Hormone Shots Boost Brain Function in Older Adults
The phrase a shot in the arm was first coined around the beginning of the 20th century and was used to mean a stimulus or boost. Older adults who participated in a recent study at the University of Washington School of Medicine in Seattle found that a daily hormone shot gave them a boost in brain function when compared with placebo.
Brain power and memory improve with hormones
It's well established that the levels of certain hormones decline as people age, and some of these hormones are taken by individuals who are trying to fight the aging process. One of those hormones is growth hormone-releasing hormone (GHRH), also known as growth hormone-releasing factor.
GHRH is a neurohormone produced by the hypothalamus, a region deep in the brain. When people are young, the hypothalamus produces a sufficient amount of GHRH, which in turn stimulates release of growth hormone from the pituitary gland, which resides at the base of the brain.
Around middle age, however, the level of GHRH declines and therefore so does the production of growth hormone from the pituitary. Some research has indicated that older adults who take injections of human growth hormone may fight the aging process by enjoying an increase in bone density and muscle mass along with a decrease in body fat.
In this new study, investigators found that daily injections of growth hormone-releasing hormone during a five-month period could battle another segment of the aging process: the injections boosted brain function, including memory, in healthy older adults as well as those who had mild cognitive impairment.
Three hormones are involved: the injection of GHRH stimulates release of growth hormone, which then triggers the release of insulin-like growth factor 1. All three of these hormones decline with age, have a role in brain function, and "likely play a role in the pathogenesis of Alzheimer's disease," according to Laura Baker, PhD, and her colleagues.
A total of 137 men and women ages 55 to 87 years completed the 20-week study. Of these, 76 were healthy volunteers and 61 had mild cognitive impairment. The participants were randomly assigned to take a placebo or tesamorelin (Egrifta), a stabilized analog of human GHRH, via subcutaneous injection which each participant administered him or herself.
To determine if the hormone had any impact on cognitive function, all the participants underwent standard tests at the beginning of the study, at weeks 10 and 20, and again after a 10-week washout period (week 30). Blood tests were conducted to track levels of the hormones.
Here is a summary of what the researchers found.
- Use of GHRH raised levels of insulin-like growth factor 1 significantly, by an average factor of 2.17. According to a recent study from Mayo Clinic (Jacksonville), the authors reported that "IGF-1 contributes to information processing in the brain" and that "further studies that detail the specific actions of this important neurotrophic hormone will likely lead to therapies that result in improved cognitive function for the elderly patients."
- GHRH significantly improved cognition overall, and the improvement was comparable among healthy subjects and those with mild cognitive impairment
- GHRH significantly improved executive function (mental processes that help people plan, organize, strategize, pay attention to and remember details, manage time and space) and seemed to improve verbal memory, but it had no effect on visual memory
- GHRH reduced body fat by 7.4% overall and raised fasting insulin levels by 35% among people with mild cognitive function
- Side effects, mostly mild, occurred in 68% of subjects who took GHRH versus 36% who received placebo. Nausea, vomiting, and changes in taste are the most common adverse reactions associated with GHRH
Much research has explored the effects of GHRH, growth hormone, and insulin-like growth factor 1 on brain function, and most of the studies have been conducted in animals or in adults with growth hormone deficiency or brain injury. A study reported last year in Brain Injury, for example, noted the effect of growth hormone treatments on cognitive abilities of patients with cognitive disorders after brain trauma.
In that study, patients who received growth hormone experienced a significant improvement in cognitive function, including vocabulary, understanding, verbal IQ, and total IQ. The authors also noted that IGF-1 levels improved, likely as a result of treatment with growth hormone.
While research into the effects of GHRH and growth hormone in animals and individuals with growth hormone deficiency or brain trauma are important, the impact of these hormones on healthy older adults and those at risk for cognitive decline demands further investigation. As the authors of this latest study concluded, "Larger and longer-duration treatments trials are needed to firmly establish the therapeutic potential of GHRH administration to promote brain health in normal aging and 'pathological aging.'"
Baker LD et al. Effects of growth hormone-releasing hormone on cognitive function in adults with mild cognitive impairment and healthy older adults: results of a controlled trial. Archives of Neurology 2012; 69(8): 1-10
Deak F, Sonntag WE. Aging, synaptic dysfunction, and insulin-like growth factor (IGF)-1. Journals of Gerontology. Series A. Biological Sciences and Medical Sciences 2012 Jun 67(6): 611-25
Reimunde P et al. Effects of growth hormone (GH) replacement and cognitive rehabilitation in patients with cognitive disorders after traumatic brain injury. Brain Injury 2011; 25(1):65-73.
This page is updated on May 11, 2013.