to offer significant clinical benefits, its effects can be attributed to the inclusion of added exogenous vitamins and micronutrients, and it is excessively priced relative to its potential benefits. Memorial Sloan-Kettering Cancer Clinic referred to Juice Plus as a "pricey supplement" that is "distributed through a multi-tiered marketing scheme with exaggerated value and cost." Nutrients and phytochemicals Concerns have been raised that the nutrients in Juice Plus+ capsules may not be bioavailable or effectively absorbed by the human body, and that some of the nutrients claimed to be in the products may not be present in significant amounts. Studies on nutrient absorption showed that subjects taking Juice Plus had elevated blood levels of folate and β-carotene, but the effects on blood levels of vitamin E and vitamin C were inconsistent. Some studies have shown significant increases in vitamin E and C levels, while other studies have shown much weaker effects on vitamin E and C levels, and that the levels of vitamin E and vitamin C are not significantly increased. Juice Plus was found to increase blood lycopene levels in several studies, while other studies have indicated that Juice Plus does not raise blood levels of lycopene or other phytochemicals in fresh fruits and vegetables such as lutein, zeaxanthin, and β-cryptoxanthin. Conflicts of interest in studies In a critique of Juice Plus, consumer health advocate and alternative medicine critic Stephen Barrett of MLM Watch remarked upon the previous association between two authors of a 1996 Juice Plus research study and United Sciences of America, Inc. (USAI), a multilevel marketing company that sold vitamin supplements with illegal claims that they could prevent many diseases. In 1986, lead author John A. Wise, who later co-authored several other Juice Plus research studies, was USAI's Executive Vice-President of Research and Development; and second author Robert J. Morin was a scientific advisor who helped design the products. State and federal enforcement actions drove USAI out of business in 1987. Wise became a consultant to Natural Alternatives International (NAI) in 1987 and a company executive (Vice-President of Research and Development) in 1992. Barrett noted that Wise was also an NAI shareholder and that production of Juice Plus for National Safety Associates (NSA) was responsible for 16% of NAIs sales in 1999. NSAs Juice Plus website cites various research articles in support of the company's marketing claims about the biological effects of Juice Plus, maintaining that these