*None of the following information should be taken as medical advice. If you have questions about your health, ask a physician.*

Muscle Growth - AKA Hypertrophy

What exactly is muscle growth? In popular nutrition and fitness it is common to hear things like ‘bigger muscles’ or ‘muscular gains’, but what exactly do these terms mean? In reality, they all refer to muscle hypertrophy - the medical term for when muscles grow in size. Much research has been conducted on the topic, and according to University of New Mexico scientists “skeletal muscle is the most adaptable tissue in the human body”.

The specific details of muscle growth are fairly technical, but the basic idea is that hypertrophy occurs when the cross-sectional area of the muscle increases in size. This means that muscle fibers get bigger, but not longer. 

A specific type of cell termed myosatellite cells (-myo being a prefix relating to muscle) is responsible for this increase in mass. When muscles undergo some form of trauma, like that which occurs during a workout, these satellite cells become activated and proliferate (multiply and divide).

They then fuse with existing muscle cells, making them larger and ‘stronger’. Importantly, this isn’t caused by an increase in the number of muscle cells, but rather an increase in the size of already existing muscle cells. 

Hypertrophic Factors

Beyond that, there are several factors that affect hypertrophy, both positively and negatively. Below, several of these are explained.

• Growth factors: these are small molecules that promote cell division and proliferation. In conjunction with satellite cells, these help promote hypertrophy.
• Cortisol: this is a steroid hormone, often referred to as a ‘stress hormone’. Cortisol inhibits the metabolism of sugars in various cell types which has the effect of preventing hypertrophy.
• Testosterone: the primary purpose of testosterone is to promote the growth and development of male characteristics and sex organs. The hormone is present in both sexes, though. Males typically exhibit a roughly 15-fold increase in testosterone levels compared to females. This difference is one of the primary reasons for differences in muscle physiology between the sexes. Testosterone has an additional effect on muscle building and causing an increase in hypertrophy. 

Omega-3

One of the more confusing aspects of this topic relates to what exactly omega-3 fatty acids are. The definition is hard to understand and is tied up in some organic nomenclature. Let’s first demystify what exactly this fatty acid is.

An Organic Refresher

In chemistry, compounds are named for what their structure is. Put more simply, they are named for what atoms they have and how those atoms are connected. Fatty acids are specific parts of some types of lipids and are composed of long chains of carbons all bonded together.

Above is a fatty acid. Notice that it has two ends: the end labeled with the alpha (α) and the other with an omega (ω), The α end is always closest to the oxygen atom (O), and the ω end is always at the end of the molecule (far right side). Every time that the black line kinks, it is representative of a carbon atom. These are numbered in red (1, 3, 6, 9, etc). Notice that next to the 3 and the 6 and the 9 there is a small line under the main black line. This represents a double bond. In the above drawing, the first instance of this double bond starts at the red-labeled third carbon. 

Let’s put this all together. An omega-3 fatty acid is a fatty acid that has a double bond on its number 3 carbon, counting from the omega (ω) end of the molecule. Any fatty acid that exhibits this characteristic can be referred to as an ‘omega-3 fatty acid’. 

Omegas and Health

Extensive research has been conducted into what exactly these fatty acids do for our health. Many fats are created by our bodies themselves. Omega-3 fatty acids are a type of essential fat. This means that our bodies don't create them, we have to eat them. This type of fatty acid is found in many kinds of food. Most notably, they can be found in fish, nuts, and certain kinds of oils. 

Omega-3 Fats and Muscles

Recently, extensive research into the link between omega-3 fatty acids and muscle growth has been conducted. According to a 2015 study by the University of Stirling in Scotland, “omega-3 fatty acids of marine origin can influence the exercise and nutritional response of skeletal muscle.” Also according to the authors, "There is now growing evidence that omega-3 PUFAs also have intrinsic anabolic/anti-catabolic properties in skeletal muscle”. In lay terms, this means that omega-3 fatty acids are linked specifically with the growth, but not the breakdown of skeletal muscle.

In terms of hypertrophy, it seems that omega-3s have a role that may be similar in nature to growth factors and testosterone. The Mayo Clinic also suggests that omega-3s are positively correlated with healthy muscle growth. If you are looking to supplement your muscle-building diet, they suggest that foods high in omega-3s can provide an extra boost to muscle hypertrophy.