Why an orange is better than popping vitamin pills

Its unique mix of antioxidants work much more effectively together than they do separately, found researchers at Brigham Young University in Utah.

Antioxidants slow ageing of cells, protect against cancer and could help ward off heart disease, although the evidence for the last is contested.

Tory Parker, assistant professor of nutrition, dietetics and food science, said: "There's something about an orange that's better than taking a vitamin C capsule, and that's really what we're trying to figure out.

"We think it's the particular mixture of antioxidants in an orange that makes it so good for you."

He and colleagues examined whether "phenolic compounds" found in oranges - biochemicals that are known to have antioxidant and antimicrobial qualities - worked in "synergy".

These compounds are used by plants to protect themselves from decay and biological attack.

The team concluded their theory was "true".

Prof Parker said: "Fruit should be your dessert – remember, before cookies, candy and other sugary snacks became so widespread, fruit was our 'sweet.' "

The research has been published in the Journal of Food Science.