Aging is associated with protein damage and imbalance in redox status in a variety of cells and tissues, yet little is known about the extent of age-related oxidative stress in the peripheral nervous system. Previously, we showed a drastic decline in the expression of glial and neuronal proteins in myelinated peripheral nerves with age, which is significantly ameliorated by lifelong calorie restriction. The age-related decline in functional molecules is associated with alterations in cellular protein homeostatic mechanisms, which could lead to a buildup of damaged, aggregated proteins. To determine the extent of oxidative damage within myelinated peripheral nerves, we studied sciatic nerves from rats of four different ages (8, 18, 29, and 38 months) maintained on an ad libitum or a 40% calorie-restricted diet. We found a prominent accumulation of polyubiquitinated substrates with age, which are associated with the conglomeration of distended lysosomes and lipofuscin adducts. The occurrence of these structures is notably less frequent within nerves of age-matched rodents kept on a lifelong reduced calorie diet. Markers for lipid peroxidation, inflammation, and immune cell infiltration are all elevated in nerves of ad libitum-fed rats, whereas food restriction is able to attenuate such deleterious processes with age. Together these results show that dietary restriction is an efficient means of defying age-related oxidative damage and maintaining a younger state in peripheral nerves.
I love an article where I can link free full text and this one is worth clicking on just to see the graphs with the difference in peripheral nerve oxidative damage with age being DRAMATICALLY less with caloric restriction. The rats in this study were on lifelong calorie restriction which is a limitation as most people have eating a lot of calories, for a long time, before they start worrying about peripheral nerve damage issues like carpal tunnel syndrome, neuropathy or intermittent claudication. It also makes me wonder if there are benefits for those with sciatica.
I thought this article was an interesting follow up after seeing the study showing that caloric restriction attenuates muscle loss with age. I have had really, really good results treating my physical therapy patients with neuropathy from the outside with electric stimulation (based on what’s becoming a fair amount of research). Ditto for intermittent claudication. So this study makes me wonder if and how much the improvements might be further enhanced by treating the body/nerves from the inside with caloric restriction or intermittent fasting diets. Though this study found caloric restriction effective, another one I looked at suggests that intermittent fasting (which may or may not also entail caloric restriction) may be better still, specifically for protecting neurons from insult. Based on piles of studies I have on caloric restriction and intermittent fasting the big side effects are just that you stay healthier, age slower, and live longer. Like research on exercise, caloric restriction appears to be pretty much win win all the way around.
As always, if you have any further questions or need for clarifications, please don’t hesitate to ask. Being aware that some of my blog ideas are contentious and occasionally a bit out of the field of my expertise, I encourage my readers to come forth with any questions/comments that are of interest or concern. Your comments are valued and welcomed.
Chad Reilly is a licensed physical therapist, located in North Phoenix, practicing science based medicine with treatment protocols unique and effective enough to proudly serve patients from Phoenix, Scottsdale, Mesa, Chandler, Tempe, Peoria, and Glendale.