According to Ohio State University researchers processing the red tomato boosts the absorption of the all important antioxidant lycopene when consumed. We usually think of processed food not being healthy, but in this case processing is better.
Lycopene belongs to a family of antioxidants named carotenoids. Carotenoids’ antioxidant properties have long been associated with protecting cells and regulating cell growth and death, all of which play a role in multiple disease processes, including protecting against prostate cancer.
When lycopene molecules in tomatoes are combined with fat and subjected to intense heat during the processing procedure, the molecules are restructured in a way that appears to ease their movement into the bloodstream and tissue.
Normally, lycopene molecules in human blood are configured in a bent shape. In the natural, unprocessed red tomato the lycopene molecule are in a linear configuration, a structure that hinders the molecule’s absorption through the intestinal walls and into the blood stream.
In order to gain the benefits of the lycopene the body somehow transforms lycopene molecules through reactions that have yet to be identified so that the lycopene are able to be absorbed into the blood and transported to tissue, or they must be bent prior to ingestion.
Heating red tomatoes and adding oils during processing has the potential of creating a sauce that contains the bent molecular forms of lycopene.
Steven Schwartz, an investigator in Ohio State’s Comprehensive Cancer Center and a professor of food science and technology at Ohio State conducted a small clinical trial in collaboration with Steven Clinton, a medical oncologist and physician scientist in Ohio State’s Comprehensive Cancer Center. The trial demonstrated that people had more lycopene in their blood after eating the specially processed sauce than they did after eating regular red tomato sauce. The trial was described at the August 20 at the American Chemical Society meeting in Philadelphia.
“What we have found is we can take the red tomato molecular form of lycopene and by processing it and heating it in combination with added oil, we can change the shape of the molecule so it is configured in this bent form,” Schwartz said.
Schwartz hypothesize that lycopene in its linear form will be absorbed into the bloodstream, but not easily. The bent forms of lycopene are able to more easily absorbed during digestion, and increasing amounts of the antioxidant in that form are more likely to be transported to the blood along with the fats.
The researchers processed two sauces: a sauce rich in cis-lycopene, the bent configuration, and a sauce containing mostly all-trans-lycopene, the linear form. Both sauces were flavored similarly and initially heated using the same methods. Corn oil was added to both sauces as well. But the sauce designed to produce lycopene in the bent molecular forms was subjected to a second round of heating at 260 degrees Fahrenheit for 40 minutes. The resulting sauce contained nine times more cis-isomers (bent form) than the regularly processed sauce.
The study only included twelve people; all ate both kinds of sauce over the course of the study. After completing each meal, blood samples were taken seven times during the following 9 1/2 hours to measure lycopene levels. The scientists used a special testing method to analyze lycopene levels in the blood associated only with the tomato sauce meal, avoiding any other possible sources of those compounds in the bloodstream.
After eating the specially processed sauce when compared to eating the regular sauce the lycopene blood levels were 55 percent higher. This finding reinforced the expectation that the bent forms of lycopene are more easily absorbed into human blood, Schwartz said.
Details of this study were first published in the British Journal of Nutrition in 2007. Additional clinical trials are ongoing.
Most currently available commercial products don’t contain the bent forms of lycopene molecules. However, some home cooking practices might be able to produce the same results as the special processing method.
“Some people like to cook tomato sauce for prolonged periods, sometimes reheating it day after day, because it tastes better on the second and third day. They add fat by using oil or meat, and that’s going to start to induce cis-isomers of lycopene if fat is present and the cooking continues,” Schwartz said. “So it’s possible people could induce this process and increase lycopene absorption by routine food preparation procedures, as well.”
So, cook and re-cook your tomato sauce. Also, don’t forget to enjoy it.
Joel Nowak MA, MSW