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A modest suppression of growth hormone and a related insulin-like growth factor (IGF-1) may delay the onset or progression of several kinds of cancer, researchers from Wake Forest University School of Medicine reported at the Endocrine Society Annual Meeting in San Diego.*
“This study is important because lately a lot of ‘anti-aging’ businesses, particularly on the Internet, have touted the seemingly limitless benefits of taking growth hormones, from weight loss to a better sex life. But the scientific support for these claims is questionable at best,” states Jeffrey Novick, MS, RD, LV/N, Director of Nutrition at the Pritikin Longevity Center.
“Far more substantive is the data, like this study from Wake Forest University, showing that less growth hormone and less IGF-1 means less cancer, so why would anyone risk their health by taking human growth hormones?”
IGF-1
Based on a study of rats, lead investigator William E. Sonntag, PhD, and colleagues at Wake Forest found that reduced levels of IGF-1 reduced cancer risk by about 45% and decreased cancer deaths by 12 to 15%.
Cancer risk increased when the animals were given growth hormone, which elevates levels of IGF-1 levels in the blood.
A small amount of IGF-1, naturally produced by the body, appears harmless, noted Dr. Sonntag. The key roles of IGF-1 are increasing cell growth and preventing cell death. But too much IGF-1 might be dangerous. “Elevated IGF-1 levels in pre-menopausal women have been demonstrated to be a risk factor for breast cancer, as well as numerous other cancers,” stated Dr. Sonntag.
Elevated levels of IGF-1 may also increase the risk of prostate cancer. In the Physicians Health Study, an on-going analysis of more than 4,000 male health professionals, Harvard researchers found that the higher the levels of IGF-1 in the blood, the greater the likelihood that the men would get prostate cancer. **
Low-Calorie Diet
“Low-calorie diets,” said Dr. Sonntag, “can reduce IGF-1 levels in the blood.” The Pritikin Pritikin, which focuses on low-calorie-dense but nutrient-rich foods like fruits, vegetables, and whole grains, has been found to lower IGF-1 levels in men. In one study, UCLA scientists took blood samples of 14 men before and after attending a 13-day program at the Pritikin Longevity Center. Compared to the “pre-Pritikin” samples, the “post-Pritikin” samples showed a 20% drop in IGF-1 levels. ***
* http://www1.wfubmc.edu/News/NewsARticle.htm?ArticleID=1619
** Science, 1998; 279: 563.
*** Cancer Causes and Control, 2002; 13(10): 929.
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