“Wonder food” fads often extol the virtues of amino acids, but do they really matter in terms of human health? In this article we take a look at the differences between essential and nonessential amino acids and why they are so important to our health.
What are amino acids?
Amino acids are essentially protein building blocks. They are extremely important because 20 percent of our bodies are made of protein. Protein is integral to virtually all biological processes.
It therefore follows that a large proportion of our cells consist of amino acids. They carry out a variety of functions—for example, giving cells their structure. Amino acids also play an integral role in the storage and transportation of nutrients throughout the body.
Amino acids help organs and tissue to function properly. They are essential to our immune systems and heal tissue damage, particularly in the skin, muscles and bones. Amino acids are also key to the waste removal process within cells. Many amino acids are highly beneficial nutritionally, with some being proven to affect metabolism.
What is the difference between nonessential and essential amino acids?
We generate nonessential amino acids within our own bodies, but cannot generate essential amino acids. We must acquire essential amino acids from external sources, so we absorb them from the food that we eat.
After ingestion, amino acids enter our bloodstream for transportation around the body. They are absorbed by cells to support biochemical functions intrinsic to human life.
Different cells within the human body perform different functions, and so have unique needs. Specific amino acids meet each of these requirements.
What are the essential amino acids?
There are nine essential amino acids that are critical to human health.
Histidine produces histamine, a neurotransmitter that plays an integral role in the immune system. It also maintains the barrier that protects nerve cells, known as the myelin sheath, and aids healthy digestion, sleep cycles and sexual function.
Isoleucine is important to healthy muscle metabolism. It also facilitates immune responses and the production of red blood cells as well as regulating energy throughout the body.
Leucine helps heal cellular damage, particularly in muscles and the skin. It is critical to the regulation of blood-sugar levels as well as protein synthesis and the production of growth hormones.
This amino acid helps with protein synthesis as well as playing a key role in enzyme and hormone production. Lysine is important in the production of collagen, elastin, and energy as well as helping the immune system.
Methionine is important for metabolism, detoxification, and tissue growth. It also helps the body absorb selenium and zinc, minerals that are both integral to human health.
Phenylalanine is essential to the production of dopamine, epinephrine, norepinephrine, and tyrosine. These neurotransmitters are crucial to wellbeing. Phenylalanine is also necessary to the production and function of enzymes and proteins.
Threonine is required for the production of elastin and collagen, which are structural proteins that help form healthy skin and connective tissue. Scientists also link threonine to the immune system and have established that this essential amino acid plays a key role in the metabolism of fat.
Although tryptophan is commonly associated with drowsiness, this amino acid serves several key functions. It is essential to regulating nitrogen levels within the human body. It is also important in the production of serotonin, the neurotransmitter associated with appetite, mood, and sleep.
This essential amino acid not only promotes muscle cell growth and regeneration, it also plays an important role in the energy production process within the human body.
Which foods provide essential amino acids?
Natural sources of essential amino acids include fish and seafood; animal proteins; legumes, nuts and seeds; and whole grains.
What happens if there is a dietary shortage of essential amino acids?
A lack or absence of essential amino acids from our diets can have serious implications in terms of health. A deficit of essential amino acids can cause physical and mental health issues, inhibiting the body’s ability to generate proteins as well as compromising the immune system.
The human body does not store essential amino acids, but rather absorbs only what it can use. It has no stockpile to fall back on if there is a shortage in a person’s diet. When the body detects a shortage of a particular essential amino acid, it will break down muscle tissue to access amino acids contained within that tissue. This can cause extreme fatigue and changes to the skin and hair as well as wasted muscles.
Certain genetic disorders can affect the body’s ability to metabolize essential amino acids. For example, maple syrup urine disease prevents children from metabolizing isoleucine, leucine, and valine, the consequences of which can be fatal. Symptoms of maple syrup urine disease include intellectual disability, seizures and neurological disorders.
Since the advent of genomics and the rise of biotechnology, scientists have begun to understand more and more about the way our bodies work at a cellular level. Essential amino acids have been found to play an integral role in cellular functions, and our ability to access and metabolize them is therefore vital.