What are the main types of antioxidants

There are three main types of antioxidants:

1. Primary Antioxidants

Primary antioxidants, also known as chain-breaking antioxidants, are the most important and effective antioxidants produced by the body. They function by terminating free radical chain reactions and include:

• Superoxide dismutase (SOD)
• Catalase (CAT) 
• Glutathione peroxidase (GPx)

These enzymes directly neutralize free radicals and reactive oxygen species, preventing them from causing cellular damage.

2. Secondary Antioxidants

Secondary antioxidants, also called preventive antioxidants, work by slowing down the rate of oxidation. They function by:

• Chelating metal ions that can catalyze oxidation
• Quenching singlet oxygen
• Decomposing hydroperoxides to non-radical species

Examples include:

• Glucose-6-phosphate dehydrogenase
• Glutathione reductase 
• Ferritin
• Transferrin
• Ceruloplasmin

3. Tertiary Antioxidants

Tertiary antioxidants repair oxidative damage to biomolecules like DNA and proteins. They include:

• DNA repair enzymes
• Methionine sulfoxide reductases
• Proteolytic enzymes that remove and degrade oxidized proteins

In addition to these three main types, antioxidants can also be classified based on their source:

• Enzymatic antioxidants produced by the body
• Non-enzymatic antioxidants obtained from the diet, including vitamins C and E, carotenoids, flavonoids, and other phytochemicals

The most potent antioxidants are often plant-based, such as polyphenols, flavonoids, and carotenoids found in fruits, vegetables, herbs, and spices. Maintaining a diet rich in these antioxidant-containing foods is crucial for combating oxidative stress and promoting overall health.