The point is that when I see numbers of test subjects, duration, measures of benefit, etc I feel more confident that some thought has gone into understanding benefits. However, Unless a test subjects only ate that one product or all test subject diets were controlled, it's difficult to measure benefits.
After reading this article, I was unsure of how rigorous this research was. Despite many references, the strength of the data wasn't analysed in a way that was quantifiable. This article isn't alone. One of the few miracle vitamins (vitamin c) also has its critics when it comes to potential benefits.
In summary, I wasn't convinced one way or another by this research.