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Juice Plus is a branded line of encapsulated dietary supplements from the United States, which contains concentrated fruit and vegetable extracts fortified with added vitamins and nutrients. Sold via direct or multi-level marketing, it is billed as "the next best thing to fruits and vegetables," a claim which has stirred considerable controversy. Proponents claim that the product can provide nutritional benefits such as reducing oxidative stress, and improving cardiovascular function. Critics say that there is no scientific proof of serious health benefit, and that Juice Plus makes deceptive claims in its marketing information. Several studies which have set out to prove or disprove Juice Plus's claims have generated conflicting and controversial results.

Product description

Juice Plus is manufactured by Natural Alternatives International in San Marcos, California and distributed by National Safety Associates in Collierville, Tennessee via direct or multi-level marketing. There are several Juice Plus products, with the primary ones being Orchard Blend and Garden Blend capsules, chewable supplements for children, and a version for dogs and cats. [1]

Research study results

It is generally accepted in the scientific community that a high intake of fruits and vegetables can result in substantial health benefits, including reduced risk of coronary heart disease and stroke.[2][3] Juice Plus markets itself as a product which can provide some of those benefits in a concentrated form. Multiple studies of varying standards have produced conflicting results as to the truth of these claims.

Nutrient absorption

Though Juice Plus does indeed contain nutrients, concerns have been raised about how many of these nutrients are in a form that can be effectively absorbed by the human body. In studies focusing on the effect of Juice Plus nutrients on human subjects, it was revealed that subjects taking Juice Plus did find high absorption of folate and beta-carotene[4][5] [3] but inconsistent absorption of vitamin E and vitamin C.[4][3][6] Other studies found that Juice Plus does not raise the blood levels of other key phytonutrients from fresh fruits and vegetables, such as lycopene,[5][3] lutein,[5][3] zeaxanthin,[5][3][7] and beta-cryptoxanthin.[5][8][3][7]

Antioxidant activity

NSA claims that the Juice Plus product is an effective antioxidant, and quotes a study, funded by the manufacturer, which showed a 75% reduction in an oxidative stress marker after 7 to 28 days.[9] Another independent study in 1999 found a 67% decrease in DNA oxidation,[5] and another independent study also reported reduction in oxidative stress. [10] Critics of these studies say that they were poorly designed, not blinded or placebo-controlled, included only a few participants (in one case no more than 15), and did not include monitoring or control of the participants' food intake.[11]

Three other studies which were conducted under more rigorous conditions, meaning randomized, double-blind, placebo-controlled studies, longer in duration and with more subjects, found no significant reductions in lipid peroxidation,[3][4][6] or other markers of oxidative stress.[3][4][7]

One study on an in vitro test of antioxidant activity, found that 1 g of Juice Plus Garden Blend/Orchard Blend powder had the corresponding antioxidant capacity to approximately 10 g (fresh weight) of fruit or vegetable, amounting to 30 g (roughly one-third of a serving) per 4 capsules.[12]

One placebo-controlled study conducted in 2002 found that Juice Plus Gummie candies did not significantly improve the antioxidant status of children, as indicated by negative results from 6 different antioxidant tests.[13] The authors explained this by saying it was possible that the supplement did not contain enough of the proper antioxidants to make a significant difference or that the antioxidants extracted in the fruit/vegetable extract were not bioavailable.

Cardiovascular effects

Several studies have examined the effects of fruit and vegetable concentrates on biochemical parameters associated with cardiovascular function, again with conflicting results.

One non-controlled study found a 37% decrease in homocysteine levels.[14]

Other more rigorous studies, including two that were randomized, double-blind, placebo-controlled trials, found that homocysteine levels were not reduced[2][15] or were reduced only marginally (7%).[3]

Two randomized, double-blind placebo controlled studies have examined the effect of Juice Plus on serum cholesterol and LDL levels. One study found that Juice Plus had no significant effects;[3] the other found slight decreases in cholesterol (6%) and LDL (9%) in subjects that took Orchard/Garden Blend, but no reductions among subjects who took Juice Plus Vineyard blend in addition.[2]

One study found that Juice Plus had no effect on blood pressure in healthy subjects.[2]

Juice Plus Children's Research Foundation

The Juice Plus Children's Research Foundation,[16] founded in 1997, is a non-profit organization whose stated goal is to initiate and/or support programs that advance the principle that improved nutrition leads to healthier lifestyle and overall better health in children. The foundation is chaired by executives of National Safety Associates and operates from the company's head office in Memphis, Tennessee.

As of 2007, no research had been published by the Foundation, but it does conduct an ongoing survey which seems to link Juice Plus consumption to a general improvement in diet and lifestyle habits. Critics, including the University of California Berkeley Wellness Letter and Dr. Stephen Barrett of MLMWatch, question the survey's scientific value, and state that the Foundation is being used mainly as a marketing gimmick to get families to buy Juice Plus products.[17][18]

Marketing claims

According to Consumer Reports, in 2005, National Safety Associates used advertising featuring Dr. William Sears, which implied that the "Juice Plus Gummies" product is low in sugar, and a nutritional alternative to fruits and vegetables. This claim resulted in consumer complaints to the Better Business Bureau's National Advertising Division (NAD). The BBB issued a complaint that NSA's claims were misleading, and as a result, NSA promised to modify its ads and stop calling Gummies “the next best thing to fruits and vegetables”.[19] However, as of 2007, the Juice Plus homepage still includes the language that Juice Plus is “the next best thing to fruits and vegetables”, though not specifically in reference to the Gummies form of the product. [1]

Concerns have also been raised about the accuracy of product labeling. Four studies which included chemical analyses of Juice Plus have indicated nutrient amounts that differ from the amounts listed on the product labels.[2] [20][21][22]

Doubts have been raised about the benefits of Juice Plus by the Memorial Sloan-Kettering Cancer Center, the University of California Berkeley and other critics. Specific criticisms include: the product’s marketing being unsupported by research data, the product contains too little fruit and vegetable powder to offer significant clinical benefits, concerns that the effects can be attributed to the inclusion of added exogenous vitamins and micronutrients, and complaints that the products are excessively priced relative to their potential benefits.[23][24][25][18][26][11][27]

References

  1. ^ a b "Juice Plus homepage". National Safety Associates. Retrieved 2006-10-15. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)
  2. ^ a b c d e Plotnick, Gary; Corretti MC, Vogel RA, Hesslink, Jr. R, Wise JA. (2003). "Effect of supplemental phytonutrients on impairment of the flow-mediated brachial artery vasoactivity after a single high-fat meal" (pdf). J Am Coll Cardiol 41 (10): 1744-9.
  3. ^ a b c d e f g h i j k Samman S.; et al. (2003). "A mixed fruit and vegetable concentrate increases plasma antioxidant vitamins and folate and lowers plasma homocysteine in men" (pdf). 133 (7): 2188–93. {{cite journal}}: Cite journal requires |journal= (help); Explicit use of et al. in: |author= (help)
  4. ^ a b c d Kiefer I, Prock P, Lawrence C, Wise J, Bieger W, Bayer P, Rathmanner T, Kunze M, Rieder A (2004). "Supplementation with mixed fruit and vegetable juice concentrates increased serum antioxidants and folate in healthy adults" (pdf). J Am Coll Nutr. 23 (3): 205–11.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  5. ^ a b c d e f Smith MJ, Inserra PF, Watson RR, Wise JA, O'Neill KL (1999). "Supplementation with fruit and vegetable extracts may decrease DNA damage in the peripheral lymphocytes of an elderly population". Nutr Res. 19 (10): 1507–18.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  6. ^ a b Bloomer RJ; et al. (2006). "Oxidative stress response to aerobic exercise: comparison of antioxidant supplements". Med Sci Sports Exerc. 38: 1098–1105. {{cite journal}}: Explicit use of et al. in: |author= (help)
  7. ^ a b c Nantz MP, Rowe CA, Nieves C Jr, Percival SS. (2006). "Immunity and antioxidant capacity in humans is enhanced by consumption of a dried, encapsulated fruit and vegetable juice concentrate". J Nutr. 136: 2606–10.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  8. ^ Inserra PF, Jiang S, Solkoff D, Lee J, Zhang Z, Xu M, Hesslink R, Wise J, Watson RR (1999). "Immune function in elderly smokers and nonsmokers improves during supplementation with fruit and vegetable extracts". Integr Med. 2 (1): 3–10.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  9. ^ Wise JA, Morin RJ, Sanderson R, Blum K (1996). "Changes in plasma carotenoid, alpha-tocopherol, and lipid peroxide levels in response to supplementation with concentrated fruit and vegetable extracts: A pilot study" (pdf). Curr Ther Res. 57 (6): 445–61.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  10. ^ Leeds AR; et al. (2000). "Availability of micronutrients from dried, encapsulated fruit and vegetable preparations: a study in healthy volunteers". J Hum Nutr Diet. 13: 21–7. {{cite journal}}: Explicit use of et al. in: |author= (help)
  11. ^ a b Stanton R (2000). "Nutrition: who can you believe?" (PDF). The Skeptic. 20 (4): 23–7.
  12. ^ Chambers SJ; et al. (1996). "Evaluation of the antioxidant properties of a methanolic extract from 'Juice Plus fruit' and 'Juice Plus vegetable' (dietary supplements)". Food Chem. 57: 271–274. {{cite journal}}: Explicit use of et al. in: |author= (help)
  13. ^ Stewart, R.J.; et al. (2002). "Antioxidant status of young children: Response to an antioxidant supplement". J Am Diet Association. 102 (11): 1652–7. {{cite journal}}: Explicit use of et al. in: |author= (help); Unknown parameter |month= ignored (help)
  14. ^ Panunzio MF; et al. (2003). "Supplementation with fruit and vegetable concentrate decreases plasma homocysteine levels in a dietary controlled trial". Nutr Res. 23: 1221–8. {{cite journal}}: Explicit use of et al. in: |author= (help)
  15. ^ Bamonti F; et al. (2006). "Increased free malondialdehyde concentrations in smokers normalise with a mixed fruit and vegetable juice concentrate: a pilot study". Clin Chem Lab Med. 44 (4): 391–6. {{cite journal}}: Explicit use of et al. in: |author= (help)
  16. ^ "Juice Plus Children's Research Foundation homepage". National Safety Associates. Retrieved 2006-10-15. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)
  17. ^ Barrett, Stephen. "Questionable Research by the Juice Plus Children's Research Foundation". MLM Watch. Retrieved 2007-02-05.
  18. ^ a b "Juiced Up and Dried Out" (pdf). University of California Berkeley Wellness Letter. Retrieved 2006-10-15. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)
  19. ^ "How Product Testimonials Bend The Rules". Consumer Reports. Retrieved 2006-10-15. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help); Italic or bold markup not allowed in: |publisher= (help)
  20. ^ "EN Squeezes the Raw Truth Out of Juice Plus Claims". Environmental Nutrition. March 2002.
  21. ^ "Multivitamin/multimineral product review: ingredient comparison tables". Consumer Lab. 2006.
  22. ^ "Are all antioxidants what they claim to be?" (pdf). GNLD International.
  23. ^ Watzl, B. "Letter to the Editor:Fruit and Vegetable Concentrate or Vitamin Supplement?" (pdf). J Nutr. 133 (7): 3725. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |yeacr= ignored (help)
  24. ^ "Juice Plus". Memorial Sloan-Kettering Cancer Center. Retrieved 2006-10-15. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)
  25. ^ "Juice Plus—and minus" (pdf). University of California Berkeley Wellness Letter. Retrieved 2006-10-15. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)
  26. ^ Goodwin, Kathy. "Dietary supplements: facts about Juice Plus". The Diet Channel. Retrieved 2006-10-15. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)
  27. ^ Barrett, Stephen. "Juice Plus: A Critical Look". MLM Watch. Retrieved 2006-10-15. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)
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