Resistant starch from high amylose maize (HAM‐RS2) reduces body fat and increases gut bacteria in ovariectomized (OVX) rats

Abstract

Objective Obesity after menopause is a health concern for older females. Changes in the microbiota are likely to occur with this condition. Modifying the microbiota with a prebiotic is a plausible strategy for improving the health of menopausal females. Design and Methods Resistant starch type 2 from high-amylose maize (HAM-RS2) was used as a prebiotic in rats in a 2 × 2 factorial study with two levels of HAM-RS2 (0 or 29.7% of weight of diet) referred to as energy control (EC) and HAM-RS2 diets, respectively; and two levels of surgery, ovariectomized (OVX) and sham. Results In a 6-week, postsurgery recovery period, OVX rats gained more body weight with consumption of a similar amount of food. Subsequently, consumption of HAM-RS2 versus EC diets resulted in reduced abdominal fat in both OVX and sham rats; but when normalized for disemboweled body weight (body weight minus GI tract), there was no effect of surgery, only reduction with HAM-RS2. Targeted bacterial populations were estimated that are known to ferment HAM-RS2 or metabolize the products of that initial fermentation. OVX and sham rats demonstrated increased bacterial levels with dietary HAM-RS2 for all bacteria. Additionally, culture techniques and qPCR provided similar results. Conclusion This study shows that, as expected, OVX increases adiposity. However, contrary to previous effects seen in obese mice, this did not prevent fermentation of HAM-RS2 and consequently, the fat gain associated with OVX was attenuated.

High fat diet partially attenuates fermentation responses in rats fed resistant starch from high-amylose maize

“…Such benefits included the following: improvement in fermentation, increased production of plasma GLP‐1 and PYY, improved insulin sensitivity, increased gene expression of proopiomelanocortin in the hypothalamic arcuate nucleus in the brain, a decreased respiratory quotient, improvements in diabetic rats, and decreased abdominal fat . Additionally, we have reported that dietary HAM‐RS2 was associated with lower body fat in mice that were fed a moderate fat diet and in a low fat diet fed to OVX rats , a model of endocrine obesity. In the present study, we investigated the effects of HAM‐RS2 included in a diet‐induced obesity study comparing the low‐fat diet with a high‐fat diet.…”

“…The four low‐fat diets had a metabolizable energy value of 3.4 kcal/g and the high‐fat diets had a value of 4.2 kcal/g. The concentration of HAM‐RS2 used in the current study is the same as used in previous proof‐of‐concept studies with low‐ and moderate‐fat diets, GK diabetic rats , OVX rats , and a study investigating glycemic index . All low fat diets and high fat diets were made isocaloric using cellulose in the control diets without HAM‐RS2.…”

Resistant starch manipulated hyperglycemia/hyperlipidemia and related genes expression in diabetic rats

“…Nevertheless, the regulation of blood lipids composition is even more complex than we have recognized. For example, the remarkable suppression of the elevated total cholesterol levels caused by RS consumption might also be associated with increased levels of the bacterial populations in the gut as well [6,21], because our previous studies suggested that the RS administration greatly increased the short-chain fatty acids via gut microbiota fermentation, in particular, propionate and butyrate [22,23], and these metabolites exhibited the inhibition of cholesterols synthesis in the livers [24].…”

Antihyperglycemic effect of rice husk derived xylooligosaccharides in high‐fat diet and low‐dose streptozotocin‐induced type 2 diabetic rat model

“…q-PCR analyses were carried out as previously described with some modifications (Keenan et al, 2013) in 96-well optical plates on the Quantstudio TM6 Flex Real-Time PCR System (Applied Biosciences).…”