A diet low in vitamins A and C could raise the risk of asthma, according to a new study.
A Nottingham University-led team reviewed 40 studies carried out over the past 30 years and found that people with a low intake of vitamin C had a 12 percent increased risk of asthma, the Thorax journal reported.
The team said, for vitamin A the raised risk was less clear cut but there was still a significant association.
To reach the conclusion, researchers analysed the relevant reports on both children and adults published since 1980. They found no link for vitamin E, but said the associations for A and C were significant.
They concluded low levels of vitamin C - found in fruit and vegetables - increased the risk of asthma by 12 percent. They were unable to put an exact figure on vitamin A - found in cheese, eggs and oily fish - but noted that those with severe asthma consumed on average half of the recommended intake of the vitamin.
"Our findings indicate that low levels of vitamin C intake and to a lesser extent vitamin A are consistently associated with asthma risk to a degree that, if causal, would be sufficient to be clinically relevant," the BBC quoted lead researcher Dr Jo Leonardi-Bee, as saying.