Physiology 101

Insulin is the gatekeeper for glucose: it allows glucose to get inside the cells where it can be utilized for energy or for storage. When glucose gets used, your cells produce ATP (your body’s energy currency). When glucose gets stored, it gets stored as triglycerides (fat).

Insulin is necessary, of course. Without it, as in Type 1 Diabetes, glucose can’t get into the cells. Without adequate replacement, this leads to blood vessel damage, cardiovascular disease, kidney disease, etc. Too much insulin, on the other hand, means insulin resistance: your cells become desensitized to its signal. This too means too much glucose in the bloodstream and not enough in the cells, rendering you susceptible to the same complications. Eventually this can lead to Type 2 Diabetes.

Opposite insulin is Growth Hormone (GH). Growth Hormone allows kids to reach their full height, and it also enables muscle growth and repair. It primarily tells the liver to produce its messenger, Insulin-Like Growth Factor-1 (IGF-1)—so called because structurally, it is quite similar to insulin. It can even bind insulin receptors (though much less strongly than insulin, and it appears to have an opposite effect when it does so.)

The job of IGF-1 is to stimulate tissue growth (muscles, bones, etc). It also helps to keep inflammation in check. Low levels of IGF-1 is associated with high levels of inflammatory cytokines, which can perpetuate autoimmunity (and inflammation of all kinds. This may be part of the reason why eating too much sugar leads to inflammation!) Low GH and IGF-1 are also found in fibromyalgia, implying that pain may at least in part occur as a result of inability of the muscles to repair themselves.

When insulin is high, GH and IGF-1 are both low, and vice versa. They’re like a teeter totter.

How to Lower Growth Hormone and IGF-1 (and Raise Insulin)

For most of us, this is the opposite of what we want to do. Factors that raise insulin include:

  • High stress. Acute stress, and early stage adrenal fatigue both mean high cortisol. Cortisol mobilizes glucose from the liver. Glucose triggers insulin, and lowers Growth Hormone. So when stress is high, it’s unlikely you’ll be able to bulk up at the gym like you’re used to.
  • High sugar intake. Eating lots of sugar spikes your glucose, which spikes your insulin. This, too, lowers Growth Hormone. (This means, too, that poor glucose regulation and insulin resistance in kids can adversely affect growth.)
  • High Growth Hormone itself. The body’s delicate hormone balance relies on feedback mechanisms: too much of any one hormone leads to feedback inhibition of itself. It’s like a rubber band snapping back. Pretty smart, actually. 

The Upshot: How to Lower Insulin (and Raise Growth Hormone and IGF-1)

If you’re looking to help your child achieve full stature, build muscle mass, or repair muscle damage, Growth Hormone and IGF-1 are your friends. To lower insulin (and increase Growth Hormone), you can:

  • Lower your blood sugar. In between meals, when blood sugar naturally falls, Growth Hormone also naturally rises. (This is why Growth Hormone rises during sleep; see bullet point 4.) To mimic this process, both intermittent fasting and ketosis work well, but they can be pretty intense. If you typically eat a Standard American Diet, even just eating like this will go a long way. (And if you’re looking to optimize your child’s growth, I’d certainly go for the Basic Healthy Eating plan.)
  • Eat plenty of protein. Protein not only stabilizes glucose levels, it also serves as the building blocks for cellular growth (since we’re made of protein ourselves). Furthermore, protein directly raises IGF-1 levels. 
  • Get plenty of sleep.  As mentioned above, the majority of Growth Hormone is released in the deeper stages of sleep. (This is part of the reason why fibromyalgia is often considered primarily a sleep disorder: lack of sleep means lack of GH, which means lack of muscle repair.) Growth Hormone declines as morning approaches, and cortisol rises, spiking glucose and therefore insulin.
  • Exercise. Particularly resistance exercise is great for muscle building. It also therefore lowers insulin and raises Growth Hormone.
  • Get your micronutrient levels checked. Zinc, magnesium, and selenium levels are significantly correlated with IGF-1 activity. If levels of any of those nutrients are low, supplementation will assist with raising Growth Hormone and IGF-1 levels.