Insulin-like Growth Factor 1 (IGF-1) is an insulin-like hormone primarily produced by the liver. Its production is stimulated by growth hormone from the pituitary gland. IGF-1 is important for normal growth and development, particularly during childhood and adolescence. In adults, it supports muscle strength and bone development. Dietary choices can influence IGF-1 levels.
Health Implications of Elevated IGF-1
While IGF-1 is a natural hormone, persistently elevated levels in adulthood can have health implications. This hormone promotes cell growth and proliferation, and it can also inhibit programmed cell death. Such sustained cellular activity may contribute to the progression of certain cancers.
Studies indicate an association between higher IGF-1 levels and an increased risk of developing specific cancers, including those of the breast, prostate, and colon. Research also suggests links to lung cancer. Consistently elevated IGF-1 levels have been connected to higher overall mortality rates from cancer.
Beyond cancer, elevated IGF-1 has been implicated in accelerated aging processes. Studies suggest an inverse relationship between high IGF-1 levels and lifespan. Maintaining moderate IGF-1 levels may support healthy aging by moderating tissue turnover and minimizing DNA damage.
Foods Associated with Higher IGF-1
Dairy Products
Dairy products, particularly cow’s milk, have been linked to increased IGF-1 levels. Dairy proteins like casein and whey are rapidly digested and absorbed. These proteins provide amino acids that stimulate IGF-1 production.
Certain dairy products may also contain growth-promoting hormones, like recombinant bovine growth hormone (rBGH or rbST), which can further amplify IGF-1 production. Research indicates that individuals with high dairy intake exhibit IGF-1 levels 10% to 20% higher than those with low intake. Some studies have even reported increases of up to 61% in IGF-1 levels from milk consumption.
Analysis showed that protein from milk and yogurt was strongly associated with higher circulating IGF-1 concentrations. Conversely, protein from cheese did not show a similar association with elevated IGF-1 levels. This suggests the type of dairy product consumed may influence its impact on IGF-1.
Red and Processed Meats
High protein intake, especially from animal sources like red and processed meats, can lead to elevated circulating IGF-1. Red meat, including beef and pork, contributes to this elevation due to its protein density and high levels of specific amino acids. These amino acids, such as leucine, methionine, and arginine, activate pathways that promote protein synthesis and cellular growth, thereby stimulating IGF-1 production.
Frequent consumption of red meat, defined as more than five servings per week, has been correlated with IGF-1 concentrations 10% to 15% higher than in those with lower intake. Poultry and eggs, also concentrated sources of animal protein, contribute to IGF-1 levels. Regular chicken consumption can lead to IGF-1 elevations comparable to red meat, though often slightly lower.
Refined Carbohydrates and Sugar
Refined carbohydrates and added sugars contribute to higher IGF-1 levels indirectly, via insulin. Foods with a high glycemic index, such as white bread and white rice, are quickly absorbed, causing a rapid spike in blood glucose levels. This rapid increase prompts the pancreas to produce more insulin.
Elevated insulin levels can then signal the liver to produce more IGF-1. Sugar, specifically sucrose, is broken down into fructose and glucose upon absorption. Fructose is metabolized in the liver, which can delay glucose metabolism, resulting in persistently high blood glucose. This sustained high glucose further stimulates insulin and, subsequently, IGF-1.
Dietary Strategies to Manage IGF-1
Specific dietary patterns can help regulate IGF-1 levels. A predominantly plant-based, whole-foods diet has been consistently associated with lower IGF-1 concentrations. Individuals following a vegan diet often exhibit lower IGF-1 levels compared to those consuming meat or even vegetarian diets.
Plant-based foods typically have a lower protein density than animal-derived foods, and the amino acid profiles differ, contributing to this effect. A plant-based diet can also enhance the body’s ability to bind and remove excess IGF-1 from the bloodstream. Long-term adherence to such a diet has shown sustained reductions in IGF-1 levels.
Ample dietary fiber and specific compounds found in vegetables can also support IGF-1 management. Cruciferous vegetables, including broccoli, cauliflower, and kale, contain phytochemicals that have demonstrated anti-cancer effects. These vegetables can also help shift hormone metabolism, potentially influencing pathways related to IGF-1 activity.
Caloric restriction or intermittent fasting have also been explored for their impact on IGF-1. Studies indicate that fasting can reduce IGF-1 levels within a few days. Similarly, energy restriction, particularly when intake is reduced by 50% or more of daily requirements, can lead to a decrease in circulating IGF-1.