Abstract: Obesity has been suggested to be related to high intake of fat and low intake of fiber. Here we show the effect of oat β-glucan, a water soluble dietary fiber, in preventing high-fat diet induced obesity in human flora-associated (HFA) mice. HFA mice fed with high-fat diet for 8 weeks, significantly increased body weight, epididymal and subcutaneous adipose tissue weight compared with HFA mice in normal diet group (p<0.01). The high fat diet with 5% oat β-glucan significantly reduced body weight, epididymal and subcutaneous adipose tissue weight compared with high-fat diet fed HFA mice (p<0.01). HFA mice fed a high-fat diet, supplementation with 5% oat β-glucan for 8 weeks also decreased fasting glycemia, area under glucose curve (AUC) and triglyceride (TG) in serum when compared with high-fat diet group (p<0.05). However, no significant differences were observed between normal diet group and normal diet with 5% oat β-glucan diet group in body weight, epididymal and subcutaneous adipose tissue weight, AUC, fasting glycemia and TG. Dietary high-fat diet with 5% oat β-glucan also decreased lipid accumulation in hepatocytes and adipocyte size compared with mice from high-fat diet group. These results provide an important role of dietary oat β-glucan in preventing high-fat diet induced obesity, serum biochemical indicators associated with obesity, fatty liver and adipocyte size.
Alex’s Notes: We all know that I have a love affair with oats, so it shouldn’t come as a surprise that I write about studies related to this amazing cereal grain (for everyone who blanket statements grains as “bad”). Anyways, the current study used human flora-associated (HFA) mice, where germ-free mice are implanted with healthy human donor microbes in order to imitate the human GI tract, to investigate the effect of dietary oat β-glucan in preventing high-fat diet induced obesity, serum biochemical indicators associated with obesity, fatty liver, and adipocyte size.
Forty six-week old HFA mice were randomly divided into 4 groups, each of which received a different diet for 8 weeks with free access to food and water. Two groups were fed a standard chow and two groups were fed a high-fat obesogenic chow. Within type of diet, one group also consumed 5% of their diet as oat β-glucan (prepared from oat bran).
|Ingredients||Control (CT)||CT + Oat β-glucan (OG)||High-fat (HF)||HF+OG|
|Oat β-glucan (%)||--||5||--||5|
|Yolk Powder (%)||--||--||5||5|
|Basal Feed (%)||95||95||75||75|
Pretty straight forward, right? Basically, the researchers inoculated a bunch of mice with healthy-human-sourced microbes and put them on one of four diets for eight weeks with no other intervention.
Some oat-of-this-world results
As would be expected, the HF mice demonstrated significantly more weight gain at week #4 that persisted throughout the intervention when compared to the standard chow groups. However, in the HF+OG mice, there was no significant difference in weight compared to the standard chow mice, and in fact weight was significantly lower compared to the HF group. These same exact observations were seen for the size of the epididymal and subcutaneous adipose tissue. Additionally, oat β-glucan blocked the high-fat diet induced fatty liver.
The HF mice also had significantly elevated fasting blood glucose concentrations, glycemic peak in response to an oral-glucose tolerance test (OGGT), and total OGGT area under the curve (AUC; indicating that the overall glucose load in the blood was larger). Yet, the simple addition of oat β-glucan to this diet maintained glucose tolerance at levels seen in the standard chow mice. Moreover, the standard chow with oat β-glucan (CT+OG) trended to reduce fasting glucose compared to the standard chow only (CT), but it failed to reach statistical significance.
Finally, for blood lipids, none of the groups had a significant change in LDL-c, but both the HF and HF+OG groups significantly increased their HDL-c. At the same time, the HF mice significantly increased their total cholesterol and serum triglycerides, but the HF+OG did not.
Eat your oats.