piperine per day (that would be the HED for an 80kg human being) could have unpredictable consequences. That being said, I am not even convinced that we would see similarly profound effects in human studies. After all, it would not be the first "proven" fat burner that turns out to be a non-starter in human trials... if you insist on trying it, do me a favor and not mix it with a lot of other supplements or even medical drugs!