IGF-1:  The Most Important Hormone You’ve Never Heard Of

“Doctor Jones, how did my test results turn out?  I can’t understand why I’m gaining weight, feeling tired and achy.  I haven’t changed my diet or exercise habits at all, yet it seems like I’m falling apart.”

“Well Mr. Smith, everything I’ve checked you for is normal – blood count, metabolic profile, urinalysis, thyroid – everything’s OK.  Your metabolism is slowing down.”

“But what else can I do Doc?  My wife and I are trying to eat better and exercise, but we’re just not getting the same response as we used to.  We’re turning into our parents and grandparents, and we don’t like the changes anymore than they did!”

“Sorry Mr. Smith, there’s nothing more for me to check.  That’s just what happens with age.”

            The goals of this article are to further explain why “your metabolism is slowing down,”  to learn more about an invaluable hormone with a funny name, and learn more about how we can increase our levels of this hormone.

            When we think about how our metabolism affects us, we normally think of our ability to optimize our weight.  Other than the amount we exercise, we frequently attribute our natural metabolism to our thyroid levels.  Although there are people with low thyroid, and benefit from thyroid replacement, doctors and patients alike frequently stop here when addressing this important issue.  The most important biologic reason for the age-related increase in fat, decrease in muscle mass, degenerative disc disease, arthritis, hearing impairment, thinning skin, and memory impairment is the age-related decline of the hormone insulin-like growth factor-1 (IGF-1).

            IGF-1 is given its silly name only because structurally it looks like insulin, but the similarity ends there.  This hormone, made in the liver, has its highest activity in adolescence, when it is the primary controlling factor of the growth of our muscles and bones (thus its name).  It is in our body throughout our lives, and its levels perfectly correlate with the function and “metabolism” of our body.

            Do levels of IGF-1 correlate with our body fat percentage, muscle mass, IQ, cardiovascular health, hearing, joint and disc health, skin thickness, bone density and fracture rate, energy level, stamina, cognition, and feeling of well-being?  Can increasing our IGF-1 levels improve all these factors?  Study, after study, after study, the answer is an unequivocally, scientifically well documented YES.

            What are ways we can increase our IGF-1 levels?  No discussion about IGF-1 can be complete without discussing the most effective way (by far) to increase its levels.  It’s the same way our body does it – increase growth hormone levels.  IGF-1 production is directly under the control of growth hormone.  In fact, very little of the effect of growth hormone has on our bodies comes directly from growth hormone – the majority of it comes directly from IGF-1.  If we increase our growth hormone levels, we increase our IGF-1 levels.

            The most effective way to increase our growth hormone and IGF-1 levels (but not the only way) is by injecting ourselves with growth hormone.  Thousands of people who wish to slow down the deleterious processes we normally attribute to aging do it every day.  It’s not rocket science -- it’s no different than injecting insulin.

            The prescription and use of growth hormone is a hot topic of medico-legal controversy.  It’s beyond the scope and intentions of this article.  Let’s focus on some scientifically documented ways of increasing IGF-1 levels without the use of growth hormone.

            Lifestyle factors that increase IGF-1:  low-fat, low-sugar diets; brief, intense exercise (not aerobic exercise lasting over one hour); not eating carbohydrates within 4 hours of bedtime.  Yes, all the things your mother and your doctor have told you to do – you still need to do (surprise, surprise)!  Another factor that increases IGF-1 is the correction of significant snoring (sleep apnea).

            Foods and supplements that increase IGF-1:  whey protein; creatine (5 grams per day);   dairy products (although this may be from the whey protein in milk)

            Medicines that increase IGF-1:  Aricept, Exelon (These are medicines used for Alzheimer’s disease.  Although they may help these patients by increasing their IGF-1 levels, these medicines are not indicated for use by anyone other than those with Alzheimer’s disease.)  Please note – oral estrogens decrease IGF-1 levels, but transdermal estrogens do not.

            Insurance companies usually pay for a blood test checking your IGF-1 level if your doctor codes for the diagnosis of fatigue.  An ideal IGF-1 level is around 350.  A suggestion has been made that an IGF-1 level below 84 may qualify for the formal diagnosis of Adult Growth Hormone Deficiency Syndrome.  Links to studies verifying the information contained in this article can be found at www.drragno.com, or probe more into it on PubMed, the website service of the National Library of Medicine and the National Institutes of Health.