Following argument is wrong for numerous reasons. The argument is based on an assumption that, control group which takes raw material show steep decline on average number of colds are in same conditions as the one who are served packaged antioxidants, rendering its main conclusion, that the raw food whould be recommended over packaged antioxidants, invalid.
The five-year old study, although carried over for a good time span, does not clearly call out the exact conditions where different control groups were present. What if, the control group fed with raw food were kept in clement weather, opposed to their counterparts being fed packaged antioxidants? This proves the study faulty. The study should call out the weather conditions to which different control groups were exposed to.
The study also fails to convey the range of ages in different control groups. What if, the control group being fed with raw food consists of young people, as opposed to old people in the second group. Falling sick amongst old people is more common as compared to the young ones. Hence, conveying the range of age is a significant aspect which the study clearly lacks.
Quality and quantity of edibles have also not been clearly called out in the argument. The packaged antioxidants manufactured by different companies, obviously, are of different qualities. What if, the control group is fed with lower quality of packaged anitoxidants. What if, the first control group is fed with larger amount of raw food. Consequently, the control group betraying positive response are getting larger quanitities of antioxidants, clearly making the study faulty.
Apart from aforementioned points, the study must also report the daily routines of the people. The group working at places exposed to bacteria or other germs, are more prone to catch cold.
Hence, we can conclude that unless the study is representative, reliable and valid, the author cannot effectively back the argument that raw food should be recommended over packaged anitoxidants.