A hormone called growth hormone-releasing hormone (GHRH) appears to have the ability to improve brain function in healthy older adults, as well as in people who show early signs of cognitive decline. Preliminary research published in the Aug. 6, 2012 issue of the Archives of Neurology suggests that daily doses of GHRH may trigger a cascade of brain effects associated with improvements on tests of memory and focus. The study’s lead author explained, “Growth hormone-releasing hormone doesn’t target one specific area in the body and brain. It stimulates a whole cascade of hormones in the body and brain. It stimulates normal function of a system that was working at a younger age so that cells can do what they were programmed to do at birth.”
“In the brain, a relative deficiency of GHRH—which is a normal consequence of aging in most individuals—results in lower levels of human growth hormone (HGH) and insulin-like growth factor 1,” explains Karen Klahr Miller, MD, a neuroendocrinologist at Massachusetts General Hospital (MGH) and an Associate Professor of Medicine at Harvard Medical School. “Decreases in levels of these peptides are common in people with Alzheimer’s disease (AD), and may also be due to advanced age.”
The researchers set out to test whether administration of synthetic GHRH would improve the mental functioning of people with mild cognitive impairment (MCI), which is characterized by a noticeable decrease in memory and thinking skills that does not interfere with the ability to carry out normal daily activities. A group of 137 older adults—76 with normal cognition and 61 with MCI—were randomly assigned to receive daily injections of GHRH or a placebo. After 20 weeks, the performance on tests of mental abilities of both healthy and MCI participants who received GHRH was significantly better than that of participants who received placebo. Improvements in planning, organizing, focusing, and shifting from one task to another, as well as verbal memory were apparent over the course of GHRH treatment, but gradually declined after daily GHRH injections were stopped.
“This research suggests that GHRH injections may have a positive effect on cognitive performance, but although its findings are promising, they are very preliminary,” cautions Dr. Miller. “Larger and longer-duration treatment trials are necessary to determine whether the findings of this study can be replicated. Such studies may or may not lead eventually to clinically available therapies based on injections of GHRH.”
Boosting GHRH and HGH
The study does suggest, however, that GHRH may provide cognitive benefits in older adults. And it may be possible to enjoy at least some of these benefits right now through natural means.
GHRH, which is naturally produced by the brain’s hypothalamus, appears to accomplish many of its beneficial effects by stimulating secretion of human growth hormone from the pituitary gland at the base of the brain. Since HGH declines as GHRH production tapers off with age, building up HGH levels through non-drug strategies that directly or indirectly support the production of HGH by the pituitary gland may be one possible way of managing age-related symptoms in older adults.
“One important way to increase the production of HGH is to lose excess weight, especially visceral, i.e. belly, fat that surrounds the internal organs of the abdomen,” says Dr. Miller. “Belly fat is highly associated with decreased secretion ofHGH. In fact, obesity in general is a major cause of low HGH.
“Exercise is another natural way to increase levels of HGH. Regular workouts also have the added benefit of helping you burn off excess fat, including belly fat.”
To evaluate your level of belly fat, measure your bare belly around the waist at the navel with a cloth measuring tape after exhaling. For men, a measurement of 37 inches and below indicates a low level of belly fat, 37.1-39.9 inches is intermediate, and 40 inches and above is high. For women, 31.5 inches and below is low, 32.6-34.9 inches is intermediate and 35 inches and above is high.