Supplementation of a low-carotenoid diet with tomato or carrot juice modulates immune functions in healthy men.
BACKGROUND
Beta-carotene has been shown to enhance immune functions in humans. Whether vegetables rich in carotenoids, such as beta-carotene or lycopene, modulate immune functions in healthy humans is presently not known. The objective of this study was to investigate the effects of a low-carotenoid diet supplemented with either tomato (providing high amounts of lycopene) or carrot juice (providing high amounts of alpha- and beta-carotene) on immune functions in healthy men.


METHODS
In a blinded, randomized, cross-over study, male subjects on a low-carotenoid diet consumed 330 ml/day of either tomato juice (37.0 mg/day lycopene) or carrot juice (27.1 mg/day beta-carotene and 13.1 mg/day alpha-carotene) for 2 weeks with a 2-week depletion period after juice intervention. Immune status was assessed by measuring lytic activity of natural killer (NK) cells, secretion of cytokines (IL-2, IL-4, TNFalpha), and proliferation by activated peripheral blood mononuclear cells.


RESULTS
Juice consumption resulted in relatively fast responses in plasma carotenoid concentrations (p < 0.0002) which were not accompanied by concomitant changes in immune functions. For IL-2, NK cell cytotoxicity, and lymphocyte proliferation, maximum responses were observed during depletion periods. The highest production rate was measured only for TNFalpha at the end of the first intervention period. Juice intervention did not modulate the secretion of IL-4.


CONCLUSIONS
Increased plasma carotenoid concentrations after vegetable juice consumption are accompanied by a time-delayed modulation of immune functions in healthy men consuming a low-carotenoid diet.
Watzl
Bernhard
B
Institute of Nutritional Physiology, Federal Research Centre for Nutrition, Haid-und-Neu-Strasse 9, DE-76131 Karlsruhe, Germany. bernhard.watzl@bfe.uni-karlsruhe.de
Bub
Achim
A
Briviba
Karlis
K
Rechkemmer
Gerhard
G
D000328:Adult; D000975:Antioxidants / Q000008:administration & dosage; D001628:Beverages; D001682:Biological Availability; D002338:Carotenoids / Q000008:administration & dosage* / Q000097:blood* / Q000493:pharmacokinetics; D002455:Cell Division; D018592:Cross-Over Studies; D016207:Cytokines / Q000378:metabolism; D018552:Daucus carota / Q000737:chemistry; D019587:Dietary Supplements; D004311:Double-Blind Method; D006801:Humans; D007107:Immune System / Q000187:drug effects / Q000502:physiology*; D007376:Interleukin-2 / Q000378:metabolism; D015847:Interleukin-4 / Q000378:metabolism; D007694:Killer Cells, Natural / Q000276:immunology; D000077276:Lycopene; D018551:Solanum lycopersicum / Q000737:chemistry; D008297:Male; D013601:T-Lymphocytes / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D000975:Antioxidants; D016207:Cytokines; D007376:Interleukin-2; D014409:Tumor Necrosis Factor-alpha; D015847:Interleukin-4; D002338:Carotenoids; D000077276:Lycopene