IGF-1 is commonly known to help build muscle or something to avoid when dealing with cancer. However, IGF-1 is also crucial in healing and tends to be low in those with chronic inflammation. There are some surprising things that you didn’t know about IGF-1 here. Read more…
- 1 What is Insulin-Like Growth Factor 1?
- 2 IGF-1, Overall Health, and Longevity
- 3 The Good
- 3.1 IGF-1 May Be Anti-aging
- 3.2 IGF-1 Increases Antioxidants
- 3.3 IGF-1 Decreases Inflammation and Autoimmunity
- 3.4 IGF-1 is Good for the Brain
- 3.5 IGF-1 Creates Bigger Muscles and Reduces Muscle Wasting
- 3.6 IGF-1 Improves Blood Sugar Balance
- 3.7 IGF-1 Protects against Heart Disease
- 3.8 IGF-1 Promotes Growth/Height
- 3.9 IGF-1 Helps Bone Density
- 3.10 IGF-1 Helps Your Gut
- 3.11 IGF-1 Might Help Clear Bacterial Infections
- 3.12 IGF-1 Boosts The Immune System
- 3.13 IGF-1 Helps With Electrolyte Balance
- 3.14 IGF-1 is Good For Skin
- 3.15 Other
- 4 The Bad
- 5 Ways to Increase IGF-1
- 6 Ways to Inhibit IGF-1
What is Insulin-Like Growth Factor 1?
Growth Hormone, made by the pituitary gland, stimulates the liver to produce IGF-1 and IGF-1 subsequently stimulates growth in cells throughout the body, leading to growth and development (as in the womb and through adolescence), strengthening of tissues (improving bone density, building muscle), and healing (skin, bones, gut lining, etc.), depending on what the body needs (R).
IGF-1 is so crucial to development that if it is not present in adequate amounts during the time when a child is developing, a short stature may result.
IGF-1, Overall Health, and Longevity
In several organisms such as fruit flies, worms, and rats, IGF-I is involved in the control of lifespan (R).
However, in humans, the association between IGF-I levels and life expectancy doesn’t hold up (R).
Unlike lab animals, humans are exposed to various infections, stress, and other environmental factors that IGF-1 might help.
Several population-based studies describing a relationship between IGF-I and risk of dying were published with conflicting results. Two studies showed higher risk with higher IGF-I levels, while three showed higher risk with lower IGF-I levels. And in six studies there was no clear association at all (R).
Overall, however, having either low or high IGF-1 increases risk of dying from all causes (R).
In a meta-analysis of twelve studies done in 2011 with 14,906 participants, the risk of dying from all causes was increased in subjects with low as well as high IGF-1 levels (R).
People with low IGF-1 were at a 1.27X increased risk of dying from all causes, while those with higher levels were at a 1.18X increased risk (R).
I would say that when you look at all of the evidence, low IGF-1 levels are more likely to be a concern than high IGF-1 levels, but you still want to strike a balance (R).
The activity of IGF-I is influenced by at least six binding proteins (IGFBP). The most abundant is IGFBP-3, which binds more than 90% of IGF-1 in the circulation. Although IGF-I and IGFBP-3 are typically well correlated, there is speculative evidence that IGF-1 has an independent impact on disease risk, for example, on cancer (R).
When it comes to cancer, it’s probably better to err on having IGF-1 lower than higher (but not low).
IGF-1 May Be Anti-aging
The length of telomeres in the DNA have shown to be important predictors of longevity. IGF-1 has been shown to correlate with greater telomere length in healthy subjects of all ages (R) and in elderly men, in another study (R).
In the famous Framingham Heart Study of 525 people between the ages of 72 and 92, greater levels of IGF-1 were associated with decreased risk of dying in the next 2 years (R).
IGF-1 helps prevent age-related cognitive decline by promoting new cell growth in the brain (in rats) (R).
Critically ill patients tended to have lowered IGF-1 levels (R).
IGF-1 Increases Antioxidants
It protects cells exposed to radiation, by preventing cell death and increasing the antioxidant status (R).
The negative to this is that if you have cancer and take chemotherapy, it may potentially protect cancer cells from dying as well.
IGF-1 Decreases Inflammation and Autoimmunity
In mouse models of autoimmunity and brain inflammation, administration of IGF-1 delayed disease onset; however, giving IGF-1 after the disease had developed led to enhanced worsening of the disease (R).
IGF-1 is Good for the Brain
It speeds up mental processing in a study of 25 older men (R).
ALS is associated with lower IGF-1 (R).
IGF-1 Creates Bigger Muscles and Reduces Muscle Wasting
IGF-1 Improves Blood Sugar Balance
Lower IGF-1 is associated with Metabolic syndrome (R).
IGF-1 Protects against Heart Disease
Cardiovascular disease (coronary artery disease, fatal ischemic heart disease, ischemic stroke, congestive heart failure, as well as slower recovery after a heart attack) is associated with reduced IGF-1 (R).
Lower IGF-1 levels were associated with higher risk of stroke in a study of a Chinese population (R).
IGF-1 Promotes Growth/Height
Growth Hormone’s (GH) activity in the body is dependent on IGF-1. So, IGF-1 deficiency causes insensitivity to GH and its effects on growth and repair.
IGF-1 helps restore height in children with IGF-deficiency (R).
Poor growth of an infant in the womb can be due to lowered IGF-1 (R).
IGF-1 Helps Bone Density
We know that IGF-1 is a direct promoter of bone growth (R).
However, IGF-1’s muscle-building (anabolic) effect may also promote bone density, since increasing muscle mass, in turn, requires greater bone strength (R).
IGF-1 Helps Your Gut
In animal models of colitis, burns and jaundice, treatment with IGF-1 improved gut health. It stimulated mucosal DNA and protein content and drastically reduced the incidence of bacterial translocation (R, R2, R3).
In animal models of small bowel transplantation, IGF-I improved the mucosal structure and absorptive function and reduced bacterial translocation (R).
Infants with gut permeability showed faster healing times when given IGF-1 (R).
IGF-1 Might Help Clear Bacterial Infections
IGF-1 Boosts The Immune System
IGF-I drives B-cells to multiply (R).
IGF-1 Helps With Electrolyte Balance
IGF-1 is Good For Skin
Reviving stagnant collagen synthesis can help protect skin against aging (R).
Insulin-like growth factor-I (IGF-I) is the most potent stimulator of collagen biosynthesis and may help prevent skin aging (R).
IGF-1 and growth hormone inhibit urea synthesis (R), which may cause lower blood urea nitrogen. Growth Hormone-deficient children given human growth hormone results in lower urea nitrogen and this is due to decreased urea synthesis (R).
Advanced liver cirrhosis correlates with low IGF-1, in adults (R).
Because IGF-1 stimulates growth, it can have negative effects on someone who is prone to cancer.
IGF-1 exerts powerful effects on each of the key stages of cancer development.
It increases cellular proliferation, angiogenesis, and metastasis and reduces cell death (apoptosis). It also can lead to resistance to chemotherapeutic agents (R).
When it comes to cancer, not only is IGF-1 important but so is IGF-1 binding protein (IGFBP), which blocks the effects of IGF-1.
So it’s the ‘free’ levels of IGF-1 that are most important.
IGF-1 May Contribute to Cancer Development
A review of 17 studies found that IGF-1 is positively associated with breast cancer risk, taking levels of IGF binding protein (IGFBP3) into account, due to its effects on estrogen-sensitive tumors (R).
However, another study found that both low and high IGF-1 increased the chance of dying from cancer (R).
NOTE: Studies are unclear. Some take into account IGF-binding protein 3, and some do not. IGF-binding protein 3 (IGFBP3) is supposed to keep IGF-1 levels in the body in balance. When IGF binding protein (IGFBP) levels are low, free IGF-1 is unchecked and can cause growth that is out of control. That’s where cancer may come in. In most cases, elevated IGF-1 is associated with a reduced cancer risk more than an elevated risk (R).
IGF-1 Contributes to Acne
Ways to Increase IGF-1
If you have low IGF-1 levels, you might want to focus a bit more on things that increase IGF-1, especially if you’re genetically predisposed to autoimmunity.
- Caloric intake
- Dietary Protein (R)
- Fat (R) – also, higher saturated fat was associated with lower IGFBP3.
- Red meat (association) (R)
- Dairy or Calcium (R)
- Increased intake of Casein (found in milk) [R].
- Increased intake of Blueberries [R].
- Growth Hormone (R, R)
- Estradiol (R)
- Cortisol (R)
- DHEA (R)
- Parathyroid Hormone (R)
- Prolactin (R)
- Resveratrol – increases IGF-1 in the memory center (hippocampus) of the brain (R)
- Cinnamon (skin) (R, R)
- Leucine (R)
- HMB (Leucine-derivative) (R)
- Zinc (R), (R2), (R3) – In humans, low zinc is associated with low IGF-1, even in the presence of adequate caloric intake. Some studies suggest that zinc potentiates the action of IGF-1 [R].
- Magnesium (R) – magnesium levels were strongly and independently associated with IGF-1 levels (R).
- Selenium (R, R2)
- Astragalus (R, R)
- Eleuthero (R)
- Ursolic acid (muscle) (R)
- Carnitine ( muscle) (R).
- Velvet Antler (R, R2).
- Soy isoflavones (R),
Ways to Inhibit IGF-1
If you have high IGF-1 levels, you might want to focus a bit more on things that inhibit IGF-1, especially if you’re genetically predisposed to cancer.
- Fasting (R), especially prolonged fasting (R)
- Carbs – Higher dietary proportion of carbohydrates is associated with lower IGF-1 (R)
- Protein restriction (R)
- Calorie restriction (R)
- Intense walking (R)
- Thyroid hormones – Thyroid hormones decrease IGF-1 (R).
- Legumes (R)
- Royal jelly (R)
- Glucosamine (R)
- Bilberry (R)
- Luteolin (R)
- Curcumin (R)
- Resveratrol (Grapes -especially the skin, mulberries, peanuts) (R). Inhibits IGF-1 in intestinal cells, reducing collagen formation that might otherwise lead to scarring and narrowing of the intestinal passageway. (Resveratrol increases IGF-1 in the brain –see below).
- Apigenin (R, R2) –in a study of human prostate cancer.
- Lycopene (Tomatoes, guava, rosehip, watermelon, papaya, apricot, pink grapefruit) (R)
- EGCG (Green tea) (R)
- Boron (fruits & vegetables, raisins, prunes, nuts, legumes) – reduces free IGF (R)
- Genistein (Soybeans and soy products, red clover, and Sicilian pistachio) (R)
- Inflammation: Histamine (R), TNF-a (R), IL-6 (R), IL-1-alpha (R)….the negative effect of IL-6 on muscle function may be caused by lower IGF-1 [R].
- Tamoxifen (R)