Cysteine – An Amino Acid for Improved Immune Function

by Ashleigh Feltham
Accredited Practising Dietitian and Accredited Nutritionist

Discussions about amino acids often lead to their role in building and maintaining muscle. Amino acids are the essential component needed to create and maintain lean muscle mass, so it is important to eat enough protein for your body’s needs each day. But amino acids also play other important roles in maintaining a healthy body, such as increasing life expectancy and potentially improving your quality of life through better health.

One such amino acid is cysteine. Cysteine is a conditionally essential amino acid. Conditionally essential means that under certain circumstances, it is essential to include foods containing this amino acid to be able to form a complete protein. Cysteine becomes conditionally essential during illness, for preterm infants and in periods of rapid growth and development.

Cysteine is a precursor for glutathione. Glutathione is an antioxidant that helps to remove excess free radicals in the body. When free radicals exist in high numbers or have resided in cells for a long period of time, they cause damage and disease. Without adequate levels of glutathione, levels of oxidative stress in your body can rise. Oxidative stress over the long term can lead to premature ageing and diseases such as kwashiorkor, seizures, Alzheimer’s disease, Parkinson’s disease, liver disease, cystic fibrosis, sickle cell anaemia, HIV, AIDS, cancer, heart attack, stroke and diabetes.

Glutathione is essential for the immune system to function well. Glutathione can either stimulate or inhibit immune responses to control inflammation and help to restore normal balance in the body. One role glutathione plays to help relieve a chest cold is its ability to loosen mucus in the airways.

Foods like dairy, poultry, legumes and eggs contain high amounts of cysteine. Most forms of seafood are good sources of cysteine, especially tuna and salmon. Ensure the tuna and salmon you buy are ethically sourced and Marine Stewardship Council (MSC) certified. Tuna and salmon contain a host of other components that increase health and quality of life.

Take home message

Amino acids such as cysteine do much more than help you get gains from the gym. Amino acids such as cysteine promote optimal health and wellbeing. Eating a balanced diet including foods rich in cysteine is a smart investment for a long and healthy life. Two cysteine rich foods to include each week are tuna and salmon. Your body will thank you for including these seafood varieties in your diet for health reasons beyond their high cysteine content.

Reference:

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