How It Works
Bottom Line: Juice Plus has not been shown to treat or prevent cancer.
Juice Plus is a dietary supplement that contains dried concentrates of fruits and vegetables. It has been studied for its antioxidant and cardiovascular effects. But more studies are needed. There are ongoing clinical studies of Juice Plus in cancer patients but it has not been proven to treat or prevent cancer. Juice Plus is not a substitute for fresh fruits and vegetables.
Purported Uses
To prevent and treat cancer
No scientific evidence supports this use
To prevent and manage heart disease
Small studies showed mixed results. Well designed clinical trials are needed.
Warnings
This product is regulated by the FDA as a dietary supplement. Unlike approved drugs, supplements are not required to be manufactured under specific standardized conditions. This product may not contain the labeled amount or may be contaminated. In addition, it may not have been tested for safety or effectiveness.
Do Not Take If
You are undergoing chemotherapy or radiation therapy (antioxidants may reduce their effectiveness).
Side Effects
Some patients reported gastrointestinal distress and hive-like rash in clinical studies.
Brand Name
Juice Plus+®
Clinical Summary
Juice Plus (JP) is a formulation derived from a variety of fruits and vegetables and contains additional vitamins. It is marketed to complement daily diet based on the notion that people do not consume enough fruits and vegetables. Studies on bioavailability suggest consumption of JP can increase serum levels of alpha-carotene, vitamin C, and folate (1) (2) but studies with other markers, such as lutein, alpha-tocopherol yielded mixed results. One report showed that JP is comparable to standard vitamin C and E supplements (3) but it remains unclear if this product is nutritionally superior to fresh produce. JP was shown to decrease plasma homocysteine levels, a risk factor for cardiovascular disease (9) (1), but the results were not reproducible (4). Studies on cardiovascular effects, such as changes in blood pressure and cholesterol levels are inconclusive (5) (4). JP is also thought to reduce oxidative stress and DNA damage (10) (6) (2).
Gastrointestinal distress (5) and hive-like rash (11) have been associated with intake of JP in clinical trials.
While there is ongoing research using JP in cancer patients, it has not been proven to prevent or treat cancers. Due to its antioxidant effects, JP may interfere with the actions of some chemotherapy drugs. Cancer patients should use this product with caution and should discuss use of supplements with their physicians.
JP is not a substitute for fresh fruits and vegetables.
Food Sources
Purported uses
Cancer prevention
Cardiovascular disease
Weight loss
Constituents
Blended fruit, vegetable, and berry from: apple, beet, bilberry, blackberry, black currant, blueberry, broccoli, cabbage, carrot, acerola cherry, Concord grape, cranberry, elderberry, kale, orange, peach, papaya, parsley, pineapple, raspberry, red currant, spinach, and tomato. B vitamins, folate, alpha carotene and soy-derived d-alpha-tocopherol are added.
(5) (9)
Mechanism of Action
JP is thought to have antioxidant and immunomodulating properties. It reduces some biomarkers of oxidative stress but not others (6) (3) (2). Inflammatory cytokine TNF alpha production increased up to 8 weeks following consumption of JP but decreased after. It had no effect on other markers including IL-4, IL-6, superoxide dismutase or glutathione (6) (7) (8). JP decreased levels of plasma homocysteine, a risk factor for cardiovascular diseases (1) (9), but failed to show similar effect in another study (4). Intake of phytochemical antioxidants may have protective effect on endothelial function by preserving the bioactivity of nitric oxide (4). JP's effects on regulating blood pressure are mixed. Consumption of fresh fruits and vegetables can lower cholesterol levels due to their high fiber content. But JP extract did not appreciably alter cholesterol levels (4) (5).
Pharmacokinetics
Some studies demonstrated that oral consumption of JP capsules can increase the serum levels of beta-carotene, vitamin C, and folate
(1) (2). JP has many ingredients that may have different bioavailability profiles. None of the studies conducted so far compared Juice Plus with fresh produce. JP has not been demonstrated to be better absorbed than regular vitamin C and E supplements.
Adverse Reactions
Gastrointestinal distress
(5) and hive-like rash
(11) were reported in clinical studies.
Herb-Drug Interactions
Theoretically, antioxidants can decrease the efficacy of certain chemotherapy drugs that rely on the generation of free radicals for their cytotoxic effects. Supplements with antioxidant properties are not recommended during chemotherapy.
Lab Interactions
May elevate serum level of some vitamins.
Literature Summary and Critique
Most Juice Plus (JP) studies are partially or fully funded by the Natural Alternative International (NAI) and National Safety Associates (NSA), its manufacturer and distributor. The studies used different doses and formulations of JP. Since dose escalation study has not been conducted, the optimal intake cannot be determined. Lack of appropriate control groups in some studies makes comparison of effects difficult.
References
1. Samman S, Sivarajah G, Man JC, Ahmad ZI, Petocz P, Caterson ID. A mixed fruit and vegetable concentrate increases plasma antioxidant vitamins and folate and lowers plasma homocysteine in men.J Nutr. Jul 2003;133(7):2188-2193.
2. Kawashima A, Madarame T, Koike H, et al. Four week supplementation with mixed fruit and vegetable juice concentrates increased protective serum antioxidants and folate and decreased plasma homocysteine in Japanese subjects. Asia Pac J Clin Nutr 2007;16(3):411-421.
3. Bloomer RJ, Goldfarb AH, McKenzie MJ. Oxidative stress response to aerobic exercise: comparison of antioxidant supplements. Med Sci Sports Exerc. Jun 2006;38(6):1098-1105.
4. Plotnick GD, Corretti MC, Vogel RA, et al. Effect of supplemental phytonutrients on impairment of the flow-mediated brachial artery vasoactivity after a single high-fat meal. J Am Coll Cardiol. May 21 2003;41(10):1744-1749.
5. Houston MC, Cooil B, Olafsson BJ, Raggi P. Juice Powder Concentrate and Systemic Blood Pressure, Progression of Coronary Artery Calcium and Antioxidant Status in Hypertensive Subjects: A Pilot Study. Evid Based Complement Alternat Med 2007;4(4):455-462.
6. Lamprecht M, Oettl K, Schwaberger G, et al. Several indicators of oxidative stress, immunity, and illness improved in trained men consuming an encapsulated juice powder concentrate for 28 weeks. J Nutr 2007;137(12):2737-2741.
7. Nantz MP, Rowe CA, Nieves C, Jr., Pervical SS. Immunity and antioxidant capacity in humans is enhanced by consumption of a dried, encapsulated fruit and vegetable juice concentrate. J Nutr 2006;136(10):2606-2610.
8. Kiefer I, Prock P, Lawrence C, et al. Supplementation with mixed fruit and vegetable juice concentrates increased serum antioxidants and folate in healthy adults. J Am Coll Nutr. Jun 2004;23(3):205-211.
9. Panunzio MF, Pisano A, Antonicielloa A, et al. Supplementation with fruit and vegetable concentrate decreases plasma homocysteine levels in a dietary controlled trial. Nutr Res 2003;23(9):1221-1228
10. Smith MJ, et al. Supplementation with fruit and vegetable extracts may decrease DNA damage in the peripheral lymphocytes on an elderly population. Nutr Res 1999;19:1507-18.
11. Inserra PF, et al. Immune function in elderly smokers and nonsmokers improves during supplementation with fruit and vegetable extracts. Integr Med 1999;2:3-10.
