London: The humble spinach makes you big and strong, but that is thanks to the presence of nitrates not iron.
Scientists say nitrates, found abundantly in green leafy vegetables, boost cellular powerhouses that provide energy.
A single helping of spinach is enough to up the efficiency of mitochondria, small bean-shaped bodies, which fuel cell activity and growth.
Until recently, the chemical was thought to be devoid of nutritional value, the journal Cell Metabolism reports.
Swedish scientists found that after taking a small dose of inorganic nitrate for three days, healthy people consumed less oxygen while riding an exercise bike, according to the Daily Mail.
Eddie Weitzberg, from the Karolinska Institute in Stockholm, Sweden, who led the study, said: "We`re talking about an amount of nitrate equivalent to what is found in two or three beetroots or a plate of spinach.
"We know that diets rich in fruits and vegetables can help prevent cardiovascular disease and diabetes, but the active nutrients haven`t been clear. This shows inorganic nitrate as a candidate to explain those benefits."
Dietary nitrate increases levels of nitric oxide in the body, a molecule that opens up blood vessels, lowers blood pressure and improves circulation.