Posted on 12/14/2020 11:55:01 AM PST by ConservativeMind
Epidemiological evidence suggests that diets rich in tomatoes and tomato products may be protective against risk for certain cancers, especially prostate cancer. The carotenoid lycopene has received the most attention as the compound in tomatoes responsible for this noted decrease in cancer risk. In raw, red tomatoes, approximately 95% of the total lycopene is present in the all-trans form. Despite the predominance of dietary all-trans-lycopene, cis-isomers account for 58-73% of total lycopene in human serum, and a surprisingly high 79-88% in benign or malignant prostate tissue. This observation is related to isomerization in vivo, as demonstrated by conventional and tracer studies, but also to the preferential absorption of cis-lycopene, with the exact mechanisms yet to be elucidated. Compared to the all-trans forms, cis-lycopene isomers are less likely to crystallize, more oil/hydrocarbon soluble, preferentially micellarized, and are more readily taken up by intestinal cells.
In contrast to red tomatoes, tangerine tomatoes are unique cis-lycopene rich tomatoes developed through conventional breeding techniques (Figure 1). These tomatoes have the recessive mutation tangerine and lack a functional form of the enzyme carotenoid isomerase (CRTISO), which converts poly-cis- into all-trans-lycopene, and is necessary for the biosynthesis of downstream cyclized carotenoids. As a result, tangerine tomatoes accumulate several cis-lycopene isomers, with tetra-cis-lycopene ((7Z, 9Z, 7′Z, 9′Z)-lycopene, also called prolycopene) predominating at the expense of the all-trans form. Tetra-cis-lycopene absorbs light maximally approximately 35 nm below all-trans-lycopene, resulting in tomatoes with an orange color (Figure 1, A2). Most processed foods containing tomato have concentrations of cis isomers less than 10% although severe food processing conditions can increase the percentage of cis-lycopenes and thus increase bioavailability. Stemming from this result, others have suggested tetra-cis-lycopene may be more bioavailable than all-trans.
(Excerpt) Read more at ncbi.nlm.nih.gov ...
Heating tomatoes for a limited period of time, like we do with sauce, helps convert a bit of the “trans” to “cis.” Heat needs to be under 180F and seemingly lycopene starts to disintegrate beyond an hour of such heat. Additionally, heating it with fat helps, too. However, one can convert it most with a healthy dose of onion and garlic with fat for an hour. In such cases, expect over 40-50% of the lycopene to be “cis.”
Lycopene helps reduce prostate size and is also needed for healthy breast tissue.
This research shows tangerine (orange) tomatoes, have the greatest amount of “cis” in raw form. Do note cooking a high cis source will turn it into trans.
I identify as a red tomato.
Oh, thought it was tangerines, which would not be keto friendly.
I’ll be making ravioli and meatballs for Christmas.
“...will turn it into trans. ....”
I become adverse to trans most anything. Is that bad?
“...will turn it into trans. ....”
I’ve become adverse to trans most anything. Is that bad?
Thus turning cis into trans through the nutrients of red tomatoes.
Catch Up with Ketchup for your health!
Bump
Ravioli? Isn’t pasta rather high in carbs for the Keto diet?
It’s Christmas. :)
I stayed with Mom six days over Thanksgiving. I took chocolate chip cookies, she had ice cream, plus turkey and stuffing, sweet potatoes, fruit salad, etc. I gained six pounds, lost that plus three more.
I got a new scale last week that calculates percentage body fat. I’m now slim, thought I was below 20%, but no, it says 27.5%. I decided to take action, so I’m nearing the end of a 72 hour fast, 2.5 more to go. Zero calories since 5 PM Friday. I almost caved at 55 hours but it passed. Other than that it’s been pretty easy.
Conversion therapy for tomatos and tangerines: I think that’s illegal in California.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.