Can eating this type of sugar prevent weight gain?

Mannose, a type of sugar, can greatly affect metabolism, weight gain, and the composition of gut bacteria in rodents. This result may lead to new treatments and prevention strategies for both obesity and weight gain.

More and more studies are unraveling the multi-layered relationship between our gut microbiome and weight gain. A few years ago, a twin study that Medical News Today reported on found that genes influence the bacteria that live in our gut, which, in turn, influence whether we gain weight or not. Another paper proposed that our diets influence our guts’ “power” to decide how much weight we gain.

Belly fat – the most harmful type of fat – in particular is known to be driven by our gut bacteria, but the food that we eat, this study suggested, plays a more important role in these weight-regulating gut processes than genes. New research brings further nuance to this latter idea. Specifically, a new study looks at how the intake of mannose, a type of sugar, affects the gut bacteria and weight gain in mice.

Hudson Freeze, Ph.D., director of the Human Genetics Program at the Sanford Burnham Prebys Medical Discovery Institute in San Diego, CA, and colleagues observed the effects of mannose on weight gain while they were studying its’ therapeutic effects on CDG (congenital glycosylation). Then the team decided to investigate the effects of mannose further.

The study revealed that mice that were fed a high-fat diet plus mannose were leaner, had less fat in their livers, were more tolerant to glucose, and had overall higher levels of fitness than mice that had the mannose-free diet.



These benefits were reflected in the gut bacterial composition of the mice that received mannose. In fact, the diversity for the gut microbiota in these mice resembled that of lean rodents that had been on a normal diet.

Also, the scientists took mannose out of the rodents’ high-fat diet and re-examined them. The mice then regained weight and their bacterial composition went back to resembling that of obese rodents that did not receive the sugar.

Significantly, these benefits only affected younger mice, while 8-week-old mice did not benefit from the sugar supplement. “The gut microbiome is very dynamic in early life,” explains first study author Vandana Sharma, Ph.D.

My Take:
Before you run out and buy D-mannose so you can eat high-fat and lose weight, reread the last paragraph. The sugar only had these effects on very young mice whose microbiome was still developing. Please read my blog “Antibiotics, Formula Feeding Might Change Baby’s ‘Microbiome’” posted on June 17, 2016. You can find it by entering “microbiome” in the search box in the upper left-hand corner of my blog site.

I use D-mannose to treat urinary tract infections (UTIs). It is absorbed from the gut intact, remains intact and then secreted in the urine. Bacteria in the urinary tract will glum onto the mannose and be excreted from the body.

I suspect that certain beneficial bacteria can metabolize mannose, although typically probiotics thrive on soluble fiber, while harmful bacteria eat fat.

Bottom Line:
D-mannose is safe and effective for the treatment and prevention of UTIs. However, please do not use it as a weight loss product.

Source: September 18, 2018 NIH