There has been a lot of controversy about the possible harms of dietary supplements over the years. The October 17 report on NPR has raised this question yet again.
http://www.npr.org/2011/10/17/141411363/americans-urged-to-reconsider-use-of-dietary-supplements

The last time I heard T. Collin Campbell (“The China Study”) speak, he stated that his research showed that it was the food and not the nutrient that gave the benefit and that the results of supplement use were unpredictable.

Common sense and experience tells us that a varied plant based diet along with life-related activity and a positive attitude are the basis of sound and lasting health. I recommend having a grain and a separate vegetable dish with every meal and making sure that you are trying to have regular variety in your diet. Brown rice and steamed kale with every meal do not count as variety—don’t be afraid to mix it up! More details can be found in my book “The Great Life Diet.”