The suggestions come after data from a Danish population study following more than 100,000 people found that the risk of cardiovascular disease and early death falls with a higher intake of fruit and vegetables - and that the association is strongly linked to circulating vitamin C levels.

"We can see that those with the highest intake of fruit and vegetables have a 15% lower risk of developing cardiovascular disease and a 20% lower risk of early death compared with those who very rarely eat fruit and vegetables,”​ explained Dr Camilla Kobylecki, at the University of Copenhagen and Herlev and Gentofte Hospital. “At the same time, we can see that the reduced risk is related to high vitamin C concentrations in the blood from the fruit and vegetables.”​

Senior author Professor Boerge Nordestgaard, also from University of Copenhagen and Herlev and Gentofte Hospital, noted that while it has been long known that fruit and vegetables are healthy, the new data may be pinpointing more precisely why this is so.

“You can get vitamin C supplements, but it is a good idea to get your vitamin C by eating a healthy diet, which will at the same time help you to develop a healthier lifestyle in the long term, for the general benefit of your health,"​ he said.

Randomised sample

Writing in The American Journal of Clinical Nutrition, the Danish team tested the hypothesis that genetically high concentrations of plasma vitamin C, such as with high intake of fruit and vegetables, are associated with low risk of ischemic heart disease and all-cause mortality using a Mendelian randomisation approach.

Using DNA analysis techniques, the team found that people expressing a certain genetic allele known as SLC23A1​ rs33972313 G has higher plasma vitamin C levels, and that these increased concentrations were also significantly associated with a lower risk of ischemic heart disease and all-cause mortality.

“Our data cannot exclude that a favorable effect of high intake of fruit and vegetables could in part be driven by high vitamin C concentrations,”​ said the team.

Nordestgaard and colleagues are now continuing their work to determine which other factors, combined with vitamin C, have an impact on cardiovascular disease and death.

Source: The American Journal of Clinical Nutrition​

Published online ahead of print, doi: 10.3945/​ajcn.114.104497​​

“Genetically high plasma vitamin C, intake of fruit and vegetables, and risk of ischemic heart disease and all-cause mortality: a Mendelian randomization study”​

Authors: Camilla J Kobylecki, et al​