Breakfast cereals lose potential cancer-fighting compounds during food processing, according to research.
As the average American diet consists of many different forms of heavily processed foods, from burgers to breakfast cereals, researchers wanted to unpick how this could affect the way our bodies absorb what are known as phenolic acids.
These are present in plants, and are of interest to scientists because they are thought to protect against diseases including coronary heart disease, cancer, and stroke.
The team at the University of Illinois studied what happens to phenolic acids in corn when it is turned into cornflakes.
To test their hypothesis, the researchers made cornflakes from 19 types of corn with varying levels of phenolic acids.
In corn, the phenolic compounds are mostly found in the outer shell of the kernel, or bran, which is removed during the milling process. The flaking grit and corn toasting stages of this process were identified as the biggest obstacles to maintaining phenolic compounds in the product.
Dr. Carrie Butts-Wilmsmeyer, lead author of the study and research assistant professor in the Department of Crop Sciences at the University of Illinois, said in a statement: "What we found was not particularly good news, but it was interesting. Regardless of the concentration in the grain at the beginning, the dry-milling process removes the majority of phenolics."
As heat can release phenolic compounds, the researchers tried heating the milled corn to see if it would boost levels of phenolics.
"We did see an increase in soluble phenolics, but it was so small, you could have gotten the same benefit from going to the refrigerator and eating a few blueberries," said Butts-Wilmsmeyer.
The researchers said a new line of inquiry could be whether waste products from dry milling could be used to fortify foods. That could help Americans who live in food deserts, said Butts-Wilmsmeyer.
The research was partly funded by Kellogg Company, the agricultural company Dow AgroSciences, and the National Institute of Food and Agriculture. It was published in the Journal of Visualized Experiments.
The act of processing the food itself is not the only obstacle to good health, it seems. A study published earlier this year indicated eating out can raise the risk of being exposed to potentially harmful chemicals called phthalates. Used to make plastics soft and flexible, they have been linked to breast cancer, fertility issues, and type 2 diabetes in previous studies.
Author Ami Zota, an assistant professor of environmental and occupational health at Milken Institute School of Public Health (Milken Institute SPH) at the George Washington University, said in a statement at the time: "This study suggests food prepared at home is less likely to contain high levels of phthalates, chemicals linked to fertility problems, pregnancy complications and other health issues."