A Colorado State University study evaluating the effect of storage antioxidants and anti-cancer properties of colored potatoes shows that while the amount of antioxidants properties increases, the anti-cancer properties of those compounds are suppressed.
The research results might also apply to all produce, which shores up the argument for eating local, in-season produce that has not been stored for a long period.
Some vegetables and fruits are stored up to a year before they appear in grocery stores, according to the project researchers.
Potato antioxidants are active against colon cancer. These studies show that purple- and red-fleshed potatoes are higher in these beneficial antioxidants. In fact, the research shows that colored potatoes can deliver antioxidants in levels comparable to blueberries and grapes if they have not been stored for prolonged periods.
While levels of white potatoes are a rich source of antioxidants as well, according to researchers, colored potatoes have higher levels of anti-cancer, antioxidant and anti-inflammatory compounds.
As an example of antioxidant properties in potatoes, a half of a recently harvested, baked purple potato delivered "significant amounts" of compounds that fight color cancer cells, the researchers report.
To get the same level of similar compounds in other foods, you would need to eat three and one-half recently-harvested baked white potatoes, 45 blueberries or 25 grapes, the researchers note.
"If a consumer wants to maximize the health benefits of potatoes, they should shop for locally-grown, in-season red or purple potatoes," advises Jairam Vanamala (cq), a CSU researcher in the Department of Food Science and Human Nutrition.
The study has documented the cancer-fighting antioxidants of plant foods for several years.
Future studies should explore farm-to-fork operations on the heath-benefiting properties of plant foods, with an aim to discover optimal conditions to preserve anti-cancer properties, says Vanamala.
The study is funded by a National Research Initiative Grant from the U.S. Department of Agriculture.