Reducing Calories Reduces Cancer Risks - But How?

http://www.niehs.nih.gov/external/resinits/ri-7.htm
A diet low in calories dramatically reduces cancer progression in rodents.
The same effect is expected to occur in humans and might, in part, explain
the diet's contribution to cancer prevention. Although there are hypotheses
to explain this observed effect, only recently has a molecular explanation
been developed. NIEHS scientists discovered that a protein, insulin-like
growth factor-1 (IGF-1), was important to this effect. This protein is part
of the molecular machinery that controls cell growth and cell death and,
thus, tumor development. In both humans and rats, a low-calorie diet reduces
the level of IGF-1 the body produces. In rodents, it was shown that lower
levels of IGF-1 favor cell death over cell growth, thus slowing tumor
progression. Furthermore, these scientists showed that in rodents under
caloric restriction, bladder cancer progression was increased when IGF-1
serum levels were restored, giving further credence to its role in enhancing
tumor growth. This finding provides insight into potential strategies for
slowing cancer growth

http://www.niehs.nih.gov/oc/news/diet.htm
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