A plant chemical found in orange and dark green vegetables may help prevent deaths from heart disease and cancer, research suggests.
High blood levels of alpha-carotene were found to reduce the risk of death by more than a third over a 14-year period.
The antioxidant is similar to the better known compound beta-carotene and found in similar vegetables, especially carrots, sweet potatoes, broccoli and spinach.
In the study it was associated with a lower risk of dying from heart disease and cancer individually, as well as "all causes".
Scientists believe it may be more effective than beta-carotene at inhibiting the growth of cancer cells in the brain, liver and skin.
"Carotenoids other than beta-carotene may contribute to the reduction in disease risk, and their effects on risk of disease merit investigation," said Dr Chaoyang Li.
The scientists found that over a 14-year-period the chances of dying were lowered as blood levels of alpha-carotene increased.