Improved Health Biomarkers: Glucose and Insulin
In humans, high calorie diets can increase glucose and insulin levels leading to diabetes, cardiovascular disease, and non-alcoholic fatty liver disease. In the HC fed mice, researchers found biomarkers that might predict diabetes, including increased levels of insulin, glucose and insulin-like growth factor-1 (IGF-1). Conversely, the HCR fed group had significantly lower levels of these markers, paralleling the SD group. For example, a standard diabetes glucose test on the HCR fed group found considerably higher insulin sensitivity, meaning the HCR group had a lower disposition toward diabetes than the HC fed group. Lower insulin levels also predict increased lifespan in mice.
Organ Protection: Heart and Liver
Three pathologists examined heart tissue from the SD, HC, and HCR mice, and while not knowing which organ belonged to which mouse group, they looked for subtle changes in the abundance of fatty lesions, degeneration and inflammation. On a relative scale of 0-4, the assessment produced mean scores of 1.6 for the SD group, 3.2 for the HC group, and 1.2 for the HCR group.
The researchers also found that the livers of mice at 18 months of age on the HC diet were greatly increased in size and weight. Liver tissue studies of these mice showed a loss of cellular integrity, and a build-up of lipids, which is common to high fat diets. In contrast, the HCR group had normal, healthy livers.
Links to Calorie Restriction Lifespan Model
The researchers also looked for metabolic ties to resveratrol's impact: pathway changes that mimicked those caused by calorie restriction. They examined AMP-activated kinase (AMPK), a metabolic regulator that promotes insulin sensitivity and fatty acid oxidation. It's been shown in previous work that the lifespan of worms has been extended by the addition of
Source:Harvard Medical School