Antioxidants play a vital role in human health by protecting cells from damage caused by free radicals, which are unstable molecules that can lead to oxidative stress and contribute to aging and various diseases. They help neutralize free radicals, reducing the risk of chronic conditions such as heart disease, cancer, and neurodegenerative disorders. Common dietary sources of antioxidants include fruits, vegetables, nuts, and whole grains, making them an essential component of a balanced diet for maintaining overall health.