Myokines and Health

In the past, we thought of skeletal muscles as machines that helped us lift things, stand up straight, chew, and so on. But, as it turns out, they’re much more complex. Scientists have now shown that muscles are endocrine organs – they release myokines that communicate with all your body’s systems.

How Muscles ‘talk’ to Your Body

Myokines are cytokines or peptides secreted by muscle cells in response to contraction, exercise, or other stimuli, and they have systemic effects on various organs and tissues.

As of now, more than 650 myokines have been cataloged, though not all of their functions are fully understood.

Key examples include IL-6, irisin, myostatin, decorin, and BDNF, among others. These myokines interact with various systems in the body, including the immune, metabolic, cardiovascular, and nervous systems.

Irisin

Irisin is a myokine, a type of signaling protein released by skeletal muscle cells, particularly during exercise. It plays a crucial role in metabolism, energy regulation, and muscle function.

Irisin's most significant function is its ability to convert white adipose tissue (the type of fat that stores energy) into brown-like adipose tissue (which burns energy and generates heat). This process is called browning. This makes irisin a key molecule in improving metabolism, and potentially a target for combating obesity and metabolic syndrome. Irisin improves glucose metabolism and enhances insulin sensitivity, which may help in the management of type 2 diabetes.

Irisin promotes muscle health by helping with muscle repair and regeneration post-exercise. It also supports the growth of mitochondria (the energy-producing structures in cells), improving muscle endurance and function.

It has been shown to promote neurogenesis (growth of new neurons) and synaptic plasticity (the ability of the brain to adapt and learn), which could be beneficial in protecting against neurodegenerative diseases such as Alzheimer’s.

Interleukin-6

Interleukin-6 (IL-6) increases during exercise. When you exercise, your muscles pump it into your blood, causing levels to rise 100-fold.

It has both pro-inflammatory and anti-inflammatory effects. It enhances glucose metabolism and lipid oxidation.

Exercise, particularly aerobic and resistance training, triggers the release of IL-6 from muscle cells. Exercise-induced IL-6 helps reduce chronic systemic inflammation, improving immune function. By enhancing glucose metabolism and fat oxidation, IL-6 contributes to better metabolic health, which in turn supports immune function.

Brain-Derived Neurotrophic Factor

Brain-Derived Neurotrophic Factor (BDNF) is a neurotrophin, a type of protein that plays a crucial role in the growth, survival, and maintenance of neurons (nerve cells) in the brain and peripheral nervous system. BDNF is essential for brain health, supporting cognitive functions such as learning and memory. BDNF enhances fat oxidation in muscle.

Synaptic plasticity is the ability of synapses (the connections between neurons) to strengthen or weaken over time, which is fundamental to learning and memory. BDNF enhances synaptic plasticity by increasing neurotransmitter release and synaptic strength.

BDNF modulates the brain's response to stress by supporting the resilience of neurons to stress-induced damage. Low levels of BDNF have been linked to stress-related disorders such as depression and anxiety.

Aging is linked to a natural decline in BDNF levels, which may contribute to age-related cognitive decline and increased risk of neurodegenerative diseases.

Myostatin

Myostatin is a negative regulator of muscle growth. It inhibits protein synthesis and muscle hypertrophy.

Decorin

Decorin plays a significant role in maintaining tissue structure and regulating cellular functions. Its name derives from its ability to "decorate" collagen fibrils, as it binds to and regulates their formation.

Decorin binds to fibrillar collagens (e.g., types I, II, and III) and regulates fibril formation. Decorin binds to vascular endothelial growth factor, and other growth factors, modulating their availability and activity.

Decorin supplementation may improve wound healing outcomes by optimizing collagen organization and reducing scar formation.

Insulin-Like Growth Factor-1

Insulin-Like Growth Factor-1 (IGF-1) stimulates muscle growth and repair. IGF-1 is important for protein synthesis. It stimulates cell growth and division, particularly during childhood and adolescence. It contributes to bone elongation and cartilage growth. It accelerates wound healing by stimulating tissue regeneration.

IGF-1 deficiency is associated with growth delays, dwarfism, and metabolic issues. It can result from growth hormone deficiency or insensitivity. IGF-1 levels decline with age, contributing to reduced muscle mass, bone density, and overall regenerative capacity.

How Myokines Enhance Immunity

Myokines play vital roles in modulating immune function and creating crosstalk between muscles and other tissues, such as the brain, liver, and adipose tissue. Myokines influence both innate and adaptive immunity and contribute to maintaining systemic health.

Physical activity triggers the release of myokines, promoting an anti-inflammatory and immune-supportive environment. Regular exercise is associated with improved immune function and reduced risk of chronic inflammatory diseases.

Exercise-induced myokines can counteract immunosenescence (age-related immune decline), preserving immune competence in older adults.

Myokines help modulate immune responses during physiological stress (e.g., exercise) and prevent excessive immune activation. Many myokines support wound healing and tissue regeneration, essential for recovery after injury. By regulating metabolism, myokines maintain an optimal environment for immune cells, which depend on metabolic signals for proper function.

Interleukin-6 stimulates the production of anti-inflammatory cytokines like IL-10. IL-6 inhibits tumor necrosis factor-alpha (TNF-α), a pro-inflammatory cytokine. It enhances the activity of natural killer cells, boosting immune defense.

Irisin enhances energy expenditure. It reduces inflammation by inhibiting pro-inflammatory cytokines. It promotes the release of anti-inflammatory cytokines.

Interleukin-15 (IL-15) enhances the proliferation and survival of natural killer cells. It supports T-cell activation, critical for adaptive immunity. It reduces adipose tissue inflammation.

Decorin acts as an anti-inflammatory mediator by inhibiting fibrosis and inflammation.

Interleukin-10 (IL-10) is an anti-inflammatory cytokine produced by muscles during exercise. It enhances immune tolerance and reduces chronic inflammation.

Tips to Increase Myokines Naturally

Exercise regularly, stay active, avoid prolonged sitting and incorporate movement throughout the day. Aim for 7–9 hours of quality sleep nightly. Manage stress by practicing yoga, meditation, or deep breathing. Drink enough water to support muscle function.

To boost myokines naturally through diet, focus on eggs, lean meats, fish, and legumes. Salmon, walnuts, flaxseeds, and chia seeds reduce inflammation. Combat oxidative stress by eating antioxidant-rich foods such as berries, spinach, kale, and citrus fruits. Whole grains such as quinoa, oats, and brown rice provide sustained energy for workouts. Polyphenol-rich foods such as green tea, turmeric, grapes, and dark chocolate enhance myokine activity. Healthy fats such as avocado, olive oil, and nuts support overall muscle function. Vitamin D sources as fatty fish, egg yolks, and fortified foods improve muscle health.