A fair number of research groups work on calorie restriction these days - a considerably different state of affairs when compared to the paucity of such research two decades past. While the phenomenon of increased longevity with reduced calorie intake was first demonstrated in the laboratory in the 1930s, the present wave of funding and interest only gathered steam after the first simple genetic manipulations were shown to extend life in a range of species, leading the research community to accept the idea of manipulating metabolism to slow aging. That is something of an oversimplification, ignoring years of advocacy within and without the scientific community, and the way that falling costs in biotechnology make fields economically viable to explore, but you can't tell the complete story in every sitting.
Sadly, for all that it took a great deal of time and work to get the research community to accept and openly talk about slowing aging as a goal, slowing aging is the wrong idea and the goal if fast results for increased human life span are your desired end result. You want to reverse aging by repairing the damage produced by its root cause mechanisms, not just slow it down by changing the pace at which those root causes operate. Slowing aging is most likely harder to achieve safely, and will be of little use to old people; no-one has a detailed plan that describes how to slow aging reliably. A detailed plan for how to reverse it does exist. There is thus yet another sweeping change of realization and strategy that must take hold in the aging and longevity science community before we can hope to see radical life extension in our lifetimes.
Back to calorie restriction; I noticed a few review papers of late, surveying ongoing work in narrow slices of the field. Calorie restriction is a large enough topic to have subfields of its own now, as researchers from different domains find points of relevance to their own work and carve out their own fiefdoms. Cancer treatment is one such, for example:
Calorie restriction (CR), or a diet modification aiming to reduce the total intake of calories by 20%-40%, has been shown to increase longevity across multiple species. Recently, there has been growing interest in investigating the potential role of CR as a treatment intervention for age-related diseases, such as cancer, because an increasing body of literature has demonstrated a metabolic component to both carcinogenesis and tumor progression.
In fact, many of the molecular pathways that are altered with CR are also known to be altered in cancer. Therefore, manipulation of these pathways using CR can render cancer cells, and most notably breast cancer cells, more susceptible to standard cytotoxic treatment with radiation and chemotherapy. In this review article we demonstrate the laboratory and clinical evidence that exists for CR and show compelling evidence through the molecular pathways CR induces about how it may be used as a treatment in tandem with radiation therapy to improve our rates of disease control.
Calorie restriction changes almost every measure related to metabolism or aging, so it isn't surprising to find that it can touch on near every field of medicine in some way. So here there is relevance for researchers who focus on neurodegeneration, dementia, and other conditions of the aging brain:
Calorie restriction extends longevity and delays ageing in model organisms and mammals, opposing the onset and progression of an array of age-related diseases. These beneficial effects also extend to the maintenance of brain cognitive functions at later age and to the prevention, at least in rodents, of brain senescence and associated neurodegenerative disorders.
In recent years, the molecular mechanisms underlying brain response to calorie restriction have begun to be elucidated, revealing the unanticipated role of a number of key nutrient sensors and nutrient-triggered signaling cascades in the translation of metabolic cues into cellular and molecular events that ultimately lead to increased cell resistance to stress, enhanced synaptic plasticity, and improved cognitive performance.
On a related note, calorie restriction improves the long-term health of the peripheral nervous system - just one of many components of the aging body that deteriorates more slowly and is better supported when you eat fewer calories while still obtaining suitable levels of micronutrients.
The peripheral nervous system (PNS) comprises of an extensive network of connections that convey information between the central nervous system (CNS) and peripheral organs. Long myelinated nerve fibers are particularly susceptible to age-related changes, as maintenance of the insulating glial membrane requires extensive synthesis and processing of many proteins.
In rodent models, peripheral demyelination caused by genetic risk factors or by normal aging are attenuated by intermittent fasting (IF) or calorie restriction (CR) supporting a role for dietary intervention in preserving neural function.