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Feeding the World

Feeding the World

These are interesting times for the potato. While many scientists believe potatoes will play a key role in providing global food security in the future, potatoes are not without their critics.

A majority of nutritionists support moderate consumption of potatoes as part of a healthy diet. Other health researchers contentiously advocate that potatoes be eaten sparingly and claim potatoes are a major cause of obesity today.

There is consensus that the United States has an obesity epidemic. During the past two decades there has been an alarming increase in the number of obese or diabetic Americans. In 2013 the American Medical Association classified obesity as a disease. About 50 percent of the U.S. population, 155 million U.S. adults, are overweight or obese.

It’s estimated that obesity-related illnesses account for nearly 21 percent of annual medical spending. Total cost to the economy is in the hundreds of billions of dollars, and includes expenses such as an estimated $4 billion of extra gasoline to transport the added weight. At the current rate, by 2030 44 percent of Americans will be obese, according to  Center for Disease Control projections.

Consequences of the obesity epidemic may ripple across the food industry for years. Signs of the changing times include efforts to make large sodas illegal in New York City, removal of snack and soda vending machines from schools, overhauled school lunch programs, proposed “sin taxes” for certain foods and recent changes by major quick service restaurants in their menus.

Because potatoes are the most consumed vegetable, they have a unique potential to provide phytonutrients to the diet. They are a nutrient-dense food that provide an equal or greater amount of nutritional value as they do calories. A 3.5 ounce portion of baked potato with skin has just 97 calories (5 percent of the daily RDA), but provides a greater percentage of various nutrients than it does calories as shown in the accompanying chart. The United Nations Food and Agriculture Organization and World Health Organization both recommend that 55 to75 percent of daily calories come from complex carbohydrates, which potatoes provide.

Given the intense national spotlight on dietary issues, along with the specific criticism directed at potatoes, Potato Association of America researchers have placed additional emphasis on nutritional work. Potatoes already provide important amounts of phytonutrients, and research is underway to breed potatoes with even higher amounts. Our lab works on phytonutrients called phenylpropanoids that have multiple health-promoting properties and are the major source of tuber antioxidants.

Red and purple-flesh potatoes have higher amounts of antioxidants than white potatoes, due to having more of these compounds. We found that “baby” or “new” potatoes harvested 60 to 80 days after harvest contain higher amounts of some phytonutrients than at maturity. Some baby potato Tri-State breeding lines we’ve analyzed have antioxidant values that rival kale or spinach, and high anthocyanin amounts of 15 to19 mg/g dry weight. Studies are documenting health-promoting benefits of high-antioxidant potatoes, including baby potatoes that reduced blood pressure in one human feeding study and another that showed anti-inflammatory effects. Several peer-reviewed scientific papers document the nutritional merits of baby potatoes, products that may especially appeal to health-conscious consumers.

Other aspects of food security include affordability and availability. The U.N. forecasts that global population will increase to 8.1 billion by 2025. Researchers estimate global crop production needs to double by 2050 to meet demand. Consequently, it is notable that potatoes yield more calories per acre than any other major crop. In the Pacific Northwest, yields are often above 30 tons per acre. From the USDA database, a baked russet potato is listed as having 97 calories per 100 grams, which is about 440 calories per pound. Using these values, potato production in the Northwest provides 26 million calories per acre compared to 7.5 million for corn, 7.4 million for rice, 3.0 million for wheat and 2.8 million for soybeans. Norkotah Russet would provide about 150,000 grams of potassium per acre, 6,700 grams of vitamin C and 19,000 grams of phenylpropanoids. The dietary plan most advocated by medical experts emphasizes increased potassium intake to promote cardiovascular health, and potatoes are an important source.

Potatoes are also affordable. A new scientific paper reported that beans and potatoes provide the most nutrients per dollar out of 98 foods studied. The minority of nutritionists who advocate replacing potatoes in the diet with other foods have not provided data on either the affordability of their suggested replacement food or how much more land would be required to produce an equivalent amount of energy and nutrition. In summary, strong evidence supports the nutrition, affordability and productivity of potatoes and their ability to be a key crop that provides food security to the growing global population.

Roy Navarre is a research scientist for the USDA’s Agricultural Research Service in Prosser, Wash.

Originally posted Thursday, Jan. 30, 2014

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