One of the master regulators of the human body is the growth hormone/IGF-1 axis. This axis is controlled by the pituitary gland, which releases growth hormones. Growth hormone triggers the production of IGF-1, and together, GH and IGF-1 coordinate the growth, rejuvenation, and rebuilding of the human body.
What is IGF-1?
Insulin-like growth factor 1 (IGF-1) is a hormone with a structure resembling insulin, but it has a completely different function. IGF-1 interacts with growth hormone to promote the growth of bones and tissues in children and maintain homeostasis of the tissues in adults.
In children, IGF-1 levels are high during growth spurts in childhood and adolescence in response to high levels of growth hormone. Together, growth hormone and IGF-1 promote the growth of the bones, muscles, skin, brain, and other tissues as children develop into adults.
In adults, homeostasis of the body is maintained by a balance between anabolism (building up) and catabolism (breaking down). When the body is in perfect balance, the process of breaking down old, damaged structures exactly matches the process of synthesizing new, fresh structures as replacements. IGF-1 participates in this process by promoting anabolism throughout the body.
Risks of low levels of IGF-1
It is normal for IGF-1 levels to slowly decline starting in the third decade, leading to very low levels in people in their 80s and 90s. This gradual decline has no functional consequences. However, after adjusting their IGF-1 levels for their age, some people have abnormally low levels of IGF-1, which has many adverse effects.
Loss of muscle mass
The adverse effects of having a low IGF-1 level are related to its anabolic properties. IGF-1 promotes growth of the tissues throughout the body. If its levels are low, individuals are likely to experience a loss of muscle mass. Although it is normal for muscle mass to decline with age, regular exercise can halt and even reverse this effect. However, individuals with low IGF-1 levels find it difficult to build or even maintain their current muscle mass.
Loss of bone density
Similarly, as individuals age, the rate at which their bone breaks down can exceed the rate at which new bone is formed, leading to a loss of bone density. Regular exercise that places mild stress on the bones can promote the formation of new bone, stopping and even reversing the decline of bone density with age. However, since IGF-1 is required to promote the production of new bone, individuals with low IGF-1 levels invariably suffer from a gradual decline in bone density.
Glucose intolerance and type 2 diabetes
The insulin and IGF-1 axes are interrelated and work together.1 IGF-1 is involved in obesity, insulin resistance, and type II diabetes. People with low levels of IGF-1 are at increased risk of developing glucose intolerance and type 2 diabetes. In people who already have type II diabetes, low levels of IGF-1 are associated with increased severity of the complications of diabetes, such as neuropathy. Increasing the levels of IGF-1 in people with diabetes reduces insulin resistance in their peripheral tissues and improves their serum lipid profile.
Altered lipid levels and cardiovascular disease
Low IGF-1 levels are also linked to cardiovascular disease. The lower the IGF-I level, the higher the risk of stroke, heart attack, and death from cardiovascular disease. This well-established correlation is thought to primarily be related to the growth-promoting effect IGF-1 has on the linings of blood vessels.2 Lesions in the walls of blood vessels characterized by inflammation, thickening, and the deposition of lipids are the underlying cause of strokes and heart attacks, and these lesions are caused by dysfunction of the endothelial cells lining the walls of blood vessels. IGF-1 promotes the growth of robust, healthy blood vessel walls.
As noted above, increased IGF-1 levels have been clinically and experimentally linked to an improved blood lipid profile. The exact mechanism underlying this effect is unclear, but it may be related to IGF-1 reducing fat production in the liver. An improved lipid profile would also be expected to reduce the risk of stroke and heart attack.
How to increase IGF-1 hormone naturally? It is possible to induce your body to increase its production of IGF-1 through natural means. Some lifestyle changes that have been clinically demonstrated to elevate IGF-1 levels include:
- Consuming more protein
- Eating more fiber
- Eating frequently
- Taking selenium and coenzyme Q10 supplements
- Getting plenty of sleep
Sleep deprivation, eating low levels of protein, and fasting have all been shown to reduce IGF-1 levels, and eating fiber has been shown to increase IGF-1 levels. Thus, a dietary pattern consisting of eating a high-fiber diet and frequently snacking on high-protein foods while getting plenty of rest is an easy way to naturally increase IGF-1 levels. In addition, a clinical study showed that taking selenium and coenzyme Q10 supplements significantly increased IGF-1 levels.3 Doctors think that many of the well-known benefits of coenzyme Q10 supplements, such as a decreased risk of death from cardiovascular events, may be mediated through an increase in IGF-1.
What are the effects of IGF-1 on the body?
Restoring IGF-1 levels to their normal level would be expected to have many healthful effects on the body:
- Improved heart health
- Increased muscle mass
- Denser bones
- Reduced blood sugar
- Better brain health
- Overall anti-aging effect
Most of these effects have been discussed above. Once IGF-1 levels have been restored to normal, the body will respond to exercise by building bone density and muscle mass. Insulin resistance will decline and the linings of the blood vessels will regenerate, reducing the risk of cardiovascular disease. A side effect of improved blood circulation and reduced glucose levels is improved cognition and brain health. Overall, a normal level of IGF-1 promotes growth and renewal of all parts of the body, which has a health-promoting and anti-aging effect.
Conclusion
IGF-1 is a vital anabolic hormone produced by the human body that affects every cell, tissue, and organ. Its levels naturally decline as people age. However, some people have abnormally low levels of IGF-1 even after adjusting for their age. Low levels of IGF-1 have many adverse consequences, such as reduced muscle mass and increased risk of heart disease and diabetes. Thankfully, there are simple lifestyle changes you can make to restore your IGF-1 levels to normal.
