Vegan Diets: Igf-1 Levels And Health Benefits

Insulin-like Growth Factor 1 (IGF-1) is a hormone that plays a crucial role in the body's growth and development. While IGF-1 is essential for normal development during childhood, elevated levels in adulthood can have detrimental health effects, potentially increasing the risk of cancer. Dietary choices, particularly the consumption of animal protein, have been linked to increased IGF-1 levels. This has sparked interest in the impact of vegan diets, which exclude animal products, on IGF-1 levels and overall health.

Animal protein increases IGF-1 levels

Insulin-like Growth Factor 1 (IGF-1) is a hormone with a similar molecular structure to insulin. It is vital to childhood growth and encourages cell growth and proliferation in adults. It is naturally produced by the liver and its production is stimulated by growth hormones.

IGF-1 is associated with an increased risk of cancer. A typical Western diet, which is rich in dairy and sugar, shifts growth hormone and IGF-1 balance to abnormally high levels. A diet high in wholegrains, pulses, fruits and vegetables normalises the levels of these hormones and contains large amounts of natural antioxidants that can prevent free radical formation and reduce oxidative stress in the body.

Vegan diets are associated with lower levels of IGF-1 and higher levels of IGF-binding proteins 1 and 2 (these proteins limit the availability of IGF-1) compared with an omnivorous or even a vegetarian diet. As such, eliminating animal protein from the diet naturally decreases IGF-1 levels and therefore lowers the risk of cancer.

However, IGF-1 is also associated with a reduced risk of cardiovascular disease, stroke, heart attack, osteoporosis, and cognitive decline. Men with low levels of IGF-1 had a 45% increased risk of hip fracture. Higher IGF-1 levels also predicted a lower loss of lean muscle mass in ageing men.

Animal protein raises IGF-1 more than other foods, but this doesn’t mean meat is bad for you. Frequent exercise cuts the risk of cancers associated with IGF-1 to a much greater extent than cutting animal protein does.

Plant protein does not increase IGF-1 levels

Insulin-like growth factor-1 (IGF-1) is a hormone that is vital to childhood growth and encourages cell growth and proliferation in adults. While it is naturally produced by the liver, high levels of IGF-1 in adulthood can be detrimental to health as it can lead to uncontrolled cellular growth and proliferation, increasing the risk of cancer.

Animal Protein vs Plant Protein

Animal protein consumption has been linked to increased IGF-1 levels, which in turn, increases the risk of cancer and overall mortality. However, this is not the case with plant protein consumption. Research has shown that a vegan diet is associated with lower levels of IGF-1 and higher levels of IGF-binding proteins compared to an omnivorous or vegetarian diet.

The Impact of Diet on IGF-1 Levels

A study comparing the effects of animal versus plant protein intake on IGF-1 levels found that both diets induced similar and significant increases in IGF-1 levels, indicating that plant protein does not have a significant impact on IGF-1 levels. This finding is supported by another study that showed that a plant-based diet and regular exercise routine can lead to a drop in IGF-1 levels in just a few days.

The Link Between IGF-1 and Cancer

IGF-1 promotes each of the key stages of cancer development: the growth of cancerous cells, vascularisation of cancerous tissue, and metastasis. Therefore, diets that increase IGF-1 levels can be dangerous in terms of facilitating cancer growth. Eliminating animal protein from the diet and adopting a vegan diet can naturally decrease IGF-1 levels and lower the risk of cancer.

The Bottom Line

While animal protein consumption has been linked to increased IGF-1 levels, plant protein does not appear to have the same effect. A vegan diet is associated with lower IGF-1 levels and a reduced risk of cancer.

Dairy products increase IGF-1 levels

Dairy products have been found to increase IGF-1 levels. Milk and dairy products contain whey proteins, which cause a rise in insulin, IGF-1, and growth hormone levels. A typical Western diet, which is rich in dairy and sugar, shifts growth hormone and IGF-1 balance to abnormally high levels.

A study by Ventura et al. found that each 400g increment in daily dairy intake was associated with a 16.8 µg/L increase in IGF-1 concentrations. Similarly, each 200g increment in milk per day was associated with a 10.0 µg/L increase in IGF-1. These findings support the hypothesis that dairy and milk intake are associated with higher IGF-1 concentrations.

Another study by Melnik et al. concluded that Western diets, with a high intake of hyperglycemic carbohydrates and insulinotropic dairy, over-stimulate the insulin/IGF-1 pathway. They suggested that a Paleolithic diet, which excludes these food groups, may be beneficial in reducing IGF-1 levels.

Vegan diets, on the other hand, are associated with lower levels of IGF-1. A study by Barnard (2004) found that a diet high in wholegrains, pulses, fruits, and vegetables not only normalises IGF-1 levels but also contains large amounts of natural antioxidants that can prevent free radical formation and reduce oxidative stress in the body.

In summary, dairy products, particularly milk, have been shown to increase IGF-1 levels, while vegan diets are associated with lower IGF-1 levels and may be beneficial in reducing the risk of cancer and other diseases associated with high IGF-1 levels.

Excess soy may increase IGF-1 levels

While a vegan diet is associated with lower levels of IGF-1, certain foods may still cause an increase in IGF-1 levels. Dairy products and excess soy may result in higher IGF-1 levels.

Soy is a plant-based protein that has been linked to an increase in IGF-1 levels. However, the amount consumed plays a significant role. Consuming more than 25 grams of soy per day may lead to a modest increase in IGF-1 levels. Vegans who consume between 7 and 18 servings of soy foods daily may have IGF-1 levels comparable to those who eat meat.

Therefore, to maintain the low IGF-1 levels typically associated with a plant-based diet, it is recommended to limit soy intake to around 3 to 5 servings per day.

Exercise can reduce IGF-1 levels

However, the effect of exercise on IGF-1 levels is not always consistent. For instance, a review of the literature found that most studies show no increase in circulating total IGF-1, while bioactivity may change in response to exercise. The review also noted that there is limited and conflicting data on the effects of growth hormone (GH) on physical function in healthy adults, despite strong evidence of a benefit in adults with GH deficiency.

The discrepancy in the effects of exercise on IGF-1 levels may be due to variations in exercise type, intensity, and duration. For instance, moderate-intensity exercise has been found to increase IGF-1 levels, while more prolonged and strenuous exercise may lead to a decrease in IGF-1. Additionally, the timing of IGF-1 measurements after exercise may also play a role, as IGF-1 levels can return to baseline within an hour after exercise.

In summary, while exercise can reduce IGF-1 levels in some cases, the overall effect may depend on various factors such as exercise type, intensity, and duration, as well as individual characteristics such as age, gender, and health status.

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