Isolated protein, especially soy protein powder, is popularly blended into shakes and smoothies, but is this a healthful way to build muscle?
The Problem With Protein Powders
Protein intake, especially animal protein, is known to be the major dietary determinant of circulating IGF-1 levels. When we consume animal protein, the body increases its production of a hormone called IGF-1 (insulin-like growth factor 1). IGF-1 is one of the body’s important growth promoters during childhood, but later in life IGF-1 promotes the aging process.
IGF-1 has been shown to promote the growth, proliferation and spread of cancer cells, and elevated IGF-1 levels are linked to increased risk of several cancers.3-7 Our society’s obsession with over-consuming protein is a contributing factor to our epidemic of cancer. In addition to the issue of IGF-1 and cancer, excess protein may negatively affect calcium stores, kidney function and bone health, and promote cardiovascular events.8-10