Growth Hormones and Intelligence
A team of scientists from the University of Bristol in the United Kingdom has published research that seems to show a link between the hormone insulin-like growth factor 1 (IGF-1) and a child’s IQ. IGF-1 has been a big interest of mine for many years. It’s production is primarily stimulated by growth hormone, particularly in the liver. At one time it was known as somatomedin. But IGF-1 is also produced and has important actions in the brain. The production of IGF-1 falls dramatically when people are malnourished, and it has been suggested that one of the primary problems in Alzheimer’s disease is malnutrition that then causes a fall in IGF-1 levels in the brain.
It has long been known that babies of low birth weight develop more slowly, and that shorter children often do worse in school. It was always assumed that their poor performance in school was because they were picked on or bullied, or because they felt the need to compensate for their height in some way. But it may be that there is also a physical component to this association between height and intelligence.
The researchers examined 547 children who completed and intelligence test at the age of eight. At the same time they measured the circulating levels of IGF-1 in their blood. They found a link between higher levels of IGF-1 and higher IQ. This study will be the first of many, but it provides some preliminary evidence that IGF-1 plays an important role in the development of the human brain, and may underlie the associations between birth weight, height and IQ.
A study from Holland provides further support for this link: 74 low birth-weight children were treated with growth hormone and followed up over two years. Not only did the children grow, but also their intelligence increased.
This work is also important because it shows one of the likely results of malnutrition is an impairment in the development of the brain.
Would there be any point in adults taking growth hormone to improve brain function? Despite the claims made in some popular books, the answer to that one is probably no. We know a great deal about the consequences of hyper-secretion of growth hormone in adults: it occurs in several illnesses, the most common is called acromegaly. Intelligence has not been examined systematically in people with acromegaly, but after seeing a great many people suffering from the condition, unusually high intelligence has not often been a feature. And there has been research on measuring IQ after giving growth hormone to people with an array of medical conditions. It only seems to help people who are actually deficient in the hormone.
And I’d just like to point out that the association between height, achievement in school and success in life is quite weak. Think Napoleon Bonaparte and Alexander the Great.
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Dr. Richard G. Petty, MD is a world-renowned authority on the brain, and his revolutionary work on human energy systems has been acclaimed around the globe.
He is also an accredited specialist in internal and metabolic medicine, endocrinology, psychiatry, acupuncture and homeopathy. He has been an innovator and leader of the human potential movement for over thirty years and is also an active researcher, teacher, writer, professional speaker and broadcaster. He is the author of five books, including the groundbreaking and best selling CD series Healing, Meaning and Purpose. He has taught in over 45 countries and 48 states in the last ten years, but spends as much time as possible on his horse farm in Georgia.
