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Tomatoes, lycopene and cancer prevention

Posted by eric_oh 6a (My Page) on
Sat, Mar 3, 07 at 15:13

A study just out from Ohio State University suggests that if you're interested in taking lycopene for antioxidant and possible cancer prevention benefits, orange tomatoes are better than red ones. From the Columbus Dispatch article (registration may be required):

Lycopene absorption from the tangerine tomatoes was 2 1 /2 times higher than that absorbed from typical red tomato varieties.

"Thats what is so dramatic," said Steven Schwartz, an Ohio State food chemist and toxicologist who is head of the research project..The new study grew out of a discovery made several years ago by Schwartz and other researchers that our blood contains an abundance of a type of lycopene called cis-lycopene...Cis-lycopenes are found in tangerine tomatoes. Trans-lycopenes are found in red tomatoes...Despite having fewer lycopenes, tangerine tomatoes far outshined the red variety in terms of lycopene absorption...The study was published in the February issue of the Journal of Agricultural and Food Chemistry."

Lycopene is under investigation for a possible role in helping to prevent prostate cancer. One new study suggests it is not effective in prostate cancers that are no longer influenced by androgen hormones (as often occurs in late-stage disease), but work is ongoing.

One other interesting thing - the Dispatch article quoted earlier included a table on lycopene content of various vegetable preparations, and a single average serving of tomato sauce contained as much lycopene as a "high potency" expensive supplement capsule. So maybe it'd be a good idea to grow your own tangerine tomatoes and use them to make sauce for cooking.


Follow-Up Postings:

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RE: Tomatoes, lycopene and cancer prevention

Well if you really want to get interesting, a new study has come out raving about Vit. A in prevention of gastric cancer, but found no correlation with lycopene there. Of even more interest is the fact a completely unrelated study has said all things being equal, high Vit. A intake seems to predict early death (from any cause)! Are we driving ourselves crazy with all of this :-)?


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RE: Tomatoes, lycopene and cancer prevention

Lucy, maybe the confusion is because what one researcher calls "high" is different from what another calls "high". In the article below, high is only relative to food sources. On the other hand, the level of Vitamin A that was recently in the news as possible health risk is from high dose vitamins, so it's probably out of the ball park compared to the "high" Vit A in food. I wanted to give this as a link, but I couldn't get it right. So here's the whole thing from PubMed. Is it what you were referring to?

Am J Clin Nutr. 2007 Feb;85(2):497-503. Links
Vitamin A, retinol, and carotenoids and the risk of gastric cancer: a prospective cohort study.Larsson SC, Bergkvist L, Naslund I, Rutegard J, Wolk A.
Division of Nutritional Epidemiology, The National Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden. susanna.larsson@ki.se

BACKGROUND: Vitamin A may influence gastric carcinogenesis through its essential role in controlling cell proliferation and differentiation. However, epidemiologic studies of vitamin A, retinol (preformed vitamin A), and provitamin A carotenoids in relation to the risk of gastric cancer have documented inconsistent results. OBJECTIVE: The objective of the study was to examine the associations between intakes of vitamin A, retinol, and specific carotenoids and the risk of gastric cancer in a prospective population-based cohort study of Swedish adults. DESIGN: The study cohort consisted of 82 002 Swedish adults aged 45-83 y who had completed a food-frequency questionnaire in 1997. The participants were followed through June 2005. RESULTS: During a mean 7.2-y follow-up, 139 incident cases of gastric cancer were diagnosed. High intakes of vitamin A and retinol from foods only (dietary intake) and from foods and supplements combined (total intake) and of dietary alpha-carotene and beta-carotene were associated with a lower risk of gastric cancer. The multivariate relative risks for the highest versus lowest quartiles of intake were 0.53 (95% CI: 0.32, 0.89; P for trend = 0.02) for total vitamin A, 0.56 (95% CI: 0.33, 0.95; P for trend = 0.05) for total retinol, 0.50 (95% CI: 0.30, 0.83; P for trend = 0.03) for alpha-carotene, and 0.55 (95% CI: 0.32, 0.94; P for trend = 0.07) for beta-carotene. No significant associations were found for beta-cryptoxanthin, lutein and zeaxanthin, or lycopene intake. CONCLUSION: High intakes of vitamin A, retinol, and provitamin A carotenoids may reduce the risk of gastric cancer.


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RE: Tomatoes, lycopene and cancer prevention

Yes that's it alright.. I was trying to be 'light' about the whole thing, because every day another study comes out with more (or less) info. on what to do, believe, etc., but in no way did I mean to put down the research or suggest that doing it is not a good idea (spent too many years involved in it myself).


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RE: Tomatoes, lycopene and cancer prevention

Lucy, I know exactly how you feel. I was in research, too, and I know how hard we all tried to do things correctly, and get real answers, even if they were disappointing. No, I didn't think you were putting down the science at all. I just think that everyone, scientists included, should try to avoid using relative words like "high" without quantifying them. For instance, if you read the phrase "high protein" in articles on PubMed you will find a big range in what is called "high" and what is considered moderate because there are still differences in opinion on the ideal amount in the diet.


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