Saturday, October 8, 2011

The other "fat burner" in coffee by Jerry Brainum

Coffee is the most common source of caffeine, and caffeine appears to help promote body fat loss through a variety of mechanisms. But coffee is a complex mixture of various substances besides caffeine. For example, the high polyphenol content of coffee makes coffee the most common source of dietary antioxidants in the American diet. These polyphenols are largely responsible for the diabetes preventive effect of coffee. But there is another substance found in coffee that is far less known, but may also offer some fat reduction effects.
    That substance is manooooligosaccharides (MOS),a type of complex sugar found naturally in coffee. Several studies have shown that it appears to promote fat loss,although for some reason, it seems to to work better for men than it does for women. A new study involved 60 overweight men and women, all of whom were on weight-loss diets, who ingested either 4 grams a day of MOS or a placebo, both ingested in an instant coffee beverage. The study lasted for 12 weeks, with weekly measurements of blood pressure, weight, and bodyfat measured weekly. Body fat levels were determined by magnetic resonance imaging (MRI), and were measured at the start and end of the study. The results showed that men who consumed the MOS showed greater losses of both subcutaneous and visceral, or deep-lying abdominal fat compared to those who ingested the placebo. In women, however, there were no differences between the placebo and MOS groups.
      As to the mechanism of how MOS works, there are two suggestions. The first is that MOS promotes increased passage of fat out of the body, before it can be digested. Since fat contains the most concentrated source of calories at nine per gram, it's not hard to understand how increased fat excretion would help you lose fat. The other possible mechanism is that MOS promotes increased intestinal short-chain fatty acid production (SCFA). SCFA are produced by probiotics, and similarly to probiotics, MOS isn't digestible, so it stimulates intestinal bacteria to produce the SCFA. Studies have shown that these SCFA, such as propionate and butyrate, lower leptin levels, and also reduce the levels of resistin, a protein produced in fat cells that promotes increased body fat deposition.
    As to why MOS failed to work in women, the study authors felt this needed added study. However, other popular fat-loss aids, including medium-chain triglycerides and green tea, also usually produce better effects in men compared to women.Thanks to their greater levels of estrogen,women store fat more efficiently than men, and men also have a higher average rate of fat oxidation compared to women. Women may have a higher resistance to fat store mobilization than men, explaining why popular supplements aimed at fat loss often work better in men.

St.Onge MP, et al. A weight-loss diet including coffee-derived mannooligosaccharides enhances adipose tissue loss in overweight men but not women.Obesity: 2011: in press.

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