Heat Shock Protein Levels Diminished by Insulin Resistance
Heat shock proteins (HSPs) are important in cellular housekeeping, the processes of removing and repairing damage - and given how important these processes are to longevity, it's no surprise that we see associations between HSP levels and longevity. Researchers have been investigating how to build therapies based on boosting HSPs in recent years, but here is a different point of view: research to show that insulin resistance reduces HSP levels, which may be another one of the ways in which being fat and sedentary enough to become insulin resistant harms your health: "Heat shock protein (HSP)70 decreases with age. Often aging is associated with coincident insulin resistance and higher blood glucose levels, which also associate with lower HSP70. We aimed to understand how these factors interrelate through a series of experiments using vervet monkeys (Chlorocebus aethiops sabaeous). Monkeys fed low-fat diets showed no association of muscle HSP70 with age, but levels were highly heritable. Insulin resistance was induced in vervet monkeys with high-fat diets, and muscle biopsies were taken after 0.3 or 6 years. HSP70 levels were significantly greater after 0.3 years but were significantly lower following 6 years of high-fat diet. Associations with glucose also switched from being positive to strikingly negative with increasing insulin resistance. In conclusion, a low-fat diet may preserve tissue HSP70 and health with aging, whereas high-fat diets, insulin resistance, and genetic factors may be more important than age for determining HSP70 levels." Which is good news for those folk who make an effort to maintain health and fitness into old age, as insulin resistance and weight gain are avoidable consequences of lifestyle for the vast majority of people.
It is not clear from the abstract how insulin resistance was induced with a high fat diet. On the surface this seems worrying for followers of LCHF diets.
However another paper http://www.ncbi.nlm.nih.gov/pubmed/17636085, also by Kavanagh, tells of a trans fat diet inducing abdominal obesity and changes in insulin sensitivity in monkeys, even without an excess of calories. Therefore it is possible that the "high fat" diet mentioned above is more specifically a trans fat diet.