British researchers say people who don't get enough vitamin C and A in their diet may have a higher risk of asthma. Scientists pooled the results of 40 studies and found that people with asthma got only one-quarter to one-third of the amount of vitamin A that non-asthmatics got. Similarly, those who had unmanageable asthma consumed only a quarter as much vitamin C as people who had mild asthma. Experts say the study does not prove that vitamin-lack causes asthma, or vice versa, but they do...