Medical Forum / Diseases and Disorders / Cancer / April 2006
Prostate tumours shrunk by lycopene, vitamin E combo
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ironjustice@aol.com - 15 Apr 2006 19:31 GMT http://www.nutraingredients.com/news/ng.asp?n=67083-lycopene-vitamin-e-prostate- cancer
Prostate tumours shrunk by lycopene, vitamin E combo
By Stephen Daniells
14/04/2006 - A combination of lycopene and vitamin E suppressed the growth of prostate cancer in mice, but had no effect when used independently, say Dutch researchers.
The role of tomato and its extracts to protect against prostate cancer has been reported in several epidemiological studies, which lycopene supplement producers have been quick to promote. The new research, led by Professor Wytske van Weerden from Erasmus MC in Rotterdam, casts doubt on the effectiveness of lycopene by itself, and suggests a synergetic effect with vitamin E, another nutrient naturally found in tomatoes. The study, published in the May issue of the Journal of Nutrition (Vol. 136, pp. 1287-1293), followed the effects on differing supplementation doses and combinations of lycopene and vitamin E on 54 mice inoculated with prostate cancer cells.
The mice were divided into six equal groups. The mice were fed a standard low vitamin E rodent diet, and three days after inoculation the diet was supplemented with one of the following: nothing (placebo); lycopene only (5 milligrams per kilogram of body weight (mg/kg BW) or 50 mg/kg BW); vitamin E only (5 mg/kg BW or 50 mg/kg BW); or vitamin E plus lycopene (5 mg/kg BW each).
BASF provided both nutrients: lycopene was provided as LycoVit 10 per cent, and vitamin E as alpha-tocopherol 50 per cent powder.
The researchers found that, after 95 days of supplementation, none of the single supplements, regardless of dose, had any effect on the tumour size.
"Compared with the control, the combined mixture of lycopene and vitamin E, at five mg/kg BW each, suppressed the growth of the prostate xenograft by 73 per cent at day 42," wrote lead author Jacqueline Limpens.
Consequently, the mice receiving the combined supplement also lived 40 per cent longer than the placebo group.
While the single supplements did not effect tumour size, the group receiving five mg/kg BW of lycopene did show slower tumour growth and a 19 per cent longer survival rate.
The researchers also reported that levels of the so-called prostate specific antigen (PSA), a protein that is used as a marker for the disease, tended to be lower in the combo supplement group. Plasma PSA levels were proportional to tumour size for all groups, adding support for the use of PSA as a marker of the disease.
Previous research has linked the benefits of tomatoes to the lycopene content of the fruit, conclusions that are not in-line with the results of Limpens and her colleagues.
Indeed, it appears as if lycopene and vitamin E exert a cooperative interaction to protect against prostate cancer growth. The mechanism, say the researchers, remains speculative but could be due to lower oxidative stress, altered hormone and growth factor signals, or apoptosis (programmed cell death).
"On the basis of our findings... we are currently assessing the effects of lycopene-vitamin E supplementation on rising PSA-levels in an exploratory phase II clinical prostate cancer trial," said the researchers.
According to the European School of Oncology, over half a million news cases of prostate cancer are diagnosed every year world wide, and the cancer is the direct cause of over 200,000 deaths. More worryingly, the incidence of the disease is increasing with a rise of 1.7 per cent over 15 years.
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Juhana Harju - 16 Apr 2006 06:06 GMT : Consequently, the mice receiving the combined supplement also lived 40 : per cent longer than the placebo group. That is impressive.
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SPHINX Technologies - 29 Apr 2006 06:38 GMT Do you know what form of alpha tocopherol these researchers used, i.e. synthetic (d + L in equal concentrations, typically) or natural (entirely d-alpha tocopherol, since plants are much cleverer, or more precisely, their Designer was much cleverer, than the usual designers of chemical synthesis process plants of the human-designed sort) ? According to most nutritional therapy experts, only the d stereoisomer is therapeutically effective, and the L stereoisomer may actually be harmful and certainly is not particularly useful. I have seen differing opinions on whether pure alpha tocopherol or mixed tocopherols are more effective, and I have seen allegations that pure alpha tocopherol is more likely to produce unpleasant cardiac side- effects. E.g., vitamin E has a reputation for exacerbating problems with hypertension in those who already have a tendency to it. I am not sure if the forms of tocopherol other than alpha are less troublesome precisely because they are biologically less active than alpha or for some other reason. Incidentally, some of the old-time experts in nutritional therapy were highly critical of early tests of the efficacy of vitamin E because those tests used mixed tocopherols and synthetic ones at that, thus a mixture which these experts said had long been known (and this was a long time ago!) to consist of only about 5% useful, active ingredient (namely the d-alpha form, which they said was known to be the only one that is useful for therapeutic purposes). I think there was suspicion that whoever funded that particular test did not want vitamin E to be shown to be useful.
I wonder if the researchers whose work you summarized mentioned any of these additional issues, at least the objective scientific ones?
I think it is very positive that they are looking at combinations of nutrients. This gets progressively harder to do as you include more and more different kinds of molecules, but that is a separate question from whether or not it is important to understand the interactions... as this study illustrates.
-John S., Wellesley Hills, MA ------------------------
>http://www.nutraingredients.com/news/ng.asp?n=67083-lycopene-vitamin-e-prostate- cancer > [quoted text clipped - 82 lines] >DEAD PEOPLE WALKING >http://pages.ivillage.com/ironjustice/deadpeoplewalking ironjustice@aol.com - 30 Apr 2006 04:12 GMT The email address here may give you those answers.
2006 American Society for Nutrition J. Nutr. 136:1287-1293, May 2006
-------------------------------------------------------------------------------- Nutrition and Disease Combined Lycopene and Vitamin E Treatment Suppresses the Growth of PC-346C Human Prostate Cancer Cells in Nude Mice Jacqueline Limpens*, Fritz H. Schrder*, Corrina M. A. de Ridder*, Cindy A. Bolder*, Mark F. Wildhagen*, Ute C. Obermller-Jevic, Klaus Krmer and Wytske M. van Weerden*,1
* Department of Urology, Erasmus MC, Rotterdam, The Netherlands and BASF Aktiengesellschaft, Ludwigshafen, Germany
1 To whom correspondence should be addressed. E-mail: w.vanweerden@erasmusmc.nl.
Epidemiologic studies have repeatedly associated a high intake of lycopene and vitamin E with reduced prostate cancer risk. The present study examined the ability of the 2 compounds to reduce tumor growth and prostate-specific antigen (PSA) plasma levels in the PC-346C orthotopic mouse model of human prostate cancer. Three days after intraprostatic tumor injection, NMRI nu/nu mice were administered a daily oral dose of synthetic lycopene [5 or 50 mg/kg body weight (BW)], vitamin E in the form of -tocopheryl acetate (5 or 50 mg/kg BW), a mixture of lycopene and vitamin E (5 mg/kg BW each), or vehicle. Intraprostatic tumor volume and plasma PSA concentrations were measured at regular intervals. Mice were killed when the tumor load exceeded 1000 mm3 or on d 95 when the study was terminated. Prostate and liver were analyzed by HPLC for lycopene isomers and - and , -tocopherol concentrations. None of the single treatments significantly reduced tumor volume. In contrast, combined treatment with lycopene and vitamin E, at 5 mg/kg BW each, suppressed orthotopic growth of PC-346C prostate tumors by 73% at d 42 (P < 0.05) and increased median survival time by 40% from 47 to 66 d (P = 0.02). The PSA index (PSA:tumor volume ratio) did not differ between experimental groups, indicating that PSA levels were not selectively affected. Lycopene was detected only in mice supplemented with lycopene. As in humans, most tissue lycopene was in the cis-isomer conformation, whereas 77% trans-lycopene was used in the dosing material. Liver -tocopherol concentrations were increased in mice supplemented with both 50 mg/kg (226%, P < 0.05) and 5 mg/kg vitamin E (41%, P < 0.05), whereas prostate -tocopherol concentrations were increased only by the higher dose (83%, P < 0.05). Our data provide evidence that lycopene combined with vitamin E may inhibit the growth of prostate cancer and that PSA can serve as a biomarker of tumor response for this treatment regimen.
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KEY WORDS: prostate cancer lycopene vitamin E chemoprevention tumor xenograft model
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