What are the Potential Benefits of Caloric Restriction?
Caloric restriction (CR), the significant decrease in calorie intake, is a strategy for improving health and increasing lifespan. Increased lifespan has been observed in many types of calorie-restricted animals, including rhesus monkeys. Significantly, restricting calories does not only lengthen lifespan, but also healthspan (the period of healthy living before the onset of age-related diseases, such as diabetes, cardiovascular disease, and some cancers).
Lifespan studies in humans are difficult; however, CR studies in humans can measure biomarkers of aging (eg, dehydroepiandrosterone sulfate [DHEA-S], the levels of which decrease with age).
CR in humans has been shown to improve heart function, reduce markers of inflammation, and reduce risk factors for cardiovascular disease and diabetes.
CR has been shown to increase risk of diminishing muscle strength, aerobic capacity, and bone mineral density; therefore, proper exercise in addition to a CR diet is crucial. Never attempt a drastic change in diet or exercise regimen without consulting a doctor.
What are Caloric Restriction Mimetics?
Maintaining a long-term CR diet can be very difficult and demanding. Therefore, calorie restriction mimetics (CRMs), or compounds that mimic the effects of CR, are desirable. CRMs mimic the metabolic, hormonal, or physiological effects of CR without reducing long-term food intake, while stimulating maintenance and repair processes, and producing CR-like effects on longevity and reduction of age-related disease.
- Tetrahydrocurcumin and green tea polyphenols have both demonstrated increases in average and maximum lifespan in mice.
- Ginkgo biloba significantly increased the lifespan of male Fischer rats.
- Rapamycin and aspirin were both identified as having CR mimetic activity in rodents.
- Resveratrol has anti-inflammatory activity, as well as CR-mimicking activity, in several species.
- It has been suggested that several plant-derived polyphenols, including quercetin, exerted health benefits via CR-like modulations of stress-response pathways.
- Nicotinamide riboside is a source of vitamin B3 and a precursor for nicotinamide adenine dinucleotide (NAD+). Nicotinamide riboside supplementation had CR-like positive effects on health in yeast and mice.
- Metformin, generally used as a diabetes drug, extended the lifespan of mice and decreased the incidence of certain tumors. Metformin can also activate adenosine monophosphate-activated protein kinase (AMPK), an enzyme that affects glucose metabolism and fat storage.
- Gynostemma pentaphyllum (G. pentaphyllum) can also activate AMPK. G. pentaphyllum supplementation in humans has been shown to exert effects seen in CR, such as improved glucose metabolism and reduced body weight.
- Hesperidin, a plant flavonoid, has demonstrated anti-inflammatory, insulin-sensitizing, and lipid-lowering activity. Evidence suggests hesperidin may help prevent and treat several age-related chronic diseases.
- Pyrroloquinoline quinone (PQQ) increased mitochondrial DNA content and stimulated oxygen respiration (both indicative of biogenesis) in mouse hepatoma cells.
- Fish oil, while not a CRM, appeared to work synergistically with CR to reduce oxidative damage.