Asparagine is an amino acid, the fundamental building block of proteins in the body. It is classified as “non-essential,” meaning the human body can produce it, so it is not strictly required from dietary sources. Despite this, asparagine plays a role in protein synthesis, contributing to the body’s structure and function.
Functions in the Body
Asparagine serves several biological roles within the human body, beyond its basic function as a protein component. It participates in protein synthesis, facilitating the formation of peptide bonds that link amino acids, constructing complex protein structures. This process supports cellular growth, aids in tissue repair, and contributes to the production of enzymes and hormones.
The amino acid also plays a part in the body’s detoxification processes, specifically in handling ammonia. Asparagine helps transport excess ammonia, a harmful byproduct of amino acid metabolism, from tissues to the liver. Once in the liver, ammonia is converted into urea, a less toxic substance the body can then excrete.
Asparagine contributes to brain development and function. It is involved in the synthesis of neurotransmitters, such as glutamate and aspartate, which are chemical messengers that facilitate communication between nerve cells. This influences neuronal signaling, impacting cognitive functions like learning, memory, and emotional regulation.
Asparagine is also involved in glycosylation, a process where sugar chains are added to proteins. This modification, known as N-linked glycosylation, occurs at asparagine residues within a protein sequence. This process aids proper protein folding, stability, and cell signaling.
Where Asparagine is Found
While the human body can synthesize asparagine, it is also present in various foods, contributing to dietary intake. Animal-based sources include poultry, beef, eggs, dairy products like milk and cheese, and types of fish and seafood.
Plant-based foods also provide asparagine. Asparagus, which is where the amino acid gets its name, contains high levels. Other plant sources include potatoes, spinach, mushrooms, and legumes such as peas, lentils, and beans. Nuts, seeds, and whole grains like oats and wheat also provide asparagine.
Asparagine and Acrylamide
Asparagine is involved in a chemical reaction that leads to the formation of acrylamide, a compound of public health concern, especially during high-temperature cooking. This reaction occurs as part of the Maillard reaction, a complex series of chemical reactions between amino acids and reducing sugars that gives browned foods their distinctive flavors and colors.
Acrylamide forms when free asparagine reacts with reducing sugars, such as glucose and fructose, at temperatures above 120°C (248°F) and under low moisture conditions. This reaction is prominent in carbohydrate-rich foods that undergo dry heat cooking methods like frying, baking, or roasting.
Common foods where this reaction leads to significant acrylamide formation include French fries, potato chips, toasted bread, and certain baked goods like cookies and cereals. The extent of acrylamide formation increases with higher temperatures and longer cooking times.
Acrylamide has been classified as “probably carcinogenic to humans” by the World Health Organization and the International Agency for Research on Cancer, based on studies in rodents. To reduce dietary exposure, advice includes cooking foods to a golden yellow color rather than dark brown, as darker browning indicates higher levels of the Maillard reaction and more acrylamide.