Concept encyclopediaMetabolism
Lipid peroxidation
MDA, malondialdehyde, 4-HNE
Lipid peroxidation is a process in which free radicals attack lipids containing carbon-carbon double bond(s), especially polyunsaturated fatty acids (PUFAs), leading to cell damage and oxidative stress. This process is often measured by the formation of malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) .
The generation of protein carbonyls by glycoxidation and lipoxidation reactions with autoxidation products of ascorbic acid and PUFAs is a significant contributor to protein damage and aging . In vitro studies have shown that incubation of proteins with arachidonate accelerates the production of protein carbonyls, MDA, and 4-HNE .
Consuming high amounts of PUFAs, such as those found in fish oil supplements, can lead to increased lipid peroxidation and MDA formation in the body . A study involving 80 men found that supplementing with n-3 fatty acids increased plasma MDA and lipid peroxides, despite an increase in vitamin E levels .
The membrane-stabilizing action of long-term calorie restriction relates to the selective modification of membrane long-chain polyunsaturated fatty acids during aging . This suggests that reducing calorie intake can help maintain the integrity of cell membranes and prevent lipid peroxidation.
Arachidonic acid and other PUFAs have been shown to cause brain swelling and increase superoxide and membrane lipid peroxidation in vitro . This indicates that these fatty acids can have toxic effects on the brain and contribute to oxidative stress.
Vitamin E has been shown to limit lipolysis and peroxidation of PUFAs, which can help reduce muscle damage during exercise . However, daily doses above 500 IU did not add further benefit, suggesting that most humans cannot utilize high doses of vitamin E.
Arachidonic acid has also been shown to interact with the mitochondrial electron transport chain, promoting reactive oxygen species generation and uncoupling of mitochondrial respiration . This suggests that arachidonic acid can have a toxic effect on mitochondria and contribute to oxidative stress.
People also ask
- What causes lipid peroxidation?Lipid peroxidation occurs when free radicals attack lipids, particularly polyunsaturated fatty acids (PUFAs), which contain carbon-carbon double bonds. This process leads to cell damage and oxidative stress.
- How is lipid peroxidation measured?The process of lipid peroxidation is often measured by detecting the formation of specific byproducts, such as malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE).
- How do PUFAs relate to lipid peroxidation?Consuming high amounts of PUFAs, like those in fish oil, can increase lipid peroxidation and MDA formation in the body. Studies have shown that n-3 fatty acid supplementation can raise plasma MDA and lipid peroxides.