Studies to assess the impact of vitamins and supplements in preventing heart disease and cancer dr. michael barry is vice chair of the u.s. preventive services task force >> we don't have enough evidence to recommend for or against them with those two exceptions of vietnam e and beta carotene which we recommend people not take. >> reporter: according to the public's analysis, beta carotene was associated with increased risk of lung cancer and death from heart disease, while vitamin e had no proven effects dr. jeffery linder wrote an op-ed about the study. is it pointless to take vitamins? >> i...