A future weapon in the battle against obesity and diabetes could
come in the form of an oil derived from the seeds of wild almond trees,
according to researchers at Missouri University of Science and
Technology.
The key to the oil’s potential lies in its ability to affect certain microorganisms living in our bellies.
In
a study presented June 18 at the American Society for Microbiology’s
general meeting in San Francisco, Missouri S&T researchers reported
that adding sterculic oil to the diets of obese laboratory mice
increased their sensitivity to insulin. This was due to the oil’s effect
on three types of microorganisms that live in the guts of the mice.
As
a result, the researchers saw a “statistically significant improvement
in glucose tolerance and insulin sensitivity in the obese mice,” says
Shreya Ghosh, a Ph.D. student in environmental engineering at Missouri
S&T. The sterculic oil had no adverse affects on lean mice fed the
same diet.
Sterculic oil is extracted from the seeds of the wild almond tree known as Sterculia foetida.
The
research by Ghosh and her advisor, Dr. Daniel Oerther, builds upon
previous studies conducted at the University of Missouri-Columbia. In
those studies, sterculic oil was found to suppress the bodily enzyme
stearoyl-CoA desaturase 1 (SCD1). SCD1 is associated with insulin
resistance, a condition that can lead to diabetes and obesity.
Other
studies have shown that obese mice deficient in the hormone leptin have
a different composition of “gut microbiota” than do lean mice. (Those
studies are referenced in a 2011
article in Nature
Reviews Microbiology). Leptin helps regulate metabolism, and a
deficiency of the hormone can contribute to obesity, says Oerther, the
John and Susan Mathes Chair of Environmental Engineering at Missouri
S&T.
In the Missouri S&T study, a diet
supplemented by sterculic oil also correlated with lower levels of three
types of gut microbiota – Actinobacteria, Bacilli and Erysipelotrichia –
in the obese mice. It isn’t clear, however, whether the lower levels of
those microbiota led to the improvement of glucose tolerance and
insulin sensitivity among the obese mice, Oerther says.
To
perform her experiments, Ghosh studied 28 male mice – 14 of them obese
and 14 normal, and each of them five weeks old at the beginning of the
study. She separated the mice into four groups and for nine weeks, fed a
standard diet to one group of obese mice and one group of non-obese
mice. Over the same period, she fed the same diet, supplemented with 0.5
percent of sterculic oil, to one group of obese mice and one group of
non-obese mice. Ghosh recorded the weights, food consumption and glucose
levels of the mice during the nine-week period.
After
the nine weeks, researchers conducted a DNA analysis of the gut
microbiota at King Abdullah Institute of Science and Technology in Saudi
Arabia. The results confirmed correlations between the diet, improved
glucose tolerance and groups of microbes. Even though the mice fed a
diet with sterculic oil did not experience weight loss, both Ghosh and
Oerther believe their findings could lead to new insights into
controlling diabetes and weight gain.
Ghosh’s
research poster presentation at the ASM meeting is titled “Responses of
Gut Microbiota to Sterculic Oil Supplemented Diet in Lean and Obese
Mice.” Her co-authors were Oerther; Dr. James W. Perfield II, assistant
professor of food science at the University of Missouri-Columbia; and
Dr. Pascal Saikaly, assistant professor of environmental science and
engineering at King Abdullah University of Science and Technology in
Saudi Arabia.