Isomerization of Lycopene in the Gastric Milieu

Re, Roberta; Fraser, Paul D.; Long, Marianne T.; Bramley, Peter M.; Rice‐Evans, Catherine

doi:10.1006/bbrc.2001.4366

Cited by 75 publications

(64 citation statements)

References 12 publications

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“…The lack of any significant increase in the cis-trans ␤-carotene and cis-trans lycopene ratios in the stomach during digestion led to the conclusion that there was no significant cis-trans isomerization of these carotenoids in the human stomach. This result seems at variance with a recent result obtained in vitro (34), which showed an effect of acidic pH on lycopene isomerization. However, in that study, the isomerization was observed at the very low pH of 1.6, a value found only in the fasting stomach and not during the digestion of the complex lycopene-rich meal used in this study (see Fig.…”

Section: Discussioncontrasting

confidence: 79%

Processing of vegetable-borne carotenoids in the human stomach and duodenum

Tyssandier

Reboul

Dumas

et al. 2003

American Journal of Physiology-Gastrointestinal and Liver Physi

239

186

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Carotenoids are thought to diminish the incidence of certain degenerative diseases, but the mechanisms involved in their intestinal absorption are poorly understood. Our aim was to obtain basic data on the fate of carotenoids in the human stomach and duodenum. Ten healthy men were intragastrically fed three liquid test meals differing only in the vegetable added 3 wk apart and in a random order. They contained 40 g sunflower oil and mashed vegetables as the sole source of carotenoids. Tomato purée provided 10 mg lycopene as the main carotenoid, chopped spinach (10 mg lutein), and carrot purée (10 mg β-carotene). Samples of stomach and duodenal contents and blood samples were collected at regular time intervals after meal intake. all -trans and ciscarotenoids were assayed in stomach and duodenal contents, in the fat and aqueous phases of those contents, and in chylomicrons. The cis-trans β-carotene and lycopene ratios did not significantly vary in the stomach during digestion. Carotenoids were recovered in the fat phase present in the stomach during digestion. The proportion of all -trans carotenoids found in the micellar phase of the duodenum was as follows (means ± SE): lutein (5.6 ± 0.4%), β-carotene (4.7 ± 0.3%), lycopene (2.0 ± 0.2%). The proportion of 13- cis β-carotene in the micellar phase was significantly higher (14.8 ± 1.6%) than that of the all -trans isomer (4.7 ± 0.3%). There was no significant variation in chylomicron lycopene after the tomato meal, whereas there was significant increase in chylomicron β-carotene and lutein after the carrot and the spinach meals, respectively. There is no significant cis-transisomerization of β-carotene and lycopene in the human stomach. The stomach initiates the transfer of carotenoids from the vegetable matrix to the fat phase of the meal. Lycopene is less efficiently transferred to micelles than β-carotene and lutein. The very small transfer of carotenoids from their vegetable matrices to micelles explains the poor bioavailability of these phytomicroconstituents.

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Section: Discussioncontrasting

confidence: 79%

Processing of vegetable-borne carotenoids in the human stomach and duodenum

Tyssandier

Reboul

Dumas

et al. 2003

American Journal of Physiology-Gastrointestinal and Liver Physi

239

186

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“…However, when tomato puree was incubated for 3 h with simulated gastric juice, the cis-lycopene content was only 18%, versus 10% on incubation with water. Thus, gastric pH and food matrix influence isomerization and subsequent absorption and increased bioavailability of cis-lycopene (Re et al, 2001).…”

Section: Bioavailability Of Lycopenementioning

confidence: 99%

Tomatoes versus lycopene in oxidative stress and carcinogenesis: conclusions from clinical trials

2006

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Objective: To review the effects of tomato product supplementation, containing lycopene, on biomarkers of oxidative stress and carcinogenesis in human clinical trials. Results: Supplementation of tomato products, containing lycopene, has been shown to lower biomarkers of oxidative stress and carcinogenesis in healthy and type II diabetic patients, and prostate cancer patients, respectively. Processed tomato products like tomato juice, tomato paste, tomato puree, tomato ketchup and tomato oleoresin have been shown to provide bioavailable sources of lycopene, with consequent increases in plasma lycopene levels versus baseline. Dietary fats enhance this process and should be consumed together with food sources of lycopene. The mechanisms of action involve protection of plasma lipoproteins, lymphocyte DNA and serum proteins against oxidative damage, and anticarcinogenic effects, including reduction of prostate-specific antigen, upregulation of connexin expression and overall decrease in prostate tumor aggressiveness. There is limited in vivo data on the health benefits of lycopene alone. Most of the clinical trials with tomato products suggest a synergistic action of lycopene with other nutrients, in lowering biomarkers of oxidative stress and carcinogenesis. Conclusions: Consumption of processed tomato products, containing lycopene, is of significant health benefit and can be attributed to a combination of naturally occurring nutrients in tomatoes. Lycopene, the main tomato carotenoid, contributes to this effect, but its role per se remains to be investigated.

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“…However, when tomato puree was incubated for 3h with simulated gastric juice, the cis-lycopene content was only 18% versus 10% on incubation with water. Thus, gastric pH and food matrix influence isomerization and subsequent absorption and increased bioavailability of cis-lycopene (Re et al, 2001). …”

Section: Bioavailability Of Lycopenementioning

confidence: 99%

The Anti-Atherogenic Effects of Lycopene

Basuny¹

2012

Lipoproteins - Role in Health and Diseases

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Isomerization of Lycopene in the Gastric Milieu

Cited by 75 publications

References 12 publications

Processing of vegetable-borne carotenoids in the human stomach and duodenum

Processing of vegetable-borne carotenoids in the human stomach and duodenum

Tomatoes versus lycopene in oxidative stress and carcinogenesis: conclusions from clinical trials

The Anti-Atherogenic Effects of Lycopene

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