The researchers at the University of California - Los Angeles have found that cruciferous vegetables like broccoli are body's powerful antioxidant defenses that help to fight aging.
The boffins found that broccoli and other such vegetables have a chemical called sulforaphane that could hold a key to restoring the body's immunity, which declines as people grow older.
According to the study, sulforaphane interacts with a protein called Nrf2, which serves as a master regulator of the body's overall antioxidant response.
This particular protein is capable of switching on hundreds of antioxidant and rejuvenating genes and enzymes in specific immune cells. These cells then fight the injurious effects of free radicals - molecules that can damage cells and lead to disease.
The study on mice was led by Dr. Andre Nel, chief of nanomedicine at the David Geffen School of Medicine at UCLA, and concentrated on pathways used by the body to suppress the production of free radicals.
"Our study contributes to the growing understanding of the importance of these antioxidant defense pathways that the body uses to fight free radicals," said Nel, a practicing clinical allergist and immunologist at the Geffen School.
"Insight into these processes points to ways in which we may be able to alleviate the effects of aging.
"As we age, the ability of the immune system to fight disease and infections and protect against cancer wears down as a result of the impact of oxygen radicals on the immune system."
As per the study, the ability of aged tissues to revive their antioxidant defence can play an important role in reversing much of the negative impact of free radicals on the immune system.
"Our defence against oxidative stress damage may determine at what rate we age, how it will manifest and how to interfere in those processes. In particular, our study shows that a chemical present in broccoli is capable of stimulating a wide range of antioxidant defense pathways and may be able to interfere with the age-related decline in immune function," Nel said.
The researchers found that not only did the direct administration of sulforaphane in broccoli reverse the decline in cellular immune function in old mice, but it also did the same for individual immune cells when they were treated outside the body and then placed back into the rodent.
In particular, the scientists discovered that dendritic cells, which introduce infectious agents and foreign substances to the immune system, were particularly effective in restoring immune function in aged animals when treated with sulforaphane.
The study is appears in this week's online edition of the Journal of Allergy and Clinical Immunology.