© PHOTOLIBRARYVegetables, including carrots, are packed with carotenoids, which scientists say help fight off disease.
Vegetables such as sweet potatoes, pumpkins and winter squashes - as well as carrots - are packed with carotenoids, which scientists say help fight off disease.
The anti-oxidants are also found in dark-green vegetables such as broccoli, green beans, and green peas, and may help combat lung cancer.
Researchers found these veg are packed with alpha-carotene, saying high blood levels of the antioxidant was linked with a reduced risk of dying over a 14-year period.
Chronic diseases like heart disease and cancer are caused by oxygen-related damage to DNA, proteins and fats.
The researchers found carotenoids including beta-carotene, alpha-carotene and lycopene produced by plants and micro-organisms act as antioxidants and counteract this damage.
Dr Chaoyang Li and colleagues from the Centre for Disease Control and Prevention in Atlanta, USA, studied 15,318 adults age 20 and up who participated in the Third National Health and Nutrition Examination Survey Follow-up Study.
They underwent examinations and gave blood tests over a six year period from 1988 and 1994 and a follow-up study in 2006.
Of the participants roughly a quarter - 3,810 - died.
Researchers found those with higher levels of blood alpha-carotene levels had a lower risk of death from cardiovascular disease or cancer.
And although chemically similar to beta-carotene, it may be more effective at inhibiting the growth of cancer cells in the brain, liver and skin.
Dr Li said:
"Moreover, results from a population-based case-control study of the association between the consumption of fruits and vegetables and risk of lung cancer suggest that consumption of yellow-orange, carrots, sweet potatoes or pumpkin and winter squash, and dark-green, broccoli, green beans, green peas, spinach, turnips greens, collards and leaf lettuce, vegetables, which have a high alpha-carotene content, was more strongly associated with a decreased risk of lung cancer than was consumption of all other types of vegetables,"Although studies suggest eating more fruits and vegetables is associated with lower risk of chronic diseases, they warned randomized controlled trials have not shown any benefit for beta-carotene supplements.
Dr Chaoyang Li said:
"Therefore, carotenoids other than beta-carotene may contribute to the reduction in disease risk, and their effects on risk of disease merit investigation."The findings were published online in the Archives of Internal Medicine.
but all of these cancer fighting agents are destroyed by heat, as in cooking them.
Of the above mentioned veg's, only the carrot is eaten raw.