An NSA-sponsored study of 15 healthy individuals found that supplementation with Juice Plus+ for 28 days raised the blood levels of five phytonutrients:, lutein/zeaxanthin, lycopene, and vitamin E. To further support his argument, DuBois correctly describes how clinical trials have found that supplementation with individual nutrients sometimes does more harm than good. The study found, for example, that beta-carotene levels were five times as high and lycopene levels were 20 times as high. But he then asserts that the Juice Plus+ nutrients are safe and more effective, because the phytonutrient content of plants is "balanced."
The above reasoning is not valid. Based on all of the above assumptions, he concludes that everyone should take Juice Plus+. Nearly all of the evidence relating disease rates to dietary composition is epidemiologic. And even if causal connections are established, they do not prove that dietary supplements will remedy a poor diet or that Juice Plus+ is an optimal supplement. Epidemiologic studies do not prove cause and effect. (In fact, it is not likely to be optimal because it lacks vitamin B12 and most of the minerals included in full-spectrum multivitamin/ Juice Plus Expert.) Only well-designed, long-term clinical trials can determine whether taking Juice Plus+ or any other pill or potion can actually prevent disease. Nor is there any logical reason to conclude that Juice Plus is "balanced" simply because its ingredients were extracted from foods.