Lycopene from tangerine tomatoes more bioavailable: study
By Stephen Daniells
21/04/2008- The lycopene content of orange tomatoes is more bioavailable than the form of lycopene found in the red variety, says new research from the US.
Lycopene is an antioxidant that is present in red- and pink-coloured fruits and vegetables. As well as being used as a food colouring, it is also used in supplements. The role of lycopene in heart health and in reducing the risk of certain cancers is supported by a body of research.
Red tomatoes typically contain about 95 per cent of their lycopene as the all-trans-isomer, reported to be the most stable form. In tangerine tomatoes, on the other hand, the lycopene is present as tetra-cis-lycopene, a geometric isomer of all-trans-lycopene.
Geometric isomers refer to two or more substances that have the same chemical make-up but the arrangement of the constituent elements is different, giving the substances different properties.
But evidence is mounting that the tetra-cis-lycopene form is more bioavailable to humans. The new study, published in the International Journal of Food Sciences and Nutrition, adds to an earlier study by researchers at the Ohio State University and published in the Journal of Agricultural and Food Chemistry.
"Our results suggest that total lycopene concentrations can be increased by substituting tetra-cis-lycopene-rich tangerine tomatoes for common red tomatoes in the diet," wrote lead author Betty Jane Burri from the USDA's ARS.
The USDA researchers, in collaboration with the University of California, Davis, and Yeungnam University (Korea), recruited 21 healthy adults and fed them lunches containing 300 grams of sauce made from tangerine or red tomatoes per day.
Using blood samples to quantify bioavailability, data from the double-blind crossover trial showed that, while both sauces were associated with increased blood concentrations of lycopene, the increase of total and tetra-cis-lycopene was greater following consumption of the tangerine tomato sauce.
According to Burri and co-workers, absorption of the trans-lycopene isomer may have been enhanced by the presence of the cis isomer.
First report
According to the Ohio State study, the reason why the tangerine tomatoes predominantly contain the tetra-cis-lycopene is because they lack a specific enzyme that converts the cis- isomer to the more stable trans form.
This study, reportedly the first report of tangerine tomato consumption in humans, showed that absorption of the cis-form was 2.5 times higher.
A trend looking at different varieties of the fruit is developing, with other researchers reporting the health potential of purple tomatoes. The purple pigmentation is due to the presence of compounds called anthocyanins - the source of the blue, purple and red colour of berries, grapes and some other fruits and vegetables. These pigments also function as antioxidants, believed to protect the human body from oxidative damage that may lead to heart disease, cancer and ageing.
Source: International Journal of Food Sciences and Nutrition
What concerns me about this study, is that it says and I quote.
According to the Ohio State study, the reason why the tangerine tomatoes predominantly contain the tetra-cis-lycopene is because they lack a specific enzyme that converts the cis- isomer to the more stable trans form.
May I'm not getting the meaning of this part, but I don't understand how something being described as less stable, can work better? If it's unstable, how does the instability manifest itself? Describing it more or less as unstable, in my mind would imply side effects and / or lowered performance.
So that section of the article appears a bit confusing to me.
but I don't understand how something being described as less stable, can work better? If it's unstable, how does the instability manifest itself? Describing it more or less as unstable, in my mind would imply side effects and / or lowered performance.
Boss,
I'm not sure if this will answer your question or not. But, I'll give it a shot:
Just because something is less-stable doesn't mean that it's less effective - I don't think.
An example might be: A pasteurized glass of juice is more stable (for a longer period of time) than a fresh glass of juice but that doesn't mean it's necessarily more beneficial.
Many antioxidants are quite short-lived in the body (possessing a short half-life). This doesn't mean that they're side-effect prone or that they're not useful.
For instance, lycopene has longer activity in the body as compared to ascorbic acid. Both are useful. One is vital. The latter (vital one) is the least stable of the two.
Orange Tomatoes - A Better Source of Lycopene
Linear Mode
