Urolithin a from pomegranate is able to effectively prevent and reverse obesity caused by a high-fat diet
Recently, ponweijun and Jiangwei Wu of Northwest A & F University found that a substance called urolithin a could enhance brown fat function, promote Beiging of white fat, increase lipid metabolism, and reduce body weight in mice. This result was published in PLoS Biology [1].
Urolithin a can be produced from ellagitannins in pomegranate via gut microbial metabolism. Previously, the FDA had completed a safety assessment of urolithin a to classify it as a gras substance (generally considered safe).
Ellagitannin, a beneficial component in pomegranate, has antioxidant and anti-inflammatory effects [2]. In humans, ellagitannins are first rapidly hydrolyzed in the gut to ellagic acid and then metabolized by gut bacteria to produce 5 urolithins urolithin a (UA), urolithin B (UB), urolithin C (UC), urolithin D (UD), and isourolithin a (ISO UA) [3].
Nevertheless, there are differences in the effect of ellagitannins on different people, largely because different people have different gut microbes and different compositions of urolithins metabolically produced. Among these 5 urolithins, UA has the greatest health benefits, exhibiting anticancer, anti-inflammatory, and antiaging bioactivities [4-6].
Studies have shown that people whose gut microbes can convert ellagitannins to UA, UB, and ISO UA have a higher cardiovascular risk than those who only convert them to UA [7]. While during aging, UA produced by gut microbial metabolism also gradually decreases and UB gradually increases [8].
Recently, it was found that UA can also decrease fat accumulation and increase fat oxidation in adipocytes and hepatocytes cultured in vitro [9]. Perhaps UA is also used to lose weight!
The researchers fed the mice a high-fat rat diet and gavaged UA at a dose of 30 mg per kg body weight per day. Two weeks later, the mice in the UA group weighed signi fi cantly less than those in the control group. By 10 weeks, the weight of the UA group was on average 23.5% lower than that of the control group.
UA protects against high fat diet induced obesity
Analysis of the body composition of the mice revealed that mice in the UA group had reduced body weight, essentially all fat. Mice in the UA group had 61.3% less fat mass and less than one-third the rate of body fat compared with control mice.
In a genetically engineered obese mouse model, 6 weeks of UA treatment also decreased mouse body weight by 17.6%. Whether it is dietary or genetically caused obesity, UA is effectively prevented! Its obesity prevention effect, similar to that of orlistat, an already marketed weight-loss drug.
Mice in the UA group had less predominantly fat and lean mass similar to controls
Obesity prevented, so did various metabolic problems that accompany obesity. Studies have found that UA can effectively prevent high-fat diet induced insulin resistance, impaired glucose tolerance, systemic inflammation, and fatty liver. For the dysregulation of glucose homeostasis that has already occurred, UA can also reverse it, restoring glucose homeostasis.
How do these effects of UA arise? The researchers measured the metabolic rate in mice. The study found that both oxygen consumption and energy expenditure were significantly greater and body temperature was 0.7 degrees C higher in the UA group than in the control group. Whereas measurement of the respiratory exchange ratio revealed that mice in the UA group burned more lipids, more non carbohydrate burned fat, and naturally less fat in the mice. The weight of brown fat, inguinal white fat, and parahigh white fat decreased by 37.4%, 57.2%, and 46.1%, respectively, in the UA group mice compared with the control mice.
The body temperature of mice in the UA group was higher than that in the control group.
Although low in weight, these fats were not weakly functional, with UA treated mice having smaller adipocytes, higher levels of the uncoupling protein UCP-1, 2.5-, 2.1-, and 1.4-fold higher mtDNA content in brown, inguinal white, and epididymal white fat, respectively, and significantly increased expression of genes involved in mitochondrial thermogenesis.
UA can activate brown fat and promote white fat Beiging!
UA converts T4 to T3, increases fat thermogenesis, and prevents obesity
Further studies revealed that the promoting effect of UA on fat thermogenesis was not dependent on conventional β- Adrenergic signals, but rather relies on thyroxine signals. It converts the less active T4 in thyroxine to the more active T3, enhancing metabolic rate and thermogenesis through thyroxine signaling.
It seems that it should be good to eat more than two pomegranates. Eating by edge how many seeds are inside the edge, there is no hope to prevent further dementia. That is, it is not known to which urolithin is metabolized by gut bacteria of the odd pastry.
