Monday, March 5, 2012

The Protective Benefits of Intermittent Fasting

In a previous article I pointed to some talking points about intermittent fasting as it pertains to health, metabolism, and weight management.

Intermittent Fasting: A Few Talking Points

Those talking points are the things that are relevant to most people, especially the weight loss aspect of it.  Intermittent Fasting has a host of other health benefits, besides just being a useful tool for improving metabolic function and weight management.  Many studies have been performed showing that Intermittent Fasting has useful implications for cancer patients, Alzheimer’s sufferers, and those recovering from peripheral nerve damage.  So what I’m trying to say is that Intermittent Fasting is REALLY COOL!

These extra therapeutic benefits are due in large part to the fact that fasting induces cell autophagy.  The previous article touched on autophagy as it relates to muscle function.  Essentially autophagosomes sweep the muscle free of disfunctioning muscle proteins and the “garbage” that accumulates and contributes to muscle cell atrophy and weakness.  Autophagy is also largely at play when it comes to brain and nerve function and tumor growth.

A Word of Caution
Many studies that have investigated dietary protocols and nervous system function and cancer have been done on mice.  Any study done on mice needs to be held at arm’s length due to the fact that we humans are, in fact, not mice.  The reason all these studies are done on mice is that A) these are relatively new topics of study and are therefore done on mice first, and B) not a lot of people would sign up to be given cancer or neurological disorders.  Some people can be so selfish.
Not a human, but if you know this movie you get a million gold stars.
Also, since I’m not going to pay hundreds of dollars to read studies I’m only looking at the abstracts.  Abstracts can put you on the right track but it is sometimes impossible to discern whether or not a study was set up correctly, carried out correctly, etc. etc.  Also, reading whole studies is like eating nothing but white bread.  Dry and boring as hell.  On to the findings.

Nerve and Brain Function
Intermittent Fasting and long-term calorie restriction have been known to help improve and retard the effects of aging in the brain and peripheral organs.  Research has shown that Intermittent Fasting can have neuroprotective benefits by increasing the expression of myelin proteins in combination with a thicker myelin sheath, less redundant basal lamina, and a reduction in Schwann cell proliferation.  What this means is that the nerve cells are better protected and are more efficient.  Intermittent Fasting also promotes the clearing of certain protein aggregates which further improve efficiency and function of locomotor skills.

When placed on Intermittent Fasting male rat brains also experience an increase in mitochondrial content in certain areas of the brain and a decrease in oxidative stress to certain proteins.  Essentially the cells get stronger and are exposed to less harmful compounds as the brain ages.

Intermittent Fasting has also been shown to improve functional recovery in rats exposed to spinal cord injury.  The study was done using every other day fasting which basically means a day of fasting followed by a day of unrestricted food intake.  The fasting group of mice had increased nerve integrity, dramatically reduced lesion volume, and increased sprouting of corticospinal axons.  These effects were manifested in improved gait pattern, increased forelimb function during ladder crossing, and increased vertical exploration (why do all of these things sound fun?).

Until recently it was thought that the brain was excluded in the fasting-induced upregulation of neuronal autophagy.  There are drug companies that are investing a lot of money to develop drugs that cross the blood-brain barrier and upregulate autophagy in the brain.  A study done in 2010 showed that this is not needed.  Hopefully the drug companies see that benefits of this essentially free therapy and don’t push unneeded drugs on patients.  I get the feeling that this won’t be the case.

Many studies have shown that Intermittent Fasting can lead to a decrease in cancer cell proliferation and tumor growth.  Intermittent Fasting has also been shown to delay tumor onset in mice that are predestined to develop cancerous tumors.  Again, the autophagy pathways that are switched on during fasting are largely at play by triggering cancer cell apoptosis (cell death).

This study mouse is a lot better off than some of his cousins.
Fasting in conjunction with chemotherapy- but not on its own- has also been shown to contribute to long-term cancer free survival in mouse models.  It was shown that the fasting had a sensitizing effect on the cancer cells.  This meant that the chemotherapy would be much more effective.  In breast cancer cells short-term fasting showed increased oxidative stress, DNA damage, and apoptosis.

Again, all of these studies have been conducted using mouse models.  Mice are similar in biology to humans but at the end of the day they still aren’t humans.  If these findings are validated in humans it will be interesting to see how the drug companies react.  I know cancer drugs are crazy expensive and make a lot of the drug companies a lot of money.  Hopefully the leaders of the pharmaceutical companies will find some kind of human emotion and not push drugs and the resultant cost on patients that don’t need them.  But I doubt it.

Is Intermittent Fasting for everyone?  I would say that many could reap some kind of benefit from it but ultimately it’s up to you to decide if it is or not.  I know that I’ve seen positives from it from a metabolic and weight management stand point.  But if it can keep me as far away from cancer and neurological disorders as possible I’ll keep doing it.  Oh, and as an end note, physical exercise promotes autophagy as well.  So eat right and sling some weight.


Intermittent fasting alleviates the neuropathic phenotype in a mouse model of Charcot-Marie-Tooth disease.  Madorsky I, et al.  Neurobiol Dis. 2009 Apr;34(1):146-54.

Late-onset intermittent fasting dietary restriction as a potential intervention to retard age-associated brain function impairments in male rats.  Singh R, et al.  Age (Dordr). 2011 Aug 23.

Neuroprotective role of intermittent fasting in senescence-accelerated mice P8 (SAMP8).  Tajes M, et al.  Exp Gerontol. 2010 Sep;45(9):702-10.

Dietary restriction started after spinal cord injury improves functional recovery.  Plunet WT, et al.  Exp Neurol. 2008 Sep;213(1):28-35.

TCD scientists discover that self-eating cells safeguard against cancer.

Autophagy inhibition induces atrophy and myopathy in adult skeletal muscles.  Masiero E, Sandri M.  Autophagy. 2010 Feb;6(2):307-9.

Short-term fasting induces profound neuronal autophagy.  Alirezaei M, et al.  Autophagy. 2010 Aug;6(6):702-10.

To Keep Muscles Strong, the 'Garbage' Has to Go.

Dose effects of modified alternate-day fasting regimens on in vivo cell proliferation and plasma insulin-like growth factor-1 in mice.  Varady KA, et al.  J Appl Physiol. 2007 Aug;103(2):547-51.

Effect of intermittent fasting on prostate cancer tumor growth in a mouse model.  Thomas JA 2nd, et al.  Prostate Cancer Prostatic Dis. 2010 Dec;13(4):350-5.

Weight-cycling decreases incidence and increases latency of mammary tumors to a greater extent than does chronic caloric restriction in mouse mammary tumor virus-transforming growth factor-alpha female mice.  Cleary MP, et al.  Cancer Epidemiol Biomarkers Prev. 2002 Sep;11(9):836-43.

Adult-onset calorie restriction and fasting delay spontaneous tumorigenesis in p53-deficient mice.  Berrigan D, et al.  Carcinogenesis. 2002 May;23(5):817-22.

Fasting Cycles Retard Growth of Tumors and Sensitize a Range of Cancer Cell Types to Chemotherapy.  Changhan L., et al.  Science Translational Medicine February 8 2012.

Activation of autophagy is required for muscle homeostasis during physical exercise.  Nair U, Klionsky DJ.  Autophagy. 2011 Dec 1;7(12).

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