Peak season: May to October
Known scientifically as Zea mays, corn has been a staple food in civilizations dating back 7,000 years. Native to the Americas, it is thought to have originated in either Mexico or Central America. When explorers came to the New World, they found corn growing from Chile to Canada. It was consumed both as a vegetable and a grain. Corn was brought back to Europe by Spanish and Portuguese explorers who later introduced it throughout the world.
Traditional dishes made with corn often included a small amount of lime in the mineral form as calcium oxide made by burning limestone. Lime was added to cornmeal to free up the B vitamin, niacin, making it available for absorption. Niacin deficiency causes a disease called pellagra, a dermatologic disorder, which plagued many people in native times until the addition of lime to corn was discovered.
Today, the largest commercial producers of corn include the US, China, Brazil, Mexico and Russia, but is grown on every continent except Antarctica. Corn consumed off the cob, known as sweet corn, is not the same corn used to make ethanol and high-fructose corn syrup. Of the more than 94 million acres of corn grown in the US, less than 1% of it is sweet corn.
Besides the stalk, a corn plant consists of a tassel (male part) and the ear (female part). The ear consists of a cob, eggs that become the kernels and silks. Pollination occurs when pollen from the tassels falls on the silks. A corn plant may produce many ears, but the uppermost will grow to be the largest.
Rich in Vitamin B1 (thiamin), Vitamin B5 (pantothenic acid), folate, fiber, Vitamin C, phosphorus and manganese, one cup of cooked yellow corn has only 177 calories.
Corn contributes to cardiovascular health from the high level of fiber and folate, a B vitamin that lowers homocysteine levels which can cause damage to blood vessels if elevated. Corn is rich in beta-cryptoxanthin, a phytochemical shown to reduce the risk of lung cancer, even in smokers (1). The thiamin in corn is not only important to prevent pellagra, but it is an integral component to energy production and critical for brain cell and cognitive function/memory. Pantothenic acid is necessary for carbohydrate, protein and lipid metabolism.
Corn, consumed as a whole grain, is one of many whole grains which contain phenolics, powerful antioxidants that work in many ways to prevent disease. Phenolics have been widely studied. Dr. Liu, an associate professor in the Department of Food Science at Cornell University in New York, has published many articles on this subject. Dr. Liu believes that the key to whole grains and plant foods being powerful cancer-fighting agents is precisely in their wholeness. “Different plant foods have different phytochemicals. These substances go to different organs, tissues and cells, where they perform different functions. What your body needs to ward off disease is this synergistic effect – this teamwork – that is produced by eating a wide variety of plant foods, including whole grains.” (2)
How to select and store:
Look for corn with fresh, green husks and not dried out. Heat rapidly converts the sugar in corn to starch, so store with husks on in a plastic bag in the refrigerator. Corn is best consumed on the day you buy it, but it can be frozen on the cob if blanched first and placed in heavy freezer bags, lasting up to 1 year. The kernels can be removed from blanched ears and frozen in freezer containers for up to 2-3 months.
Corn comes in many other colors besides yellow, such as white, red, blue, pink, black, spotted and striped. Blue corn contains 20% more protein and 8% less starch, giving it a lower glycemic index than white or yellow corn, so a good choice if concerned about weight or blood sugar levels.
A large percentage of conventionally grown corn in the US comes from genetically modified (GM) seeds. If you want to reduce your exposure to these products, choose organically grown corn, since USDA organic regulations prohibit use of GM seeds.
1.Yuan JM, Ross RK, Chu XD, Gao YT, Yu MC. Prediagnostic levels of serum beta-cryptoxanthin and retinol predict smoking-related lung cancer risk in Shanghai, China. Cancer Epidemiol
2.Biomarkers Prev 2001 Jul;10(7):767-73 2001Liu RH. Potential synergy of phytochemicals in cancer prevention: mechanism of action. J Nutr. 2004 Dec;134(12 Suppl):3479S-3485S.