My concern—and hence our looking backward in time— is with the beneficial impact of reduced caloric intake on retarding, and in some cases reducing, the spread of prostate cancer. Dietary restriction, as I noted in our last blog, seems to trigger an ancient strategy written into all animal genomes, that when food is scarce, resources are switched from breeding to tissue maintenance.
In recent years biologists had considerable success in identifying the mechanisms by which cells detect the level of nutrients available to the body. One goal now is to find drugs that trick these mechanisms into thinking that famine is at hand. The positive results even include evidence that the immune system benefits from reduced caloric intake, and that there is a connection between brain function and adipose tissue in relation to obesity.
A recent study in PLOS Biology discusses the relationship between LDL, hunger, leptin, the brain, and the benefits in a number of areas: there is a ubiquitous receptor in the brain, adipose, and liver called the low-density lipoprotein receptor-related protein 1 (LRP1) which regulates leptin signaling. LRP1 has some of the following properties: lipoprotein metabolism, neurotransmission, synaptic plasticity (adaptability of the neuronal junctions), clearance of beta amyloid. (note the variant epoE4 of epoE is associated with Alzheimer's Disease), and basic cell survival.
There is now a small subculture whose members seek good health through a selective return to the habits of their Paleolithic ancestors. Or as they sometimes refer to themselves, “dietary cavemen.” Their interpretation of this metaphor involves fasting between meals to approximate the lean times that his distant ancestors faced between hunts. Vegetables and fruit are appropriate, but they avoid foods like bread and pasta that were unavailable before the invention of agriculture. These Dietary Cavemen are convinced that the human body evolved from a hunter-gatherer lifestyle, and that our survival in today's world depends weaning ourselves off many millenniums of bad habits.
Now imagine if you will that you are a caveman, out innocently picking berries when you suddenly come nose to nose with a saber-tooth tiger. While you were simply gathering, the tiger was actually hunting, and the sight of you makes his mouth water.
It is our good fortune that millions of years of evolution have endowed you with a set of responses that take over automatically in the event of an emergency. Faced with the tiger, your hypothalamus sends a message to your adrenal glands and within seconds, you can run faster, hit harder, hear more acutely, think faster, and jump higher than you could only seconds earlier.
The transformation is instantaneous. In a heartbeat, so to speak, your heart is pumping at two to three times the normal speed, sending nutrient rich blood to the major muscles in your arms and legs. The tiny blood vessels (called capillaries) under the surface of your skin close down so you can sustain a surface wound and not bleed to death. Even your eyes dilate so you can see better.
In the same instant, all functions of your body not required for the life-saving struggle about to commence are shut down. Digestion stops; ditto sexual function; even your immune system is temporarily turned off. If necessary, excess waste is eliminated to make you light on your feet.
Your suddenly supercharged body is designed to help improve the odds of survival, with the result that you narrowly escape death. Once the danger is past, you find a safe place to lie down and rest your exhausted body. Much the same situation appears to apply when your “attacker” is prostate cancer.
In my next blog I will consider the elements of a diet that increases the possibility of such survival.
