Food Of the Week: Corn

This information comes from The World's Healthiest Foods www.whfoods.org

What vegetable is more synonymous with the coming of summer than freshly picked corn on the cob? Although corn is now available in markets year-round, it is the locally grown varieties that you can purchase during the summer months that not only tastes the best but are usually the least expensive.

Corn grows in "ears," each of which is covered in rows of kernels that are then protected by the silk-like threads called "corn silk" and encased in a husk. Corn is known scientifically as Zea mays. This moniker reflects its traditional name, maize, by which it was known to the Native Americans as well as many other cultures throughout the world.

Go enjoy some corn!



Health Benefits
Description
History
How to Select and Store
How to Enjoy
Safety
Nutritional Profile
References
Health Benefits

Hot, fresh corn-on-the-cob is an almost essential part of any summertime party. Fortunately, it is also worthy part of any healthful menu. Our food ranking system qualified corn as a good source of many nutrients including thiamin (vitamin B1), pantothenic acid (vitamin B5), folate, dietary fiber, vitamin C, phosphorus and manganese.

Corn for Cardiovascular Health

Corn's contribution to heart health lies not just in its fiber, but in the significant amounts of folate that corn supplies.

Folate, which you may know about as a B-vitamin needed to prevent birth defects, also helps to lower levels of homocysteine, an amino acid that is an intermediate product in an important metabolic process called the methylation cycle. Homocysteine can directly damage blood vessels, so elevated blood levels of this dangerous molecule are an independent risk factor for heart attack, stroke, or peripheral vascular disease, and are found in between 20-40% of patients with heart disease. It has been estimated that consumption of 100% of the daily value (DV) of folate would, by itself, reduce the number of heart attacks suffered by Americans each year by 10%. Folate-rich diets are also associated with a reduced risk of colon cancer. A cup of corn supplies 19.0% of the DV for folate

Supports Lung Health

Consuming foods rich in beta-cryptoxanthin, an orange-red carotenoid found in highest amounts in corn, pumpkin, papaya, red bell peppers, tangerines, oranges and peaches, may significantly lower one's risk of developing lung cancer. A study published in Cancer Epidemiology, Biomarkers and Prevention reviewed dietary and lifestyle data collected from over 63,000 adults in Shanghai, China, who were followed for 8 years. Those eating the most crytpoxanthin-rich foods showed a 27% reduction in lung cancer risk. When current smokers were evaluated, those who were also in the group consuming the most cryptoxanthin-rich foods were found to have a 37% lower risk of lung cancer compared to smokers who ate the least of these health-protective foods.

Maintain Your Memory with Thiamin (Vitamin B1)

Corn is a good source of thiamin, providing about one-quarter (24.0%) of the daily value for this nutrient in a single cup. Thiamin is an integral participant in enzymatic reactions central to energy production and is also critical for brain cell/cognitive function. This is because thiamin is needed for the synthesis of acetylcholine, a neurotransmitter essential for memory, whose lack has been found to be a significant contributing factor in age-related impairment in mental function (senility) and Alzheimer's disease. In fact, Alzheimer's disease is clinically characterized by a decrease in acetylcholine levels. Don't forget to make corn a staple in your healthy diet.

Support for Energy Production, Even Under Stress

In addition to its thiamin, corn is a good source of pantothenic acid. This B vitamin is necessary for carbohydrate, protein and lipid metabolism. Pantothenic acid is an especially valuable B-vitamin when you're under stress since it supports the function of the adrenal glands. A cup of corn supplies 14.4% of the daily value for pantothenic acid.

Health-Promoting Activity Equal to or Even Higher than that of Vegetables and Fruits

Research reported at the American Institute for Cancer Research (AICR) International Conference on Food, Nutrition and Cancer, by Rui Hai Liu, M.D., Ph.D., and his colleagues at Cornell University shows that whole grains, such as corn, contain many powerful phytonutrients whose activity has gone unrecognized because research methods have overlooked them.

Despite the fact that for years researchers have been measuring the antioxidant power of a wide array of phytonutrients, they have typically measured only the "free" forms of these substances, which dissolve quickly and are immediately absorbed into the bloodstream. They have not looked at the "bound" forms, which are attached to the walls of plant cells and must be released by intestinal bacteria during digestion before they can be absorbed.

Phenolics, powerful antioxidants that work in multiple ways to prevent disease, are one major class of phytonutrients that have been widely studied. Included in this broad category are such compounds as quercetin, curcumin, ellagic acid, catechins, and many others that appear frequently in the health news.

When Dr. Liu and his colleagues measured the relative amounts of phenolics, and whether they were present in bound or free form, in common fruits and vegetables like apples, red grapes, broccoli and spinach, they found that phenolics in the "free" form averaged 76% of the total number of phenolics in these foods. In whole grains, however, "free" phenolics accounted for less than 1% of the total, while the remaining 99% were in "bound" form.

In his presentation, Dr. Liu explained that because researchers have examined whole grains with the same process used to measure antioxidants in vegetables and fruits-looking for their content of "free" phenolics"-the amount and activity of antioxidants in whole grains has been vastly underestimated.

Despite the differences in fruits', vegetables' and whole grains' content of "free" and "bound" phenolics, the total antioxidant activity in all three types of whole foods is similar, according to Dr. Liu's research. His team measured the antioxidant activity of various foods, assigning each a rating based on a formula (micromoles of vitamin C equivalent per gram). Broccoli and spinach measured 80 and 81, respectively; apple and banana measured 98 and 65; and of the whole grains tested, corn measured 181, whole wheat 77, oats 75, and brown rice 56.

Dr. Liu's findings may help explain why studies have shown that populations eating diets high in fiber-rich whole grains consistently have lower risk for colon cancer, yet short-term clinical trials that have focused on fiber alone in lowering colon cancer risk, often to the point of giving subjects isolated fiber supplements, yield inconsistent results. The explanation is most likely that these studies have not taken into account the interactive effects of all the nutrients in whole grains-not just their fiber, but also their many phytonutrients. As far as whole grains are concerned, Dr. Liu believes that the key to their powerful cancer-fighting potential is precisely their wholeness. A grain of whole wheat consists of three parts-its endosperm (starch), bran and germ. When wheat-or any whole grain-is refined, its bran and germ are removed. Although these two parts make up only 15-17% of the grain's weight, they contain 83% of its phenolics. Dr. Liu says his recent findings on the antioxidant content of whole grains reinforce the message that a variety of foods should be eaten good health. "Different plant foods have different phytochemicals," he said. "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."

Description

Corn is an icon of American culture. Not only does it represent Native American traditions and serve as a symbol of both summertime BBQ fun and a night out at the movies, but corn, in the form of corn syrup, is also an added ingredient in many other foods that we consume in our daily diets.

Although we often associate corn with the color yellow, it actually comes in host of different varieties featuring an array of different colors, such as red, pink, black, and blue. Corn grows in "ears," each of which is covered in rows of kernels that are then protected by the silk-like threads called "corn silk" and encased in a husk.

Corn is known scientifically as Zea mays. This moniker reflect its traditional name, maize, by which it is known throughout many areas of the world.

History

An important food plant that is native to America, corn is thought to have originated in either Mexico or Central America. It has been a staple food in native civilizations since primitive times with some of the earliest traces of meal made from corn dating back about 7,000 years.

Corn has played and still continues to play a vital role in Native American cultures. It has been greatly honored for its ability to provide not only sustenance as food but shelter, fuel, decoration and more. Because of the vital role that corn played in the livelihood of many native cultures, it has been one of the important icons represented in the mythological traditions of the Mayan, Aztec and Incan civilizations.

Traditional dishes made with corn often included a small amount of lime-not the fruit, but calcium oxide, the mineral complex that can be made by burning limestone. Limestone is a sedimentary rock that is composed of calcium carbonate and occurs naturally across the United States. This lime added to a cornmeal was generally obtained from the fire ash because a small amount of lime is produced simply from the burning of wood into ash. The reason for this process was simple: people seemed healthier when the pot ash was added. Now we know why. The niacin (vitamin B3) in corn is not readily available for absorption into the body, and lime helps free this B vitamin, making it available for absorption.

When Christopher Columbus and other explorers came to the New World, they found corn growing throughout the Americas, from Chile to Canada. It was consumed both as a vegetable and as a grain in the form of cornmeal seasoned and eaten as an accompaniment to vegetables, fish or meat. The corn that was prized was not just limited to the yellow and white kernel varieties that we know, but many other more popular varieties that featured kernels of red, blue, pink and black and were not only solidly colored, but spotted or striped.

Corn was brought back to Europe by Spanish and Portuguese explorers who later introduced it throughout the world. However, many of the European explorers coming over to North America ignored Native American traditions-including the pot ash tradition-and later fell victim to the vitmamin B3 deficiency disease called pellagra. Today, the largest commercial producers of corn include the United States, China, Brazil, Mexico and the Russian Federation.

How to Select and Store

Since heat rapidly converts the sugar in corn to starch, it is very important to choose corn that is displayed in a cool place. If shopping for corn in the supermarket, make sure it is refrigerated. If purchasing corn at a farmer's market or roadside stand, make sure that if the corn is not refrigerated, it has at least been kept in the shade, out of direct sunlight.

Look for corn whose husks are fresh and green and not dried out. They should envelope the ear and not fit too loosely around it. To examine the kernels, pull back part of the husk. The kernels should be plump and tightly arranged in rows. You can test for the juiciness of the corn by taking your fingernail and pressing on a kernel. Corn that is fresh will exude a white milky substance.

To enjoy corn's maximum flavor, purchase it on the day you are going to cook it since corn has a tendency to lose its flavor relatively rapidly. Store corn in a plastic bag in the refrigerator. Do not remove its husk since this will protect its flavor. To enjoy its optimal sweetness, corn should be eaten as soon as possible.

Fresh corn freezes well if placed in heavy-duty freezer bags. To prepare whole ears for freezing, blanch them first for seven to eleven minutes depending upon their size (larger ears take a longer time to blanch than smaller ones). If you just want to freeze the kernels, first blanch the ears for about five minutes and then cut the kernels off the cob at about three-quarters of their depths. Whole corn on the cob will keep for up to one year, while the kernels can be frozen for two to three months.

If you're watching your weight or your blood sugar levels, choose blue corn chips and tortillas. Corn comes in a rainbow of colors, including violet, blue, and black. Darker varieties contain greater quantities of antioxidant pigments called anthocyanins. Blue corn tortillas contain about 20% more protein and 8% less starch giving them a lower glycemic index than the more common version made with white corn; plus blue corn tortillas have a softer texture and sweeter flavor than those made with white corn, reports Dr. Luis Bello-Perez in the Journal of the Science of Food and Agriculture. Hernández-Uribe JP, Agama-Acevedo E, et al. J Sci Food Agric Epub 2007 July.

How to Enjoy

For some of our favorite recipes, click Recipes.

Tips for Preparing Corn:

Corn can be cooked either with or without its husk in a variety of different ways. If using the wet heat methods of boiling or steaming, make sure not to add salt or overcook as the corn will tend to become hard and lose its flavor. Or, they can be broiled in the husk. If broiling, first soak the corn in the husk ahead.

When purchasing corn tortillas, purchase those that include lime (the mineral complex calcium oxide, not the fruit juice) in their ingredient list. The addition of lime to the corn meal helps make the niacin (vitamin B3) in the tortilla more available for absorption.

A Few Quick Serving Ideas:

Eat corn on the cob either just as is or seasoned with a little organic butter, olive oil or flaxseed oil, salt and pepper, nutritional yeast or any other herbs or spices you enjoy.

Healthy sauté cooked corn with green chilis and onions. Served hot, this makes a wonderful side dish.

Enjoy a cold salad with an ancient Incan influence by combining cooked corn kernels, quinoa, tomatoes, green peppers and red kidney beans.

Use polenta (a type of cornmeal) as a pizza crust for a healthy pizza.

Add corn kernels and diced tomatoes to guacamole to give it extra zing.

Adding corn to soup, whether it chili or chowder, enhances the soup's hardiness, let alone its nutritional profile.

Safety

Corn and Genetically Modified Organisms (GMOs)

A large percentage of the conventionally grown corn in the United States come from genetically modified (GM) seeds. If you are looking your exposure to GM foods, choose organically grown corn, since the current USDA organic regulations prohibit the use of GM seeds for growing foods to be labeled as organically grown. A wide assortment of processed food contain corn-based ingredients (such as high-fructose corn syrup and corn starch); look for the organic version of these items in your foods and/or look for foods that note that they do not contain any genetically modified ingredients (sometimes this is noted on the packaged as "GMO-free"). For more on this subject, see this Q+A.

Nutritional Profile

Introduction to Food Rating System Chart

The following chart shows the nutrients for which this food is either an excellent, very good or good source. Next to the nutrient name you will find the following information: the amount of the nutrient that is included in the noted serving of this food; the %Daily Value (DV) that that amount represents (similar to other information presented in the website, this DV is calculated for 25-50 year old healthy woman); the nutrient density rating; and, the food's World's Healthiest Foods Rating. Underneath the chart is a table that summarizes how the ratings were devised. Read detailed information on our Food and Recipe Rating System.
Corn, yellow, cooked
1.00 cup
164.00 grams
177.12 calories
Nutrient Amount DV
(%) Nutrient
Density World's Healthiest
Foods Rating
vitamin B1 (thiamin) 0.36 mg 24.0 2.4 good
folate 76.10 mcg 19.0 1.9 good
dietary fiber 4.60 g 18.4 1.9 good
vitamin C 10.16 mg 16.9 1.7 good
phosphorus 168.92 mg 16.9 1.7 good
manganese 0.32 mg 16.0 1.6 good
vitamin B5 (pantothenic acid) 1.44 mg 14.4 1.5 good
World's Healthiest
Foods Rating Rule
excellent DV>=75% OR Density>=7.6 AND DV>=10%
very good DV>=50% OR Density>=3.4 AND DV>=5%
good DV>=25% OR Density>=1.5 AND DV>=2.5%