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Milk consumption increases IGF-1 serum levels
High milk consumption is associated with a 10–20%
increase in circulating IGF-1 levels among adults and a 20–
30% increase among children (77–80). In 2109 European
women, serum IGF-1 levels were positively related with the
intake of milk (81). Milk and dairy products increase IGF-1
levels more than other dietary sources of protein such as
meat (78). Moreover, milk consumption raises the ratio of
IGF-1 ⁄IGFBP-3 indicating an increased bioavailability of
IGF-1. Prolonged consumption of ultraheat-treated (UHT)
milk shifts the GH ⁄IGF-1 axis in children to higher levels
(82). After a month of drinking 710 ml of UHT milk daily,
Mongolian children, who had not previously consumed
milk, had a higher mean plasma level of IGF-1, higher
IGF-1 ⁄IGFBP-3 and GH levels (82). Their mean serum
IGF-1 levels were significantly raised after 4 weeks of milk
consumption by 23.4% (82)
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IGF-1 and Animal Protein
One thing that many bodybuilders and gym rats assume prima facie is that the natural (sans steroids) bodybuilding lifestyle is the ultimate and ideal in healthy living. There is definitely much truth to this as muscle is a great calorie-burner, improves appearance and self-image and many other important physiological factors. However, there is a dark side to bodybuilding that few discuss: animal protein and its impact on IGF-1.
The rule of thumb for bodybuilding is at least 1.0 g of protein per pound of weight. Thus, an 180 pound guy would need to consume about 180 g of protein per day. That's a lot of protein and - let's face it - that's probably anything but "natural". And, as I document in Muscle Madness link, eating meat, casein and soy can easily lead to cancer and heart disease (from the Saturated Fat)), inflammation and brain shrinkage.
Even worse, there is a substantial body of research that shows that animal protein leads to increased levels of IGF-1. IGF-1 is Insulin-like Growth Factor and is one of those things, like folate, in the human body that stimulates growth and tissue development. This may sound good, except that both IGF-1 and folic acid have numerous studies linking them with cancer. Yes, they stimulate growth of both good and bad cells and that can lead to an early and painful death if one is not careful.
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