the Science of Living Well: Calorie Restriction

Calorie restriction (CR) is a dietary construct based intentionally on the consumption of less calories than required to sustain the premeasured metabolic needs of a living organism.

CR without malnutrition has been shown to increase both the median* and maximum life spans of different species, including yeast, worms, flies, fish, rodents and dogs. CR has been proven to decelerate the biological aging process and expand multiple characteristics associated with youthful health, energy and vitality.

In 1934, Crowell and McCay of Cornell University observed that lab rats fed a reduced intake of calories while maintaining adequate micronutrient levels resulted in life spans that doubled compared to controls.

In addition to living longer, rodents forced to live on a calorie restricted diet maintained youthful appearances longer, demonstrated a natural tendency to engage in physical activity and showed less overall degeneration.

Delays in many age-related diseases were also noted including cardiovascular, loss of lean functional mass (sarcopenia), memory loss, excess body fat and obesity, liver failure, brain atrophy, cancer, diabetes and stroke.

CR is known in rhesus monkeys and rodents to lower fasting insulin and glucose levels, increase insulin sensitivity, improve blood lipid profiles, reduce LDL, prevent collapse of the immune system and optimize body composition.

Numerous scientists, gerontologists and anti-aging physicians throughout the world have proposed a variety of possible mechanisms to explain in whole or in part the biological 'effects' of calorie restriction on various species of living organisms and include the following:

• decelerated rate of cell division
• reduced metabolic rate
• lower production of free radicals
• decreased oxidative stress
• decreased glycation rate
• less damage to DNA and mitochondria
• increased genetic expression of telomerase
• reduced telomere shortening
• activation of hormesis
• increased activation of Sir2/SIRT 1 genes
• increased movement and physical activity
• reduced exposure to toxins & poisons

Hormesis is derived from the Greek word hormaein meaning "to excite". Hypothetically, CR imposes a low-intensity biological stress on the organism which ignites or stimulates a built-in defensive response to help protect cells against oxidation and potential damage, resulting in improved health and longer life. This switch to a defensive state is thought to be managed by specialized longevity genes.

CR lowers insulin concentration and substances related to insulin, such as IGF-1 and GH. This effect acts to up-regulate a process called autophagy, a key repair mechanism of the cell. Autophagy (auto "self" and phagein "to eat") is the basic catabolic mechanism that involves cell degradation of unnecessary or dysfunctional cellular components. Such degradation carried out by specialized enzymes, ensures cellular survival during periods of starvation by maintaining cellular energy levels.

Sirtuin or Sir2 proteins are a class of proteins that regulate many important cell activities including aging, apoptosis, inflammation, stress resistance, circadian clocks and the biogenesis of mitochondria.

Biologist David Sinclair is credited with co-discovering sirtuin activating compounds including the polyphenol resveratrol, found naturally in the skin of red grapes, blueberries, peanuts and cacao.

Resveratrol has also been chemically synthesized and in extremely high doses has been shown to extend the lifespan of yeast, worms, flies and fish. In 2006 Johan Auwerx showed that mice supplemented with resveratrol had better treadmill endurance times due to activation of the sirtuin 1 gene. In other animal studies resveratrol has been shown to reduce plaque formation in the brain, inhibit herpes simplex virus, increase testosterone and function as a inflammatory agent in arthritic models.

Multi-Dimensional Factors

No single variable or determinant associated with both our internal or external environment exclusively controls or dictates our potential to successfully survive and thrive in this world. There never has been nor will there ever be a magic bullet, miracle cure or supernatural transformation, however, due to the efforts of objective rationality and the power of logic sustained by the scientific method, the haystack is getting smaller thus making the needle easier to find.

Optimum health is managed by everything we do and don't do. First, by poorly understood subconscious instinctive neural mechanisms and programs deposited in our genes and neurons from conception and second, by our conscious willful efforts and focused mindfulness to choose the best possible path and environment according to our unique individual design, genetic features and personal lifestyle objectives.

“Choose wisely grasshopper…”

Photo by Samuel Mitchell from Burst

More on this topic...

the Science of Living Well: Life Extension
the Science of Living Well: Telomeres
the Science of Living Well: Neuroplasticity
the Science of Living Well: Blue Zones

As always...Stay well and Live Free!