Feeding butter with elevated content of trans-10, cis-12 conjugated linoleic acid to obese-prone rats impairs glucose and insulin tolerance

This study was conducted to evaluate dietary CLAt10c12 consumption by obese prone rats considering supplemental doses have shown to contribute to the development of insulin resistance. We created butter from cows with subacute ruminal acidosis (SARA), a condition that decreases the pH of a dairy cow’s rumen and increases CLAt10c12 10-fold making this an enriched naturally occurring source of CLAt10c12. We evaluated if SARA butter would result in a greater risk of developing glucose and insulin intolerance, impaired insulin signaling and increased markers of inflammation compared to various diets (Lean Zuckers: low (10%) fat (LF), Obese Zuckers: LF, 45% lard, 45% non-SARA butter). After 8 weeks, SARA was comparable with Lard for its negative impact on glucose and insulin tolerance, followed by non- SARA, LF and leans respectively. Differences were not reflected in the insulin signaling markers. Markers of inflammation were variable across tissues (adipose, skeletal muscle, liver).