What’s The Link Between IGF-1 And Cancer?

A previous article on the potential anti-aging benefits of intermittent fasting mentioned IGF-1.  This hormone is essential for normal growth and cellular activity and so is naturally very important when we are young. But high levels of IGF-1 seem to be associated with aging effects and the development of cancer as we get older.  

Prof Valter Longo, of the University of Southern California’s Longevity Institute explains that high levels of IGF-1 drive the body relentlessly, like a car driven constantly flat out, with no maintenance or repairs.  This could be how IGF-1 is implicated in causing cancer, which often occurs after the accumulation over years of small ‘defects’ in cells.  

Does fasting affect IGF-1?

The British physician, Dr Michael Mosley had researched the benefits of fasting for health and weight loss and tried fasts of various lengths. But from this experience he found fasting for more than one day to be hard, and difficult to incorporate into modern life.  As a result he developed the 5:2 intermittent fasting plan, which involves fasting for two days of the week and eating normally on the remainder.  Before he tried it out he had a full medical examination and it was found that he had high IGF-1 levels.  As he had a family history of diabetes and cancer, this concerned him. 

Larger human and animal studies of different types of fasting, including intermittent fasting, have fairly consistently shown reductions in IGF-1 levels.  It is thought that fasting makes our bodies turn off growth and concentrate more on repair and maintenanceactivities.  As well as reducing IGF-1 levels, fasting appears to switch on repair genes which carry out maintenance on cells, repairing any damage that has occurred.

Targeting cancer cells

One of the things which distinguishes cancer cells from normal cells is that they grow and turn over in a very rapid and uncontrolled manner.  Chemotherapy and radiotherapy for cancer take advantage of this fact, by targeting rapidly growing cells. While this works well on the cancer cells, it also affects those normal cells which also grow rapidly such as hair cells, leading to hair loss and cells lining the gut, leading to sickness.

Fasting and chemotherapy

When fasting, normal cells which are fully under the control of the body’s growth mechanisms slow downand concentrate on repair and maintenance.  But cancer cells shown no such restraint and continue to multiply.  Hence there is some preliminary evidence to show that fasting before, and/or after chemotherapy may reduce the toxic side effects of treatment. 

But the rapidly-dividing cancer cells are still susceptible to the treatment.  As well as making treatment more tolerable for patients, other harmful effects such as reduction in white cells were reduced in studies. This may enable higher doses of chemotherapy to be given (which is often limited by toxic side effects).

Research in this area is in very early stages, and if you are undergoing cancer treatment you must NOT attempt any kind of fasting without consulting your doctor.